1
|
Xun G, Zhu Z, Singh N, Lu J, Jain PK, Zhao H. Harnessing noncanonical crRNA for highly efficient genome editing. Nat Commun 2024; 15:3823. [PMID: 38714643 PMCID: PMC11076584 DOI: 10.1038/s41467-024-48012-x] [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: 03/06/2024] [Accepted: 04/18/2024] [Indexed: 05/10/2024] Open
Abstract
The CRISPR-Cas12a system is more advantageous than the widely used CRISPR-Cas9 system in terms of specificity and multiplexibility. However, its on-target editing efficiency is typically much lower than that of the CRISPR-Cas9 system. Here we improved its on-target editing efficiency by simply incorporating 2-aminoadenine (base Z, which alters canonical Watson-Crick base pairing) into the crRNA to increase the binding affinity between crRNA and its complementary DNA target. The resulting CRISPR-Cas12a (named zCRISPR-Cas12a thereafter) shows an on-target editing efficiency comparable to that of the CRISPR-Cas9 system but with much lower off-target effects than the CRISPR-Cas9 system in mammalian cells. In addition, zCRISPR-Cas12a can be used for precise gene knock-in and highly efficient multiplex genome editing. Overall, the zCRISPR-Cas12a system is superior to the CRISPR-Cas9 system, and our simple crRNA engineering strategy may be extended to other CRISPR-Cas family members as well as their derivatives.
Collapse
Affiliation(s)
- Guanhua Xun
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
| | - Zhixin Zhu
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
| | - Nilmani Singh
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
| | - Jingxia Lu
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
| | - Piyush K Jain
- Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Huimin Zhao
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA.
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA.
| |
Collapse
|
2
|
Whittaker MN, Brooks DL, Quigley A, Jindal I, Qu P, Wang JZ, Ahrens-Nicklas RC, Musunuru K, Alameh MG, Peranteau WH, Wang X. Improved specificity and efficacy of base-editing therapies with hybrid guide RNAs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.22.590531. [PMID: 38712058 PMCID: PMC11071363 DOI: 10.1101/2024.04.22.590531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Phenylketonuria (PKU), hereditary tyrosinemia type 1 (HT1), and mucopolysaccharidosis type 1 (MPSI) are autosomal recessive disorders linked to the phenylalanine hydroxylase (PAH) gene, fumarylacetoacetate hydrolase (FAH) gene, and alpha-L-iduronidase (IDUA) gene, respectively. Potential therapeutic strategies to ameliorate disease include corrective editing of pathogenic variants in the PAH and IDUA genes and, as a variant-agnostic approach, inactivation of the 4-hydroxyphenylpyruvate dioxygenase (HPD) gene, a modifier of HT1, via adenine base editing. Here we evaluated the off-target editing profiles of therapeutic lead guide RNAs (gRNAs) that, when combined with adenine base editors correct the recurrent PAH P281L variant, PAH R408W variant, or IDUA W402X variant or disrupt the HPD gene in human hepatocytes. To mitigate off-target mutagenesis, we systematically screened hybrid gRNAs with DNA nucleotide substitutions. Comprehensive and variant-aware specificity profiling of these hybrid gRNAs reveal dramatically reduced off-target editing and reduced bystander editing. Lastly, in a humanized PAH P281L mouse model, we showed that when formulated in lipid nanoparticles (LNPs) with adenine base editor mRNA, selected hybrid gRNAs revert the PKU phenotype, substantially enhance on-target editing, and reduce bystander editing in vivo. These studies highlight the utility of hybrid gRNAs to improve the safety and efficacy of base-editing therapies.
Collapse
Affiliation(s)
- Madelynn N. Whittaker
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Dominique L. Brooks
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Aidan Quigley
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ishaan Jindal
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ping Qu
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Rebecca C. Ahrens-Nicklas
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Human Genetics and Metabolism, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kiran Musunuru
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- These authors jointly directed this work: Kiran Musunuru, Mohamad-Gabriel Alameh, William H. Peranteau, and Xiao Wang
| | - Mohamad-Gabriel Alameh
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Bioengineering, George Mason University, Fairfax, VA 22030, USA
| | - William H. Peranteau
- The Center for Fetal Research, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Pediatric General, Thoracic, and Fetal Surgery, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- These authors jointly directed this work: Kiran Musunuru, Mohamad-Gabriel Alameh, William H. Peranteau, and Xiao Wang
| | - Xiao Wang
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- These authors jointly directed this work: Kiran Musunuru, Mohamad-Gabriel Alameh, William H. Peranteau, and Xiao Wang
| |
Collapse
|
3
|
Degagné É, Donohoue PD, Roy S, Scherer J, Fowler TW, Davis RT, Reyes GA, Kwong G, Stanaway M, Larroca Vicena V, Mutha D, Guo R, Edwards L, Schilling B, Shaw M, Smith SC, Kohrs B, Kufeldt HJ, Churchward G, Ruan F, Nyer DB, McSweeney K, Irby MJ, Fuller CK, Banh L, Toh MS, Thompson M, Owen AL, An Z, Gradia S, Skoble J, Bryan M, Garner E, Kanner SB. High-Specificity CRISPR-Mediated Genome Engineering in Anti-BCMA Allogeneic CAR T Cells Suppresses Allograft Rejection in Preclinical Models. Cancer Immunol Res 2024; 12:462-477. [PMID: 38345397 PMCID: PMC10985478 DOI: 10.1158/2326-6066.cir-23-0679] [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: 08/21/2023] [Revised: 11/16/2023] [Accepted: 01/31/2024] [Indexed: 04/04/2024]
Abstract
Allogeneic chimeric antigen receptor (CAR) T cell therapies hold the potential to overcome many of the challenges associated with patient-derived (autologous) CAR T cells. Key considerations in the development of allogeneic CAR T cell therapies include prevention of graft-vs-host disease (GvHD) and suppression of allograft rejection. Here, we describe preclinical data supporting the ongoing first-in-human clinical study, the CaMMouflage trial (NCT05722418), evaluating CB-011 in patients with relapsed/refractory multiple myeloma. CB-011 is a hypoimmunogenic, allogeneic anti-B-cell maturation antigen (BCMA) CAR T cell therapy candidate. CB-011 cells feature 4 genomic alterations and were engineered from healthy donor-derived T cells using a Cas12a CRISPR hybrid RNA-DNA (chRDNA) genome-editing technology platform. To address allograft rejection, CAR T cells were engineered to prevent endogenous HLA class I complex expression and overexpress a single-chain polyprotein complex composed of beta-2 microglobulin (B2M) tethered to HLA-E. In addition, T-cell receptor (TCR) expression was disrupted at the TCR alpha constant locus in combination with the site-specific insertion of a humanized BCMA-specific CAR. CB-011 cells exhibited robust plasmablast cytotoxicity in vitro in a mixed lymphocyte reaction in cell cocultures derived from patients with multiple myeloma. In addition, CB-011 cells demonstrated suppressed recognition by and cytotoxicity from HLA-mismatched T cells. CB-011 cells were protected from natural killer cell-mediated cytotoxicity in vitro and in vivo due to endogenous promoter-driven expression of B2M-HLA-E. Potent antitumor efficacy, when combined with an immune-cloaking armoring strategy to dampen allograft rejection, offers optimized therapeutic potential in multiple myeloma. See related Spotlight by Caimi and Melenhorst, p. 385.
Collapse
Affiliation(s)
| | | | - Suparna Roy
- Caribou Biosciences, Inc., Berkeley, California
| | | | | | | | | | | | | | | | - Devin Mutha
- Caribou Biosciences, Inc., Berkeley, California
| | - Raymond Guo
- Caribou Biosciences, Inc., Berkeley, California
| | | | | | - McKay Shaw
- Caribou Biosciences, Inc., Berkeley, California
| | | | - Bryan Kohrs
- Caribou Biosciences, Inc., Berkeley, California
| | | | | | - Finey Ruan
- Caribou Biosciences, Inc., Berkeley, California
| | | | | | | | | | - Lynda Banh
- Caribou Biosciences, Inc., Berkeley, California
| | | | | | | | - Zili An
- Caribou Biosciences, Inc., Berkeley, California
| | | | | | - Mara Bryan
- Caribou Biosciences, Inc., Berkeley, California
| | | | | |
Collapse
|
4
|
Pacesa M, Pelea O, Jinek M. Past, present, and future of CRISPR genome editing technologies. Cell 2024; 187:1076-1100. [PMID: 38428389 DOI: 10.1016/j.cell.2024.01.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 03/03/2024]
Abstract
Genome editing has been a transformative force in the life sciences and human medicine, offering unprecedented opportunities to dissect complex biological processes and treat the underlying causes of many genetic diseases. CRISPR-based technologies, with their remarkable efficiency and easy programmability, stand at the forefront of this revolution. In this Review, we discuss the current state of CRISPR gene editing technologies in both research and therapy, highlighting limitations that constrain them and the technological innovations that have been developed in recent years to address them. Additionally, we examine and summarize the current landscape of gene editing applications in the context of human health and therapeutics. Finally, we outline potential future developments that could shape gene editing technologies and their applications in the coming years.
Collapse
Affiliation(s)
- Martin Pacesa
- Laboratory of Protein Design and Immunoengineering, École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, Station 19, CH-1015 Lausanne, Switzerland
| | - Oana Pelea
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| |
Collapse
|
5
|
Bischof J, Hierl M, Koller U. Emerging Gene Therapeutics for Epidermolysis Bullosa under Development. Int J Mol Sci 2024; 25:2243. [PMID: 38396920 PMCID: PMC10889532 DOI: 10.3390/ijms25042243] [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: 12/21/2023] [Revised: 02/01/2024] [Accepted: 02/11/2024] [Indexed: 02/25/2024] Open
Abstract
The monogenetic disease epidermolysis bullosa (EB) is characterised by the formation of extended blisters and lesions on the patient's skin upon minimal mechanical stress. Causal for this severe condition are genetic mutations in genes, leading to the functional impairment, reduction, or absence of the encoded protein within the skin's basement membrane zone connecting the epidermis to the underlying dermis. The major burden of affected families justifies the development of long-lasting and curative therapies operating at the genomic level. The landscape of causal therapies for EB is steadily expanding due to recent breakthroughs in the gene therapy field, providing promising outcomes for patients suffering from this severe disease. Currently, two gene therapeutic approaches show promise for EB. The clinically more advanced gene replacement strategy was successfully applied in severe EB forms, leading to a ground-breaking in vivo gene therapy product named beremagene geperpavec (B-VEC) recently approved from the US Food and Drug Administration (FDA). In addition, the continuous innovations in both designer nucleases and gene editing technologies enable the efficient and potentially safe repair of mutations in EB in a potentially permanent manner, inspiring researchers in the field to define and reach new milestones in the therapy of EB.
Collapse
Affiliation(s)
- Johannes Bischof
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria; (J.B.); (M.H.)
| | - Markus Hierl
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria; (J.B.); (M.H.)
- Department of Biosciences and Medical Biology, University of Salzburg, 5020 Salzburg, Austria
| | - Ulrich Koller
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria; (J.B.); (M.H.)
| |
Collapse
|
6
|
Zhang H, Kelly K, Lee J, Echeverria D, Cooper D, Panwala R, Amrani N, Chen Z, Gaston N, Wagh A, Newby G, Xie J, Liu DR, Gao G, Wolfe S, Khvorova A, Watts J, Sontheimer E. Self-delivering, chemically modified CRISPR RNAs for AAV co-delivery and genome editing in vivo. Nucleic Acids Res 2024; 52:977-997. [PMID: 38033325 PMCID: PMC10810193 DOI: 10.1093/nar/gkad1125] [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: 03/09/2023] [Revised: 11/01/2023] [Accepted: 11/13/2023] [Indexed: 12/02/2023] Open
Abstract
Guide RNAs offer programmability for CRISPR-Cas9 genome editing but also add challenges for delivery. Chemical modification, which has been key to the success of oligonucleotide therapeutics, can enhance the stability, distribution, cellular uptake, and safety of nucleic acids. Previously, we engineered heavily and fully modified SpyCas9 crRNA and tracrRNA, which showed enhanced stability and retained activity when delivered to cultured cells in the form of the ribonucleoprotein complex. In this study, we report that a short, fully stabilized oligonucleotide (a 'protecting oligo'), which can be displaced by tracrRNA annealing, can significantly enhance the potency and stability of a heavily modified crRNA. Furthermore, protecting oligos allow various bioconjugates to be appended, thereby improving cellular uptake and biodistribution of crRNA in vivo. Finally, we achieved in vivo genome editing in adult mouse liver and central nervous system via co-delivery of unformulated, chemically modified crRNAs with protecting oligos and AAV vectors that express tracrRNA and either SpyCas9 or a base editor derivative. Our proof-of-concept establishment of AAV/crRNA co-delivery offers a route towards transient editing activity, target multiplexing, guide redosing, and vector inactivation.
Collapse
Affiliation(s)
- Han Zhang
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Karen Kelly
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jonathan Lee
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Dimas Echeverria
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - David Cooper
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Rebecca Panwala
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Nadia Amrani
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Zexiang Chen
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Nicholas Gaston
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Atish Wagh
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02139, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02139, USA
| | - Jun Xie
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Viral Vector Core, University of Massachusetts Chan Medical, School, Worcester, MA 01605, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02139, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02139, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Viral Vector Core, University of Massachusetts Chan Medical, School, Worcester, MA 01605, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Scot A Wolfe
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Anastasia Khvorova
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- NeuroNexus Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jonathan K Watts
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- NeuroNexus Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Erik J Sontheimer
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| |
Collapse
|
7
|
Newton MD, Losito M, Smith QM, Parnandi N, Taylor BJ, Akcakaya P, Maresca M, van Eijk P, Reed SH, Boulton SJ, King GA, Cuomo ME, Rueda DS. Negative DNA supercoiling induces genome-wide Cas9 off-target activity. Mol Cell 2023; 83:3533-3545.e5. [PMID: 37802026 DOI: 10.1016/j.molcel.2023.09.008] [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: 08/19/2022] [Revised: 05/30/2023] [Accepted: 09/07/2023] [Indexed: 10/08/2023]
Abstract
CRISPR-Cas9 is a powerful gene-editing technology; however, off-target activity remains an important consideration for therapeutic applications. We have previously shown that force-stretching DNA induces off-target activity and hypothesized that distortions of the DNA topology in vivo, such as negative DNA supercoiling, could reduce Cas9 specificity. Using single-molecule optical-tweezers, we demonstrate that negative supercoiling λ-DNA induces sequence-specific Cas9 off-target binding at multiple sites, even at low forces. Using an adapted CIRCLE-seq approach, we detect over 10,000 negative-supercoiling-induced Cas9 off-target double-strand breaks genome-wide caused by increased mismatch tolerance. We further demonstrate in vivo that directed local DNA distortion increases off-target activity in cells and that induced off-target events can be detected during Cas9 genome editing. These data demonstrate that Cas9 off-target activity is regulated by DNA topology in vitro and in vivo, suggesting that cellular processes, such as transcription and replication, could induce off-target activity at previously overlooked sites.
Collapse
Affiliation(s)
- Matthew D Newton
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0HS, UK; Single Molecule Imaging, MRC-London Institute of Medical Sciences, Du Cane Road, London W12 0HS, UK; DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Marialucrezia Losito
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0HS, UK; Single Molecule Imaging, MRC-London Institute of Medical Sciences, Du Cane Road, London W12 0HS, UK; Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge CB2 0AA, UK
| | - Quentin M Smith
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0HS, UK; Single Molecule Imaging, MRC-London Institute of Medical Sciences, Du Cane Road, London W12 0HS, UK
| | - Nishita Parnandi
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Benjamin J Taylor
- Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge CB2 0AA, UK
| | - Pinar Akcakaya
- Genome Engineering, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Marcello Maresca
- Genome Engineering, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Patrick van Eijk
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff CF14 4AW, UK
| | - Simon H Reed
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff CF14 4AW, UK
| | - Simon J Boulton
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Graeme A King
- Institute of Structural and Molecular Biology, University College London, London WC1E 6BT, UK.
| | | | - David S Rueda
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0HS, UK; Single Molecule Imaging, MRC-London Institute of Medical Sciences, Du Cane Road, London W12 0HS, UK.
| |
Collapse
|
8
|
Park J, Kang SJ, Go S, Lee J, An J, Chung HS, Jeong C, Ahn DR. Split-tracrRNA as an efficient tracrRNA system with an improved potential of scalability. Biomater Sci 2023; 11:3241-3251. [PMID: 36938935 DOI: 10.1039/d2bm01901a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Due to the relatively long sequence, tracrRNAs are chemically less synthesizable than crRNAs, leading to limited scalability of RNA guides for CRISPR-Cas9 systems. To develop shortened versions of RNA guides with improved cost-effectiveness, we have developed a split-tracrRNA system by nicking the 67-mer tracrRNA (tracrRNA(67)). Cellular gene editing assays and in vitro DNA cleavage assays revealed that the position of the nick is critical for maintaining the activity of tracrRNA(67). TracrRNA(41 + 23), produced by nicking in stem loop 2, showed gene editing efficiency and specificity comparable to those of tracrRNA(67). Removal of the loop of stem loop 2 was further possible without compromising the efficiency and specificity when the stem duplex was stabilized via a high GC content. Binding assays and single-molecule experiments suggested that efficient split-tracrRNAs could be engineered as long as their binding affinity to Cas9 and their reaction kinetics are similar to those of tracrRNA(67).
Collapse
Affiliation(s)
- Jihyun Park
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea.
| | - Seong Jae Kang
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea.
| | - Seulgi Go
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea. .,Department of Pharmacology, College of Medicine, Korea University, Seoul 02841, Korea
| | - Jeongmin Lee
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea. .,Department of Life Sciences, Korea University, Seoul 02841, South Korea
| | - Jinsu An
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea. .,Division of Biomedical Science and Technology, KIST School, University of Science and Technology (UST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea
| | - Hak Suk Chung
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea. .,Division of Biomedical Science and Technology, KIST School, University of Science and Technology (UST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea
| | - Cherlhyun Jeong
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea. .,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, South Korea
| | - Dae-Ro Ahn
- Chemical and Biological Integrative Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea. .,Division of Biomedical Science and Technology, KIST School, University of Science and Technology (UST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Korea
| |
Collapse
|
9
|
Hoy A, Zheng YY, Sheng J, Royzen M. Bio-Orthogonal Chemistry Conjugation Strategy Facilitates Investigation of N-methyladenosine and Thiouridine Guide RNA Modifications on CRISPR Activity. CRISPR J 2022; 5:787-798. [PMID: 36378256 PMCID: PMC9805849 DOI: 10.1089/crispr.2022.0065] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The CRISPR-Cas9 system is an important genome editing tool that holds enormous potential toward the treatment of human genetic diseases. Clinical success of CRISPR technology is dependent on the incorporation of modifications into the single-guide RNA (sgRNA). However, chemical synthesis of modified sgRNAs, which are over 100 nucleotides in length, is difficult and low-yielding. We developed a conjugation strategy that utilized bio-orthogonal chemistry to efficiently assemble functional sgRNAs containing nucleobase modifications. The described approach entails the chemical synthesis of two shorter RNA oligonucleotides: a 31-mer containing tetrazine (Tz) group and a 70-mer modified with a trans-cyclooctene (TCO) moiety. The two oligonucleotides were conjugated to form functional sgRNAs. The two-component conjugation methodology was utilized to synthesize a library of sgRNAs containing nucleobase modifications such as N1-methyladenosine (m1A), N6-methyladenosine (m6A), 2-thiouridine (s2U), and 4-thiouridine (s4U). The impact of these RNA modifications on overall CRISPR activity were investigated in vitro and in Cas9-expressing HEK293T cells.
Collapse
Affiliation(s)
- Alyssa Hoy
- Department of Chemistry, University at Albany, SUNY, Albany, New York, USA
| | - Ya Ying Zheng
- Department of Chemistry, University at Albany, SUNY, Albany, New York, USA
| | - Jia Sheng
- Department of Chemistry, University at Albany, SUNY, Albany, New York, USA.,Address correspondence to: Jia Sheng, Department of Chemistry, University at Albany, SUNY, 1400 Washington Ave., Albany, NY 12222, USA,
| | - Maksim Royzen
- Department of Chemistry, University at Albany, SUNY, Albany, New York, USA.,Address correspondence to: Maksim Royzen, Department of Chemistry, University at Albany, SUNY, 1400 Washington Ave., Albany, NY 12222, USA,
| |
Collapse
|
10
|
Sakovina L, Vokhtantsev I, Vorobyeva M, Vorobyev P, Novopashina D. Improving Stability and Specificity of CRISPR/Cas9 System by Selective Modification of Guide RNAs with 2'-fluoro and Locked Nucleic Acid Nucleotides. Int J Mol Sci 2022; 23:13460. [PMID: 36362256 PMCID: PMC9655745 DOI: 10.3390/ijms232113460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 10/27/2022] [Accepted: 11/02/2022] [Indexed: 09/01/2023] Open
Abstract
The genome editing approach using the components of the CRISPR/Cas system has found wide application in molecular biology, fundamental medicine and genetic engineering. A promising method is to increase the efficacy and specificity of CRISPR/Cas-based genome editing systems by modifying their components. Here, we designed and chemically synthesized guide RNAs (crRNA, tracrRNA and sgRNA) containing modified nucleotides (2'-O-methyl, 2'-fluoro, LNA-locked nucleic acid) or deoxyribonucleotides in certain positions. We compared their resistance to nuclease digestion and examined the DNA cleavage efficacy of the CRISPR/Cas9 system guided by these modified guide RNAs. The replacement of ribonucleotides with 2'-fluoro modified or LNA nucleotides increased the lifetime of the crRNAs, while other types of modification did not change their nuclease resistance. Modification of crRNA or tracrRNA preserved the efficacy of the CRISPR/Cas9 system. Otherwise, the CRISPR/Cas9 systems with modified sgRNA showed a remarkable loss of DNA cleavage efficacy. The kinetic constant of DNA cleavage was higher for the system with 2'-fluoro modified crRNA. The 2'-modification of crRNA also decreased the off-target effect upon in vitro dsDNA cleavage.
Collapse
Affiliation(s)
- Lubov Sakovina
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
- Faculty of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Ivan Vokhtantsev
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
- Faculty of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Mariya Vorobyeva
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
| | - Pavel Vorobyev
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
| | - Darya Novopashina
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia
| |
Collapse
|
11
|
Okafor IC, Choi J, Ha T. Single molecule methods for studying CRISPR Cas9-induced DNA unwinding. Methods 2022; 204:319-326. [PMID: 34767923 DOI: 10.1016/j.ymeth.2021.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/12/2021] [Accepted: 11/03/2021] [Indexed: 12/12/2022] Open
Abstract
Like helicases, CRISPR proteins such as Cas9 and Cas12a unwind DNA, but unlike helicases, these CRISPR proteins do not use ATP. Instead, they use binding energy to melt DNA locally and then utilize basepairing between guide (g) RNA and target strand to continue to unwind the DNA. CRISPR Cas9 is the most widely used tool for genome editing applications. The Cas9 endonuclease forms a complex with gRNA that can be programmed to bind a specific 20 bp segment of DNA, the protospacer. If there is enough of a sequence match between sgRNA and protospacer, Cas9 undergoes a conformational change, which activates the two nuclease domains, causing a double strand break in the DNA. We can use single-molecule FRET (smFRET) to probe the state of DNA unwinding as a function of mismatches between sgRNA and DNA. This approach can also be used to probe the position of Cas9's HNH domain before and after cleavage.
Collapse
Affiliation(s)
- Ikenna C Okafor
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Janice Choi
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Howard Hughes Medical Institute, Baltimore, MD, USA.
| |
Collapse
|
12
|
Saito-Tarashima N, Ueno M, Murai A, Matsuo A, Minakawa N. Cas9-mediated DNA cleavage guided by enzymatically prepared 4'-thio-modified RNA. Org Biomol Chem 2022; 20:5245-5248. [PMID: 35726625 DOI: 10.1039/d2ob00742h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
CRISPR-Cas9-mediated DNA editing relies on guide RNAs (gRNAs) that direct site-specific DNA cleavage by the Cas endonuclease. Because natural gRNA is susceptible to intracellular degradation, it is desirable to chemically protect it for efficient editing. Using 4'-thioribonucleoside 5'-triphosphates and T7 transcription, we have prepared 4'-thio-modified gRNAs that guide Cas9-mediated DNA cleavage. This approach is a simple way to obtain chemically modified RNA suitable for CRISPR-Cas9 DNA editing.
Collapse
Affiliation(s)
- Noriko Saito-Tarashima
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Mana Ueno
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Akiho Murai
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Ayako Matsuo
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| | - Noriaki Minakawa
- Graduate School of Pharmaceutical Science, Tokushima University, Shomachi 1-78-1, Tokushima, 770-8505, Japan.
| |
Collapse
|
13
|
Chen Z, Devi G, Arif A, Zamore PD, Sontheimer EJ, Watts JK. Tetrazine-Ligated CRISPR sgRNAs for Efficient Genome Editing. ACS Chem Biol 2022; 17:1045-1050. [PMID: 35446558 PMCID: PMC9127786 DOI: 10.1021/acschembio.2c00116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/23/2022] [Indexed: 12/19/2022]
Abstract
CRISPR-Cas technology has revolutionized genome editing. Its broad and fast-growing application in biomedical research and therapeutics has led to increased demand for guide RNAs. The synthesis of chemically modified single-guide RNAs (sgRNAs) containing >100 nucleotides remains a bottleneck. Here we report the development of a tetrazine ligation method for the preparation of sgRNAs. A tetrazine moiety on the 3'-end of the crRNA and a norbornene moiety on the 5'-end of the tracrRNA enable successful ligation between crRNA and tracrRNA to form sgRNA under mild conditions. Tetrazine-ligated sgRNAs allow efficient genome editing of reporter and endogenous loci in human cells. High-efficiency editing requires structural optimization of the linker.
Collapse
Affiliation(s)
- Zexiang Chen
- RNA
Therapeutics Institute, University of Massachusetts
Chan Medical School, Worcester, Massachusetts 01605, United States
| | - Gitali Devi
- RNA
Therapeutics Institute, University of Massachusetts
Chan Medical School, Worcester, Massachusetts 01605, United States
| | - Amena Arif
- RNA
Therapeutics Institute, University of Massachusetts
Chan Medical School, Worcester, Massachusetts 01605, United States
| | - Phillip D. Zamore
- RNA
Therapeutics Institute, University of Massachusetts
Chan Medical School, Worcester, Massachusetts 01605, United States
- Howard
Hughes Medical Institute, University of
Massachusetts Chan Medical School, Worcester, Massachusetts 01605, United States
| | - Erik J. Sontheimer
- RNA
Therapeutics Institute, University of Massachusetts
Chan Medical School, Worcester, Massachusetts 01605, United States
- Program
in Molecular Medicine, University of Massachusetts
Chan Medical School, Worcester, Massachusetts 01605, United States
| | - Jonathan K. Watts
- RNA
Therapeutics Institute, University of Massachusetts
Chan Medical School, Worcester, Massachusetts 01605, United States
- Department
of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts 01605, United States
| |
Collapse
|
14
|
Park H, Osman EA, Cromwell CR, St Laurent CD, Liu Y, Kitova EN, Klassen JS, Hubbard BP, Macauley MS, Gibbs JM. CRISPR-Click Enables Dual-Gene Editing with Modular Synthetic sgRNAs. Bioconjug Chem 2022; 33:858-868. [PMID: 35436106 DOI: 10.1021/acs.bioconjchem.2c00106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gene-editing systems such as CRISPR-Cas9 readily enable individual gene phenotypes to be studied through loss of function. However, in certain instances, gene compensation can obfuscate the results of these studies, necessitating the editing of multiple genes to properly identify biological pathways and protein function. Performing multiple genetic modifications in cells remains difficult due to the requirement for multiple rounds of gene editing. While fluorescently labeled guide RNAs (gRNAs) are routinely used in laboratories for targeting CRISPR-Cas9 to disrupt individual loci, technical limitations in single gRNA (sgRNA) synthesis hinder the expansion of this approach to multicolor cell sorting. Here, we describe a modular strategy for synthesizing sgRNAs where each target sequence is conjugated to a unique fluorescent label, which enables fluorescence-activated cell sorting (FACS) to isolate cells that incorporate the desired combination of gene-editing constructs. We demonstrate that three short strands of RNA functionalized with strategically placed 5'-azide and 3'-alkyne terminal deoxyribonucleotides can be assembled in a one-step, template-assisted, copper-catalyzed alkyne-azide cycloaddition to generate fully functional, fluorophore-modified sgRNAs. Using these synthetic sgRNAs in combination with FACS, we achieved selective cleavage of two targeted genes, either separately as a single-color experiment or in combination as a dual-color experiment. These data indicate that our strategy for generating double-clicked sgRNA allows for Cas9 activity in cells. By minimizing the size of each RNA fragment to 41 nucleotides or less, this strategy is well suited for custom, scalable synthesis of sgRNAs.
Collapse
Affiliation(s)
- Hansol Park
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Eiman A Osman
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | | | - Chris D St Laurent
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yuning Liu
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Elena N Kitova
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - John S Klassen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Basil P Hubbard
- Department of Pharmacology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Matthew S Macauley
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2R7, Canada
| | - Julianne M Gibbs
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| |
Collapse
|
15
|
Saito-Tarashima N, Murai A, Minakawa N. Rewriting the Central Dogma with Synthetic Genetic Polymers. Chem Pharm Bull (Tokyo) 2022; 70:310-315. [DOI: 10.1248/cpb.c21-00960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Akiho Murai
- Graduate School of Pharmaceutical Science, Tokushima University
| | | |
Collapse
|
16
|
Guide RNAs containing universal bases enable Cas9/Cas12a recognition of polymorphic sequences. Nat Commun 2022; 13:1617. [PMID: 35338140 PMCID: PMC8956631 DOI: 10.1038/s41467-022-29202-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 03/03/2022] [Indexed: 12/15/2022] Open
Abstract
CRISPR/Cas complexes enable precise gene editing in a wide variety of organisms. While the rigid identification of DNA sequences by these systems minimizes the potential for off-target effects, it consequently poses a problem for the recognition of sequences containing naturally occurring polymorphisms. The presence of genetic variance such as single nucleotide polymorphisms (SNPs) in a gene sequence can compromise the on-target activity of CRISPR systems. Thus, when attempting to target multiple variants of a human gene, or evolved variants of a pathogen gene using a single guide RNA, more flexibility is desirable. Here, we demonstrate that Cas9 can tolerate the inclusion of universal bases in individual guide RNAs, enabling simultaneous targeting of polymorphic sequences. Crucially, we find that specificity is selectively degenerate at the site of universal base incorporation, and remains otherwise preserved. We demonstrate the applicability of this technology to targeting multiple naturally occurring human SNPs with individual guide RNAs and to the design of Cas12a/Cpf1-based DETECTR probes capable of identifying multiple evolved variants of the HIV protease gene. Our findings extend the targeting capabilities of CRISPR/Cas systems beyond their canonical spacer sequences and highlight a use of natural and synthetic universal bases.
Collapse
|
17
|
Newton MD, Taylor BJ, Cuomo ME, Rueda DS. CRISPR/Cas9 On- and Off-Target Activity Using Correlative Force and Fluorescence Single-Molecule Microscopy. Methods Mol Biol 2022; 2478:349-378. [PMID: 36063327 DOI: 10.1007/978-1-0716-2229-2_13] [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] [Indexed: 06/15/2023]
Abstract
The discovery of CRISPR/Cas9 as an easily programmable endonuclease heralds a new era of genetic manipulation. With this comes the prospect of novel gene therapy approaches, and the potential to cure previously untreatable genetic diseases. However, reports of spurious off-target editing by CRISPR/Cas9 pose a significant hurdle to realizing this potential. A deeper understanding of the factors that affect Cas9 specificity is vital for development of safe and efficient therapeutics. Here, we describe methods for the use of optical tweezers combined with confocal fluorescence microscopy and microfluidics for the analysis of on- and off-target activity of Cas9 activity.
Collapse
Affiliation(s)
- Matthew D Newton
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
- Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London, UK
| | | | | | - David S Rueda
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK.
- Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London, UK.
| |
Collapse
|
18
|
Ageely EA, Chilamkurthy R, Jana S, Abdullahu L, O'Reilly D, Jensik PJ, Damha MJ, Gagnon KT. Gene editing with CRISPR-Cas12a guides possessing ribose-modified pseudoknot handles. Nat Commun 2021; 12:6591. [PMID: 34782635 PMCID: PMC8593028 DOI: 10.1038/s41467-021-26989-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 11/01/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas12a is a leading technology for development of model organisms, therapeutics, and diagnostics. These applications could benefit from chemical modifications that stabilize or tune enzyme properties. Here we chemically modify ribonucleotides of the AsCas12a CRISPR RNA 5' handle, a pseudoknot structure that mediates binding to Cas12a. Gene editing in human cells required retention of several native RNA residues corresponding to predicted 2'-hydroxyl contacts. Replacing these RNA residues with a variety of ribose-modified nucleotides revealed 2'-hydroxyl sensitivity. Modified 5' pseudoknots with as little as six out of nineteen RNA residues, with phosphorothioate linkages at remaining RNA positions, yielded heavily modified pseudoknots with robust cell-based editing. High trans activity was usually preserved with cis activity. We show that the 5' pseudoknot can tolerate near complete modification when design is guided by structural and chemical compatibility. Rules for modification of the 5' pseudoknot should accelerate therapeutic development and be valuable for CRISPR-Cas12a diagnostics.
Collapse
Affiliation(s)
- Eman A Ageely
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL, USA
| | - Ramadevi Chilamkurthy
- Department of Biochemistry and Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, IL, USA
| | - Sunit Jana
- Department of Chemistry, McGill University, Montreal, Canada
| | | | - Daniel O'Reilly
- Department of Chemistry, McGill University, Montreal, Canada
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Philip J Jensik
- Department of Physiology, School of Medicine, Southern Illinois University, Carbondale, IL, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Canada.
| | - Keith T Gagnon
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, IL, USA.
- Department of Biochemistry and Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, IL, USA.
| |
Collapse
|
19
|
Allen D, Rosenberg M, Hendel A. Using Synthetically Engineered Guide RNAs to Enhance CRISPR Genome Editing Systems in Mammalian Cells. Front Genome Ed 2021; 2:617910. [PMID: 34713240 PMCID: PMC8525374 DOI: 10.3389/fgeed.2020.617910] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/14/2020] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas9 is quickly revolutionizing the way we approach gene therapy. CRISPR-Cas9 is a complexed, two-component system using a short guide RNA (gRNA) sequence to direct the Cas9 endonuclease to the target site. Modifying the gRNA independent of the Cas9 protein confers ease and flexibility to improve the CRISPR-Cas9 system as a genome-editing tool. gRNAs have been engineered to improve the CRISPR system's overall stability, specificity, safety, and versatility. gRNAs have been modified to increase their stability to guard against nuclease degradation, thereby enhancing their efficiency. Additionally, guide specificity has been improved by limiting off-target editing. Synthetic gRNA has been shown to ameliorate inflammatory signaling caused by the CRISPR system, thereby limiting immunogenicity and toxicity in edited mammalian cells. Furthermore, through conjugation with exogenous donor DNA, engineered gRNAs have been shown to improve homology-directed repair (HDR) efficiency by ensuring donor proximity to the edited site. Lastly, synthetic gRNAs attached to fluorescent labels have been developed to enable highly specific nuclear staining and imaging, enabling mechanistic studies of chromosomal dynamics and genomic mapping. Continued work on chemical modification and optimization of synthetic gRNAs will undoubtedly lead to clinical and therapeutic benefits and, ultimately, routinely performed CRISPR-based therapies.
Collapse
Affiliation(s)
- Daniel Allen
- Institute of Nanotechnology and Advanced Materials, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Michael Rosenberg
- Institute of Nanotechnology and Advanced Materials, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Ayal Hendel
- Institute of Nanotechnology and Advanced Materials, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| |
Collapse
|
20
|
Donohoue PD, Pacesa M, Lau E, Vidal B, Irby MJ, Nyer DB, Rotstein T, Banh L, Toh MS, Gibson J, Kohrs B, Baek K, Owen ALG, Slorach EM, van Overbeek M, Fuller CK, May AP, Jinek M, Cameron P. Conformational control of Cas9 by CRISPR hybrid RNA-DNA guides mitigates off-target activity in T cells. Mol Cell 2021; 81:3637-3649.e5. [PMID: 34478654 DOI: 10.1016/j.molcel.2021.07.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 05/28/2021] [Accepted: 07/28/2021] [Indexed: 12/26/2022]
Abstract
The off-target activity of the CRISPR-associated nuclease Cas9 is a potential concern for therapeutic genome editing applications. Although high-fidelity Cas9 variants have been engineered, they exhibit varying efficiencies and have residual off-target effects, limiting their applicability. Here, we show that CRISPR hybrid RNA-DNA (chRDNA) guides provide an effective approach to increase Cas9 specificity while preserving on-target editing activity. Across multiple genomic targets in primary human T cells, we show that 2'-deoxynucleotide (dnt) positioning affects guide activity and specificity in a target-dependent manner and that this can be used to engineer chRDNA guides with substantially reduced off-target effects. Crystal structures of DNA-bound Cas9-chRDNA complexes reveal distorted guide-target duplex geometry and allosteric modulation of Cas9 conformation. These structural effects increase specificity by perturbing DNA hybridization and modulating Cas9 activation kinetics to disfavor binding and cleavage of off-target substrates. Overall, these results pave the way for utilizing customized chRDNAs in clinical applications.
Collapse
Affiliation(s)
- Paul D Donohoue
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA.
| | - Martin Pacesa
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Elaine Lau
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Bastien Vidal
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Matthew J Irby
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - David B Nyer
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Tomer Rotstein
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Lynda Banh
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Mckenzi S Toh
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Jason Gibson
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Bryan Kohrs
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Kevin Baek
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Arthur L G Owen
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Euan M Slorach
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Megan van Overbeek
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Christopher K Fuller
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA
| | - Andrew P May
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA.
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| | - Peter Cameron
- Caribou Biosciences, Inc., 2929 Seventh Street, Suite 105, Berkeley, CA 94710, USA.
| |
Collapse
|
21
|
Sledzinski P, Dabrowska M, Nowaczyk M, Olejniczak M. Paving the way towards precise and safe CRISPR genome editing. Biotechnol Adv 2021; 49:107737. [PMID: 33785374 DOI: 10.1016/j.biotechadv.2021.107737] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 03/11/2021] [Accepted: 03/19/2021] [Indexed: 12/13/2022]
Abstract
As the possibilities of CRISPR-Cas9 technology have been revealed, we have entered a new era of research aimed at increasing its specificity and safety. This stage of technology development is necessary not only for its wider application in the clinic but also in basic research to better control the process of genome editing. Research during the past eight years has identified some factors influencing editing outcomes and led to the development of highly specific endonucleases, modified guide RNAs and computational tools supporting experiments. More recently, large-scale experiments revealed a previously overlooked feature: Cas9 can generate reproducible mutation patterns. As a result, it has become apparent that Cas9-induced double-strand break (DSB) repair is nonrandom and can be predicted to some extent. Here, we review the present state of knowledge regarding the specificity and safety of CRISPR-Cas9 technology to define gRNA, protein and target-related problems and solutions. These issues include sequence-specific off-target effects, immune responses, genetic variation and chromatin accessibility. We present new insights into the role of DNA repair in genome editing and define factors influencing editing outcomes. In addition, we propose practical guidelines for increasing the specificity of editing and discuss novel perspectives in improvement of this technology.
Collapse
Affiliation(s)
- Pawel Sledzinski
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland
| | - Magdalena Dabrowska
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland
| | - Mateusz Nowaczyk
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland
| | - Marta Olejniczak
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Noskowskiego 12/14, 61-704, Poland.
| |
Collapse
|
22
|
Zhang Y, Wang Q, Wang J, Tang X. Chemical Modification and Transformation Strategies of Guide RNAs in CRISPR-Cas9 Gene Editing Systems. Chempluschem 2021; 86:587-600. [PMID: 33830675 DOI: 10.1002/cplu.202000785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/13/2021] [Indexed: 12/19/2022]
Abstract
The CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 (CRISPR-associated protein 9) is a most powerful tool and has been widely used in gene editing and gene regulation since its discovery. However, wild-type CRISPR-Cas9 suffers from off-target effects and low editing efficiency. To overcome these limitations, engineered Cas9 proteins have been extensively investigated. In addition to Cas9 protein engineering, chemically synthesized guide RNAs have been developed to improve the efficiency and specificity of genome editing as well as spatiotemporal controllability, which broadens the biological applications of CRISPR-Cas9 gene editing system and increases their potentials as therapeutics. In this review, we summarize the latest research advances in remodeling guide RNAs through length optimization, chemical modifications, and conditional control, as well as their powerful applications in gene editing tools and promising therapeutic agents.
Collapse
Affiliation(s)
- Yu Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, No. 38, Xueyuan Rd., Beijing, 100191, P. R. China
| | - Qian Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, No. 38, Xueyuan Rd., Beijing, 100191, P. R. China
| | - Jing Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, No. 38, Xueyuan Rd., Beijing, 100191, P. R. China
| | - Xinjing Tang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, No. 38, Xueyuan Rd., Beijing, 100191, P. R. China
| |
Collapse
|
23
|
Feng W, Newbigging AM, Tao J, Cao Y, Peng H, Le C, Wu J, Pang B, Li J, Tyrrell DL, Zhang H, Le XC. CRISPR technology incorporating amplification strategies: molecular assays for nucleic acids, proteins, and small molecules. Chem Sci 2021; 12:4683-4698. [PMID: 34163728 PMCID: PMC8179559 DOI: 10.1039/d0sc06973f] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/19/2021] [Indexed: 12/19/2022] Open
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) protein systems have transformed the field of genome editing and transcriptional modulation. Progress in CRISPR-Cas technology has also advanced molecular detection of diverse targets, ranging from nucleic acids to proteins. Incorporating CRISPR-Cas systems with various nucleic acid amplification strategies enables the generation of amplified detection signals, enrichment of low-abundance molecular targets, improvements in analytical specificity and sensitivity, and development of point-of-care (POC) diagnostic techniques. These systems take advantage of various Cas proteins for their particular features, including RNA-guided endonuclease activity, sequence-specific recognition, multiple turnover trans-cleavage activity of Cas12 and Cas13, and unwinding and nicking ability of Cas9. Integrating a CRISPR-Cas system after nucleic acid amplification improves detection specificity due to RNA-guided recognition of specific sequences of amplicons. Incorporating CRISPR-Cas before nucleic acid amplification enables enrichment of rare and low-abundance nucleic acid targets and depletion of unwanted abundant nucleic acids. Unwinding of dsDNA to ssDNA using CRISPR-Cas9 at a moderate temperature facilitates techniques for achieving isothermal exponential amplification of nucleic acids. A combination of CRISPR-Cas systems with functional nucleic acids (FNAs) and molecular translators enables the detection of non-nucleic acid targets, such as proteins, metal ions, and small molecules. Successful integrations of CRISPR technology with nucleic acid amplification techniques result in highly sensitive and rapid detection of SARS-CoV-2, the virus that causes the COVID-19 pandemic.
Collapse
Affiliation(s)
- Wei Feng
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| | - Ashley M Newbigging
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| | - Jeffrey Tao
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| | - Yiren Cao
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| | - Hanyong Peng
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| | - Connie Le
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2E1 Canada
| | - Jinjun Wu
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| | - Bo Pang
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
- School of Public Health, Jilin University 1163 Xinmin Street Changchun Jilin 130021 China
| | - Juan Li
- School of Public Health, Jilin University 1163 Xinmin Street Changchun Jilin 130021 China
| | - D Lorne Tyrrell
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2E1 Canada
| | - Hongquan Zhang
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| | - X Chris Le
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta Edmonton Alberta T6G 2G3 Canada +1-780-492-7800 +1-780-492-6416
| |
Collapse
|
24
|
Taemaitree L, Shivalingam A, El-Sagheer AH, Brown T. "Split-and-Click" sgRNA. Methods Mol Biol 2021; 2162:61-78. [PMID: 32926378 DOI: 10.1007/978-1-0716-0687-2_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] [Indexed: 06/11/2023]
Abstract
CRISPR-Cas9 gene editing is dependent on a programmable single guide RNA (sgRNA) that directs Cas9 endonuclease activity. This RNA is often generated by enzymatic reactions, however the process becomes time-consuming as the number of sgRNAs increases and does not allow the incorporation of chemical modifications that can improve or expand the functionality of CRISPR. Solid-phase RNA synthesis can overcome these issues, but highly pure full-length sgRNA remains at the limits of current synthetic methods. Here, we demonstrate a "split-and-click" approach that separates the sgRNA into its two smaller components - a DNA-targeting ~20-mer RNA and a constant Cas9-binding 79-mer RNA - and chemically ligates them together to generate a biologically active sgRNA. The benefits of our approach lie in the stringent purification of the DNA-targeting 20-mer, the reduced synthesis of the constant 79-mer each time a new sgRNA is required, and the rapid access it provides to custom libraries of sgRNAs.
Collapse
Affiliation(s)
- Lapatrada Taemaitree
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Arun Shivalingam
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Afaf H El-Sagheer
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
- Chemistry Branch, Department of Science and Mathematics, Faculty of Petroleum and Mining Engineering, Suez University, Suez, Egypt
| | - Tom Brown
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK.
| |
Collapse
|
25
|
Chen Q, Zhang Y, Yin H. Recent advances in chemical modifications of guide RNA, mRNA and donor template for CRISPR-mediated genome editing. Adv Drug Deliv Rev 2021; 168:246-258. [PMID: 33122087 DOI: 10.1016/j.addr.2020.10.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/14/2022]
Abstract
The discovery and applications of clustered regularly interspaced short palindromic repeat (CRISPR) systems have revolutionized our ability to track and manipulate specific nucleic acid sequences in many cell types of various organisms. The robustness and simplicity of these platforms have rapidly extended their applications from basic research to the development of therapeutics. However, many hurdles remain on the path to translation of the CRISPR systems to therapeutic applications: efficient delivery, detectable off-target effects, potential immunogenicity, and others. Chemical modifications provide a variety of protection options for guide RNA, Cas9 mRNA and donor templates. For example, chemically modified gRNA demonstrated enhanced on-target editing efficiency, minimized immune response and decreased off-target genome editing. In this review, we summarize the use of chemically modified nucleotides for CRISPR-mediated genome editing and emphasize open questions that remain to be addressed in clinical applications.
Collapse
Affiliation(s)
- Qiubing Chen
- Department of Urology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China; Department of Pathology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China
| | - Ying Zhang
- Medical Research Institute, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China.
| | - Hao Yin
- Department of Urology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China; Department of Pathology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China.
| |
Collapse
|
26
|
Abstract
CRISPR-associated nuclease (Cas) has been widely applied to modify the genomes of various cell types. As RNA-guided endonucleases, Cas enzymes can target different genomic sequences simply by changing the guide sequence of the CRISPR RNA (crRNA) or single guide RNA (sgRNA). Recent studies have demonstrated that DNA-RNA chimeric crRNA or sgRNA can efficiently guide the Cas9 protein for genome editing with reduced off-target effects. This chapter aims to describe a procedure for using chimeric RNA to modify the genomes of mammalian cells.
Collapse
Affiliation(s)
- Shuhan Lu
- Department of Pathology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
- Department of Urology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
| | - Ying Zhang
- Medical Research Institute, Renmin Hospital of Wuhan University, Wuhan, China.
| | - Hao Yin
- Department of Pathology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
- Department of Urology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
| |
Collapse
|
27
|
Park J, Choi J, Duong MTH, Ahn H, Hong SW, Hwang GT, An J, Chung HS, Ahn D. Chimeric
crRNAs
Retaining Activity of Cas12a with Potential to Improve Specificity. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jihyun Park
- Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST) Hwarangno 14‐gil 5, Seongbuk‐gu, Seoul 02792 Republic of Korea
| | - Jaewoo Choi
- Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST) Hwarangno 14‐gil 5, Seongbuk‐gu, Seoul 02792 Republic of Korea
| | - Men Thi Hoai Duong
- Department of Pharmacy Dongguk University‐Seoul 32 Dongguk‐ro, Ilsandong‐gu, Goyang Gyeonggi 13024 Republic of Korea
| | - Hee‐Chul Ahn
- Department of Pharmacy Dongguk University‐Seoul 32 Dongguk‐ro, Ilsandong‐gu, Goyang Gyeonggi 13024 Republic of Korea
| | - Seung Woo Hong
- Department of Chemistry Kyungpook National University 80 Daehakro, Bukgu, Daegu 41566 Republic of Korea
| | - Gil Tae Hwang
- Department of Chemistry Kyungpook National University 80 Daehakro, Bukgu, Daegu 41566 Republic of Korea
| | - Jinsu An
- Division of Bio‐Medical Science and Technology KIST School, University of Science and Technology (UST) Seoul 02792 Republic of Korea
| | - Hak Suk Chung
- Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST) Hwarangno 14‐gil 5, Seongbuk‐gu, Seoul 02792 Republic of Korea
- Division of Bio‐Medical Science and Technology KIST School, University of Science and Technology (UST) Seoul 02792 Republic of Korea
| | - Dae‐Ro Ahn
- Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST) Hwarangno 14‐gil 5, Seongbuk‐gu, Seoul 02792 Republic of Korea
- Division of Bio‐Medical Science and Technology KIST School, University of Science and Technology (UST) Seoul 02792 Republic of Korea
| |
Collapse
|
28
|
McKenzie LK, El-Khoury R, Thorpe JD, Damha MJ, Hollenstein M. Recent progress in non-native nucleic acid modifications. Chem Soc Rev 2021; 50:5126-5164. [DOI: 10.1039/d0cs01430c] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While Nature harnesses RNA and DNA to store, read and write genetic information, the inherent programmability, synthetic accessibility and wide functionality of these nucleic acids make them attractive tools for use in a vast array of applications.
Collapse
Affiliation(s)
- Luke K. McKenzie
- Institut Pasteur
- Department of Structural Biology and Chemistry
- Laboratory for Bioorganic Chemistry of Nucleic Acids
- CNRS UMR3523
- 75724 Paris Cedex 15
| | | | | | | | - Marcel Hollenstein
- Institut Pasteur
- Department of Structural Biology and Chemistry
- Laboratory for Bioorganic Chemistry of Nucleic Acids
- CNRS UMR3523
- 75724 Paris Cedex 15
| |
Collapse
|
29
|
Cromwell CR, Hubbard BP. In Vitro Assays for Comparing the Specificity of First- and Next-Generation CRISPR/Cas9 Systems. Methods Mol Biol 2021; 2162:215-232. [PMID: 32926385 DOI: 10.1007/978-1-0716-0687-2_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
CRISPR/Cas9 has revolutionized the ability to edit cellular DNA and is poised to transform the treatment of genetic diseases. One of the major concerns regarding its therapeutic use is the potential for off-target DNA cleavage, which could have detrimental consequences in vivo. To circumvent this, a number of strategies have been employed to develop next-generation CRISPR/Cas9 systems with improved specificity. These include the development of new protein variants of Cas9, as well as chemically modified guide RNA molecules. Here, we provide detailed protocols for two in vitro methods that enable the specificity of first- and next-generation CRISPR/Cas9 systems to be compared, and we demonstrate their applicability to evaluating chemically modified guide RNAs. One of these assays allows the specificity of different guide RNA/Cas9 complexes to be compared on a set of known off-target DNA sequences, while the second provides a broad specificity profile based on cleavage of a massive library of potential off-target DNA sequences. Collectively, these assays may be used to evaluate the specificity of different CRISPR/Cas9 systems on any DNA target sequence in a time- and cost-effective manner.
Collapse
Affiliation(s)
| | - Basil P Hubbard
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
30
|
Wang K, Wang XY, Gao GJ, Ren XW, Cai XY, Yu QK, Xing S, Zhu B. Multistimuli responsive RNA amphiphilic polymeric assembly constructed by calixpyridinium-based supramolecular interactions. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.131620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
31
|
Wang Y, Liu Y, Xie F, Lin J, Xu L. Photocontrol of CRISPR/Cas9 function by site-specific chemical modification of guide RNA. Chem Sci 2020; 11:11478-11484. [PMID: 34094391 PMCID: PMC8162494 DOI: 10.1039/d0sc04343e] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/25/2020] [Indexed: 12/27/2022] Open
Abstract
The function of CRISPR/Cas9 can be conditionally controlled by the rational engineering of guide RNA (gRNA) to target the gene of choice for precise manipulation of the genome. Particularly, chemically modified gRNA that can be activated by using specific stimuli provides a unique tool to expand the versatility of conditional control. Herein, unlike previous engineering of gRNA that generally focused on the RNA part only but neglected RNA-protein interactions, we aimed at the interactive sites between 2'-OH of ribose in the seed region of gRNA and the Cas9 protein and identified that chemical modifications at specific sites could be utilized to regulate the Cas9 activity. By introducing a photolabile group at these specific sites, we achieved optical control of Cas9 activity without disrupting the Watson-Crick base pairing. We further examined our design through CRISPR-mediated gene activation and nuclease cleavage in living cells and successfully manipulated the gene expression by using light irradiation. Our site-specific modification strategy exhibited a highly efficient and dynamic optical response and presented a new perspective for manipulating gRNA based on the RNA-protein interaction rather than the structure of RNA itself. In addition, these specific sites could also be potentially utilized for modification of other stimuli-responsive groups, which would further enrich the toolbox for conditional control of CRISPR/Cas9 function.
Collapse
Affiliation(s)
- Yang Wang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University Guangzhou 510275 China
| | - Yan Liu
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University Guangzhou 510275 China
| | - Fan Xie
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University Guangzhou 510275 China
| | - Jiao Lin
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University Guangzhou 510275 China
| | - Liang Xu
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University Guangzhou 510275 China
| |
Collapse
|
32
|
Kim H, Lee WJ, Oh Y, Kang SH, Hur JK, Lee H, Song W, Lim KS, Park YH, Song BS, Jin YB, Jun BH, Jung C, Lee DS, Kim SU, Lee SH. Enhancement of target specificity of CRISPR-Cas12a by using a chimeric DNA-RNA guide. Nucleic Acids Res 2020; 48:8601-8616. [PMID: 32687187 PMCID: PMC7470973 DOI: 10.1093/nar/gkaa605] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/14/2020] [Accepted: 07/06/2020] [Indexed: 12/24/2022] Open
Abstract
The CRISPR-Cas9 system is widely used for target-specific genome engineering. CRISPR-Cas12a (Cpf1) is one of the CRISPR effectors that controls target genes by recognizing thymine-rich protospacer adjacent motif (PAM) sequences. Cas12a has a higher sensitivity to mismatches in the guide RNA than does Cas9; therefore, off-target sequence recognition and cleavage are lower. However, it tolerates mismatches in regions distant from the PAM sequence (TTTN or TTN) in the protospacer, and off-target cleavage issues may become more problematic when Cas12a activity is improved for therapeutic purposes. Therefore, we investigated off-target cleavage by Cas12a and modified the Cas12a (cr)RNA to address the off-target cleavage issue. We developed a CRISPR-Cas12a that can induce mutations in target DNA sequences in a highly specific and effective manner by partially substituting the (cr)RNA with DNA to change the energy potential of base pairing to the target DNA. A model to explain how chimeric (cr)RNA guided CRISPR-Cas12a and SpCas9 nickase effectively work in the intracellular genome is suggested. Chimeric guide-based CRISPR- Cas12a genome editing with reduced off-target cleavage, and the resultant, increased safety has potential for therapeutic applications in incurable diseases caused by genetic mutations.
Collapse
Affiliation(s)
- Hanseop Kim
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- School of Life Sciences and Biotechnology, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Wi-jae Lee
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
| | - Yeounsun Oh
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Seung-Hun Kang
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Junho K Hur
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
- Department of Medical Genetics, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - Hyomin Lee
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - WooJeung Song
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Kyung-Seob Lim
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Young-Ho Park
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Bong-Seok Song
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Yeung Bae Jin
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Republic of Korea
| | - Bong-Hyun Jun
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
| | - Cheulhee Jung
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Dong-Seok Lee
- School of Life Sciences and Biotechnology, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Sun-Uk Kim
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Seung Hwan Lee
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Republic of Korea
| |
Collapse
|
33
|
Duffy K, Arangundy-Franklin S, Holliger P. Modified nucleic acids: replication, evolution, and next-generation therapeutics. BMC Biol 2020; 18:112. [PMID: 32878624 PMCID: PMC7469316 DOI: 10.1186/s12915-020-00803-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Modified nucleic acids, also called xeno nucleic acids (XNAs), offer a variety of advantages for biotechnological applications and address some of the limitations of first-generation nucleic acid therapeutics. Indeed, several therapeutics based on modified nucleic acids have recently been approved and many more are under clinical evaluation. XNAs can provide increased biostability and furthermore are now increasingly amenable to in vitro evolution, accelerating lead discovery. Here, we review the most recent discoveries in this dynamic field with a focus on progress in the enzymatic replication and functional exploration of XNAs.
Collapse
Affiliation(s)
- Karen Duffy
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | | | - Philipp Holliger
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| |
Collapse
|
34
|
Coelho MA, De Braekeleer E, Firth M, Bista M, Lukasiak S, Cuomo ME, Taylor BJM. CRISPR GUARD protects off-target sites from Cas9 nuclease activity using short guide RNAs. Nat Commun 2020; 11:4132. [PMID: 32807781 PMCID: PMC7431537 DOI: 10.1038/s41467-020-17952-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/23/2020] [Indexed: 11/16/2022] Open
Abstract
Precise genome editing using CRISPR-Cas9 is a promising therapeutic avenue for genetic diseases, although off-target editing remains a significant safety concern. Guide RNAs shorter than 16 nucleotides in length effectively recruit Cas9 to complementary sites in the genome but do not permit Cas9 nuclease activity. Here we describe CRISPR Guide RNA Assisted Reduction of Damage (CRISPR GUARD) as a method for protecting off-targets sites by co-delivery of short guide RNAs directed against off-target loci by competition with the on-target guide RNA. CRISPR GUARD reduces off-target mutagenesis while retaining on-target editing efficiencies with Cas9 and base editor. However, we discover that short guide RNAs can also support base editing if they contain cytosines within the deaminase activity window. We explore design rules and the universality of this method through in vitro studies and high-throughput screening, revealing CRISPR GUARD as a rapidly implementable strategy to improve the specificity of genome editing for most genomic loci. Finally, we create an online tool for CRISPR GUARD design.
Collapse
Affiliation(s)
- Matthew A Coelho
- Discovery Sciences, R&D, AstraZeneca, Cambridge, UK.
- Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1RQ, UK.
| | | | - Mike Firth
- Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
| | - Michal Bista
- Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
| | | | | | | |
Collapse
|
35
|
Glazier DA, Liao J, Roberts BL, Li X, Yang K, Stevens CM, Tang W. Chemical Synthesis and Biological Application of Modified Oligonucleotides. Bioconjug Chem 2020; 31:1213-1233. [PMID: 32227878 DOI: 10.1021/acs.bioconjchem.0c00060] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RNA plays a myriad of roles in the body including the coding, decoding, regulation, and expression of genes. RNA oligonucleotides have garnered significant interest as therapeutics via antisense oligonucleotides or small interfering RNA strategies for the treatment of diseases ranging from hyperlipidemia, HCV, and others. Additionally, the recently developed CRISPR-Cas9 mediated gene editing strategy also relies on Cas9-associated RNA strands. However, RNA presents numerous challenges as both a synthetic target and a potential therapeutic. RNA is inherently unstable, difficult to deliver into cells, and potentially immunogenic by itself or upon modification. Despite these challenges, with the help of chemically modified oligonucleotides, multiple RNA-based drugs have been approved by the FDA. The progress is made possible due to the nature of chemically modified oligonucleotides bearing advantages of nuclease stability, stronger binding affinity, and some other unique properties. This review will focus on the chemical synthesis of RNA and its modified versions. How chemical modifications of the ribose units and of the phosphatediester backbone address the inherent issues with using native RNA for biological applications will be discussed along the way.
Collapse
Affiliation(s)
- Daniel A Glazier
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States.,Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Junzhuo Liao
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Brett L Roberts
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Xiaolei Li
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Ka Yang
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Christopher M Stevens
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Weiping Tang
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States.,Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| |
Collapse
|
36
|
Ray A, Di Felice R. Protein-Mutation-Induced Conformational Changes of the DNA and Nuclease Domain in CRISPR/Cas9 Systems by Molecular Dynamics Simulations. J Phys Chem B 2020; 124:2168-2179. [PMID: 32079396 DOI: 10.1021/acs.jpcb.9b07722] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Class 2 CRISPR (clustered regularly interspaced short palindromic repeats) systems offer a unique protocol for genome editing in eukaryotic cells. The nuclease activity of Cas9 has been harnessed to perform precise genome editing by creating double-strand breaks. However, the nuclease activity of Cas9 can be triggered when there is imperfect complementarity between the RNA guide sequence and an off-target genomic site, which is a major limitation of the CRISPR technique for practical applications. Hence, understanding the binding mechanisms in CRISPR/Cas9 for predicting ways to increase cleavage specificity is a timely research target. One way to understand and tune the binding strength is to study wild-type and mutant Cas9, in complex with a guide RNA and a target DNA. We have performed classical all-atom MD simulations over a cumulative time scale of 13.5 μs of CRISPR/Cas9 ternary complexes with the wild-type Cas9 from Streptococcus pyogenes and three of its mutants: K855A, H982A, and the combination K855A+H982A, selected from the outcome of experimental work. Our results reveal significant structural impact of the mutations, with implications for specificity. We find that the "unwound" part of the nontarget DNA strand exhibits enhanced flexibility in complexes with Cas9 mutants and tries to move away from the HNH/RuvC interface, where it is otherwise stabilized by electrostatic couplings in the wild-type complex. Our findings refine an electrostatic model by which cleavage specificity can be optimized through protein mutations.
Collapse
Affiliation(s)
- Angana Ray
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Rosa Di Felice
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States.,Department of Biological Sciences, Quantitative and Computational Biology Sector, University of Southern California, Los Angeles, California 90089, United States.,CNR Institute of Nanosciences, Via Campi 213/A, 41125 Modena, Italy
| |
Collapse
|
37
|
Manghwar H, Li B, Ding X, Hussain A, Lindsey K, Zhang X, Jin S. CRISPR/Cas Systems in Genome Editing: Methodologies and Tools for sgRNA Design, Off-Target Evaluation, and Strategies to Mitigate Off-Target Effects. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1902312. [PMID: 32195078 PMCID: PMC7080517 DOI: 10.1002/advs.201902312] [Citation(s) in RCA: 129] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/07/2019] [Indexed: 05/03/2023]
Abstract
Life sciences have been revolutionized by genome editing (GE) tools, including zinc finger nucleases, transcription activator-Like effector nucleases, and CRISPR (clustered regulatory interspaced short palindromic repeats)/Cas (CRISPR-associated) systems, which make the targeted modification of genomic DNA of all organisms possible. CRISPR/Cas systems are being widely used because of their accuracy, efficiency, and cost-effectiveness. Various classes of CRISPR/Cas systems have been developed, but their extensive use may be hindered by off-target effects. Efforts are being made to reduce the off-target effects of CRISPR/Cas9 by generating various CRISPR/Cas systems with high fidelity and accuracy. Several approaches have been applied to detect and evaluate the off-target effects. Here, the current GE tools, the off-target effects generated by GE technology, types of off-target effects, mechanisms of off-target effects, major concerns, and outcomes of off-target effects in plants and animals are summarized. The methods to detect off-target effects, tools for single-guide RNA (sgRNA) design, evaluation and prediction of off-target effects, and strategies to increase the on-target efficiency and mitigate the off-target impact on intended genome-editing outcomes are summarized.
Collapse
Affiliation(s)
- Hakim Manghwar
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubei430070P. R. China
| | - Bo Li
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubei430070P. R. China
- Institute of Nuclear and Biological TechnologiesXinjiang Academy of Agricultural SciencesUrumqiXinjiang830091P. R. China
| | - Xiao Ding
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubei430070P. R. China
| | - Amjad Hussain
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubei430070P. R. China
| | - Keith Lindsey
- Department of BiosciencesDurham UniversityDurhamDH1 3LEUK
| | - Xianlong Zhang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubei430070P. R. China
| | - Shuangxia Jin
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubei430070P. R. China
| |
Collapse
|
38
|
Engineering nucleic acid chemistry for precise and controllable CRISPR/Cas9 genome editing. Sci Bull (Beijing) 2019; 64:1841-1849. [PMID: 36659580 DOI: 10.1016/j.scib.2019.07.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/16/2019] [Accepted: 07/23/2019] [Indexed: 01/21/2023]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein 9 (CRISPR/Cas9) genome editing technology is revolutionizing our approach and capability to precisely manipulate the genetic flow of mammalians. The facile programmability of Cas9 protein and guide RNA (gRNA) sequence has recently expanded biomedical application of CRISPR/Cas9 technology from editing mammalian genome to various genetic manipulations. The therapeutic and clinical translation potential of CRISPR/Cas9 genome editing, however, are challenged by its off-target effect and low genome editing efficiency. In this regard, developing new Cas9 variants and conditional control of Cas9/gRNA activity are of great potential for improving genome editing accuracy and on-target efficiency. In this review, we summarize chemical strategies that have been developed recently to engineer the nucleic acid chemistry of gRNA to enhance CRISPR/Cas9 genome editing efficacy, specificity and controllability. This review aims to highlight the endeavor that has been made to solve bottleneck problems in the field of CRISPR/Cas9 and inspire innovative researches to fulfill the gap between bench and bed.
Collapse
|
39
|
Okafor IC, Singh D, Wang Y, Jung M, Wang H, Mallon J, Bailey S, Lee JK, Ha T. Single molecule analysis of effects of non-canonical guide RNAs and specificity-enhancing mutations on Cas9-induced DNA unwinding. Nucleic Acids Res 2019; 47:11880-11888. [PMID: 31713616 PMCID: PMC7145707 DOI: 10.1093/nar/gkz1058] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 10/22/2019] [Accepted: 10/25/2019] [Indexed: 12/20/2022] Open
Abstract
Cas9 has made a wide range of genomic manipulation possible. However, its specificity continues to be a challenge. Non-canonical gRNAs and new engineered variants of Cas9 have been developed to improve specificity, but at the cost of the on-target activity. DNA unwinding is a checkpoint before cleavage by Cas9, and was shown to be made more sensitive to sequence mismatches by specificity-enhancing mutations in engineered Cas9s. Here we performed single-molecule FRET-based DNA unwinding experiments using various combinations of non-canonical gRNAs and different Cas9s. All engineered Cas9s were less promiscuous than wild type when canonical gRNA was used, but HypaCas9 had much-reduced on-target unwinding. Cas9-HF1 and eCas9 showed the best balance between low promiscuity and high on-target activity with canonical gRNA. When extended gRNAs with one or two non-matching guanines added to the 5' end were used, Sniper1-Cas9 showed the lowest promiscuity while maintaining high on-target activity. Truncated gRNA generally reduced unwinding and adding a non-matching guanine to the 5' end of gRNA influenced unwinding in a sequence-context dependent manner. Our results are consistent with cell-based cleavage data and provide a mechanistic understanding of how various Cas9/gRNA combinations perform in genome engineering.
Collapse
Affiliation(s)
- Ikenna C Okafor
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Digvijay Singh
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yanbo Wang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | - Haobo Wang
- Bloomberg School of Public Health, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - John Mallon
- Bloomberg School of Public Health, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Scott Bailey
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Bloomberg School of Public Health, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, Baltimore, MD 21205, USA
| |
Collapse
|
40
|
Wu J, Yin H. Engineering guide RNA to reduce the off-target effects of CRISPR. J Genet Genomics 2019; 46:523-529. [PMID: 31902584 DOI: 10.1016/j.jgg.2019.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 11/05/2019] [Accepted: 11/15/2019] [Indexed: 12/26/2022]
Abstract
As versatile and robust genome editing tools, clustered regularly interspaced short palindromic repeats (CRISPR) technologies have been broadly used in basic research, biotechnology, and therapeutic development. Off-target mutagenesis by CRISPR systems has been demonstrated, and various methods have been developed to markedly increase their specificity. In this review, we highlight the efforts of producing and modifying guide RNA (gRNA) to minimize off-target activities, including sequence and structure design, tuning expression and chemical modification. The modalities of gRNA engineering can be applied across CRISPR systems. In conjunction with CRISPR protein effectors, the engineered gRNA enables efficient and precise genome editing.
Collapse
Affiliation(s)
- Jing Wu
- Department of Pathology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China; Frontier Science Center for Immunology and Metabolism, Wuhan University, 430071, China
| | - Hao Yin
- Department of Pathology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China; Frontier Science Center for Immunology and Metabolism, Wuhan University, 430071, China; Department of Urology, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| |
Collapse
|
41
|
O'Reilly D, Kartje ZJ, Ageely EA, Malek-Adamian E, Habibian M, Schofield A, Barkau CL, Rohilla KJ, DeRossett LB, Weigle AT, Damha MJ, Gagnon KT. Extensive CRISPR RNA modification reveals chemical compatibility and structure-activity relationships for Cas9 biochemical activity. Nucleic Acids Res 2019; 47:546-558. [PMID: 30517736 PMCID: PMC6344873 DOI: 10.1093/nar/gky1214] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/29/2018] [Indexed: 12/26/2022] Open
Abstract
CRISPR (clustered regularly interspaced short palindromic repeat) endonucleases are at the forefront of biotechnology, synthetic biology and gene editing. Methods for controlling enzyme properties promise to improve existing applications and enable new technologies. CRISPR enzymes rely on RNA cofactors to guide catalysis. Therefore, chemical modification of the guide RNA can be used to characterize structure-activity relationships within CRISPR ribonucleoprotein (RNP) enzymes and identify compatible chemistries for controlling activity. Here, we introduce chemical modifications to the sugar–phosphate backbone of Streptococcus pyogenes Cas9 CRISPR RNA (crRNA) to probe chemical and structural requirements. Ribose sugars that promoted or accommodated A-form helical architecture in and around the crRNA ‘seed’ region were tolerated best. A wider range of modifications were acceptable outside of the seed, especially D-2′-deoxyribose, and we exploited this property to facilitate exploration of greater chemical diversity within the seed. 2′-fluoro was the most compatible modification whereas bulkier O-methyl sugar modifications were less tolerated. Activity trends could be rationalized for selected crRNAs using RNP stability and DNA target binding experiments. Cas9 activity in vitro tolerated most chemical modifications at predicted 2′-hydroxyl contact positions, whereas editing activity in cells was much less tolerant. The biochemical principles of chemical modification identified here will guide CRISPR-Cas9 engineering and enable new or improved applications.
Collapse
Affiliation(s)
- Daniel O'Reilly
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Zachary J Kartje
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Eman A Ageely
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Elise Malek-Adamian
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Maryam Habibian
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Annabelle Schofield
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Christopher L Barkau
- Department of Biochemistry & Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Kushal J Rohilla
- Department of Biochemistry & Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Lauren B DeRossett
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Austin T Weigle
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Keith T Gagnon
- Department of Chemistry & Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA.,Department of Biochemistry & Molecular Biology, School of Medicine, Southern Illinois University, Carbondale, Illinois 62901, USA
| |
Collapse
|
42
|
Moon SB, Kim DY, Ko JH, Kim JS, Kim YS. Improving CRISPR Genome Editing by Engineering Guide RNAs. Trends Biotechnol 2019; 37:870-881. [PMID: 30846198 DOI: 10.1016/j.tibtech.2019.01.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 12/26/2022]
Abstract
CRISPR technology is a two-component gene editing system in which the effector protein induces genetic alterations with the aid of a gene targeting guide RNA. Guide RNA can be produced through chemical synthesis, in vitro transcription, or intracellular transcription. Guide RNAs can be engineered to have chemical modifications, alterations in the spacer length, sequence modifications, fusion of RNA or DNA components, and incorporation of deoxynucleotides. Engineered guide RNA can improve genome editing efficiency and target specificity, regulation of biological toxicity, sensitive and specific molecular imaging, multiplexing, and editing flexibility. Therefore, engineered guide RNA will enable more specific, efficient, and safe gene editing, ultimately improving the clinical benefits of gene therapy.
Collapse
Affiliation(s)
- Su Bin Moon
- Genome Editing Research Center, KRIBB, Daejeon, Republic of Korea; KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, Republic of Korea; These authors contributed equally to this work
| | - Do Yon Kim
- Genome Editing Research Center, KRIBB, Daejeon, Republic of Korea; KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, Republic of Korea; These authors contributed equally to this work
| | - Jeong-Heon Ko
- Genome Editing Research Center, KRIBB, Daejeon, Republic of Korea; KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Jin-Soo Kim
- Center for Genome Engineering, Institute for Basic Science, Daejeon, Republic of Korea; IBS School, Korea University of Science and Technology (UST), Daejeon, Republic of Korea; Department of Chemistry, Seoul National University, Seoul, Republic of Korea
| | - Yong-Sam Kim
- Genome Editing Research Center, KRIBB, Daejeon, Republic of Korea; KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, Republic of Korea.
| |
Collapse
|
43
|
Taemaitree L, Shivalingam A, El-Sagheer AH, Brown T. An artificial triazole backbone linkage provides a split-and-click strategy to bioactive chemically modified CRISPR sgRNA. Nat Commun 2019; 10:1610. [PMID: 30962447 PMCID: PMC6453947 DOI: 10.1038/s41467-019-09600-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 03/18/2019] [Indexed: 12/26/2022] Open
Abstract
As the applications of CRISPR-Cas9 technology diversify and spread beyond the laboratory to diagnostic and therapeutic use, the demands of gRNA synthesis have increased and access to tailored gRNAs is now restrictive. Enzymatic routes are time-consuming, difficult to scale-up and suffer from polymerase-bias while existing chemical routes are inefficient. Here, we describe a split-and-click convergent chemical route to individual or pools of sgRNAs. The synthetic burden is reduced by splitting the sgRNA into a variable DNA/genome-targeting 20-mer, produced on-demand and in high purity, and a fixed Cas9-binding chemically-modified 79-mer, produced cost-effectively on large-scale, a strategy that provides access to site-specific modifications that enhance sgRNA activity and in vivo stability. Click ligation of the two components generates an artificial triazole linkage that is tolerated in functionally critical regions of the sgRNA and allows efficient DNA cleavage in vitro as well as gene-editing in cells with no unexpected off-target effects.
Collapse
Affiliation(s)
- Lapatrada Taemaitree
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Arun Shivalingam
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Afaf H El-Sagheer
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
- Chemistry Branch, Department of Science and Mathematics, Faculty of Petroleum and Mining Engineering, Suez University, Suez, 43721, Egypt
| | - Tom Brown
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| |
Collapse
|
44
|
Kim HY, Kang SJ, Jeon Y, An J, Park J, Lee HJ, Jang JE, Ahn J, Bang D, Chung HS, Jeong C, Ahn DR. Chimeric crRNAs with 19 DNA residues in the guide region show the retained DNA cleavage activity of Cas9 with potential to improve the specificity. Chem Commun (Camb) 2019; 55:3552-3555. [PMID: 30843540 DOI: 10.1039/c8cc08468h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We demonstrated that 19 out of 20 RNA residues in the guide region of crRNA can be replaced with DNA residues with high GC-contents. The cellular activity of the chimeric crRNAs to disrupt the target gene was comparable to that of the native crRNA.
Collapse
Affiliation(s)
- Hyo Young Kim
- Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Newton MD, Taylor BJ, Driessen RPC, Roos L, Cvetesic N, Allyjaun S, Lenhard B, Cuomo ME, Rueda DS. DNA stretching induces Cas9 off-target activity. Nat Struct Mol Biol 2019; 26:185-192. [PMID: 30804513 PMCID: PMC7613072 DOI: 10.1038/s41594-019-0188-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/18/2019] [Indexed: 12/24/2022]
Abstract
CRISPR/Cas9 is a powerful genome-editing tool, but spurious off-target edits present a barrier to therapeutic applications. To understand how CRISPR/Cas9 discriminates between on-targets and off-targets, we have developed a single-molecule assay combining optical tweezers with fluorescence to monitor binding to λ-DNA. At low forces, the Streptococcus pyogenes Cas9 complex binds and cleaves DNA specifically. At higher forces, numerous off-target binding events appear repeatedly at the same off-target sites in a guide-RNA-sequence-dependent manner, driven by the mechanical distortion of the DNA. Using single-molecule Förster resonance energy transfer (smFRET) and cleavage assays, we show that DNA bubbles induce off-target binding and cleavage at these sites, even with ten mismatches, as well as at previously identified in vivo off-targets. We propose that duplex DNA destabilization during cellular processes (for example, transcription, replication, etc.) can expose these cryptic off-target sites to Cas9 activity, highlighting the need for improved off-target prediction algorithms.
Collapse
Affiliation(s)
- Matthew D Newton
- Molecular Virology, Department of Medicine, Imperial College London, London, UK
- Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London, UK
| | | | | | - Leonie Roos
- Computational Regulatory Genomics, MRC-London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Nevena Cvetesic
- Computational Regulatory Genomics, MRC-London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Shenaz Allyjaun
- Molecular Virology, Department of Medicine, Imperial College London, London, UK
- Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London, UK
| | - Boris Lenhard
- Computational Regulatory Genomics, MRC-London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | | | - David S Rueda
- Molecular Virology, Department of Medicine, Imperial College London, London, UK.
- Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London, UK.
| |
Collapse
|
46
|
Wilkinson RA, Martin C, Nemudryi AA, Wiedenheft B. CRISPR RNA-guided autonomous delivery of Cas9. Nat Struct Mol Biol 2019; 26:14-24. [PMID: 30598555 PMCID: PMC7703833 DOI: 10.1038/s41594-018-0173-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/13/2018] [Indexed: 02/06/2023]
Abstract
Cas9 is an endonuclease that can be programed to autonomously deliver diverse effectors to specified genetic addresses. High-resolution structures of this protein and its associated CRISPR RNA guide explain the molecular mechanisms of CRISPR-RNA-guided DNA recognition and provide a molecular blueprint that has facilitated structure-guided functional remodeling. Here we retrace events that led from early efforts to understand the central role of Cas9 in CRISPR-mediated adaptive immunity to contemporary efforts aimed at developing and deploying this enzyme for programmable genetic editing.
Collapse
Affiliation(s)
- Royce A Wilkinson
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Coleman Martin
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Artem A Nemudryi
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Blake Wiedenheft
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA.
| |
Collapse
|
47
|
Kartje ZJ, Barkau CL, Rohilla KJ, Ageely EA, Gagnon KT. Chimeric Guides Probe and Enhance Cas9 Biochemical Activity. Biochemistry 2018; 57:3027-3031. [PMID: 29746102 DOI: 10.1021/acs.biochem.8b00107] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
DNA substitutions in RNA can probe the importance of A-form structure, 2'-hydroxyl contacts, and conformational constraints within RNA-guided enzymes. Using this approach, we found that Cas9 biochemical activity tolerated significant substitution with DNA nucleotides in the clustered regularly interspaced short palindromic repeat RNA (crRNA). Only minimal RNA content was needed in or near the seed region. Simultaneous substitution at all positions with predicted crRNA-Cas9 2'-hydroxyl contacts had no effect on enzyme activity. The trans-activating crRNA (tracrRNA) also tolerated >50% substitution with DNA. DNA substitutions in the tracrRNA-pairing region of crRNA consistently enhanced cleavage activity while maintaining or improving target specificity. Together, results point to a prominent role for guide:target A-form-like helical structure and a possible regulatory role for the crRNA-tracrRNA pairing motif. A model chimeric crRNA with high activity did not significantly alter RNP assembly or target binding but did reduce Cas9 ribonucleoprotein stability, suggesting effects through conformation or dynamics. Cas9 directed by chimeric RNA-DNA guides may represent a cost-effective synthetic or molecular biology tool for robust and specific DNA cleavage.
Collapse
Affiliation(s)
- Zachary J Kartje
- Department of Chemistry and Biochemistry , Southern Illinois University , Carbondale , Illinois 62901 , United States
| | - Christopher L Barkau
- Department of Biochemistry and Molecular Biology, School of Medicine , Southern Illinois University , Carbondale , Illinois 62901 , United States
| | - Kushal J Rohilla
- Department of Biochemistry and Molecular Biology, School of Medicine , Southern Illinois University , Carbondale , Illinois 62901 , United States
| | - Eman A Ageely
- Department of Chemistry and Biochemistry , Southern Illinois University , Carbondale , Illinois 62901 , United States
| | - Keith T Gagnon
- Department of Chemistry and Biochemistry , Southern Illinois University , Carbondale , Illinois 62901 , United States
- Department of Biochemistry and Molecular Biology, School of Medicine , Southern Illinois University , Carbondale , Illinois 62901 , United States
| |
Collapse
|
48
|
Cromwell CR, Sung K, Park J, Krysler AR, Jovel J, Kim SK, Hubbard BP. Incorporation of bridged nucleic acids into CRISPR RNAs improves Cas9 endonuclease specificity. Nat Commun 2018; 9:1448. [PMID: 29654299 PMCID: PMC5899152 DOI: 10.1038/s41467-018-03927-0] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/22/2018] [Indexed: 12/26/2022] Open
Abstract
Off-target DNA cleavage is a paramount concern when applying CRISPR-Cas9 gene-editing technology to functional genetics and human therapeutic applications. Here, we show that incorporation of next-generation bridged nucleic acids (2',4'-BNANC[N-Me]) as well as locked nucleic acids (LNA) at specific locations in CRISPR-RNAs (crRNAs) broadly reduces off-target DNA cleavage by Cas9 in vitro and in cells by several orders of magnitude. Using single-molecule FRET experiments we show that BNANC incorporation slows Cas9 kinetics and improves specificity by inducing a highly dynamic crRNA-DNA duplex for off-target sequences, which shortens dwell time in the cleavage-competent, "zipped" conformation. In addition to describing a robust technique for improving the precision of CRISPR/Cas9-based gene editing, this study illuminates an application of synthetic nucleic acids.
Collapse
Affiliation(s)
| | - Keewon Sung
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jinho Park
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Amanda R Krysler
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2R7, Canada
| | - Juan Jovel
- The Applied Genomics Core, Office of Research, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Seong Keun Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Basil P Hubbard
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2R7, Canada.
| |
Collapse
|