1
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Belica CA, Carpenter MA, Chen Y, Brown WL, Moeller NH, Boylan IT, Harris RS, Aihara H. A real-time biochemical assay for quantitative analyses of APOBEC-catalyzed DNA deamination. J Biol Chem 2024:107410. [PMID: 38796062 DOI: 10.1016/j.jbc.2024.107410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 05/10/2024] [Accepted: 05/12/2024] [Indexed: 05/28/2024] Open
Abstract
Over the past decade, the connection between APOBEC3 cytosine deaminases and cancer mutagenesis has become increasingly apparent. This growing awareness has created a need for biochemical tools that can be used to identify and characterize potential inhibitors of this enzyme family. In response to this challenge, we have developed a Real-time APOBEC3-mediated DNA Deamination (RADD) assay. This assay offers a single-step set-up and real-time fluorescent read-out, and it is capable of providing insights into enzyme kinetics and also offering a high-sensitivity and easily scalable method for identifying APOBEC3 inhibitors. This assay serves as a crucial addition to the existing APOBEC3 biochemical and cellular toolkit and possesses the versatility to be readily adapted into a high-throughput format for inhibitor discovery.
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Affiliation(s)
- Christopher A Belica
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455; Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Michael A Carpenter
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA; Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
| | - Yanjun Chen
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
| | - William L Brown
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455; Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Nicholas H Moeller
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455; Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Ian T Boylan
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455; Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Reuben S Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA; Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA.
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455; Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA; Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA.
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2
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Belica CA, Carpenter MA, Chen Y, Brown WL, Moeller NH, Boylan IT, Harris RS, Aihara H. A real-time biochemical assay for quantitative analyses of APOBEC-catalyzed DNA deamination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.11.593688. [PMID: 38766133 PMCID: PMC11100776 DOI: 10.1101/2024.05.11.593688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Over the past decade, the connection between APOBEC3 cytosine deaminases and cancer mutagenesis has become increasingly apparent. This growing awareness has created a need for biochemical tools that can be used to identify and characterize potential inhibitors of this enzyme family. In response to this challenge, we have developed a Real-time APOBEC3-mediated DNA Deamination (RADD) assay. This assay offers a single-step set-up and real-time fluorescent read-out, and it is capable of providing insights into enzyme kinetics and also offering a high-sensitivity and easily scalable method for identifying APOBEC3 inhibitors. This assay serves as a crucial addition to the existing APOBEC3 biochemical and cellular toolkit and possesses the versatility to be readily adapted into a high-throughput format for inhibitor discovery.
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Affiliation(s)
- Christopher A. Belica
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Michael A. Carpenter
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
| | - Yanjun Chen
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
| | - William L. Brown
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Nicholas H. Moeller
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Ian T. Boylan
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Reuben S. Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA, 55455
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota, 55455, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, 55455, USA
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3
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Ren CY, Liu YS, He YS, Zhang LP, Rao JH, Rao Y, Chen JH. Engineered CBEs based on Macaca fascicularis A3A with improved properties for precise genome editing. Cell Rep 2024; 43:113878. [PMID: 38431844 DOI: 10.1016/j.celrep.2024.113878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 11/20/2023] [Accepted: 02/13/2024] [Indexed: 03/05/2024] Open
Abstract
Cytidine deaminase defines the properties of cytosine base editors (CBEs) for C-to-T conversion. Replacing the cytidine deaminase rat APOBEC1 (rA1) in CBEs with a human APOBEC3A (hA3A) improves CBE properties. However, the potential CBE application of macaque A3A orthologs remains undetermined. Our current study develops and evaluates engineered CBEs based on Macaca fascicularis A3A (mA3A). Here, we demonstrate that BE4-mA3A and its RNA-editing-derived variants exhibit improved CBE properties, except for DNA off-target activity, compared to BE3-rA1 and BE4-rA1. Unexpectedly, deleting Ser-Val-Arg (SVR) in BE4-mA3A dramatically reduces DNA and RNA off-target activities and improves editing accuracy, with on-target efficiency unaffected. In contrast, a chimeric BE4-hA3A-SVR+ shows editing efficiency increased by about 50%, with other properties unaffected. Our findings demonstrate that mA3A-based CBEs could provide prototype options with advantages over rA1- and hA3A-based CBEs for further optimization, highlighting the importance of the SVR motif in defining CBE intrinsic properties.
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Affiliation(s)
- Chun-Yan Ren
- Laboratory of Genomic and Precision Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Carbohydrate Chemistry and Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Yan-Shan Liu
- Laboratory of Genomic and Precision Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, China; Department of Pediatric Laboratory, Affiliated Children's Hospital of Jiangnan University (Wuxi Children's Hospital), Wuxi, Jiangsu, China
| | - Yu-Shan He
- Laboratory of Genomic and Precision Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, China
| | - Lin-Pei Zhang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Jun-Hua Rao
- Joint Primate Research Center for Chronic Diseases, Jiangnan University and Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China; Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China; Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yijian Rao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Jian-Huan Chen
- Laboratory of Genomic and Precision Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, China; Joint Primate Research Center for Chronic Diseases, Jiangnan University and Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China; Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China; Jiangnan University-Xinshijie Eye Hospital Joint Ophthalmic Research Center, Xinshijie Eye Hospital, Wuxi, China.
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4
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Sanchez A, Ortega P, Sakhtemani R, Manjunath L, Oh S, Bournique E, Becker A, Kim K, Durfee C, Temiz NA, Chen XS, Harris RS, Lawrence MS, Buisson R. Mesoscale DNA features impact APOBEC3A and APOBEC3B deaminase activity and shape tumor mutational landscapes. Nat Commun 2024; 15:2370. [PMID: 38499542 PMCID: PMC10948877 DOI: 10.1038/s41467-024-45909-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 01/09/2024] [Indexed: 03/20/2024] Open
Abstract
Antiviral DNA cytosine deaminases APOBEC3A and APOBEC3B are major sources of mutations in cancer by catalyzing cytosine-to-uracil deamination. APOBEC3A preferentially targets single-stranded DNAs, with a noted affinity for DNA regions that adopt stem-loop secondary structures. However, the detailed substrate preferences of APOBEC3A and APOBEC3B have not been fully established, and the specific influence of the DNA sequence on APOBEC3A and APOBEC3B deaminase activity remains to be investigated. Here, we find that APOBEC3B also selectively targets DNA stem-loop structures, and they are distinct from those subjected to deamination by APOBEC3A. We develop Oligo-seq, an in vitro sequencing-based method to identify specific sequence contexts promoting APOBEC3A and APOBEC3B activity. Through this approach, we demonstrate that APOBEC3A and APOBEC3B deaminase activity is strongly regulated by specific sequences surrounding the targeted cytosine. Moreover, we identify the structural features of APOBEC3B and APOBEC3A responsible for their substrate preferences. Importantly, we determine that APOBEC3B-induced mutations in hairpin-forming sequences within tumor genomes differ from the DNA stem-loop sequences mutated by APOBEC3A. Together, our study provides evidence that APOBEC3A and APOBEC3B can generate distinct mutation landscapes in cancer genomes, driven by their unique substrate selectivity.
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Affiliation(s)
- Ambrocio Sanchez
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, CA, USA
- Center for Epigenetics and Metabolism, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA, USA
| | - Pedro Ortega
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, CA, USA
- Center for Epigenetics and Metabolism, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA, USA
| | - Ramin Sakhtemani
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Lavanya Manjunath
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, CA, USA
- Center for Epigenetics and Metabolism, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA, USA
| | - Sunwoo Oh
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, CA, USA
- Center for Epigenetics and Metabolism, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA, USA
| | - Elodie Bournique
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, CA, USA
- Center for Epigenetics and Metabolism, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA, USA
| | - Alexandrea Becker
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, CA, USA
- Center for Epigenetics and Metabolism, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA, USA
| | - Kyumin Kim
- Molecular and Computational Biology, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Cameron Durfee
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Nuri Alpay Temiz
- Institute for Health Informatics, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Reuben S Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Michael S Lawrence
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rémi Buisson
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, CA, USA.
- Center for Epigenetics and Metabolism, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA, USA.
- Department of Pharmaceutical Sciences, School of Pharmacy & Pharmaceutical Sciences, University of California Irvine, Irvine, CA, USA.
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5
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Huang CH, Chiu SY, Chou YC, Wu KJ. A refined Uni-vector prime editing system improves genome editing outcomes in mammalian cells. Biotechnol J 2024; 19:e2300353. [PMID: 38403398 DOI: 10.1002/biot.202300353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/27/2024]
Abstract
Prime editing is an advanced technology in CRISPR/Cas research with increasing numbers of improved methodologies. The original multi-vector method hampers the efficiency and precision of prime editing and also has inherent difficulty in generating homozygous mutations in mammalian cells. To overcome these technical issues, we developed a Uni-vector prime editing system, wherein the major components for prime editing were constructed in all-in-one plasmids, pPE3-pPuro and pePEmax-pPuro. The Uni-vector prime editing plasmids enhance the editing efficiency of prime editing and improved the generation of homozygous mutated mammalian cell lines. The editing efficiency is dependent of the transfection efficiency. Remarkably, the Uni-vector ePE5max system achieved an impressive editing rate approximately 79% in average, even in cell lines that are traditionally difficult to transfect, such as FaDu cell line. Furthermore, it resulted in a high frequency of homozygous knocked-in cells, with a rate of 99% in HeLa and 85% in FaDu cells. Together, our Uni-vector approach simplifies the delivery of editing components and improves the editing efficiency, especially in cells with low transfection efficiency. This approach presents an advancement in the field of prime editing.
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Affiliation(s)
- Ching-Hui Huang
- Cancer Genome Research Center, Chang Gung Memorial Hospital, Taoyuan City, Taiwan
| | - Szu-Ying Chiu
- Cancer Genome Research Center, Chang Gung Memorial Hospital, Taoyuan City, Taiwan
| | - Yu-Chi Chou
- Biomedical Translation Research Center, Academia Sinica, Taipei, Taiwan
| | - Kou-Juey Wu
- Cancer Genome Research Center, Chang Gung Memorial Hospital, Taoyuan City, Taiwan
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6
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Rieffer AE, Chen Y, Salamango DJ, Moraes SN, Harris RS. APOBEC Reporter Systems for Evaluating diNucleotide Editing Levels. CRISPR J 2023; 6:430-446. [PMID: 37672599 PMCID: PMC10611974 DOI: 10.1089/crispr.2023.0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/14/2023] [Indexed: 09/08/2023] Open
Abstract
Precision genome editing has become a reality with the discovery of base editors. Cytosine base editor (CBE) technologies are improving rapidly but are mostly optimized for TC dinucleotide targets. Here, we report the development and implementation of APOBEC Reporter Systems for Evaluating diNucleotide Editing Levels (ARSENEL) in living cells. The ARSENEL panel is comprised of four constructs that quantitatively report editing of each of the four dinucleotide motifs (AC/CC/GC/TC) through real-time accumulation of eGFP fluorescence. Editing rates of APOBEC3Bctd and AIDΔC CBEs reflect established mechanistic preferences with intrinsic biases to TC and GC, respectively. Twelve different (new and established) base editors are tested here using this system with a full-length APOBEC3B CBE showing the greatest on-target TC specificity and an APOBEC3A construct showing the highest editing efficiency. In addition, ARSENEL enables real-time assessment of natural and synthetic APOBEC inhibitors with the most potent to-date being the large subunit of the Epstein-Barr virus ribonucleotide reductase. These reporters have the potential to play important roles in research and development as precision genome engineering technologies progress toward achieving maximal specificity and efficiency.
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Affiliation(s)
- Amanda E. Rieffer
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota—Twin Cities, Minneapolis, Minnesota, USA; University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Yanjun Chen
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, USA; and University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Daniel J. Salamango
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota—Twin Cities, Minneapolis, Minnesota, USA; University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Sofia N. Moraes
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota—Twin Cities, Minneapolis, Minnesota, USA; University of Texas Health San Antonio, San Antonio, Texas, USA
| | - Reuben S. Harris
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota—Twin Cities, Minneapolis, Minnesota, USA; University of Texas Health San Antonio, San Antonio, Texas, USA
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas, USA; and University of Texas Health San Antonio, San Antonio, Texas, USA
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, Texas, USA
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7
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Mikkelsen NS, Bak RO. Enrichment strategies to enhance genome editing. J Biomed Sci 2023; 30:51. [PMID: 37393268 PMCID: PMC10315055 DOI: 10.1186/s12929-023-00943-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 06/26/2023] [Indexed: 07/03/2023] Open
Abstract
Genome editing technologies hold great promise for numerous applications including the understanding of cellular and disease mechanisms and the development of gene and cellular therapies. Achieving high editing frequencies is critical to these research areas and to achieve the overall goal of being able to manipulate any target with any desired genetic outcome. However, gene editing technologies sometimes suffer from low editing efficiencies due to several challenges. This is often the case for emerging gene editing technologies, which require assistance for translation into broader applications. Enrichment strategies can support this goal by selecting gene edited cells from non-edited cells. In this review, we elucidate the different enrichment strategies, their many applications in non-clinical and clinical settings, and the remaining need for novel strategies to further improve genome research and gene and cellular therapy studies.
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Affiliation(s)
- Nanna S Mikkelsen
- Department of Biomedicine, Aarhus University, Høegh-Guldbergsgade 10, Bldg. 1115, 8000, Aarhus C., Denmark
| | - Rasmus O Bak
- Department of Biomedicine, Aarhus University, Høegh-Guldbergsgade 10, Bldg. 1115, 8000, Aarhus C., Denmark.
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8
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Granadillo Rodríguez M, Wong L, Chelico L. Similar deamination activities but different phenotypic outcomes induced by APOBEC3 enzymes in breast epithelial cells. Front Genome Ed 2023; 5:1196697. [PMID: 37324648 PMCID: PMC10267419 DOI: 10.3389/fgeed.2023.1196697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
APOBEC3 (A3) enzymes deaminate cytosine to uracil in viral single-stranded DNA as a mutagenic barrier for some viruses. A3-induced deaminations can also occur in human genomes resulting in an endogenous source of somatic mutations in multiple cancers. However, the roles of each A3 are unclear since few studies have assessed these enzymes in parallel. Thus, we developed stable cell lines expressing A3A, A3B, or A3H Hap I using non-tumorigenic MCF10A and tumorigenic MCF7 breast epithelial cells to assess their mutagenic potential and cancer phenotypes in breast cells. The activity of these enzymes was characterized by γH2AX foci formation and in vitro deamination. Cell migration and soft agar colony formation assays assessed cellular transformation potential. We found that all three A3 enzymes had similar γH2AX foci formation, despite different deamination activities in vitro. Notably, in nuclear lysates, the in vitro deaminase activity of A3A, A3B, and A3H did not require digestion of cellular RNA, in contrast to that of A3B and A3H in whole-cell lysates. Their similar activities in cells, nonetheless, resulted in distinct phenotypes where A3A decreased colony formation in soft agar, A3B decreased colony formation in soft agar after hydroxyurea treatment, and A3H Hap I promoted cell migration. Overall, we show that in vitro deamination data do not always reflect cell DNA damage, all three A3s induce DNA damage, and the impact of each is different.
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9
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Naumann JA, Argyris PP, Carpenter MA, Gupta HB, Chen Y, Temiz NA, Zhou Y, Durfee C, Proehl J, Koniar BL, Conticello SG, Largaespada DA, Brown WL, Aihara H, Vogel RI, Harris RS. DNA Deamination Is Required for Human APOBEC3A-Driven Hepatocellular Carcinoma In Vivo. Int J Mol Sci 2023; 24:9305. [PMID: 37298259 PMCID: PMC10253583 DOI: 10.3390/ijms24119305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/20/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Although the APOBEC3 family of single-stranded DNA cytosine deaminases is well-known for its antiviral factors, these enzymes are rapidly gaining attention as prominent sources of mutation in cancer. APOBEC3's signature single-base substitutions, C-to-T and C-to-G in TCA and TCT motifs, are evident in over 70% of human malignancies and dominate the mutational landscape of numerous individual tumors. Recent murine studies have established cause-and-effect relationships, with both human APOBEC3A and APOBEC3B proving capable of promoting tumor formation in vivo. Here, we investigate the molecular mechanism of APOBEC3A-driven tumor development using the murine Fah liver complementation and regeneration system. First, we show that APOBEC3A alone is capable of driving tumor development (without Tp53 knockdown as utilized in prior studies). Second, we show that the catalytic glutamic acid residue of APOBEC3A (E72) is required for tumor formation. Third, we show that an APOBEC3A separation-of-function mutant with compromised DNA deamination activity and wildtype RNA-editing activity is defective in promoting tumor formation. Collectively, these results demonstrate that APOBEC3A is a "master driver" that fuels tumor formation through a DNA deamination-dependent mechanism.
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Affiliation(s)
- Jordan A. Naumann
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Prokopios P. Argyris
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA
- Division of Oral and Maxillofacial Pathology, College of Dentistry, Ohio State University, Columbus, OH 43210, USA
| | - Michael A. Carpenter
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Harshita B. Gupta
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Yanjun Chen
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Nuri A. Temiz
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Institute for Health Informatics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yufan Zhou
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Cameron Durfee
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Joshua Proehl
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
| | - Brenda L. Koniar
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Silvestro G. Conticello
- Core Research Laboratory, ISPRO, 50139 Florence, Italy;
- Institute of Clinical Physiology, National Research Council, 56124 Pisa, Italy
| | - David A. Largaespada
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - William L. Brown
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (J.A.N.); (P.P.A.); (W.L.B.); (H.A.)
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
| | - Rachel I. Vogel
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA; (N.A.T.); (B.L.K.); (D.A.L.); (R.I.V.)
- Department of Obstetrics, Gynecology, and Women’s Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Reuben S. Harris
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX 78229, USA; (M.A.C.); (H.B.G.); (Y.C.); (Y.Z.); (C.D.); (J.P.)
- Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, TX 78229, USA
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10
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Zhao X, Qu K, Curci B, Yang H, Bolund L, Lin L, Luo Y. Comparison of In-Frame Deletion, Homology-Directed Repair, and Prime Editing-Based Correction of Duchenne Muscular Dystrophy Mutations. Biomolecules 2023; 13:biom13050870. [PMID: 37238739 DOI: 10.3390/biom13050870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 04/25/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Recent progress in CRISPR gene editing tools has substantially increased the opportunities for curing devastating genetic diseases. Here we compare in-frame deletion by CRISPR-based non-homologous blunt end joining (NHBEJ), homology-directed repair (HDR), and prime editing (PE, PE2, and PE3)-based correction of two Duchenne Muscular Dystrophy (DMD) loss-of-function mutations (c.5533G>T and c.7893delC). To enable accurate and rapid evaluation of editing efficiency, we generated a genomically integrated synthetic reporter system (VENUS) carrying the DMD mutations. The VENUS contains a modified enhanced green fluorescence protein (EGFP) gene, in which expression was restored upon the CRISPR-mediated correction of DMD loss-of-function mutations. We observed that the highest editing efficiency was achieved by NHBEJ (74-77%), followed by HDR (21-24%) and PE2 (1.5%) in HEK293T VENUS reporter cells. A similar HDR (23%) and PE2 (1.1%) correction efficiency is achieved in fibroblast VENUS cells. With PE3 (PE2 plus nicking gRNA), the c.7893delC correction efficiency was increased 3-fold. Furthermore, an approximately 31% correction efficiency of the endogenous DMD: c.7893delC is achieved in the FACS-enriched HDR-edited VENUS EGFP+ patient fibroblasts. We demonstrated that a highly efficient correction of DMD loss-of-function mutations in patient cells can be achieved by several means of CRISPR gene editing.
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Affiliation(s)
- Xiaoying Zhao
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 101408, China
- Lars Bolund Institute of Regenerative Medicine, Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Kunli Qu
- Lars Bolund Institute of Regenerative Medicine, Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
- Department of Biology, Copenhagen University, 2200 Copenhagen, Denmark
| | - Benedetta Curci
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Huanming Yang
- Lars Bolund Institute of Regenerative Medicine, Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
- HIM-BGI Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou 310022, China
| | - Lars Bolund
- Lars Bolund Institute of Regenerative Medicine, Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Lin Lin
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Yonglun Luo
- Lars Bolund Institute of Regenerative Medicine, Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
- HIM-BGI Center, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou 310022, China
- Steno Diabetes Center Aarhus, Aarhus University Hospital, 8200 Aarhus, Denmark
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11
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Yu SY, Carlaw T, Thomson T, Birkenshaw A, Basha G, Kurek D, Huang C, Kulkarni J, Zhang LH, Ross CJD. A luciferase reporter mouse model to optimize in vivo gene editing validated by lipid nanoparticle delivery of adenine base editors. Mol Ther 2023; 31:1159-1166. [PMID: 36793209 PMCID: PMC10124072 DOI: 10.1016/j.ymthe.2023.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/20/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
The rapid development of CRISPR genome editing technology has provided the potential to treat genetic diseases effectively and precisely. However, efficient and safe delivery of genome editors to affected tissues remains a challenge. Here, we developed luminescent ABE (LumA), a luciferase reporter mouse model containing the R387X mutation (c.A1159T) in the luciferase gene located in the Rosa26 locus of the mouse genome. This mutation eliminates luciferase activity but can be restored upon A-to-G correction by SpCas9 adenine base editors (ABEs). The LumA mouse model was validated through intravenous injection of two FDA-approved lipid nanoparticle (LNP) formulations consisting of either MC3 or ALC-0315 ionizable cationic lipids, encapsulated with ABE mRNA and LucR387X-specific guide RNA (gRNA). Whole-body bioluminescence live imaging showed consistent restoration of luminescence lasting up to 4 months in treated mice. Compared with mice carrying the wild-type luciferase gene, the ALC-0315 and MC3 LNP groups showed 83.5% ± 17.5% and 8.4% ± 4.3% restoration of luciferase activity in the liver, respectively, as measured by tissue luciferase assays. These results demonstrated successful development of a luciferase reporter mouse model that can be used to evaluate the efficacy and safety of different genome editors, LNP formulations, and tissue-specific delivery systems for optimizing genome editing therapeutics.
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Affiliation(s)
- Si-Yue Yu
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Tiffany Carlaw
- Department of Medical Genetics, Faculty of Science, University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Tyler Thomson
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Alexandra Birkenshaw
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Genc Basha
- NanoMedicines Research Group, Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Daniel Kurek
- Nanovation Therapeutics, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Cassie Huang
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Jayesh Kulkarni
- Nanovation Therapeutics, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Lin-Hua Zhang
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Colin J D Ross
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada.
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12
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Multiplex base editing to convert TAG into TAA codons in the human genome. Nat Commun 2022; 13:4482. [PMID: 35918324 PMCID: PMC9345975 DOI: 10.1038/s41467-022-31927-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 07/11/2022] [Indexed: 11/17/2022] Open
Abstract
Whole-genome recoding has been shown to enable nonstandard amino acids, biocontainment and viral resistance in bacteria. Here we take the first steps to extend this to human cells demonstrating exceptional base editing to convert TAG to TAA for 33 essential genes via a single transfection, and examine base-editing genome-wide (observing ~40 C-to-T off-target events in essential gene exons). We also introduce GRIT, a computational tool for recoding. This demonstrates the feasibility of recoding, and highly multiplex editing in mammalian cells. Whole-genome recoding has been shown to enable nonstandard amino acids, biocontainment and viral resistance in bacteria. Here the authors extend this to human cells using base editing to convert TAG to TAA for 33 essential genes via a single transfection followed by examining base-editing genome-wide.
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13
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Song R, Wang Y, Zheng Q, Yao J, Cao C, Wang Y, Zhao J. One-step base editing in multiple genes by direct embryo injection for pig trait improvement. SCIENCE CHINA. LIFE SCIENCES 2022; 65:739-752. [PMID: 35060075 DOI: 10.1007/s11427-021-2013-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/17/2021] [Indexed: 10/19/2022]
Abstract
The precise and simultaneous acquisition of multiple beneficial alleles in the genome is in great demand for the development of elite pig breeders. Cytidine base editors (CBEs) that convert C:G to T:A have emerged as powerful tools for single-nucleotide replacement. Whether CBEs can effectively mediate C-to-T substitution at multiple sites/loci for trait improvement by direct zygote injection has not been verified in large animals. Here, we determined the editing efficiency of four CBE variants in porcine embryonic fibroblast cells and embryos. The findings showed that hA3A-BE3-Y130F and hA3A-eBE-Y130F consistently resulted in increased base-editing efficiency and low toxic effects in embryonic development. Further, we verified that using a one-step approach, direct zygote microinjection of the CBE system can generate pigs harboring multiple point mutations. Our process resulted in a stop codon in CD163 and myostatin (MSTN) and introduced a beneficial allele in insulin-like growth factor-2 (IGF2). The pigs showed disrupted expression of CD163 and MSTN and increased expression of IGF2, which significantly improved growth performance and infectious disease resistance. Our approach allows immediate introduction of multiple mutations in transgene-free animals to comprehensively improve economic traits through direct embryo microinjection, providing a potential new route to produce elite pig breeders.
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Affiliation(s)
- Ruigao Song
- State Key Laboratory of Stem cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,The Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan, 030032, China
| | - Yu Wang
- State Key Laboratory of Stem cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Qiantao Zheng
- State Key Laboratory of Stem cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jing Yao
- State Key Laboratory of Stem cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.,Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China
| | - Chunwei Cao
- State Key Laboratory of Stem cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanfang Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
| | - Jianguo Zhao
- State Key Laboratory of Stem cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China. .,Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
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14
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The current toolbox for APOBEC drug discovery. Trends Pharmacol Sci 2022; 43:362-377. [PMID: 35272863 PMCID: PMC9018551 DOI: 10.1016/j.tips.2022.02.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 02/03/2022] [Accepted: 02/09/2022] [Indexed: 12/14/2022]
Abstract
Mutational processes driving genome evolution and heterogeneity contribute to immune evasion and therapy resistance in viral infections and cancer. APOBEC3 (A3) enzymes promote such mutations by catalyzing the deamination of cytosines to uracils in single-stranded DNA. Chemical inhibition of A3 enzymes may yield an antimutation therapeutic strategy to improve the durability of current drug therapies that are prone to resistance mutations. A3 small-molecule drug discovery efforts to date have been restricted to a single high-throughput biochemical activity assay; however, the arsenal of discovery assays has significantly expanded in recent years. The assays used to study A3 enzymes are reviewed here with an eye towards their potential for small-molecule discovery efforts.
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15
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Simon DA, Tálas A, Kulcsár PI, Biczók Z, Krausz SL, Várady G, Welker E. PEAR, a flexible fluorescent reporter for the identification and enrichment of successfully prime edited cells. eLife 2022; 11:69504. [PMID: 35196219 PMCID: PMC8865850 DOI: 10.7554/elife.69504] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 02/09/2022] [Indexed: 12/26/2022] Open
Abstract
Prime editing is a recently developed CRISPR/Cas9 based gene engineering tool that allows the introduction of short insertions, deletions, and substitutions into the genome. However, the efficiency of prime editing, which typically achieves editing rates of around 10%–30%, has not matched its versatility. Here, we introduce the prime editor activity reporter (PEAR), a sensitive fluorescent tool for identifying single cells with prime editing activity. PEAR has no background fluorescence and specifically indicates prime editing events. Its design provides apparently unlimited flexibility for sequence variation along the entire length of the spacer sequence, making it uniquely suited for systematic investigation of sequence features that influence prime editing activity. The use of PEAR as an enrichment marker for prime editing can increase the edited population by up to 84%, thus significantly improving the applicability of prime editing for basic research and biotechnological applications.
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Affiliation(s)
- Dorottya Anna Simon
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.,ProteoScientia, Budapest, Hungary.,School of Ph.D. Studies, Semmelweis University, Budapest, Hungary
| | - András Tálas
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Péter István Kulcsár
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.,Biospiral-2006, Szeged, Hungary
| | - Zsuzsanna Biczók
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.,School of Ph.D. Studies, Semmelweis University, Budapest, Hungary
| | - Sarah Laura Krausz
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.,School of Ph.D. Studies, Semmelweis University, Budapest, Hungary
| | - György Várady
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Ervin Welker
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.,Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
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16
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Yang F, Zhang H, Cai S, Imtiaz K, Li M, Wang M, Liu Y, Xue F, Zhang L, Gu F. Green Fluorescent Protein Tagged Polycistronic Reporter System Reveals Functional Editing Characteristics of CRISPR-Cas. CRISPR J 2022; 5:254-263. [PMID: 35085009 DOI: 10.1089/crispr.2021.0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The green fluorescent protein (GFP)-based reporter system has been widely harnessed as a quick quantitative activity assessment method for characterizing CRISPR-Cas via flow cytometry. However, due to the small size (738 nt) of the GFP coding sequence, the targeting sites for certain CRISPR-Cas are greatly restricted. To address this, here we developed a GFP tagged polycistronic reporter system to determine the activity of CRISPR-Cas in human cells. Specifically, the system contains the herpes simplex virus thymidine kinase (TK) gene, bacterial neomycin phosphotransferase (Neo) gene, and green fluorescent protein (GFP), named TNG gene, with a coding sequence of 2,577 nt. To investigate its performance, we generated a human cell line harboring the TNG expression cassette at the AAVS1 locus, and then we tested it with different Cas orthologs (SaCas9, St1Cas9, and AsCas12a). Our results demonstrated that using the TNG reporter system greatly expands the targeting site selection (3- to 13-fold) with CRISPR-Cas genome editing. The study therefore reports an additional method for the characterization of CRISPR-Cas technology.
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Affiliation(s)
- Fayu Yang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Hao Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Shuo Cai
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Kiran Imtiaz
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Mingchun Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Mi Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Yingchun Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Feiqun Xue
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Lifang Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
| | - Feng Gu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, P.R. China; and Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China.,Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture and Rural Affairs, Shanghai, P.R. China
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17
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BEAR reveals that increased fidelity variants can successfully reduce the mismatch tolerance of adenine but not cytosine base editors. Nat Commun 2021; 12:6353. [PMID: 34732717 PMCID: PMC8566456 DOI: 10.1038/s41467-021-26461-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 09/27/2021] [Indexed: 12/26/2022] Open
Abstract
Adenine and cytosine base editors (ABE, CBE) allow for precision genome engineering. Here, Base Editor Activity Reporter (BEAR), a plasmid-based fluorescent tool is introduced, which can be applied to report on ABE and CBE editing in a virtually unrestricted sequence context or to label base edited cells for enrichment. Using BEAR-enrichment, we increase the yield of base editing performed by nuclease inactive base editors to the level of the nickase versions while maintaining significantly lower indel background. Furthermore, by exploiting the semi-high-throughput potential of BEAR, we examine whether increased fidelity SpCas9 variants can be used to decrease SpCas9-dependent off-target effects of ABE and CBE. Comparing them on the same target sets reveals that CBE remains active on sequences, where increased fidelity mutations and/or mismatches decrease the activity of ABE. Our results suggest that the deaminase domain of ABE is less effective to act on rather transiently separated target DNA strands, than that of CBE explaining its lower mismatch tolerance.
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18
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Banerjee D, Langberg K, Abbas S, Odermatt E, Yerramothu P, Volaric M, Reidenbach MA, Krentz KJ, Rubinstein CD, Brautigan DL, Abbas T, Gelfand BD, Ambati J, Kerur N. A non-canonical, interferon-independent signaling activity of cGAMP triggers DNA damage response signaling. Nat Commun 2021; 12:6207. [PMID: 34707113 PMCID: PMC8551335 DOI: 10.1038/s41467-021-26240-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 09/24/2021] [Indexed: 12/17/2022] Open
Abstract
Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), produced by cyclic GMP-AMP synthase (cGAS), stimulates the production of type I interferons (IFN). Here we show that cGAMP activates DNA damage response (DDR) signaling independently of its canonical IFN pathways. Loss of cGAS dampens DDR signaling induced by genotoxic insults. Mechanistically, cGAS activates DDR in a STING-TBK1-dependent manner, wherein TBK1 stimulates the autophosphorylation of the DDR kinase ATM, with the consequent activation of the CHK2-p53-p21 signal transduction pathway and the induction of G1 cell cycle arrest. Despite its stimulatory activity on ATM, cGAMP suppresses homology-directed repair (HDR) through the inhibition of polyADP-ribosylation (PARylation), in which cGAMP reduces cellular levels of NAD+; meanwhile, restoring NAD+ levels abrogates cGAMP-mediated suppression of PARylation and HDR. Finally, we show that cGAMP also activates DDR signaling in invertebrate species lacking IFN (Crassostrea virginica and Nematostella vectensis), suggesting that the genome surveillance mechanism of cGAS predates metazoan interferon-based immunity.
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Affiliation(s)
- Daipayan Banerjee
- Aravind Medical Research Foundation, Madurai, 625020, India
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Kurt Langberg
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Salar Abbas
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Eric Odermatt
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Praveen Yerramothu
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Martin Volaric
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
| | - Matthew A Reidenbach
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
| | - Kathy J Krentz
- Genome Editing & Animal Models Core, University of Wisconsin Biotechnology Center, Madison, WI, USA
| | - C Dustin Rubinstein
- Genome Editing & Animal Models Core, University of Wisconsin Biotechnology Center, Madison, WI, USA
| | - David L Brautigan
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Tarek Abbas
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, USA
| | - Bradley D Gelfand
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Pathology, University of Virginia, Charlottesville, VA, USA
| | - Nagaraj Kerur
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Department of Ophthalmology and Visual Sciences, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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19
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Tekel SJ, Brookhouser N, Standage-Beier K, Wang X, Brafman DA. Cytosine and adenosine base editing in human pluripotent stem cells using transient reporters for editing enrichment. Nat Protoc 2021; 16:3596-3624. [PMID: 34172975 DOI: 10.1038/s41596-021-00552-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 04/06/2021] [Indexed: 02/06/2023]
Abstract
Deaminase fused-Cas9 base editing technologies have enabled precise single-nucleotide genomic editing without the need for the introduction of damaging double-stranded breaks and inefficient homology-directed repair. However, current methods to isolate base-edited cell populations are ineffective, especially when utilized with human pluripotent stem cells, a cell type resistant to genome modification. Here, we outline a series of methods that employ transient reporters of editing enrichment (TREE) to facilitate the highly efficient single-base editing of human cells at precise genomic loci. Briefly, these transient reporters of editing enrichment based methods employ a transient episomal fluorescent reporter that allows for the real-time, flow-cytometry-based enrichment of cells that have had single nucleotide changes at precise genomic locations. This protocol details how these approaches can enable the rapid (~3-4 weeks) and efficient (clonal editing efficiencies >80%) generation of biallelic or multiplexed edited isogenic hPSC lines using adenosine and cytosine base editors.
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Affiliation(s)
- Stefan J Tekel
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ, USA
| | - Nicholas Brookhouser
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
| | - Kylie Standage-Beier
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
- Molecular and Cellular Biology Graduate Program, Arizona State University, Tempe, AZ, USA
| | - Xiao Wang
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
| | - David A Brafman
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA.
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20
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Base editing-coupled survival screening enabled high-sensitive analysis of PAM compatibility and finding of the new possible off-target. iScience 2021; 24:102769. [PMID: 34337358 PMCID: PMC8324807 DOI: 10.1016/j.isci.2021.102769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/20/2021] [Accepted: 06/21/2021] [Indexed: 11/21/2022] Open
Abstract
Base editing (BE) is a promising genome engineering tool for modifying DNA or RNA and has been widely used in various microorganisms as well as eukaryotic cells. Despite the proximal protospacer adjacent motif (PAM) is critical to the targeting range and off-target effect of BE, there is still lack of a specific approach to analyze the PAM pattern in BE systems. Here, we developed a base editing-coupled survival screening method. Using dCas9 from Streptococcus pyogenes (SpdCas9) and its variants xdCas9 3.7 and dCas9 NG as example, their PAM patterns in BE systems were extensively characterized using the NNNN PAM library with high sensitivity. In addition to the typical PAM recognition features, we observed more unique PAMs exhibiting BE activity. These PAM patterns will boost the finding of potential off-target editing event arising from non-canonical PAMs and provide the guidelines for PAM usage in the BE system.
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21
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Thompson MK, Sobol RW, Prakash A. Exploiting DNA Endonucleases to Advance Mechanisms of DNA Repair. BIOLOGY 2021; 10:530. [PMID: 34198612 PMCID: PMC8232306 DOI: 10.3390/biology10060530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 12/17/2022]
Abstract
The earliest methods of genome editing, such as zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALENs), utilize customizable DNA-binding motifs to target the genome at specific loci. While these approaches provided sequence-specific gene-editing capacity, the laborious process of designing and synthesizing recombinant nucleases to recognize a specific target sequence, combined with limited target choices and poor editing efficiency, ultimately minimized the broad utility of these systems. The discovery of clustered regularly interspaced short palindromic repeat sequences (CRISPR) in Escherichia coli dates to 1987, yet it was another 20 years before CRISPR and the CRISPR-associated (Cas) proteins were identified as part of the microbial adaptive immune system, by targeting phage DNA, to fight bacteriophage reinfection. By 2013, CRISPR/Cas9 systems had been engineered to allow gene editing in mammalian cells. The ease of design, low cytotoxicity, and increased efficiency have made CRISPR/Cas9 and its related systems the designer nucleases of choice for many. In this review, we discuss the various CRISPR systems and their broad utility in genome manipulation. We will explore how CRISPR-controlled modifications have advanced our understanding of the mechanisms of genome stability, using the modulation of DNA repair genes as examples.
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Affiliation(s)
- Marlo K. Thompson
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Robert W. Sobol
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
| | - Aishwarya Prakash
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
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22
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Alvarez-Gonzalez J, Yasgar A, Maul RW, Rieffer AE, Crawford DJ, Salamango DJ, Dorjsuren D, Zakharov AV, Jansen DJ, Rai G, Marugan J, Simeonov A, Harris RS, Kohli RM, Gearhart PJ. Small Molecule Inhibitors of Activation-Induced Deaminase Decrease Class Switch Recombination in B Cells. ACS Pharmacol Transl Sci 2021; 4:1214-1226. [PMID: 34151211 DOI: 10.1021/acsptsci.1c00064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Indexed: 11/30/2022]
Abstract
Activation-induced deaminase (AID) not only mutates DNA within the immunoglobulin loci to generate antibody diversity, but it also promotes development of B cell lymphomas. To tame this mutagen, we performed a quantitative high-throughput screen of over 90 000 compounds to see if AID activity could be mitigated. The enzymatic activity was assessed in biochemical assays to detect cytosine deamination and in cellular assays to measure class switch recombination. Three compounds showed promise via inhibition of switching in a transformed B cell line and in murine splenic B cells. These compounds have similar chemical structures, which suggests a shared mechanism of action. Importantly, the inhibitors blocked AID, but not a related cytosine DNA deaminase, APOBEC3B. We further determined that AID was continually expressed for several days after B cell activation to induce switching. This first report of small molecules that inhibit AID can be used to gain regulatory control over base editors.
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Affiliation(s)
- Juan Alvarez-Gonzalez
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Adam Yasgar
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20816, United States
| | - Robert W Maul
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Amanda E Rieffer
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Daniel J Crawford
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Daniel J Salamango
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Dorjbal Dorjsuren
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20816, United States
| | - Alexey V Zakharov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20816, United States
| | - Daniel J Jansen
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20816, United States
| | - Ganesha Rai
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20816, United States
| | - Juan Marugan
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20816, United States
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20816, United States
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Howard Hughes Medical Institute, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Rahul M Kohli
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patricia J Gearhart
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, United States
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23
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Kuang J, Lyu Q, Wang J, Cui Y, Zhao J. Advances in base editing with an emphasis on an AAV-based strategy. Methods 2021; 194:56-64. [PMID: 33774157 DOI: 10.1016/j.ymeth.2021.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/07/2021] [Accepted: 03/21/2021] [Indexed: 01/01/2023] Open
Abstract
The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based base editors have been developed for precisely installing point mutations in genomes with high efficiency. Two editing systems of cytosine base editors (CBEs) and adenine base editors (ABEs) have been developed for conversion of C.G-to-T.A and A.T-to-G.C, respectively, showing the prominence in genomic DNA correction and mutation. Here, we summarize recent optimized approaches in improving base editors, including the evolution of Cas proteins, the choice of deamination enzymes, modification on linker length, base-editor expression, and addition of functional domains. Specifically, in this paper we highlight a strategy of split-intein mediated base-editor reconstitution for its adeno-associated virus (AAV) delivery. The purpose of this article is to offer readers with a better understanding of AAV-mediated base editors, and facilitate them to use this tool in in vivo experiments and potential clinical applications.
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Affiliation(s)
- Jiajie Kuang
- Shenzhen Eye Institute, Shenzhen Eye Hospital, Jinan University, Shenzhen 518000, China; Department of Ophthalmology, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China
| | - Qinghua Lyu
- School of Ophthalmology & Optometry, Shenzhen Eye Hospital, Shenzhen University, Shenzhen 518000, China; Institute of Microscale Optoelectronics, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jiao Wang
- School of Ophthalmology & Optometry, Shenzhen Eye Hospital, Shenzhen University, Shenzhen 518000, China
| | - Yubo Cui
- Department of Ophthalmology, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China
| | - Jun Zhao
- Shenzhen Eye Institute, Shenzhen Eye Hospital, Jinan University, Shenzhen 518000, China; Department of Ophthalmology, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, China.
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24
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Huang TP, Newby GA, Liu DR. Precision genome editing using cytosine and adenine base editors in mammalian cells. Nat Protoc 2021; 16:1089-1128. [PMID: 33462442 DOI: 10.1038/s41596-020-00450-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 10/20/2020] [Indexed: 01/29/2023]
Abstract
Genome editing has transformed the life sciences and has exciting prospects for use in treating genetic diseases. Our laboratory developed base editing to enable precise and efficient genome editing while minimizing undesired byproducts and toxicity associated with double-stranded DNA breaks. Adenine and cytosine base editors mediate targeted A•T-to-G•C or C•G-to-T•A base pair changes, respectively, which can theoretically address most human disease-associated single-nucleotide polymorphisms. Current base editors can achieve high editing efficiencies-for example, approaching 100% in cultured mammalian cells or 70% in adult mouse neurons in vivo. Since their initial description, a large set of base editor variants have been developed with different on-target and off-target editing characteristics. Here, we describe a protocol for using base editing in cultured mammalian cells. We provide guidelines for choosing target sites, appropriate base editor variants and delivery strategies to best suit a desired application. We further describe standard base-editing experiments in HEK293T cells, along with computational analysis of base-editing outcomes using CRISPResso2. Beginning with target DNA site selection, base-editing experiments in mammalian cells can typically be completed within 1-3 weeks and require only standard molecular biology techniques and readily available plasmid constructs.
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Affiliation(s)
- Tony P Huang
- Merkin Institute of Transformative Technologies in Healthcare, The Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, The Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, The Broad Institute of Harvard and MIT, Cambridge, MA, USA.
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
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25
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Li S, Akrap N, Cerboni S, Porritt MJ, Wimberger S, Lundin A, Möller C, Firth M, Gordon E, Lazovic B, Sieńska A, Pane LS, Coelho MA, Ciotta G, Pellegrini G, Sini M, Xu X, Mitra S, Bohlooly-Y M, Taylor BJM, Sienski G, Maresca M. Universal toxin-based selection for precise genome engineering in human cells. Nat Commun 2021; 12:497. [PMID: 33479216 PMCID: PMC7820243 DOI: 10.1038/s41467-020-20810-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 12/21/2020] [Indexed: 01/29/2023] Open
Abstract
Prokaryotic restriction enzymes, recombinases and Cas proteins are powerful DNA engineering and genome editing tools. However, in many primary cell types, the efficiency of genome editing remains low, impeding the development of gene- and cell-based therapeutic applications. A safe strategy for robust and efficient enrichment of precisely genetically engineered cells is urgently required. Here, we screen for mutations in the receptor for Diphtheria Toxin (DT) which protect human cells from DT. Selection for cells with an edited DT receptor variant enriches for simultaneously introduced, precisely targeted gene modifications at a second independent locus, such as nucleotide substitutions and DNA insertions. Our method enables the rapid generation of a homogenous cell population with bi-allelic integration of a DNA cassette at the selection locus, without clonal isolation. Toxin-based selection works in both cancer-transformed and non-transformed cells, including human induced pluripotent stem cells and human primary T-lymphocytes, as well as it is applicable also in vivo, in mice with humanized liver. This work represents a flexible, precise, and efficient selection strategy to engineer cells using CRISPR-Cas and base editing systems.
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Affiliation(s)
- Songyuan Li
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
| | - Nina Akrap
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Silvia Cerboni
- Translational Science and Experimental Medicine, Respiratory & Immunology, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Michelle J Porritt
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Sandra Wimberger
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
- Department of Chemistry & Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Anders Lundin
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Carl Möller
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Mike Firth
- R&D Data Infrastructure & Tools, AstraZeneca, Cambridge, UK
| | - Euan Gordon
- Discovery Biology SWE, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Bojana Lazovic
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Aleksandra Sieńska
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Luna Simona Pane
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | | | - Giovanni Ciotta
- Discovery Biology UK, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Giovanni Pellegrini
- CVRM pathology, Clinical Pharmacology & Safety Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Marcella Sini
- CVRM pathology, Clinical Pharmacology & Safety Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Xiufeng Xu
- Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden
| | - Suman Mitra
- Inserm UMR1277 CNRS UMR9020 - CANTHER, Institut pour la Recherche sur le Cancer de Lille, Lille, France
| | - Mohammad Bohlooly-Y
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Benjamin J M Taylor
- Discovery Biology UK, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Grzegorz Sienski
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
| | - Marcello Maresca
- Translational Genomics, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
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26
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Brookhouser N, Nguyen T, Tekel SJ, Standage-Beier K, Wang X, Brafman DA. A Cas9-mediated adenosine transient reporter enables enrichment of ABE-targeted cells. BMC Biol 2020. [PMID: 33317513 DOI: 10.1186/s12915-020-00929-7.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Adenine base editors (ABE) enable single nucleotide modifications without the need for double-stranded DNA breaks (DSBs) induced by conventional CRIPSR/Cas9-based approaches. However, most approaches that employ ABEs require inefficient downstream technologies to identify desired targeted mutations within large populations of manipulated cells. In this study, we developed a fluorescence-based method, named "Cas9-mediated adenosine transient reporter for editing enrichment" (CasMAs-TREE; herein abbreviated XMAS-TREE), to facilitate the real-time identification of base-edited cell populations. RESULTS To establish a fluorescent-based assay able to detect ABE activity within a cell in real time, we designed a construct encoding a mCherry fluorescent protein followed by a stop codon (TGA) preceding the coding sequence for a green fluorescent protein (GFP), allowing translational readthrough and expression of GFP after A-to-G conversion of the codon to "TGG." At several independent loci, we demonstrate that XMAS-TREE can be used for the highly efficient purification of targeted cells. Moreover, we demonstrate that XMAS-TREE can be employed in the context of multiplexed editing strategies to simultaneous modify several genomic loci. In addition, we employ XMAS-TREE to efficiently edit human pluripotent stem cells (hPSCs), a cell type traditionally resistant to genetic modification. Furthermore, we utilize XMAS-TREE to generate clonal isogenic hPSCs at target sites not editable using well-established reporter of transfection (RoT)-based strategies. CONCLUSION We established a method to detect adenosine base-editing activity within a cell, which increases the efficiency of editing at multiple genomic locations through an enrichment of edited cells. In the future, XMAS-TREE will greatly accelerate the application of ABEs in biomedical research.
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Affiliation(s)
- Nicholas Brookhouser
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA.,Graduate Program in Clinical Translational Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Toan Nguyen
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA
| | - Stefan J Tekel
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA
| | - Kylie Standage-Beier
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA.,Molecular and Cellular Biology Graduate Program, Arizona State University, Tempe, AZ, 85287, USA
| | - Xiao Wang
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA.
| | - David A Brafman
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA.
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27
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Brookhouser N, Nguyen T, Tekel SJ, Standage-Beier K, Wang X, Brafman DA. A Cas9-mediated adenosine transient reporter enables enrichment of ABE-targeted cells. BMC Biol 2020; 18:193. [PMID: 33317513 PMCID: PMC7737295 DOI: 10.1186/s12915-020-00929-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 11/18/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Adenine base editors (ABE) enable single nucleotide modifications without the need for double-stranded DNA breaks (DSBs) induced by conventional CRIPSR/Cas9-based approaches. However, most approaches that employ ABEs require inefficient downstream technologies to identify desired targeted mutations within large populations of manipulated cells. In this study, we developed a fluorescence-based method, named "Cas9-mediated adenosine transient reporter for editing enrichment" (CasMAs-TREE; herein abbreviated XMAS-TREE), to facilitate the real-time identification of base-edited cell populations. RESULTS To establish a fluorescent-based assay able to detect ABE activity within a cell in real time, we designed a construct encoding a mCherry fluorescent protein followed by a stop codon (TGA) preceding the coding sequence for a green fluorescent protein (GFP), allowing translational readthrough and expression of GFP after A-to-G conversion of the codon to "TGG." At several independent loci, we demonstrate that XMAS-TREE can be used for the highly efficient purification of targeted cells. Moreover, we demonstrate that XMAS-TREE can be employed in the context of multiplexed editing strategies to simultaneous modify several genomic loci. In addition, we employ XMAS-TREE to efficiently edit human pluripotent stem cells (hPSCs), a cell type traditionally resistant to genetic modification. Furthermore, we utilize XMAS-TREE to generate clonal isogenic hPSCs at target sites not editable using well-established reporter of transfection (RoT)-based strategies. CONCLUSION We established a method to detect adenosine base-editing activity within a cell, which increases the efficiency of editing at multiple genomic locations through an enrichment of edited cells. In the future, XMAS-TREE will greatly accelerate the application of ABEs in biomedical research.
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Affiliation(s)
- Nicholas Brookhouser
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA
- Graduate Program in Clinical Translational Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA
| | - Toan Nguyen
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA
| | - Stefan J Tekel
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA
| | - Kylie Standage-Beier
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA
- Molecular and Cellular Biology Graduate Program, Arizona State University, Tempe, AZ, 85287, USA
| | - Xiao Wang
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA.
| | - David A Brafman
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler Mall, ECG 334A, Tempe, AZ, 85287, USA.
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28
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Lau CH, Tin C, Suh Y. CRISPR-based strategies for targeted transgene knock-in and gene correction. Fac Rev 2020; 9:20. [PMID: 33659952 PMCID: PMC7886068 DOI: 10.12703/r/9-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The last few years have seen tremendous advances in CRISPR-mediated genome editing. Great efforts have been made to improve the efficiency, specificity, editing window, and targeting scope of CRISPR/Cas9-mediated transgene knock-in and gene correction. In this article, we comprehensively review recent progress in CRISPR-based strategies for targeted transgene knock-in and gene correction in both homology-dependent and homology-independent approaches. We cover homology-directed repair (HDR), synthesis-dependent strand annealing (SDSA), microhomology-mediated end joining (MMEJ), and homology-mediated end joining (HMEJ) pathways for a homology-dependent strategy and alternative DNA repair pathways such as non-homologous end joining (NHEJ), base excision repair (BER), and mismatch repair (MMR) for a homology-independent strategy. We also discuss base editing and prime editing that enable direct conversion of nucleotides in genomic DNA without damaging the DNA or requiring donor DNA. Notably, we illustrate the key mechanisms and design principles for each strategy, providing design guidelines for multiplex, flexible, scarless gene insertion and replacement at high efficiency and specificity. In addition, we highlight next-generation base editors that provide higher editing efficiency, fewer undesired by-products, and broader targeting scope.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biomedical Engineering, Academic 1, 83 Tat Chee Avenue, City University of Hong Kong, Hong Kong
| | - Chung Tin
- Department of Biomedical Engineering, Academic 1, 83 Tat Chee Avenue, City University of Hong Kong, Hong Kong
| | - Yousin Suh
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
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29
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Vasquez CA, Cowan QT, Komor AC. Base Editing in Human Cells to Produce Single-Nucleotide-Variant Clonal Cell Lines. ACTA ACUST UNITED AC 2020; 133:e129. [PMID: 33151638 DOI: 10.1002/cpmb.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Base-editing technologies enable the introduction of point mutations at targeted genomic sites in mammalian cells, with higher efficiency and precision than traditional genome-editing methods that use DNA double-strand breaks, such as zinc finger nucleases (ZFNs), transcription-activator-like effector nucleases (TALENs), and the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (CRISPR-Cas9) system. This allows the generation of single-nucleotide-variant isogenic cell lines (i.e., cell lines whose genomic sequences differ from each other only at a single, edited nucleotide) in a more time- and resource-effective manner. These single-nucleotide-variant clonal cell lines represent a powerful tool with which to assess the functional role of genetic variants in a native cellular context. Base editing can therefore facilitate genotype-to-phenotype studies in a controlled laboratory setting, with applications in both basic research and clinical applications. Here, we provide optimized protocols (including experimental design, methods, and analyses) to design base-editing constructs, transfect adherent cells, quantify base-editing efficiencies in bulk, and generate single-nucleotide-variant clonal cell lines. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Design and production of plasmids for base-editing experiments Basic Protocol 2: Transfection of adherent cells and harvesting of genomic DNA Basic Protocol 3: Genotyping of harvested cells using Sanger sequencing Alternate Protocol 1: Next-generation sequencing to quantify base editing Basic Protocol 4: Single-cell isolation of base-edited cells using FACS Alternate Protocol 2: Single-cell isolation of base-edited cells using dilution plating Basic Protocol 5: Clonal expansion to generate isogenic cell lines and genotyping of clones.
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Affiliation(s)
- Carlos A Vasquez
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
| | - Quinn T Cowan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
| | - Alexis C Komor
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
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30
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Jin S, Fei H, Zhu Z, Luo Y, Liu J, Gao S, Zhang F, Chen YH, Wang Y, Gao C. Rationally Designed APOBEC3B Cytosine Base Editors with Improved Specificity. Mol Cell 2020; 79:728-740.e6. [PMID: 32721385 DOI: 10.1016/j.molcel.2020.07.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/08/2020] [Accepted: 07/02/2020] [Indexed: 12/20/2022]
Abstract
Cytosine base editors (CBEs) generate C-to-T nucleotide substitutions in genomic target sites without inducing double-strand breaks. However, CBEs such as BE3 can cause genome-wide off-target changes via sgRNA-independent DNA deamination. By leveraging the orthogonal R-loops generated by SaCas9 nickase to mimic actively transcribed genomic loci that are more susceptible to cytidine deaminase, we set up a high-throughput assay for assessing sgRNA-independent off-target effects of CBEs in rice protoplasts. The reliability of this assay was confirmed by the whole-genome sequencing (WGS) of 10 base editors in regenerated rice plants. The R-loop assay was used to screen a series of rationally designed A3Bctd-BE3 variants for improved specificity. We obtained 2 efficient CBE variants, A3Bctd-VHM-BE3 and A3Bctd-KKR-BE3, and the WGS analysis revealed that these new CBEs eliminated sgRNA-independent DNA off-target edits in rice plants. Moreover, these 2 base editor variants were more precise at their target sites by producing fewer multiple C edits.
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Affiliation(s)
- Shuai Jin
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Hongyuan Fei
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zixu Zhu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yingfeng Luo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jinxing Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Shenghan Gao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Feng Zhang
- Department of Plant and Microbial Biology, Center for Plant Precision Genomics, The Microbial and Plant Genomics Institute, University of Minnesota, Minneapolis, MN 55108, USA
| | - Yu-Hang Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Yanpeng Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.
| | - Caixia Gao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.
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31
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Wang S, Zong Y, Lin Q, Zhang H, Chai Z, Zhang D, Chen K, Qiu JL, Gao C. Precise, predictable multi-nucleotide deletions in rice and wheat using APOBEC-Cas9. Nat Biotechnol 2020; 38:1460-1465. [PMID: 32601432 DOI: 10.1038/s41587-020-0566-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/19/2020] [Indexed: 01/24/2023]
Abstract
Short insertions and deletions can be produced in plant genomes using CRISPR-Cas editors, but reliable production of larger deletions in specific target sites has proven difficult to achieve. We report the development of a series of APOBEC-Cas9 fusion-induced deletion systems (AFIDs) that combine Cas9 with human APOBEC3A (A3A), uracil DNA-glucosidase and apurinic or apyrimidinic site lyase. In rice and wheat, AFID-3 generated deletions from 5'-deaminated C bases to the Cas9-cleavage site. Approximately one-third of deletions produced using AFID-3 in rice and wheat protoplasts (30.2%) and regenerated plants (34.8%) were predictable. We show that eAFID-3, in which the A3A in AFID-3 is replaced with truncated APOBEC3B (A3Bctd), produced more uniform deletions from the preferred TC motif to the double-strand break. AFIDs could be applied to study regulatory regions and protein domains to improve crop plants.
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Affiliation(s)
- Shengxing Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Yuan Zong
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Qiupeng Lin
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Huawei Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Zhuangzhuang Chai
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Dandan Zhang
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Kunling Chen
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Jin-Long Qiu
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Caixia Gao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China. .,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.
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32
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Carlaw TM, Zhang LH, Ross CJD. CRISPR/Cas9 Editing: Sparking Discussion on Safety in Light of the Need for New Therapeutics. Hum Gene Ther 2020; 31:794-807. [PMID: 32586150 DOI: 10.1089/hum.2020.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Recent advances in genome sequencing have greatly improved our ability to understand and identify the causes of genetic diseases. However, there remains an urgent need for innovative, safe, and effective treatments for these diseases. CRISPR-based genome editing systems have become important and powerful tools in the laboratory, and efforts are underway to translate these into patient therapies. Therapeutic base editing is one form of genome engineering that has gained much interest because of its simplicity, specificity, and effectiveness. Base editors are a fusion of a partially deactivated Cas9 enzyme with nickase function, together with a base-modifying enzyme. They are capable of precisely targeting and repairing a pathogenic mutation to restore the normal function of a gene, ideally without disturbing the rest of the genome. In the past year, research has identified new safety concerns of base editors and sparked new innovations to improve their safety. In this review, we provide an overview of the recent advances in the safety and effectiveness of therapeutic base editors and prime editing.
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Affiliation(s)
| | - Lin-Hua Zhang
- Faculty of Pharmaceutical Sciences; University of British Columbia, Vancouver, Canada
| | - Colin J D Ross
- Faculty of Pharmaceutical Sciences; University of British Columbia, Vancouver, Canada
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33
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Anzalone AV, Koblan LW, Liu DR. Genome editing with CRISPR-Cas nucleases, base editors, transposases and prime editors. Nat Biotechnol 2020; 38:824-844. [PMID: 32572269 DOI: 10.1038/s41587-020-0561-9] [Citation(s) in RCA: 1038] [Impact Index Per Article: 259.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022]
Abstract
The development of new CRISPR-Cas genome editing tools continues to drive major advances in the life sciences. Four classes of CRISPR-Cas-derived genome editing agents-nucleases, base editors, transposases/recombinases and prime editors-are currently available for modifying genomes in experimental systems. Some of these agents have also moved rapidly into the clinic. Each tool comes with its own capabilities and limitations, and major efforts have broadened their editing capabilities, expanded their targeting scope and improved editing specificity. We analyze key considerations when choosing genome editing agents and identify opportunities for future improvements and applications in basic research and therapeutics.
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Affiliation(s)
- Andrew V Anzalone
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Luke W Koblan
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA. .,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA. .,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
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34
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Doman JL, Raguram A, Newby GA, Liu DR. Evaluation and minimization of Cas9-independent off-target DNA editing by cytosine base editors. Nat Biotechnol 2020; 38:620-628. [PMID: 32042165 PMCID: PMC7335424 DOI: 10.1038/s41587-020-0414-6] [Citation(s) in RCA: 239] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 01/07/2020] [Indexed: 12/21/2022]
Abstract
Cytosine base editors (CBEs) enable targeted C•G-to-T•A conversions in genomic DNA. Recent studies report that BE3, the original CBE, induces a low frequency of genome-wide Cas9-independent off-target C•G-to-T•A mutation in mouse embryos and in rice. Here we develop multiple rapid, cost-effective methods to screen the propensity of different CBEs to induce Cas9-independent deamination in Escherichia coli and in human cells. We use these assays to identify CBEs with reduced Cas9-independent deamination and validate via whole-genome sequencing that YE1, a narrowed-window CBE variant, displays background levels of Cas9-independent off-target editing. We engineered YE1 variants that retain the substrate-targeting scope of high-activity CBEs while maintaining minimal Cas9-independent off-target editing. The suite of CBEs characterized and engineered in this study collectively offer ~10-100-fold lower average Cas9-independent off-target DNA editing while maintaining robust on-target editing at most positions targetable by canonical CBEs, and thus are especially promising for applications in which off-target editing must be minimized.
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Affiliation(s)
- Jordan L Doman
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Aditya Raguram
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA.
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
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35
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McCann JL, Salamango DJ, Law EK, Brown WL, Harris RS. MagnEdit-interacting factors that recruit DNA-editing enzymes to single base targets. Life Sci Alliance 2020; 3:3/4/e201900606. [PMID: 32094150 PMCID: PMC7043409 DOI: 10.26508/lsa.201900606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 12/17/2022] Open
Abstract
This study reports a new, non-covalent strategy—called MagnEdit—that attracts the DNA cytosine deaminase APOBEC3B to a Cas9-directed site for C-to-T editing. Although CRISPR/Cas9 technology has created a renaissance in genome engineering, particularly for gene knockout generation, methods to introduce precise single base changes are also highly desirable. The covalent fusion of a DNA-editing enzyme such as APOBEC to a Cas9 nickase complex has heightened hopes for such precision genome engineering. However, current cytosine base editors are prone to undesirable off-target mutations, including, most frequently, target-adjacent mutations. Here, we report a method to “attract” the DNA deaminase, APOBEC3B, to a target cytosine base for specific editing with minimal damage to adjacent cytosine bases. The key to this system is fusing an APOBEC-interacting protein (not APOBEC itself) to Cas9n, which attracts nuclear APOBEC3B transiently to the target site for editing. Several APOBEC3B interactors were tested and one, hnRNPUL1, demonstrated proof-of-concept with successful C-to-T editing of episomal and chromosomal substrates and lower frequencies of target-adjacent events.
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Affiliation(s)
- Jennifer L McCann
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.,Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.,Center for Genome Engineering, University of Minnesota, Minneapolis, MN, USA.,Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN, USA
| | - Daniel J Salamango
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.,Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.,Center for Genome Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Emily K Law
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.,Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.,Center for Genome Engineering, University of Minnesota, Minneapolis, MN, USA.,Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN, USA
| | - William L Brown
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.,Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.,Center for Genome Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA .,Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.,Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.,Center for Genome Engineering, University of Minnesota, Minneapolis, MN, USA.,Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN, USA
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36
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Xu W, Yang Y, Liu Y, Kang G, Wang F, Li L, Lv X, Zhao S, Yuan S, Song J, Wu Y, Feng F, He X, Zhang C, Song W, Zhao J, Yang J. Discriminated sgRNAs-Based SurroGate System Greatly Enhances the Screening Efficiency of Plant Base-Edited Cells. MOLECULAR PLANT 2020; 13:169-180. [PMID: 31634585 DOI: 10.1016/j.molp.2019.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/27/2019] [Accepted: 10/13/2019] [Indexed: 05/13/2023]
Abstract
The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still challenging. In this study, an efficient surrogate reporter system based on a defective hygromycin resistance gene was established in rice to enrich base-edited cells. After step-by-step optimization, the Discriminated sgRNAs-based SurroGate system (DisSUGs) was established by artificially differentiating the editing abilities of a wild-type single guide RNA (sgRNA) targeting the surrogate reporter gene and an enhanced sgRNA targeting endogenous sites. The DisSUGs enhanced the efficiency of screening base-edited cells by 3- to 5-fold for a PmCDA1-based cytosine-to-tyrosine base editor (PCBE), and 2.5- to 6.5-fold for an adenine base editor (ABE) at endogenous targets. These targets showed editing efficiencies of <25% in the conventional systems. The DisSUGs greatly enhanced the frequency of homozygous substitutions and expanded the activity window slightly for both a PCBE and an ABE. Analyses of the total number of single-nucleotide variants from whole-genome sequencing revealed that, compared with the no-enrichment PCBE strategy, the DisSUGs did not alter the frequency of genome-wide sgRNA-independent off-target mutations, but slightly increased the frequency of target-dependent off-target mutations. Collectively, the DisSUGs developed in this study greatly enhances the efficiency of screening plant base-edited cells and will be a useful system in future applications.
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Affiliation(s)
- Wen Xu
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Yongxing Yang
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Ya Liu
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Guiting Kang
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Feipeng Wang
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Lu Li
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Xinxin Lv
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Si Zhao
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Shuang Yuan
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Jinling Song
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Ying Wu
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Feng Feng
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Xiaoqing He
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Chengwei Zhang
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China
| | - Wei Song
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China.
| | - Jiuran Zhao
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China.
| | - Jinxiao Yang
- Beijing Key Laboratory of Maize DNA Fingerprinting and Molecular Breeding, Beijing Academy of Agriculture & Forestry Sciences, Beijing 100080, China.
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37
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Yang G, Huang X. Methods and applications of CRISPR/Cas system for genome editing in stem cells. CELL REGENERATION (LONDON, ENGLAND) 2019; 8:33-41. [PMID: 31666940 PMCID: PMC6806369 DOI: 10.1016/j.cr.2019.08.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/28/2019] [Accepted: 08/30/2019] [Indexed: 12/26/2022]
Abstract
Genome editing technology holds great promise for genome manipulation and gene therapy. While widespread utilization, genome editing has been used to unravel the roles of specific genes in differentiation and pluripotency of stem cells, and reinforce the stem cell-based applications. In this review, we summarize the advances of genome editing technology, as well as the derivative technologies from CRISPR/Cas system, which show tremendous potential in various fields. We also highlight the key findings in the studies of stem cells and regeneration by genome editing technology.
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Affiliation(s)
- Guang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xingxu Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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38
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Targeting specificity of APOBEC-based cytosine base editor in human iPSCs determined by whole genome sequencing. Nat Commun 2019; 10:5353. [PMID: 31767844 PMCID: PMC6877639 DOI: 10.1038/s41467-019-13342-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/29/2019] [Indexed: 12/26/2022] Open
Abstract
DNA base editors have enabled genome editing without generating DNA double strand breaks. The applications of this technology have been reported in a variety of animal and plant systems, however, their editing specificity in human stem cells has not been studied by unbiased genome-wide analysis. Here we investigate the fidelity of cytidine deaminase-mediated base editing in human induced pluripotent stem cells (iPSCs) by whole genome sequencing after sustained or transient base editor expression. While base-edited iPSC clones without significant off-target modifications are identified, this study also reveals the potential of APOBEC-based base editors in inducing unintended point mutations outside of likely in silico-predicted CRISPR-Cas9 off-targets. The majority of the off-target mutations are C:G->T:A transitions or C:G->G:C transversions enriched for the APOBEC mutagenesis signature. These results demonstrate that cytosine base editor-mediated editing may result in unintended genetic modifications with distinct patterns from that of the conventional CRISPR-Cas nucleases.
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39
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Liu LD, Huang M, Dai P, Liu T, Fan S, Cheng X, Zhao Y, Yeap LS, Meng FL. Intrinsic Nucleotide Preference of Diversifying Base Editors Guides Antibody Ex Vivo Affinity Maturation. Cell Rep 2019; 25:884-892.e3. [PMID: 30355495 DOI: 10.1016/j.celrep.2018.09.090] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/13/2018] [Accepted: 09/27/2018] [Indexed: 12/27/2022] Open
Abstract
Base editors (BEs) are emerging tools used for precision correction or diversifying mutation. It provides a potential way to recreate somatic hypermutations (SHM) for generating high-affinity antibody, which is usually screened from antigen-challenged animal models or synthetic combinatorial libraries. By comparing somatic mutations in the same genomic context, we screened engineered deaminases and CRISPR-deaminase coupling approaches and updated diversifying base editors (DBEs) to generate SHM. The deaminase used in DBEs retains its intrinsic nucleotide preference and mutates cytidines at its preferred motifs. DBE with AID targets the same hotspots as physiological AID does in vivo, while DBE with other deaminases generates distinct mutation profiles from the same DNA substrate. Downstream DNA repair pathways further diversified the sequence, while Cas9-nickase restricted mutation spreading. Finally, application of DBE in an antibody display system achieved antibody affinity maturation ex vivo. Our findings provide insight of DBE working mechanism and an alternative antibody engineering approach.
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Affiliation(s)
- Liu Daisy Liu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Min Huang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Pengfei Dai
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Tingting Liu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Shuangshuang Fan
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Xueqian Cheng
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Yaofeng Zhao
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Leng-Siew Yeap
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Fei-Long Meng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China.
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40
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Evanoff M, Komor AC. Base Editors: Modular Tools for the Introduction of Point Mutations in Living Cells. Emerg Top Life Sci 2019; 3:483-491. [PMID: 32270050 PMCID: PMC7141416 DOI: 10.1042/etls20190088] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Base editors are a new family of programmable genome editing tools that fuse ssDNA (single stranded DNA) modifying enzymes to catalytically inactive CRISPR-associated (Cas) endonucleases to induce highly efficient single base changes. With dozens of base editors now reported, it is apparent that these tools are highly modular; many combinations of ssDNA modifying enzymes and Cas proteins have resulted in a variety of base editors, each with its own unique properties and potential uses. In this perspective, we describe currently available base editors, highlighting their modular nature and describing the various options available for each component. Furthermore, we briefly discuss applications in synthetic biology and genome engineering where base editors have presented unique advantages over alternative techniques.
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Affiliation(s)
- Mallory Evanoff
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, 92093
| | - Alexis C. Komor
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, 92093
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41
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Thuronyi BW, Koblan LW, Levy JM, Yeh WH, Zheng C, Newby GA, Wilson C, Bhaumik M, Shubina-Oleinik O, Holt JR, Liu DR. Continuous evolution of base editors with expanded target compatibility and improved activity. Nat Biotechnol 2019; 37:1070-1079. [PMID: 31332326 PMCID: PMC6728210 DOI: 10.1038/s41587-019-0193-0] [Citation(s) in RCA: 181] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 06/14/2019] [Indexed: 12/15/2022]
Abstract
Base editors use DNA-modifying enzymes targeted with a catalytically impaired CRISPR protein to precisely install point mutations. Here, we develop phage-assisted continuous evolution of base editors (BE-PACE) to improve their editing efficiency and target sequence compatibility. We used BE-PACE to evolve cytosine base editors (CBEs) that overcome target sequence context constraints of canonical CBEs. One evolved CBE, evoAPOBEC1-BE4max, is up to 26-fold more efficient at editing cytosine in the GC context, a disfavored context for wild-type APOBEC1 deaminase, while maintaining efficient editing in all other sequence contexts tested. Another evolved deaminase, evoFERNY, is 29% smaller than APOBEC1 and edits efficiently in all tested sequence contexts. We also evolved a CBE based on CDA1 deaminase with much higher editing efficiency at difficult target sites. Finally, we used data from evolved CBEs to illuminate the relationship between deaminase activity, base editing efficiency, editing window width and byproduct formation. These findings establish a system for rapid evolution of base editors and inform their use and improvement.
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Affiliation(s)
- B W Thuronyi
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Chemistry, Williams College, Williamstown, MA, USA
| | - Luke W Koblan
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Jonathan M Levy
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Wei-Hsi Yeh
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, USA
| | - Christine Zheng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Christopher Wilson
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Mantu Bhaumik
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Olga Shubina-Oleinik
- Departments of Otolaryngology and Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA.
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
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42
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Wang R, Zhang JY, Lu KH, Lu SS, Zhu XX. Efficient generation of GHR knockout Bama minipig fibroblast cells using CRISPR/Cas9-mediated gene editing. In Vitro Cell Dev Biol Anim 2019; 55:784-792. [PMID: 31456163 DOI: 10.1007/s11626-019-00397-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022]
Abstract
Dwarfism, also known as growth hormone deficiency (GHD), is a disease caused by genetic mutations that result in either a lack of growth hormone or insufficient secretion of growth hormone, resulting in a person's inability to grow normally. In the past, many studies focusing on GHD have made use of models of other diseases such as metabolic or infectious diseases. A viable GHD specific model system has not been used previously, thus limiting the interpretation of GHD results. The Bama minipig is unique to Guangxi province and has strong adaptability and disease resistance, and an incredibly short stature, which is especially important for the study of GHD. In addition, studies of GHR knockout Bama minipigs and GHR knockout Bama minipig fibroblast cells generated using CRISPR/Cas9 have not been previously reported. Therefore, the Bama minipig was selected as an animal model and as a tool for the study of GHD in this work. In this study, a Cas9 plasmid with sgRNA targeting the first exon of the GHR gene was transfected into Bama minipig kidney fibroblast cells to generate 22 GHR knockout Bama minipig kidney fibroblast cell lines (12 male monoclonal cells and 10 female monoclonal cells). After culture and identification, 11 of the 12 male clone cell lines showed double allele mutations, and the rate of positive alteration of GHR was 91.67%. Diallelic mutation of the target sequence occurred in 10 female clonal cell lines, with an effective positive mutation rate of 100%. Our experimental results not only showed that CRISPR/Cas9 could efficiently be used for gene editing in Bama minipig cells but also identified a highly efficient target site for the generation of a GHR knockout in other porcine models. Thus, the generation of GHR knockout male and female Bama fibroblast cells could lay a foundation for the birth of a future dwarfism model pig. We anticipate that the "mini" Bama minipig will be of improved use for biomedical and agricultural scientific research and for furthering our understanding of the genetic underpinnings of GHD.
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Affiliation(s)
- Rui Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources; Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology; Faculty of Animal Science & Technology, Guangxi University, Nanning, 530004, China
| | - Jian-Ying Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources; Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology; Faculty of Animal Science & Technology, Guangxi University, Nanning, 530004, China
| | - Ke-Huan Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources; Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology; Faculty of Animal Science & Technology, Guangxi University, Nanning, 530004, China
| | - Sheng-Sheng Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources; Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology; Faculty of Animal Science & Technology, Guangxi University, Nanning, 530004, China.
| | - Xiang-Xing Zhu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources; Guangxi High Education Key Laboratory for Animal Reproduction and Biotechnology; Faculty of Animal Science & Technology, Guangxi University, Nanning, 530004, China. .,Guangdong Center of Gene Editing Engineering, Foshan University, Foshan, 528000, China.
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43
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Wagner JR, Demir Ö, Carpenter MA, Aihara H, Harki DA, Harris RS, Amaro RE. Determinants of Oligonucleotide Selectivity of APOBEC3B. J Chem Inf Model 2019; 59:2264-2273. [PMID: 30130104 PMCID: PMC6644697 DOI: 10.1021/acs.jcim.8b00427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
APOBEC3B (A3B) is a prominent source of mutation in many cancers. To date, it has been difficult to capture the native protein-DNA interactions that confer A3B's substrate specificity by crystallography due to the highly dynamic nature of wild-type A3B active site. We use computational tools to restore a recent crystal structure of a DNA-bound A3B C-terminal domain mutant construct to its wild type sequence, and run molecular dynamics simulations to study its substrate recognition mechanisms. Analysis of these simulations reveal dynamics of the native A3Bctd-oligonucleotide interactions, including the experimentally inaccessible loop 1-oligonucleotide interactions. A second series of simulations in which the target cytosine nucleotide was computationally mutated from a deoxyribose to a ribose show a change in sugar ring pucker, leading to a rearrangement of the binding site and revealing a potential intermediate in the binding pathway. Finally, apo simulations of A3B, starting from the DNA-bound open state, experience a rapid and consistent closure of the binding site, reaching conformations incompatible with substrate binding. This study reveals a more realistic and dynamic view of the wild type A3B binding site and provides novel insights for structure-guided design efforts for A3B.
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Affiliation(s)
- Jeffrey R Wagner
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093-0340 , United States
| | - Özlem Demir
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093-0340 , United States
| | - Michael A Carpenter
- Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , Minneapolis , Minnesota 55455 , United States
- Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
- Institute for Molecular Virology , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , Minneapolis , Minnesota 55455 , United States
- Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
- Institute for Molecular Virology , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Daniel A Harki
- Department of Medicinal Chemistry , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , Minneapolis , Minnesota 55455 , United States
- Masonic Cancer Center , University of Minnesota , Minneapolis , Minnesota 55455 , United States
- Institute for Molecular Virology , University of Minnesota , Minneapolis , Minnesota 55455 , United States
- Howard Hughes Medical Institute , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Rommie E Amaro
- Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093-0340 , United States
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44
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Tang J, Lee T, Sun T. Single-nucleotide editing: From principle, optimization to application. Hum Mutat 2019; 40:2171-2183. [PMID: 31131955 DOI: 10.1002/humu.23819] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/30/2019] [Accepted: 05/23/2019] [Indexed: 12/26/2022]
Abstract
Cytosine base editors (CBEs) and adenine base editors (ABEs), which are generally composed of an engineered deaminase and a catalytically impaired CRISPR-Cas9 variant, are new favorite tools for single base substitution in cells and organisms. In this review, we summarize the principle of base-editing systems and elaborate on the evolution of different platforms of CBEs and ABEs, including their deaminase, Cas9 variants, and editing outcomes. Moreover, we highlight their applications in mouse and human cells and discuss the challenges and prospects of base editors. The ABE- and CBE systems have been used in gene silencing, pathogenic gene correction, and functional genetic screening. Single base editing is becoming a new promising genetic tool in biomedical research and gene therapy.
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Affiliation(s)
- Jinling Tang
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen, Fujian, China
| | - Trevor Lee
- Department of Cell and Developmental Biology, Weill Medical College, Cornell University, New York, New York
| | - Tao Sun
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, Xiamen, Fujian, China
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45
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Emerging CRISPR/Cas9 applications for T-cell gene editing. Emerg Top Life Sci 2019; 3:261-275. [PMID: 33523139 DOI: 10.1042/etls20180144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/04/2019] [Accepted: 03/08/2019] [Indexed: 12/17/2022]
Abstract
Gene editing tools are being rapidly developed, accelerating many areas of cell and gene therapy research. Each successive gene editing technology promises increased efficacy, improved specificity, reduced manufacturing cost and design complexity; all of which are currently epitomised by the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein (Cas9) platform. Since its conceptualisation, CRISPR-based gene editing has been applied to existing methodologies and has further allowed the exploration of novel avenues of research. Implementation of CRISPR/Cas9 has been instrumental to recent progress in the treatment of cancer, primary immunodeficiency, and infectious diseases. To this end, T-cell therapies have attempted to harness and redirect antigen recognition function, and through gene editing, broaden T-cell targeting capabilities and enhance their potency. The purpose of this review is to provide insights into emerging applications of CRISPR/Cas9 in T-cell therapies, to briefly address concerns surrounding CRISPR-mediated indel formation, and to introduce CRISPR/Cas9 base editing technologies that hold vast potential for future research and clinical translation.
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46
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A panel of eGFP reporters for single base editing by APOBEC-Cas9 editosome complexes. Sci Rep 2019; 9:497. [PMID: 30679582 PMCID: PMC6345908 DOI: 10.1038/s41598-018-36739-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 11/26/2018] [Indexed: 01/16/2023] Open
Abstract
The prospect of introducing a single C-to-T change at a specific genomic location has become feasible with APOBEC-Cas9 editing technologies. We present a panel of eGFP reporters for quantification and optimization of single base editing by APOBEC-Cas9 editosomes. Reporter utility is demonstrated by comparing activities of seven human APOBEC3 enzymes and rat APOBEC1 (BE3). APOBEC3A and RNA binding-defective variants of APOBEC3B and APOBEC3H display the highest single base editing efficiencies. APOBEC3B catalytic domain complexes also elicit the lowest frequencies of adjacent off-target events. However, unbiased deep-sequencing of edited reporters shows that all editosomes have some degree of local off-target editing. Thus, further optimization is required to generate true single base editors and the eGFP reporters described here have the potential to facilitate this process.
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47
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Coelho MA, Li S, Pane LS, Firth M, Ciotta G, Wrigley JD, Cuomo ME, Maresca M, Taylor BJM. BE-FLARE: a fluorescent reporter of base editing activity reveals editing characteristics of APOBEC3A and APOBEC3B. BMC Biol 2018; 16:150. [PMID: 30593278 PMCID: PMC6309101 DOI: 10.1186/s12915-018-0617-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 12/03/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Base Editing is a precise genome editing method that uses a deaminase-Cas9 fusion protein to mutate cytidine to thymidine in target DNA in situ without the generation of a double-strand break. However, the efficient enrichment of genetically modified cells using this technique is limited by the ability to detect such events. RESULTS We have developed a Base Editing FLuorescent Activity REporter (BE-FLARE), which allows for the enrichment of cells that have undergone editing of target loci based on a fluorescence shift from BFP to GFP. We used BE-FLARE to evaluate the editing efficiency of APOBEC3A and APOBEC3B family members as alternatives deaminase domains to the rat APOBEC1 domain used in base editor 3 (BE3). We identified human APOBEC3A and APOBEC3B as highly efficient cytidine deaminases for base editing applications with unique properties. CONCLUSIONS Using BE-FLARE to report on the efficiency and precision of editing events, we outline workflows for the accelerated generation of genetically engineered cell models and the discovery of alternative base editors.
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Affiliation(s)
| | - Songyuan Li
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Luna Simona Pane
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Mike Firth
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | - Giovanni Ciotta
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | | | | | - Marcello Maresca
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
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48
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Zong Y, Song Q, Li C, Jin S, Zhang D, Wang Y, Qiu JL, Gao C. Efficient C-to-T base editing in plants using a fusion of nCas9 and human APOBEC3A. Nat Biotechnol 2018; 36:nbt.4261. [PMID: 30272679 DOI: 10.1038/nbt.4261] [Citation(s) in RCA: 228] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/25/2018] [Indexed: 02/07/2023]
Abstract
Base editors (BEs) have been used to create C-to-T substitutions in various organisms. However, editing with rat APOBEC1-based BE3 is limited to a 5-nt sequence editing window and is inefficient in GC contexts. Here, we show that a base editor fusion protein composed of Cas9 nickase and human APOBEC3A (A3A-PBE) converts cytidine to thymidine efficiently in wheat, rice and potato with a 17-nucleotide editing window at all examined sites, independent of sequence context.
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Affiliation(s)
- Yuan Zong
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qianna Song
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chao Li
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shuai Jin
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dingbo Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yanpeng Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Jin-Long Qiu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Caixia Gao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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49
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Gilani U, Shaukat M, Rasheed A, Shahid M, Tasneem F, Arshad M, Rashid N, Shahzad N. The implication of CRISPR/Cas9 genome editing technology in combating human oncoviruses. J Med Virol 2018; 91:1-13. [PMID: 30133783 DOI: 10.1002/jmv.25292] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/31/2018] [Indexed: 12/23/2022]
Abstract
It is evidenced that 20% of all tumors in humans are caused by oncoviruses, including human papilloma viruses, Epstein-Barr virus, Kaposi sarcoma virus, human polyomaviruses, human T-lymphotrophic virus-1, and hepatitis B and C viruses. Human immunodeficiency virus is also involved in carcinogenesis, although not directly, but by facilitating the infection of many oncoviruses through compromising the immune system. Being intracellular parasites with the property of establishing latency and integrating into the host genome, these viruses are a therapeutic challenge for biomedical researchers. Therefore, strategies able to target nucleotide sequences within episomal or integrated viral genomes are of prime importance in antiviral or anticancerous armamentarium. Recently, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) has emerged as a powerful genome editing tool. Standing out as a precise and efficient oncoviruses method, it has been extensively applied in recent experimental ventures in the field of molecular medicine, particularly in combating infections including tumor inducing viruses. This review is aimed at collating the experimental and clinical advances in CRISPR/Cas9 technology in terms of its applications against oncoviruses. Primarily, it will focus on the application of CRISPR/Cas9 in combating tumor viruses, types of mechanisms targeted, and the significant outcomes till date. The technical pitfalls of the CRISPR/Cas9 and the comparative approaches in evaluating this technique with respect to other available alternatives are also described briefly. Furthermore, the review also discussed the clinical aspects and the ethical, legal, and social issues associated with the use of CRISPR/Cas9.
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Affiliation(s)
- Usman Gilani
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Memoona Shaukat
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Arisha Rasheed
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Mehak Shahid
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Fareeda Tasneem
- Department of Zoology, University of the Punjab, Lahore, Pakistan
| | - Muhammad Arshad
- Institute of Microbiology, University of Agriculture, Faisalabad, Pakistan
| | - Naeem Rashid
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Naveed Shahzad
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
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50
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Wang X, Li J, Wang Y, Yang B, Wei J, Wu J, Wang R, Huang X, Chen J, Yang L. Efficient base editing in methylated regions with a human APOBEC3A-Cas9 fusion. Nat Biotechnol 2018; 36:946-949. [PMID: 30125268 DOI: 10.1038/nbt.4198] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/03/2018] [Indexed: 01/02/2023]
Abstract
Base editors (BEs) enable the generation of targeted single-nucleotide mutations, but currently used rat APOBEC1-based BEs are relatively inefficient in editing cytosines in highly methylated regions or in GpC contexts. By screening a variety of APOBEC and AID deaminases, we show that human APOBEC3A-conjugated BEs and versions we engineered to have narrower editing windows can mediate efficient C-to-T base editing in regions with high methylation levels and GpC dinucleotide content.
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Affiliation(s)
- Xiao Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jianan Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ying Wang
- Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Bei Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Jia Wei
- Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jing Wu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ruixuan Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xingxu Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jia Chen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Li Yang
- Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
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