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Recktenwald M, Hutt E, Davis L, MacAulay J, Daringer NM, Galie PA, Staehle MM, Vega SL. Engineering transcriptional regulation for cell-based therapies. SLAS Technol 2024; 29:100121. [PMID: 38340892 DOI: 10.1016/j.slast.2024.100121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/10/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024]
Abstract
A major aim in the field of synthetic biology is developing tools capable of responding to user-defined inputs by activating therapeutically relevant cellular functions. Gene transcription and regulation in response to external stimuli are some of the most powerful and versatile of these cellular functions being explored. Motivated by the success of chimeric antigen receptor (CAR) T-cell therapies, transmembrane receptor-based platforms have been embraced for their ability to sense extracellular ligands and to subsequently activate intracellular signal transduction. The integration of transmembrane receptors with transcriptional activation platforms has not yet achieved its full potential. Transient expression of plasmid DNA is often used to explore gene regulation platforms in vitro. However, applications capable of targeting therapeutically relevant endogenous or stably integrated genes are more clinically relevant. Gene regulation may allow for engineered cells to traffic into tissues of interest and secrete functional proteins into the extracellular space or to differentiate into functional cells. Transmembrane receptors that regulate transcription have the potential to revolutionize cell therapies in a myriad of applications, including cancer treatment and regenerative medicine. In this review, we will examine current engineering approaches to control transcription in mammalian cells with an emphasis on systems that can be selectively activated in response to extracellular signals. We will also speculate on the potential therapeutic applications of these technologies and examine promising approaches to expand their capabilities and tighten the control of gene regulation in cellular therapies.
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Affiliation(s)
- Matthias Recktenwald
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Evan Hutt
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Leah Davis
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - James MacAulay
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Nichole M Daringer
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Peter A Galie
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Mary M Staehle
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Sebastián L Vega
- Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA; Department of Orthopaedic Surgery, Cooper Medical School of Rowan University, Camden, NJ 08103, USA.
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2
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Kasianchuk N, Dobrowolska K, Harkava S, Bretcan A, Zarębska-Michaluk D, Jaroszewicz J, Flisiak R, Rzymski P. Gene-Editing and RNA Interference in Treating Hepatitis B: A Review. Viruses 2023; 15:2395. [PMID: 38140636 PMCID: PMC10747710 DOI: 10.3390/v15122395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
The hepatitis B virus (HBV) continues to cause substantial health and economic burdens, and its target of elimination may not be reached in 2030 without further efforts in diagnostics, non-pharmaceutical prevention measures, vaccination, and treatment. Current therapeutic options in chronic HBV, based on interferons and/or nucleos(t)ide analogs, suppress the virus replication but do not eliminate the pathogen and suffer from several constraints. This paper reviews the progress on biotechnological approaches in functional and definitive HBV treatments, including gene-editing tools, i.e., zinc-finger proteins, transcription activator-like effector nucleases, and CRISPR/Cas9, as well as therapeutics based on RNA interference. The advantages and challenges of these approaches are also discussed. Although the safety and efficacy of gene-editing tools in HBV therapies are yet to be demonstrated, they show promise for the revitalization of a much-needed advance in the field and offer viral eradication. Particular hopes are related to CRISPR/Cas9; however, therapeutics employing this system are yet to enter the clinical testing phases. In contrast, a number of candidates based on RNA interference, intending to confer a functional cure, have already been introduced to human studies. However, larger and longer trials are required to assess their efficacy and safety. Considering that prevention is always superior to treatment, it is essential to pursue global efforts in HBV vaccination.
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Affiliation(s)
- Nadiia Kasianchuk
- Faculty of Biology, Adam Mickiewicz University in Poznań, 61-614 Poznań, Poland
| | | | - Sofiia Harkava
- Junior Academy of Sciences of Ukraine, Regional Branch in Dnipro, 49000 Dnipro, Ukraine;
| | - Andreea Bretcan
- National College “Ienăchiță Văcărescu”, 130016 Târgoviște, Romania;
| | - Dorota Zarębska-Michaluk
- Department of Infectious Diseases and Allergology, Jan Kochanowski University, 25-317 Kielce, Poland;
| | - Jerzy Jaroszewicz
- Department of Infectious Diseases and Hepatology, Medical University of Silesia in Katowice, 41-902 Bytom, Poland;
| | - Robert Flisiak
- Department of Infectious Diseases and Hepatology, Medical University of Białystok, 15-540 Białystok, Poland;
| | - Piotr Rzymski
- Department of Environmental Medicine, Poznan University of Medical Sciences, 60-806 Poznań, Poland
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3
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Rhiel M, Geiger K, Andrieux G, Rositzka J, Boerries M, Cathomen T, Cornu TI. T-CAST: An optimized CAST-Seq pipeline for TALEN confirms superior safety and efficacy of obligate-heterodimeric scaffolds. Front Genome Ed 2023; 5:1130736. [PMID: 36890979 PMCID: PMC9986454 DOI: 10.3389/fgeed.2023.1130736] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 02/06/2023] [Indexed: 02/22/2023] Open
Abstract
Transcription activator-like effector nucleases (TALENs) are programmable nucleases that have entered the clinical stage. Each subunit of the dimer consists of a DNA-binding domain composed of an array of TALE repeats fused to the catalytically active portion of the FokI endonuclease. Upon DNA-binding of both TALEN arms in close proximity, the FokI domains dimerize and induce a staggered-end DNA double strand break. In this present study, we describe the implementation and validation of TALEN-specific CAST-Seq (T-CAST), a pipeline based on CAST-Seq that identifies TALEN-mediated off-target effects, nominates off-target sites with high fidelity, and predicts the TALEN pairing conformation leading to off-target cleavage. We validated T-CAST by assessing off-target effects of two promiscuous TALENs designed to target the CCR5 and TRAC loci. Expression of these TALENs caused high levels of translocations between the target sites and various off-target sites in primary T cells. Introduction of amino acid substitutions to the FokI domains, which render TALENs obligate-heterodimeric (OH-TALEN), mitigated the aforementioned off-target effects without loss of on-target activity. Our findings highlight the significance of T-CAST to assess off-target effects of TALEN designer nucleases and to evaluate mitigation strategies, and advocate the use of obligate-heterodimeric TALEN scaffolds for therapeutic genome editing.
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Affiliation(s)
- Manuel Rhiel
- Institute for Transfusion Medicine and Gene Therapy, Medical Center-University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency (CCI), Medical Center-University of Freiburg, Freiburg, Germany
| | - Kerstin Geiger
- Institute for Transfusion Medicine and Gene Therapy, Medical Center-University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency (CCI), Medical Center-University of Freiburg, Freiburg, Germany.,Ph.D. Program, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Geoffroy Andrieux
- Institute of Medical Bioinformatics and Systems Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site Freiburg, and German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julia Rositzka
- Institute for Transfusion Medicine and Gene Therapy, Medical Center-University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency (CCI), Medical Center-University of Freiburg, Freiburg, Germany
| | - Melanie Boerries
- Institute of Medical Bioinformatics and Systems Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Cancer Consortium (DKTK), Partner Site Freiburg, and German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Comprehensive Cancer Center Freiburg (CCCF), Medical Center-University of Freiburg, Freiburg, Germany
| | - Toni Cathomen
- Institute for Transfusion Medicine and Gene Therapy, Medical Center-University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency (CCI), Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Tatjana I Cornu
- Institute for Transfusion Medicine and Gene Therapy, Medical Center-University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency (CCI), Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
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4
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Dashtaki ME, Ghasemi S. CRISPR/Cas9-based Gene Therapies for Fighting Drug Resistance Mediated by Cancer Stem Cells. Curr Gene Ther 2023; 23:41-50. [PMID: 36056851 DOI: 10.2174/1566523222666220831161225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/11/2022] [Accepted: 06/11/2022] [Indexed: 02/08/2023]
Abstract
Cancer stem cells (CSCs) are cancer-initiating cells found in most tumors and hematological cancers. CSCs are involved in cells progression, recurrence of tumors, and drug resistance. Current therapies have been focused on treating the mass of tumor cells and cannot eradicate the CSCs. CSCs drug-specific targeting is considered as an approach to precisely target these cells. Clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) gene-editing systems are making progress and showing promise in the cancer research field. One of the attractive applications of CRISPR/Cas9 as one approach of gene therapy is targeting the critical genes involved in drug resistance and maintenance of CSCs. The synergistic effects of gene editing as a novel gene therapy approach and traditional therapeutic methods, including chemotherapy, can resolve drug resistance challenges and regression of the cancers. This review article considers different aspects of CRISPR/Cas9 ability in the study and targeting of CSCs with the intention to investigate their application in drug resistance.
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Affiliation(s)
- Masoumeh Eliyasi Dashtaki
- Clinical Biochemistry Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Sorayya Ghasemi
- Cancer Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
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5
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Danila F, Schreiber T, Ermakova M, Hua L, Vlad D, Lo S, Chen Y, Lambret‐Frotte J, Hermanns AS, Athmer B, von Caemmerer S, Yu S, Hibberd JM, Tissier A, Furbank RT, Kelly S, Langdale JA. A single promoter-TALE system for tissue-specific and tuneable expression of multiple genes in rice. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1786-1806. [PMID: 35639605 PMCID: PMC9398400 DOI: 10.1111/pbi.13864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/06/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
In biological discovery and engineering research, there is a need to spatially and/or temporally regulate transgene expression. However, the limited availability of promoter sequences that are uniquely active in specific tissue-types and/or at specific times often precludes co-expression of multiple transgenes in precisely controlled developmental contexts. Here, we developed a system for use in rice that comprises synthetic designer transcription activator-like effectors (dTALEs) and cognate synthetic TALE-activated promoters (STAPs). The system allows multiple transgenes to be expressed from different STAPs, with the spatial and temporal context determined by a single promoter that drives expression of the dTALE. We show that two different systems-dTALE1-STAP1 and dTALE2-STAP2-can activate STAP-driven reporter gene expression in stable transgenic rice lines, with transgene transcript levels dependent on both dTALE and STAP sequence identities. The relative strength of individual STAP sequences is consistent between dTALE1 and dTALE2 systems but differs between cell-types, requiring empirical evaluation in each case. dTALE expression leads to off-target activation of endogenous genes but the number of genes affected is substantially less than the number impacted by the somaclonal variation that occurs during the regeneration of transformed plants. With the potential to design fully orthogonal dTALEs for any genome of interest, the dTALE-STAP system thus provides a powerful approach to fine-tune the expression of multiple transgenes, and to simultaneously introduce different synthetic circuits into distinct developmental contexts.
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Affiliation(s)
- Florence Danila
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Tom Schreiber
- Department of Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryHalleGermany
| | - Maria Ermakova
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Lei Hua
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
| | - Daniela Vlad
- Department of Plant SciencesUniversity of OxfordOxfordUK
| | - Shuen‐Fang Lo
- Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
| | - Yi‐Shih Chen
- Institute of Molecular BiologyAcademia SinicaTaipeiTaiwan
| | | | - Anna S. Hermanns
- Department of Plant SciencesUniversity of OxfordOxfordUK
- Present address:
Plant Breeding and Genetics Section, School of Integrative Plant ScienceCornell UniversityIthacaNew YorkUSA
| | - Benedikt Athmer
- Department of Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryHalleGermany
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Su‐May Yu
- Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
- Institute of Molecular BiologyAcademia SinicaTaipeiTaiwan
| | | | - Alain Tissier
- Department of Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryHalleGermany
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Steven Kelly
- Department of Plant SciencesUniversity of OxfordOxfordUK
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6
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Nowack MK, Holmes DR, Lahaye T. TALE-induced cell death executors: an origin outside immunity? TRENDS IN PLANT SCIENCE 2022; 27:536-548. [PMID: 34924289 PMCID: PMC7612725 DOI: 10.1016/j.tplants.2021.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/21/2021] [Accepted: 11/01/2021] [Indexed: 05/19/2023]
Abstract
Phytopathogenic bacteria inject effector proteins into plant host cells to promote disease. Plant resistance (R) genes encoding nucleotide-binding leucine-rich repeat (NLR) proteins mediate the recognition of functionally and structurally diverse microbial effectors, including transcription-activator like effectors (TALEs) from the bacterial genus Xanthomonas. TALEs bind to plant promoters and transcriptionally activate either disease-promoting host susceptibility (S) genes or cell death-inducing executor-type R genes. It is perplexing that plants contain TALE-perceiving executor-type R genes in addition to NLRs that also mediate the recognition of TALE-containing xanthomonads. We present recent findings on the evolvability of TALEs, which suggest that the native function of executors is not in plant immunity, but possibly in the regulation of developmentally controlled programmed cell death (PCD) processes.
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Affiliation(s)
- Moritz K Nowack
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; VIB Center of Plant Systems Biology, 9052 Ghent, Belgium.
| | - Danalyn R Holmes
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076 Tuebingen, Germany
| | - Thomas Lahaye
- University of Tübingen, ZMBP - General Genetics, Auf der Morgenstelle 32, 72076 Tuebingen, Germany.
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7
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Becker S, Mücke S, Grau J, Boch J. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2387-2400. [PMID: 35150566 PMCID: PMC8887545 DOI: 10.1093/nar/gkac098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/28/2022] [Accepted: 02/02/2022] [Indexed: 11/25/2022] Open
Abstract
Transcription activator-like effectors (TALEs) are bacterial proteins with a programmable DNA-binding domain, which turned them into exceptional tools for biotechnology. TALEs contain a central array of consecutive 34 amino acid long repeats to bind DNA in a simple one-repeat-to-one-nucleotide manner. However, a few naturally occurring aberrant repeat variants break this strict binding mechanism, allowing for the recognition of an additional sequence with a −1 nucleotide frameshift. The limits and implications of this extended TALE binding mode are largely unexplored. Here, we analyse the complete diversity of natural and artificially engineered aberrant repeats for their impact on the DNA binding of TALEs. Surprisingly, TALEs with several aberrant repeats can loop out multiple repeats simultaneously without losing DNA-binding capacity. We also characterized members of the only natural TALE class harbouring two aberrant repeats and confirmed that their target is the major virulence factor OsSWEET13 from rice. In an aberrant TALE repeat, the position and nature of the amino acid sequence strongly influence its function. We explored the tolerance of TALE repeats towards alterations further and demonstrate that inserts as large as GFP can be tolerated without disrupting DNA binding. This illustrates the extraordinary DNA-binding capacity of TALEs and opens new uses in biotechnology.
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Affiliation(s)
- Sebastian Becker
- Department of Plant Biotechnology, Institute of Plant Genetics, Leibniz Universität Hannover, 30419 Hannover, Germany
| | - Stefanie Mücke
- Department of Plant Biotechnology, Institute of Plant Genetics, Leibniz Universität Hannover, 30419 Hannover, Germany
| | - Jan Grau
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Jens Boch
- To whom correspondence should be addressed. Tel: +49 511 762 4082; Fax: +49 511 762 4088;
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8
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Erkes A, Mücke S, Reschke M, Boch J, Grau J. Epigenetic features improve TALE target prediction. BMC Genomics 2021; 22:914. [PMID: 34965853 PMCID: PMC8717664 DOI: 10.1186/s12864-021-08210-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/25/2021] [Indexed: 11/20/2022] Open
Abstract
Background The yield of many crop plants can be substantially reduced by plant-pathogenic Xanthomonas bacteria. The infection strategy of many Xanthomonas strains is based on transcription activator-like effectors (TALEs), which are secreted into the host cells and act as transcriptional activators of plant genes that are beneficial for the bacteria.The modular DNA binding domain of TALEs contains tandem repeats, each comprising two hyper-variable amino acids. These repeat-variable diresidues (RVDs) bind to their target box and determine the specificity of a TALE.All available tools for the prediction of TALE targets within the host plant suffer from many false positives. In this paper we propose a strategy to improve prediction accuracy by considering the epigenetic state of the host plant genome in the region of the target box. Results To this end, we extend our previously published tool PrediTALE by considering two epigenetic features: (i) chromatin accessibility of potentially bound regions and (ii) DNA methylation of cytosines within target boxes. Here, we determine the epigenetic features from publicly available DNase-seq, ATAC-seq, and WGBS data in rice.We benchmark the utility of both epigenetic features separately and in combination, deriving ground-truth from RNA-seq data of infections studies in rice. We find an improvement for each individual epigenetic feature, but especially the combination of both.Having established an advantage in TALE target predicting considering epigenetic features, we use these data for promoterome and genome-wide scans by our new tool EpiTALE, leading to several novel putative virulence targets. Conclusions Our results suggest that it would be worthwhile to collect condition-specific chromatin accessibility data and methylation information when studying putative virulence targets of Xanthomonas TALEs. Supplementary Information The online version contains supplementary material available at (10.1186/s12864-021-08210-z).
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Affiliation(s)
- Annett Erkes
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle, Germany.
| | - Stefanie Mücke
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Maik Reschke
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Jens Boch
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Jan Grau
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle, Germany.
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9
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Newby GA, Liu DR. In vivo somatic cell base editing and prime editing. Mol Ther 2021; 29:3107-3124. [PMID: 34509669 PMCID: PMC8571176 DOI: 10.1016/j.ymthe.2021.09.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/26/2021] [Accepted: 09/06/2021] [Indexed: 12/16/2022] Open
Abstract
Recent advances in genome editing technologies have magnified the prospect of single-dose cures for many genetic diseases. For most genetic disorders, precise DNA correction is anticipated to best treat patients. To install desired DNA changes with high precision, our laboratory developed base editors (BEs), which can correct the four most common single-base substitutions, and prime editors, which can install any substitution, insertion, and/or deletion over a stretch of dozens of base pairs. Compared to nuclease-dependent editing approaches that involve double-strand DNA breaks (DSBs) and often result in a large percentage of uncontrolled editing outcomes, such as mixtures of insertions and deletions (indels), larger deletions, and chromosomal rearrangements, base editors and prime editors often offer greater efficiency with fewer byproducts in slowly dividing or non-dividing cells, such as those that make up most of the cells in adult animals. Both viral and non-viral in vivo delivery methods have now been used to deliver base editors and prime editors in animal models, establishing that base editors and prime editors can serve as effective agents for in vivo therapeutic genome editing in animals. This review summarizes examples of in vivo somatic cell (post-natal) base editing and prime editing and prospects for future development.
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Affiliation(s)
- 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 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02142 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 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02142 USA.
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10
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Bhardwaj A, Nain V. TALENs-an indispensable tool in the era of CRISPR: a mini review. J Genet Eng Biotechnol 2021; 19:125. [PMID: 34420096 PMCID: PMC8380213 DOI: 10.1186/s43141-021-00225-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/08/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND Genome of an organism has always fascinated life scientists. With the discovery of restriction endonucleases, scientists were able to make targeted manipulations (knockouts) in any gene sequence of any organism, by the technique popularly known as genome engineering. Though there is a range of genome editing tools, but this era of genome editing is dominated by the CRISPR/Cas9 tool due to its ease of design and handling. But, when it comes to clinical applications, CRISPR is not usually preferred. In this review, we will elaborate on the structural and functional role of designer nucleases with emphasis on TALENs and CRISPR/Cas9 genome editing system. We will also present the unique features of TALENs and limitations of CRISPRs which makes TALENs a better genome editing tool than CRISPRs. MAIN BODY Genome editing is a robust technology used to make target specific DNA modifications in the genome of any organism. With the discovery of robust programmable endonucleases-based designer gene manipulating tools such as meganucleases (MN), zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats associated protein (CRISPR/Cas9), the research in this field has experienced a tremendous acceleration giving rise to a modern era of genome editing with better precision and specificity. Though, CRISPR-Cas9 platform has successfully gained more attention in the scientific world, TALENs and ZFNs are unique in their own ways. Apart from high-specificity, TALENs are proven to target the mitochondrial DNA (mito-TALEN), where gRNA of CRISPR is difficult to import. This review talks about genome editing goals fulfilled by TALENs and drawbacks of CRISPRs. CONCLUSIONS This review provides significant insights into the pros and cons of the two most popular genome editing tools TALENs and CRISPRs. This mini review suggests that, TALENs provides novel opportunities in the field of therapeutics being highly specific and sensitive toward DNA modifications. In this article, we will briefly explore the special features of TALENs that makes this tool indispensable in the field of synthetic biology. This mini review provides great perspective in providing true guidance to the researchers working in the field of trait improvement via genome editing.
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Affiliation(s)
- Anuradha Bhardwaj
- Department of Biotechnology, Gautam Buddha University, Greater Noida, Uttar Pradesh, 201312, India
| | - Vikrant Nain
- Department of Biotechnology, Gautam Buddha University, Greater Noida, Uttar Pradesh, 201312, India.
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11
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Sgro A, Blancafort P. Epigenome engineering: new technologies for precision medicine. Nucleic Acids Res 2021; 48:12453-12482. [PMID: 33196851 PMCID: PMC7736826 DOI: 10.1093/nar/gkaa1000] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/10/2020] [Accepted: 10/16/2020] [Indexed: 02/07/2023] Open
Abstract
Chromatin adopts different configurations that are regulated by reversible covalent modifications, referred to as epigenetic marks. Epigenetic inhibitors have been approved for clinical use to restore epigenetic aberrations that result in silencing of tumor-suppressor genes, oncogene addictions, and enhancement of immune responses. However, these drugs suffer from major limitations, such as a lack of locus selectivity and potential toxicities. Technological advances have opened a new era of precision molecular medicine to reprogram cellular physiology. The locus-specificity of CRISPR/dCas9/12a to manipulate the epigenome is rapidly becoming a highly promising strategy for personalized medicine. This review focuses on new state-of-the-art epigenome editing approaches to modify the epigenome of neoplasms and other disease models towards a more 'normal-like state', having characteristics of normal tissue counterparts. We highlight biomolecular engineering methodologies to assemble, regulate, and deliver multiple epigenetic effectors that maximize the longevity of the therapeutic effect, and we discuss limitations of the platforms such as targeting efficiency and intracellular delivery for future clinical applications.
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Affiliation(s)
- Agustin Sgro
- Cancer Epigenetics Laboratory, The Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia.,School of Human Sciences, The University of Western Australia, Crawley, Perth, Western Australia 6009, Australia
| | - Pilar Blancafort
- Cancer Epigenetics Laboratory, The Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia.,School of Human Sciences, The University of Western Australia, Crawley, Perth, Western Australia 6009, Australia.,The Greehey Children's Cancer Research Institute, The University of Texas Health Science Center, San Antonio, TX 78229, USA
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12
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Fal K, Tomkova D, Vachon G, Chabouté ME, Berr A, Carles CC. Chromatin Manipulation and Editing: Challenges, New Technologies and Their Use in Plants. Int J Mol Sci 2021; 22:E512. [PMID: 33419220 PMCID: PMC7825600 DOI: 10.3390/ijms22020512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 12/25/2022] Open
Abstract
An ongoing challenge in functional epigenomics is to develop tools for precise manipulation of epigenetic marks. These tools would allow moving from correlation-based to causal-based findings, a necessary step to reach conclusions on mechanistic principles. In this review, we describe and discuss the advantages and limits of tools and technologies developed to impact epigenetic marks, and which could be employed to study their direct effect on nuclear and chromatin structure, on transcription, and their further genuine role in plant cell fate and development. On one hand, epigenome-wide approaches include drug inhibitors for chromatin modifiers or readers, nanobodies against histone marks or lines expressing modified histones or mutant chromatin effectors. On the other hand, locus-specific approaches consist in targeting precise regions on the chromatin, with engineered proteins able to modify epigenetic marks. Early systems use effectors in fusion with protein domains that recognize a specific DNA sequence (Zinc Finger or TALEs), while the more recent dCas9 approach operates through RNA-DNA interaction, thereby providing more flexibility and modularity for tool designs. Current developments of "second generation", chimeric dCas9 systems, aiming at better targeting efficiency and modifier capacity have recently been tested in plants and provided promising results. Finally, recent proof-of-concept studies forecast even finer tools, such as inducible/switchable systems, that will allow temporal analyses of the molecular events that follow a change in a specific chromatin mark.
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Affiliation(s)
- Kateryna Fal
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000 Grenoble, France; (K.F.); (G.V.)
| | - Denisa Tomkova
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg CEDEX, France; (D.T.); (M.-E.C.)
| | - Gilles Vachon
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000 Grenoble, France; (K.F.); (G.V.)
| | - Marie-Edith Chabouté
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg CEDEX, France; (D.T.); (M.-E.C.)
| | - Alexandre Berr
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg CEDEX, France; (D.T.); (M.-E.C.)
| | - Cristel C. Carles
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS, CEA, INRAE, IRIG-LPCV, 38000 Grenoble, France; (K.F.); (G.V.)
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13
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Zhang ZY, Thrasher AJ, Zhang F. Gene therapy and genome editing for primary immunodeficiency diseases. Genes Dis 2020; 7:38-51. [PMID: 32181274 PMCID: PMC7063425 DOI: 10.1016/j.gendis.2019.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 07/20/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022] Open
Abstract
In past two decades the gene therapy using genetic modified autologous hematopoietic stem cells (HSCs) transduced with the viral vector has become a promising alternative option for treating primary immunodeficiency diseases (PIDs). Despite of some pitfalls at early stage clinical trials, the field of gene therapy has advanced significantly in the last decade with improvements in viral vector safety, preparatory regime for manufacturing high quality virus, automated CD34 cell purification. Hence, the overall outcome from the clinical trials for the different PIDs has been very encouraging. In addition to the viral vector based gene therapy, the recent fast moving forward developments in genome editing using engineered nucleases in HSCs has provided a new promising platform for the treatment of PIDs. This review provides an overall outcome and progress in gene therapy clinical trials for SCID-X, ADA-SCID, WAS, X- CGD, and the recent developments in genome editing technology applied in HSCs for developing potential therapy, particular in the key studies for PIDs.
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Affiliation(s)
- Zhi-Yong Zhang
- Department of Immunology and Rheumatology, Children's Hospital of Chongqing Medical University, China
| | - Adrian J. Thrasher
- Molecular and Cellular Immunology, Great Ormond Street Institute of Child Health, University Colleage London, UK
| | - Fang Zhang
- Molecular and Cellular Immunology, Great Ormond Street Institute of Child Health, University Colleage London, UK
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14
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Ashmore-Harris C, Fruhwirth GO. The clinical potential of gene editing as a tool to engineer cell-based therapeutics. Clin Transl Med 2020; 9:15. [PMID: 32034584 PMCID: PMC7007464 DOI: 10.1186/s40169-020-0268-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/29/2020] [Indexed: 12/13/2022] Open
Abstract
The clinical application of ex vivo gene edited cell therapies first began a decade ago with zinc finger nuclease editing of autologous CD4+ T-cells. Editing aimed to disrupt expression of the human immunodeficiency virus co-receptor gene CCR5, with the goal of yielding cells resistant to viral entry, prior to re-infusion into the patient. Since then the field has substantially evolved with the arrival of the new editing technologies transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR), and the potential benefits of gene editing in the arenas of immuno-oncology and blood disorders were quickly recognised. As the breadth of cell therapies available clinically continues to rise there is growing interest in allogeneic and off-the-shelf approaches and multiplex editing strategies are increasingly employed. We review here the latest clinical trials utilising these editing technologies and consider the applications on the horizon.
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Affiliation(s)
- Candice Ashmore-Harris
- Imaging Therapy and Cancer Group, Dept of Imaging Chemistry & Biology, School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London (KCL), London, SE1 7EH, UK
- Centre for Stem Cells & Regenerative Medicine, School of Basic and Medical Biosciences, Guy's Hospital, KCL, London, SE1 9RT, UK
| | - Gilbert O Fruhwirth
- Imaging Therapy and Cancer Group, Dept of Imaging Chemistry & Biology, School of Biomedical Engineering & Imaging Sciences, St Thomas' Hospital, King's College London (KCL), London, SE1 7EH, UK.
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15
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Liu L, Zhang Y, Liu M, Wei W, Yi C, Peng J. Structural Insights into the Specific Recognition of 5-methylcytosine and 5-hydroxymethylcytosine by TAL Effectors. J Mol Biol 2020; 432:1035-1047. [DOI: 10.1016/j.jmb.2019.11.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/12/2019] [Accepted: 11/27/2019] [Indexed: 01/02/2023]
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16
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Anderson JT, Rogers JM, Barrera LA, Bulyk ML. Context and number of noncanonical repeat variable diresidues impede the design of TALE proteins with improved DNA targeting. Protein Sci 2019; 29:606-616. [PMID: 31833142 DOI: 10.1002/pro.3801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 12/18/2022]
Abstract
Transcription activator-like effector (TALE) proteins have been used extensively for targeted binding of fusion proteins to loci of interest in (epi)genome engineering. Such approaches typically utilize four canonical TALE repeat variable diresidue (RVD) types, corresponding to the identities of two key amino acids, to target each nucleotide. Alternate RVDs with improved specificity are desired. Here, we focused on seven noncanonical RVDs that have been suggested to have improved specificity for their target nucleotides. We used custom protein binding microarrays to characterize the DNA-binding activity of 65 TALEs containing these alternate or corresponding canonical RVDs at multiple positions to ~5,000 unique DNA sequences per protein. We found that none of the noncanonical thymine-targeting RVDs displayed stronger preference for thymine than did the canonical RVD. Of the noncanonical RVDs with putatively improved specificity for guanine, only EN and NH showed greater discrimination of guanine over adenine. This improved specificity, however, comes at a cost: more substitutions of a noncanonical RVD for a canonical RVD generally decreased the protein's DNA-binding activity. Our results highlight the need to investigate RVD-nucleotide specificities in multiple protein contexts and suggest that a balance between canonical and noncanonical RVDs is needed to build TALEs with improved specificity.
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Affiliation(s)
- James T Anderson
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Julia M Rogers
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts
| | - Luis A Barrera
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts.,Harvard-MIT Division of Health Sciences and Technology (HST), Harvard Medical School, Boston, Massachusetts
| | - Martha L Bulyk
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts.,Harvard-MIT Division of Health Sciences and Technology (HST), Harvard Medical School, Boston, Massachusetts.,Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
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17
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Shin E, Kim W, Lee S, Bae J, Kim S, Ko W, Seo HS, Lim S, Lee HS, Jo K. Truncated TALE-FP as DNA Staining Dye in a High-salt Buffer. Sci Rep 2019; 9:17197. [PMID: 31748571 PMCID: PMC6868158 DOI: 10.1038/s41598-019-53722-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/05/2019] [Indexed: 01/19/2023] Open
Abstract
Large DNA molecules are a promising platform for in vitro single-molecule biochemical analysis to investigate DNA-protein interactions by fluorescence microscopy. For many studies, intercalating fluorescent dyes have been primary DNA staining reagents, but they often cause photo-induced DNA breakage as well as structural deformation. As a solution, we previously developed several fluorescent-protein DNA-binding peptides or proteins (FP-DBP) for reversibly staining DNA molecules without structural deformation or photo-induced damage. However, they cannot stain DNA in a condition similar to a physiological salt concentration that most biochemical reactions require. Given these concerns, here we developed a salt-tolerant FP-DBP: truncated transcription activator-like effector (tTALE-FP), which can stain DNA up to 100 mM NaCl. Moreover, we found an interesting phenomenon that the tTALE-FP stained DNA evenly in 1 × TE buffer but showed AT-rich specific patterns from 40 mM to 100 mM NaCl. Using an assay based on fluorescence resonance energy transfer, we demonstrated that this binding pattern is caused by a higher DNA binding affinity of tTALE-FP for AT-rich compared to GC-rich regions. Finally, we used tTALE-FP in a single molecule fluorescence assay to monitor real-time restriction enzyme digestion of single DNA molecules. Altogether, our results demonstrate that this protein can provide a useful alternative as a DNA stain over intercalators.
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Affiliation(s)
- Eunji Shin
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Woojung Kim
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Seonghyun Lee
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Jaeyoung Bae
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Sanggil Kim
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Wooseok Ko
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Ho Seong Seo
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Korea
| | - Sangyong Lim
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Korea
| | - Hyun Soo Lee
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea.
| | - Kyubong Jo
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea.
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18
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Meygret A, Peuchant O, Dordet-Frisoni E, Sirand-Pugnet P, Citti C, Bébéar C, Béven L, Pereyre S. High Prevalence of Integrative and Conjugative Elements Encoding Transcription Activator-Like Effector Repeats in Mycoplasma hominis. Front Microbiol 2019; 10:2385. [PMID: 31681239 PMCID: PMC6813540 DOI: 10.3389/fmicb.2019.02385] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/01/2019] [Indexed: 12/02/2022] Open
Abstract
Integrative and conjugative elements (ICEs) are modular mobile genetic elements that can disseminate through excision, circularization, and transfer. Mycoplasma ICEs have recently been found distributed among some mycoplasma species and there is accumulating evidence that they play a pivotal role in horizontal gene transfers. The occurrence of ICEs has not been documented in Mycoplasma hominis, a human urogenital pathogen responsible for urogenital infections, neonatal infections and extragenital infections. In this study, we searched for, characterized, and compared ICEs by genome analyses of 12 strains of M. hominis. ICEs of 27–30 kb were found in one or two copies in seven of the 12 M. hominis strains sequenced. Only five of these ICEs seemed to be functional, as assessed by detection of circular forms of extrachromosomal ICE. Moreover, the prevalence of ICEs in M. hominis was estimated to be 45% in a collection of 120 clinical isolates of M. hominis, including 27 tetracycline-resistant tet(M)-positive isolates. The proportion of ICEs was not higher in isolates carrying the tet(M) gene, suggesting that ICEs are not involved in tetracycline resistance. Notably, all M. hominis ICEs had a very similar structure, consisting of a 4.0–5.1 kb unusual module composed of five to six juxtaposed CDSs. All the genes forming this module were specific to M. hominis ICEs as they had no homologs in other mycoplasma ICEs. In each M. hominis ICE, one to three CDSs encode proteins that share common structural features with transcription activator-like (TAL) effectors involved in polynucleotide recognition and signal transduction in symbiotic plant pathogen bacteria. The conserved and specific structure of M. hominis ICEs and the high prevalence in clinical strains suggest that these ICEs may confer a selective advantage for the physiology or pathogenicity of this human pathogenic bacterium. These data open the way for further studies aiming at unraveling horizontal gene transfers and virulence factors in M. hominis.
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Affiliation(s)
- Alexandra Meygret
- USC EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,INRA, USC-EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,Department of Bacteriology, French National Reference Center for Bacterial STI, CHU Bordeaux, Bordeaux, France
| | - Olivia Peuchant
- USC EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,INRA, USC-EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,Department of Bacteriology, French National Reference Center for Bacterial STI, CHU Bordeaux, Bordeaux, France
| | - Emilie Dordet-Frisoni
- IHAP, INRA, Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, Toulouse, France
| | - Pascal Sirand-Pugnet
- UMR 1332, BFP, University of Bordeaux, Bordeaux, France.,INRA, UMR 1332, BFP, Bordeaux, France
| | - Christine Citti
- IHAP, INRA, Ecole Nationale Vétérinaire de Toulouse, Université de Toulouse, Toulouse, France
| | - Cécile Bébéar
- USC EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,INRA, USC-EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,Department of Bacteriology, French National Reference Center for Bacterial STI, CHU Bordeaux, Bordeaux, France
| | - Laure Béven
- UMR 1332, BFP, University of Bordeaux, Bordeaux, France.,INRA, UMR 1332, BFP, Bordeaux, France
| | - Sabine Pereyre
- USC EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,INRA, USC-EA 3671 Mycoplasmal and Chlamydial Infections in Humans, University of Bordeaux, Bordeaux, France.,Department of Bacteriology, French National Reference Center for Bacterial STI, CHU Bordeaux, Bordeaux, France
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19
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Miller JC, Patil DP, Xia DF, Paine CB, Fauser F, Richards HW, Shivak DA, Bendaña YR, Hinkley SJ, Scarlott NA, Lam SC, Reik A, Zhou Y, Paschon DE, Li P, Wangzor T, Lee G, Zhang L, Rebar EJ. Enhancing gene editing specificity by attenuating DNA cleavage kinetics. Nat Biotechnol 2019; 37:945-952. [PMID: 31359006 DOI: 10.1038/s41587-019-0186-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 06/11/2019] [Indexed: 12/22/2022]
Abstract
Engineered nucleases have gained broad appeal for their ability to mediate highly efficient genome editing. However the specificity of these reagents remains a concern, especially for therapeutic applications, given the potential mutagenic consequences of off-target cleavage. Here we have developed an approach for improving the specificity of zinc finger nucleases (ZFNs) that engineers the FokI catalytic domain with the aim of slowing cleavage, which should selectively reduce activity at low-affinity off-target sites. For three ZFN pairs, we engineered single-residue substitutions in the FokI domain that preserved full on-target activity but showed a reduction in off-target indels of up to 3,000-fold. By combining this approach with substitutions that reduced the affinity of zinc fingers, we developed ZFNs specific for the TRAC locus that mediated 98% knockout in T cells with no detectable off-target activity at an assay background of ~0.01%. We anticipate that this approach, and the FokI variants we report, will enable routine generation of nucleases for gene editing with no detectable off-target activity.
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Affiliation(s)
| | | | - Danny F Xia
- Sangamo Therapeutics, Inc., Richmond, CA, USA
| | | | | | | | | | | | | | | | | | | | | | | | - Patrick Li
- Sangamo Therapeutics, Inc., Richmond, CA, USA
| | | | - Gary Lee
- Sangamo Therapeutics, Inc., Richmond, CA, USA
| | - Lei Zhang
- Sangamo Therapeutics, Inc., Richmond, CA, USA
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20
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Erkes A, Mücke S, Reschke M, Boch J, Grau J. PrediTALE: A novel model learned from quantitative data allows for new perspectives on TALE targeting. PLoS Comput Biol 2019; 15:e1007206. [PMID: 31295249 PMCID: PMC6650089 DOI: 10.1371/journal.pcbi.1007206] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 07/23/2019] [Accepted: 06/20/2019] [Indexed: 11/18/2022] Open
Abstract
Plant-pathogenic Xanthomonas bacteria secrete transcription activator-like effectors (TALEs) into host cells, where they act as transcriptional activators on plant target genes to support bacterial virulence. TALEs have a unique modular DNA-binding domain composed of tandem repeats. Two amino acids within each tandem repeat, termed repeat-variable diresidues, bind to contiguous nucleotides on the DNA sequence and determine target specificity. In this paper, we propose a novel approach for TALE target prediction to identify potential virulence targets. Our approach accounts for recent findings concerning TALE targeting, including frame-shift binding by repeats of aberrant lengths, and the flexible strand orientation of target boxes relative to the transcription start of the downstream target gene. The computational model can account for dependencies between adjacent RVD positions. Model parameters are learned from the wealth of quantitative data that have been generated over the last years. We benchmark the novel approach, termed PrediTALE, using RNA-seq data after Xanthomonas infection in rice, and find an overall improvement of prediction performance compared with previous approaches. Using PrediTALE, we are able to predict several novel putative virulence targets. However, we also observe that no target genes are predicted by any prediction tool for several TALEs, which we term orphan TALEs for this reason. We postulate that one explanation for orphan TALEs are incomplete gene annotations and, hence, propose to replace promoterome-wide by genome-wide scans for target boxes. We demonstrate that known targets from promoterome-wide scans may be recovered by genome-wide scans, whereas the latter, combined with RNA-seq data, are able to detect putative targets independent of existing gene annotations. Diseases caused by plant-pathogenic Xanthomonas bacteria are a serious threat for many important crop plants including rice. Efficiently protecting plants from these pathogens requires a deeper understanding of infection strategies. For many Xanthomonas strains, such infection strategies depend on a special class of effector proteins, termed transcription activator-like effectors (TALEs). TALEs may specifically activate genes of the host plant and, by this means, re-program the plant cell for the benefit of the pathogen. Target sequences and, consequently, target genes of a specific TALE may be predicted computationally from its amino acids. Here, we propose a novel approach for TALE target prediction that makes use of several insights into TALE biology but also of broad experimental data gained over the last years. We demonstrate that this approach yields a higher prediction accuracy than previous approaches. We further postulate that a strategy change from a restricted search only considering promoters of annotated genes to a broad genome-wide search is feasible and yields novel targets including previously neglected protein-coding genes but also non-coding RNAs of possibly regulatory function.
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Affiliation(s)
- Annett Erkes
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Stefanie Mücke
- Department of Plant Biotechnology, Leibniz Universität Hannover, Hannover, Germany
| | - Maik Reschke
- Department of Plant Biotechnology, Leibniz Universität Hannover, Hannover, Germany
| | - Jens Boch
- Department of Plant Biotechnology, Leibniz Universität Hannover, Hannover, Germany
| | - Jan Grau
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle, Germany
- * E-mail:
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21
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Tsuji S, Imanishi M. Modified nucleobase-specific gene regulation using engineered transcription activator-like effectors. Adv Drug Deliv Rev 2019; 147:59-65. [PMID: 31513826 DOI: 10.1016/j.addr.2019.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/20/2019] [Accepted: 08/22/2019] [Indexed: 01/10/2023]
Abstract
Epigenetic modification, as typified by cytosine methylation, is a key aspect of gene regulation that affects many biological processes. However, the biological roles of individual methylated cytosines are poorly understood. Sequence-specific DNA recognition tools can be used to investigate the roles of individual instances of DNA methylation. Transcription activator-like effectors (TALEs), which are DNA-binding proteins, are promising candidate tools with designable sequence specificity and sensitivity to DNA methylation. In this review, we describe the bases of DNA recognition of TALEs, including methylated cytosine recognition, and the applications of TALEs for the study of methylated DNA. In addition, we discuss TALE-based epigenome editing and oxidized methylated cytosine recognition.
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22
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Satheesh V, Zhang H, Wang X, Lei M. Precise editing of plant genomes - Prospects and challenges. Semin Cell Dev Biol 2019; 96:115-123. [PMID: 31002868 DOI: 10.1016/j.semcdb.2019.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 12/26/2022]
Abstract
The past decade has witnessed unprecedented development in genome engineering, a process that enables targeted modification of genomes. The identification of sequence-specific nucleases such as zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and the CRISPR/Cas system, in particular, has led to precise and efficient introduction of genetic variations into genomes of various organisms. Since the CRISPR/Cas system is highly versatile, cost-effective and much superior to ZFNs and TALENs, its widespread adoption by the research community has been inevitable. In plants, a number of studies have shown that CRISPR/Cas could be a potential tool in basic research where insertion, deletion and/or substitution in the genetic sequence could help answer fundamental questions about plant processes, and in applied research these technologies could help build or reverse-engineer plant systems to make them more useful. In this review article, we summarize technologies for precise editing of genomes with a special focus on the CRISPR/Cas system, highlight the latest developments in the CRISPR/Cas system and discuss the challenges and prospects in using the system for plant biology research.
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Affiliation(s)
- Viswanathan Satheesh
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Hui Zhang
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Xianting Wang
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mingguang Lei
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
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23
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Patsali P, Turchiano G, Papasavva P, Romito M, Loucari CC, Stephanou C, Christou S, Sitarou M, Mussolino C, Cornu TI, Antoniou MN, Lederer CW, Cathomen T, Kleanthous M. Correction of IVS I-110(G>A) β-thalassemia by CRISPR/Cas-and TALEN-mediated disruption of aberrant regulatory elements in human hematopoietic stem and progenitor cells. Haematologica 2019; 104:e497-e501. [PMID: 31004018 DOI: 10.3324/haematol.2018.215178] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Petros Patsali
- Department of Molecular Genetics Thalassemia, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Giandomenico Turchiano
- Institute for Transfusion Medicine and Gene Therapy, Medical Center, University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency, Medical Center, University of Freiburg, Freiburg, Germany
| | - Panayiota Papasavva
- Department of Molecular Genetics Thalassemia, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Marianna Romito
- Institute for Transfusion Medicine and Gene Therapy, Medical Center, University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency, Medical Center, University of Freiburg, Freiburg, Germany
| | - Constantinos C Loucari
- Department of Molecular Genetics Thalassemia, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Coralea Stephanou
- Department of Molecular Genetics Thalassemia, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Department of Medical and Molecular Genetics, King's College London, London, UK
| | | | - Maria Sitarou
- Thalassemia Center, Cyprus Ministry of Health, Cyprus
| | - Claudio Mussolino
- Institute for Transfusion Medicine and Gene Therapy, Medical Center, University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency, Medical Center, University of Freiburg, Freiburg, Germany
| | - Tatjana I Cornu
- Institute for Transfusion Medicine and Gene Therapy, Medical Center, University of Freiburg, Freiburg, Germany.,Center for Chronic Immunodeficiency, Medical Center, University of Freiburg, Freiburg, Germany
| | - Michael N Antoniou
- Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Carsten W Lederer
- Department of Molecular Genetics Thalassemia, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus .,Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Toni Cathomen
- Institute for Transfusion Medicine and Gene Therapy, Medical Center, University of Freiburg, Freiburg, Germany .,Center for Chronic Immunodeficiency, Medical Center, University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marina Kleanthous
- Department of Molecular Genetics Thalassemia, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus .,Cyprus School of Molecular Medicine, Nicosia, Cyprus
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24
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Paschon DE, Lussier S, Wangzor T, Xia DF, Li PW, Hinkley SJ, Scarlott NA, Lam SC, Waite AJ, Truong LN, Gandhi N, Kadam BN, Patil DP, Shivak DA, Lee GK, Holmes MC, Zhang L, Miller JC, Rebar EJ. Diversifying the structure of zinc finger nucleases for high-precision genome editing. Nat Commun 2019; 10:1133. [PMID: 30850604 PMCID: PMC6408524 DOI: 10.1038/s41467-019-08867-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 01/28/2019] [Indexed: 12/27/2022] Open
Abstract
Genome editing for therapeutic applications often requires cleavage within a narrow sequence window. Here, to enable such high-precision targeting with zinc-finger nucleases (ZFNs), we have developed an expanded set of architectures that collectively increase the configurational options available for design by a factor of 64. These new architectures feature the functional attachment of the FokI cleavage domain to the amino terminus of one or both zinc-finger proteins (ZFPs) in the ZFN dimer, as well as the option to skip bases between the target triplets of otherwise adjacent fingers in each zinc-finger array. Using our new architectures, we demonstrate targeting of an arbitrarily chosen 28 bp genomic locus at a density that approaches 1.0 (i.e., efficient ZFNs available for targeting almost every base step). We show that these new architectures may be used for targeting three loci of therapeutic significance with a high degree of precision, efficiency, and specificity.
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Affiliation(s)
- David E Paschon
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Stephanie Lussier
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Tenzin Wangzor
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Danny F Xia
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Patrick W Li
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Sarah J Hinkley
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Nicholas A Scarlott
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Stephen C Lam
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Adam J Waite
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Lynn N Truong
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Nimisha Gandhi
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Bhakti N Kadam
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Deepak P Patil
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - David A Shivak
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Gary K Lee
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Michael C Holmes
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Lei Zhang
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Jeffrey C Miller
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA
| | - Edward J Rebar
- Sangamo Therapeutics, Inc., 501 Canal Boulevard, Suite A100, Richmond, California, 94804, USA.
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25
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Geiger-Schuller K, Mitra J, Ha T, Barrick D. Functional instability allows access to DNA in longer transcription Activator-Like effector (TALE) arrays. eLife 2019; 8:38298. [PMID: 30810525 PMCID: PMC6461438 DOI: 10.7554/elife.38298] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 02/27/2019] [Indexed: 12/14/2022] Open
Abstract
Transcription activator-like effectors (TALEs) bind DNA through an array of tandem 34-residue repeats. How TALE repeat domains wrap around DNA, often extending more than 1.5 helical turns, without using external energy is not well understood. Here, we examine the kinetics of DNA binding of TALE arrays with varying numbers of identical repeats. Single molecule fluorescence analysis and deterministic modeling reveal conformational heterogeneity in both the free- and DNA-bound TALE arrays. Our findings, combined with previously identified partly folded states, indicate a TALE instability that is functionally important for DNA binding. For TALEs forming less than one superhelical turn around DNA, partly folded states inhibit DNA binding. In contrast, for TALEs forming more than one turn, partly folded states facilitate DNA binding, demonstrating a mode of ‘functional instability’ that facilitates macromolecular assembly. Increasing repeat number slows down interconversion between the various DNA-free and DNA-bound states. The DNA contains all the information needed to build an organism. It is made up of two strands that wind around each other like a twisted ladder to form the double helix. The strands consist of sugar and phosphate molecules, which attach to one of for bases. Genes are built from DNA, and contain specific sequences of these bases. Being able to modify DNA by deleting, inserting or changing certain sequences allows researchers to engineer tissues or even organisms for therapeutical and practical applications. One of these gene editing tools is the so-called transcription activator-like effector protein (or TALE for short). TALE proteins are derived from bacteria and are built from simple repeating units that can be linked to form a string-like structure. They have been found to be unstable proteins. To bind to DNA, TALES need to follow the shape of the double helix, adopting a spiral structure, but how exactly TALE proteins thread their way around the DNA is not clear. To investigate this, Geiger-Schuller et al. monitored single TALE units using fluorescent microscopy. This way, they could exactly measure the time it takes for single TALE proteins to bind and release DNA. The results showed that some TALE proteins bind DNA quickly, whereas others do this slowly. Using a computer model to analyze the different speeds of binding suggested that the fast binding comes from partly unfolded proteins that quickly associate with DNA, and that the slow binding comes from rigid, folded TALE proteins, which have a harder time wrapping around DNA. This suggest that the unstable nature of TALEs, helps these proteins to bind to DNA and turn on genes. These findings will help to design future TALE-based gene editing tools and also provide more insight into how large molecules can assemble into complex structures. A next step will be to identify TALE repeats with unstable states and to test TALE gene editing tools that have intentionally placed unstable units.
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Affiliation(s)
- Kathryn Geiger-Schuller
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, United States.,Program in Molecular Biophysics, Johns Hopkins University, Baltimore, United States
| | - Jaba Mitra
- Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, United States
| | - Taekjip Ha
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, United States.,Program in Molecular Biophysics, Johns Hopkins University, Baltimore, United States.,Department of Physics, Center for the Physics of Living Cells, University of Illinois at Urbana Champaign, Urbana, United States.,Institute for Genomic Biology, University of Illinois at Urbana Champaign, Urbana, United States.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, United States.,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, United States.,Howard Hughes Medical Institute, Baltimore, United States
| | - Doug Barrick
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, United States.,Program in Molecular Biophysics, Johns Hopkins University, Baltimore, United States
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26
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Anuar ND, Kurscheid S, Field M, Zhang L, Rebar E, Gregory P, Buchou T, Bowles J, Koopman P, Tremethick DJ, Soboleva TA. Gene editing of the multi-copy H2A.B gene and its importance for fertility. Genome Biol 2019; 20:23. [PMID: 30704500 PMCID: PMC6357441 DOI: 10.1186/s13059-019-1633-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 01/16/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Altering the biochemical makeup of chromatin by the incorporation of histone variants during development represents a key mechanism in regulating gene expression. The histone variant H2A.B, H2A.B.3 in mice, appeared late in evolution and is most highly expressed in the testis. In the mouse, it is encoded by three different genes. H2A.B expression is spatially and temporally regulated during spermatogenesis being most highly expressed in the haploid round spermatid stage. Active genes gain H2A.B where it directly interacts with polymerase II and RNA processing factors within splicing speckles. However, the importance of H2A.B for gene expression and fertility are unknown. RESULTS Here, we report the first mouse knockout of this histone variant and its effects on fertility, nuclear organization, and gene expression. In view of the controversy related to the generation of off-target mutations by gene editing approaches, we test the specificity of TALENs by disrupting the H2A.B multi-copy gene family using only one pair of TALENs. We show that TALENs do display a high level of specificity since no off-target mutations are detected by bioinformatics analyses of exome sequences obtained from three consecutive generations of knockout mice and by Sanger DNA sequencing. Male H2A.B.3 knockout mice are subfertile and display an increase in the proportion of abnormal sperm and clogged seminiferous tubules. Significantly, a loss of proper RNA Pol II targeting to distinct transcription-splicing territories and changes to pre-mRNA splicing are observed. CONCLUSION We have produced the first H2A.B knockout mouse using the TALEN approach.
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Affiliation(s)
- Nur Diana Anuar
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia
| | - Sebastian Kurscheid
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Matt Field
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.,Present Address: James Cook University, PO Box 6811, Cairns, QLD, 4870, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Lei Zhang
- Sangamo Therapeutics, 501 Canal Blvd, Richmond, CA, 94804, USA
| | - Edward Rebar
- Sangamo Therapeutics, 501 Canal Blvd, Richmond, CA, 94804, USA
| | - Philip Gregory
- Sangamo Therapeutics, 501 Canal Blvd, Richmond, CA, 94804, USA.,Present Address: bluebird bio, 60 Binney St, Cambridge, MA, 02142, USA
| | - Thierry Buchou
- CNRS UMR 5309, Inserm U1209, Universite' Grenoble Alpes, Institute for Advanced Biosciences, 38700, Grenoble, France
| | - Josephine Bowles
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Peter Koopman
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - David J Tremethick
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
| | - Tatiana A Soboleva
- The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
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27
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Bogdanove AJ, Bohm A, Miller JC, Morgan RD, Stoddard BL. Engineering altered protein-DNA recognition specificity. Nucleic Acids Res 2018; 46:4845-4871. [PMID: 29718463 PMCID: PMC6007267 DOI: 10.1093/nar/gky289] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/03/2018] [Accepted: 04/06/2018] [Indexed: 02/07/2023] Open
Abstract
Protein engineering is used to generate novel protein folds and assemblages, to impart new properties and functions onto existing proteins, and to enhance our understanding of principles that govern protein structure. While such approaches can be employed to reprogram protein-protein interactions, modifying protein-DNA interactions is more difficult. This may be related to the structural features of protein-DNA interfaces, which display more charged groups, directional hydrogen bonds, ordered solvent molecules and counterions than comparable protein interfaces. Nevertheless, progress has been made in the redesign of protein-DNA specificity, much of it driven by the development of engineered enzymes for genome modification. Here, we summarize the creation of novel DNA specificities for zinc finger proteins, meganucleases, TAL effectors, recombinases and restriction endonucleases. The ease of re-engineering each system is related both to the modularity of the protein and the extent to which the proteins have evolved to be capable of readily modifying their recognition specificities in response to natural selection. The development of engineered DNA binding proteins that display an ideal combination of activity, specificity, deliverability, and outcomes is not a fully solved problem, however each of the current platforms offers unique advantages, offset by behaviors and properties requiring further study and development.
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Affiliation(s)
- Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Andrew Bohm
- Sackler School of Graduate Biomedical Sciences, Tufts University, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Jeffrey C Miller
- Sangamo Therapeutics Inc. 501 Canal Blvd., Richmond, CA 94804, USA
| | - Richard D Morgan
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98019, USA
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28
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Tsuji S, Futaki S, Imanishi M. Sequence-specific recognition of methylated DNA by an engineered transcription activator-like effector protein. Chem Commun (Camb) 2018; 52:14238-14241. [PMID: 27872906 DOI: 10.1039/c6cc06824c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A 5mC-selective TALE-repeat was created by screening a TALE repeat library containing randomized amino acids at repeat variable diresidues and their neighboring residues. The new repeat showed high 5mC discrimination ability. An artificial TALE containing the new repeat activated an endogenous gene in a genomic methylation status-dependent manner.
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Affiliation(s)
- Shogo Tsuji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
| | - Shiroh Futaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
| | - Miki Imanishi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
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29
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Waryah CB, Moses C, Arooj M, Blancafort P. Zinc Fingers, TALEs, and CRISPR Systems: A Comparison of Tools for Epigenome Editing. Methods Mol Biol 2018. [PMID: 29524128 DOI: 10.1007/978-1-4939-7774-1_2] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The completion of genome, epigenome, and transcriptome mapping in multiple cell types has created a demand for precision biomolecular tools that allow researchers to functionally manipulate DNA, reconfigure chromatin structure, and ultimately reshape gene expression patterns. Epigenetic editing tools provide the ability to interrogate the relationship between epigenetic modifications and gene expression. Importantly, this information can be exploited to reprogram cell fate for both basic research and therapeutic applications. Three different molecular platforms for epigenetic editing have been developed: zinc finger proteins (ZFs), transcription activator-like effectors (TALEs), and the system of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) proteins. These platforms serve as custom DNA-binding domains (DBDs), which are fused to epigenetic modifying domains to manipulate epigenetic marks at specific sites in the genome. The addition and/or removal of epigenetic modifications reconfigures local chromatin structure, with the potential to provoke long-lasting changes in gene transcription. Here we summarize the molecular structure and mechanism of action of ZF, TALE, and CRISPR platforms and describe their applications for the locus-specific manipulation of the epigenome. The advantages and disadvantages of each platform will be discussed with regard to genomic specificity, potency in regulating gene expression, and reprogramming cell phenotypes, as well as ease of design, construction, and delivery. Finally, we outline potential applications for these tools in molecular biology and biomedicine and identify possible barriers to their future clinical implementation.
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Affiliation(s)
- Charlene Babra Waryah
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia
| | - Colette Moses
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia
| | - Mahira Arooj
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Pilar Blancafort
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia.
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia.
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30
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Abstract
PURPOSE OF REVIEW The opportunities afforded through the recent advent of genome-editing technologies have allowed investigators to more easily study a number of diseases. The advantages and limitations of the most prominent genome-editing technologies are described in this review, along with potential applications specifically focused on cardiovascular diseases. RECENT FINDINGS The recent genome-editing tools using programmable nucleases, such as zinc-finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9), have rapidly been adapted to manipulate genes in a variety of cellular and animal models. A number of recent cardiovascular disease-related publications report cases in which specific mutations are introduced into disease models for functional characterization and for testing of therapeutic strategies. Recent advances in genome-editing technologies offer new approaches to understand and treat diseases. Here, we discuss genome editing strategies to easily characterize naturally occurring mutations and offer strategies with potential clinical relevance.
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Affiliation(s)
- Alexandra C Chadwick
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Kiran Musunuru
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. .,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
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31
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Techniques and strategies employing engineered transcription factors. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017. [DOI: 10.1016/j.cobme.2017.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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32
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Rathi P, Witte A, Summerer D. Engineering DNA Backbone Interactions Results in TALE Scaffolds with Enhanced 5-Methylcytosine Selectivity. Sci Rep 2017; 7:15067. [PMID: 29118409 PMCID: PMC5678105 DOI: 10.1038/s41598-017-15361-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/25/2017] [Indexed: 12/14/2022] Open
Abstract
Transcription activator-like effectors (TALEs) are DNA major-groove binding proteins widely used for genome targeting. TALEs contain an N-terminal region (NTR) and a central repeat domain (CRD). Repeats of the CRD selectively recognize each one DNA nucleobase, offering programmability. Moreover, repeats with selectivity for 5-methylcytosine (5mC) and its oxidized derivatives can be designed for analytical applications. However, both TALE domains also nonspecifically interact with DNA phosphates via basic amino acids. To enhance the 5mC selectivity of TALEs, we aimed to decrease the nonselective binding energy of TALEs. We substituted basic amino acids with alanine in the NTR and identified TALE mutants with increased selectivity. We then analysed conserved, DNA phosphate-binding KQ diresidues in CRD repeats and identified further improved mutants. Combination of mutations in the NTR and CRD was highly synergetic and resulted in TALE scaffolds with up to 4.3-fold increased selectivity in genomic 5mC analysis via affinity enrichment. Moreover, transcriptional activation in HEK293T cells by a TALE-VP64 construct based on this scaffold design exhibited a 3.5-fold increased 5mC selectivity. This provides perspectives for improved 5mC analysis and for the 5mC-conditional control of TALE-based editing constructs in vivo.
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Affiliation(s)
- Preeti Rathi
- Department of Chemistry and Chemical Biology, Technical University of Dortmund, Otto-Hahn-Str. 4a, 44227, Dortmund, Germany
| | - Anna Witte
- Department of Chemistry and Chemical Biology, Technical University of Dortmund, Otto-Hahn-Str. 4a, 44227, Dortmund, Germany
| | - Daniel Summerer
- Department of Chemistry and Chemical Biology, Technical University of Dortmund, Otto-Hahn-Str. 4a, 44227, Dortmund, Germany.
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33
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Rinaldi FC, Doyle LA, Stoddard BL, Bogdanove AJ. The effect of increasing numbers of repeats on TAL effector DNA binding specificity. Nucleic Acids Res 2017; 45:6960-6970. [PMID: 28460076 PMCID: PMC5499867 DOI: 10.1093/nar/gkx342] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/21/2017] [Indexed: 01/27/2023] Open
Abstract
Transcription activator-like effectors (TALEs) recognize their DNA targets via tandem repeats, each specifying a single nucleotide base in a one-to-one sequential arrangement. Due to this modularity and their ability to bind long DNA sequences with high specificity, TALEs have been used in many applications. Contributions of individual repeat-nucleotide associations to affinity and specificity have been characterized. Here, using in vitro binding assays, we examined the relationship between the number of repeats in a TALE and its affinity, for both target and non-target DNA. Each additional repeat provides extra binding energy for the target DNA, with the gain decaying exponentially such that binding energy saturates. Affinity for non-target DNA also increases non-linearly with the number of repeats, but with a slower decay of gain. The difference between the effect of length on affinity for target versus non-target DNA manifests in specificity increasing then diminishing with increasing TALE length, peaking between 15 and 19 repeats. Modeling across different hypothetical saturation levels and rates of gain decay, reflecting different repeat compositions, yielded a similar range of specificity optima. This range encompasses the mean and median length of native TALEs, suggesting that these proteins as a group have evolved for maximum specificity.
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Affiliation(s)
- Fabio C Rinaldi
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Lindsey A Doyle
- Division of Basic Sciences, Fred Hutchinson Cancer Research, Seattle, WA 98019, USA
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research, Seattle, WA 98019, USA
| | - Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
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34
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Gautron AS, Juillerat A, Guyot V, Filhol JM, Dessez E, Duclert A, Duchateau P, Poirot L. Fine and Predictable Tuning of TALEN Gene Editing Targeting for Improved T Cell Adoptive Immunotherapy. MOLECULAR THERAPY-NUCLEIC ACIDS 2017; 9:312-321. [PMID: 29246309 PMCID: PMC5684446 DOI: 10.1016/j.omtn.2017.10.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/11/2017] [Accepted: 10/11/2017] [Indexed: 12/25/2022]
Abstract
Using a TALEN-mediated gene-editing approach, we have previously described a process for the large-scale manufacturing of “off-the-shelf” CAR T cells from third-party donor T cells by disrupting the gene encoding TCRα constant chain (TRAC). Taking advantage of a previously described strategy to control TALEN targeting based on the exclusion capacities of non-conventional RVDs, we have developed highly efficient and specific nucleases targeting a key T cell immune checkpoint, PD-1, to improve engineered CAR T cells’ functionalities. Here, we demonstrate that this approach allows combined TRAC and PDCD1 TALEN processing at the desired locus while eliminating low-frequency off-site processing. Thus, by replacing few RVDs, we provide here an easy and rapid redesign of optimal TALEN combinations. We anticipate that this method can greatly benefit multiplex editing, which is of key importance especially for therapeutic applications where high editing efficiencies need to be associated with maximal specificity and safety.
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Affiliation(s)
| | | | - Valérie Guyot
- Cellectis SA, 8 Rue de la Croix Jarry, 75013 Paris, France
| | | | - Emilie Dessez
- Cellectis SA, 8 Rue de la Croix Jarry, 75013 Paris, France
| | | | | | - Laurent Poirot
- Cellectis SA, 8 Rue de la Croix Jarry, 75013 Paris, France
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35
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Deciphering TAL effectors for 5-methylcytosine and 5-hydroxymethylcytosine recognition. Nat Commun 2017; 8:901. [PMID: 29026078 PMCID: PMC5638953 DOI: 10.1038/s41467-017-00860-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 08/01/2017] [Indexed: 12/29/2022] Open
Abstract
DNA recognition by transcription activator-like effector (TALE) proteins is mediated by tandem repeats that specify nucleotides through repeat-variable diresidues. These repeat-variable diresidues form direct and sequence-specific contacts to DNA bases; hence, TALE-DNA interaction is sensitive to DNA chemical modifications. Here we conduct a thorough investigation, covering all theoretical repeat-variable diresidue combinations, for their recognition capabilities for 5-methylcytosine and 5-hydroxymethylcytosine, two important epigenetic markers in higher eukaryotes. We identify both specific and degenerate repeat-variable diresidues for 5-methylcytosine and 5-hydroxymethylcytosine. Utilizing these novel repeat-variable diresidues, we achieve methylation-dependent gene activation and genome editing in vivo; we also report base-resolution detection of 5hmC in an in vitro assay. Our work deciphers repeat-variable diresidues for 5-methylcytosine and 5-hydroxymethylcytosine, and provides tools for TALE-dependent epigenome recognition.Transcription activator-like effector proteins recognise specific DNA sequences via tandem repeats. Here the authors demonstrate TALEs can recognise the methylated bases 5mC and 5hmC, enabling them to detect epigenetic modifications.
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36
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Refining strategies to translate genome editing to the clinic. Nat Med 2017; 23:415-423. [PMID: 28388605 DOI: 10.1038/nm.4313] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 02/27/2017] [Indexed: 12/17/2022]
Abstract
Recent progress in developing programmable nucleases, such as zinc-finger nucleases, transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeat (CRISPR)-Cas nucleases, have paved the way for gene editing to enter clinical practice. This translation is a result of combining high nuclease activity with high specificity and successfully applying this technology in various preclinical disease models, including infectious disease, primary immunodeficiencies, hemoglobinopathies, hemophilia and muscular dystrophy. Several clinical gene-editing trials, both ex vivo and in vivo, have been initiated in the past 2 years, including studies that aim to knockout genes as well as to add therapeutic transgenes. Here we discuss the advances made in the gene-editing field in recent years, and specify priorities that need to be addressed to expand therapeutic genome editing to further disease entities.
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37
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Flade S, Jasper J, Gieß M, Juhasz M, Dankers A, Kubik G, Koch O, Weinhold E, Summerer D. The N6-Position of Adenine Is a Blind Spot for TAL-Effectors That Enables Effective Binding of Methylated and Fluorophore-Labeled DNA. ACS Chem Biol 2017; 12:1719-1725. [PMID: 28493677 DOI: 10.1021/acschembio.7b00324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transcription-activator-like effectors (TALEs) are programmable DNA binding proteins widely used for genome targeting. TALEs consist of multiple concatenated repeats, each selectively recognizing one nucleobase via a defined repeat variable diresidue (RVD). Effective use of TALEs requires knowledge about their binding ability to epigenetic and other modified nucleobases occurring in target DNA. However, aside from epigenetic cytosine-5 modifications, the binding ability of TALEs to modified DNA is unknown. We here study the binding of TALEs to the epigenetic nucleobase N6-methyladenine (6mA) found in prokaryotic and recently also eukaryotic genomes. We find that the natural, adenine (A)-binding RVD NI is insensitive to 6mA. Model-assisted structure-function studies reveal accommodation of 6mA by RVDs with altered hydrophobic surfaces and abilities of hydrogen bonding to the N6-amino group or N7 atom of A. Surprisingly, this tolerance of N6 substitution was transferrable to bulky N6-alkynyl substituents usable for click chemistry and even to a large rhodamine dye, establishing the N6 position of A as the first site of DNA that offers label introduction within TALE target sites without interference. These findings will guide future in vivo studies with TALEs and expand their applicability as DNA capture probes for analytical applications in vitro.
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Affiliation(s)
- Sarah Flade
- Department
of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Julia Jasper
- Department
of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Mario Gieß
- Department
of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Matyas Juhasz
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Andreas Dankers
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Grzegorz Kubik
- Department
of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Oliver Koch
- Department
of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Elmar Weinhold
- Institute
of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany
| | - Daniel Summerer
- Department
of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
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38
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Geiger-Schuller K, Barrick D. Broken TALEs: Transcription Activator-like Effectors Populate Partly Folded States. Biophys J 2017; 111:2395-2403. [PMID: 27926841 DOI: 10.1016/j.bpj.2016.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 01/14/2023] Open
Abstract
Transcription activator-like effector proteins (TALEs) contain large numbers of repeats that bind double-stranded DNA, wrapping around DNA to form a continuous superhelix. Since unbound TALEs retain superhelical structure, it seems likely that DNA binding requires a significant structural distortion or partial unfolding. In this study, we use nearest-neighbor "Ising" analysis of consensus TALE (cTALE) repeat unfolding to quantify intrinsic folding free energies, coupling energies between repeats, and the free energy distribution of partly unfolded states, and to determine how those energies depend on the sequence that determines DNA-specificity (called the "RVD"). We find a moderate level of cooperativity for both the HD and NS RVD sequences (stabilizing interfaces combined with unstable repeats), as has been seen in other linear repeat proteins. Surprisingly, RVD sequence identity influences both the overall stability and the balance of intrinsic repeat stability and interfacial coupling energy. Using parameters from the Ising analysis, we have analyzed the distribution of partly folded states as a function of cTALE length and RVD sequence. We find partly unfolded states where one or more repeats are unfolded to be energetically accessible. Mixing repeats with different RVD sequences increases the population of partially folded states. Local folding free energies plateau for central repeats, suggesting that TALEs access partially folded states where a single internal repeat is unfolded while adjacent repeats remain folded. This breakage should allow TALEs to access superhelically-broken states, and may facilitate DNA binding.
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Affiliation(s)
- Kathryn Geiger-Schuller
- Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland; T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland
| | - Doug Barrick
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland.
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39
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Abstract
Therapeutic gene editing is significant for medical advancement. Safety is intricately linked to the specificity of the editing tools used to cut at precise genomic targets. Improvements can be achieved by thoughtful design of nucleases and repair templates, analysis of off-target editing, and careful utilization of viral vectors. Advancements in DNA repair mechanisms and development of new generations of tools improve targeting of specific sequences while minimizing risks. It is important to plot a safe course for future clinical trials. This article reviews safety and specificity for therapeutic gene editing to spur dialogue and advancement.
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Affiliation(s)
- Christopher T Lux
- Department of Pediatrics, Cancer and Blood Disorders Center, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA
| | - Andrew M Scharenberg
- Department of Pediatrics, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA; Department of Immunology, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA.
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40
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Generation of dTALEs and Libraries of Synthetic TALE-Activated Promoters for Engineering of Gene Regulatory Networks in Plants. Methods Mol Biol 2017. [PMID: 28623587 DOI: 10.1007/978-1-4939-7125-1_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Transcription factors with programmable DNA-binding specificity constitute valuable tools for the design of orthogonal gene regulatory networks for synthetic biology. Transcription activator-like effectors (TALEs), as natural transcription regulators, were used to design, build, and test libraries of synthetic TALE-activated promoters (STAPs) that show a broad range of expression levels in plants. In this chapter, we present protocols for the construction of artificial TALEs and corresponding STAPs.
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41
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Abstract
PURPOSE OF REVIEW Alternative approaches to conventional drug-based cancer treatments have seen T cell therapies deployed more widely over the last decade. This is largely due to their ability to target and kill specific cell types based on receptor recognition. Introduction of recombinant T cell receptors (TCRs) using viral vectors and HLA-independent T cell therapies using chimeric antigen receptors (CARs) are discussed. This article reviews the tools used for genome editing, with particular emphasis on the applications of site-specific DNA nuclease mediated editing for T cell therapies. RECENT FINDINGS Genetic engineering of T cells using TCRs and CARs with redirected antigen-targeting specificity has resulted in clinical success of several immunotherapies. In conjunction, the application of genome editing technologies has resulted in the generation of HLA-independent universal T cells for allogeneic transplantation, improved T cell sustainability through knockout of the checkpoint inhibitor, programmed cell death protein-1 (PD-1), and has shown efficacy as an antiviral therapy through direct targeting of viral genomic sequences and entry receptors. SUMMARY The combined use of engineered antigen-targeting moieties and innovative genome editing technologies have recently shown success in a small number of clinical trials targeting HIV and hematological malignancies and are now being incorporated into existing strategies for other immunotherapies.
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Affiliation(s)
- Juliette M. K. M. Delhove
- Molecular Immunology Unit, UCL Great Ormond Street Institute of Child Health, University College London (UCL), 30 Guilford Street, London, WC1N 1EH UK
| | - Waseem Qasim
- Molecular Immunology Unit, UCL Great Ormond Street Institute of Child Health, University College London (UCL), 30 Guilford Street, London, WC1N 1EH UK
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42
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Haas SA, Dettmer V, Cathomen T. Therapeutic genome editing with engineered nucleases. Hamostaseologie 2017; 37:45-52. [PMID: 28070592 DOI: 10.5482/hamo-16-09-0035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 12/20/2016] [Indexed: 01/17/2023] Open
Abstract
Targeted genome editing with designer nucleases, such as zinc finger nucleases, TALE nucleases, and CRISPR-Cas nucleases, has heralded a new era in gene therapy. Genetic disorders, which have not been amenable to conventional gene-addition-type gene therapy approaches, such as disorders with dominant inheritance or diseases caused by mutations in tightly regulated genes, can now be treated by precise genome surgery. Moreover, engineered nucleases enable novel genetic interventions to fight infectious diseases or to improve cancer immunotherapies. Here, we review the development of the different classes of programmable nucleases, discuss the challenges and improvements in translating gene editing into clinical use, and give an outlook on what applications can expect to enter the clinic in the near future.
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Affiliation(s)
| | | | - Toni Cathomen
- Toni Cathomen, Ph.D., Institute for Cell and Gene Therapy, Medical Center - University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany, Phone: +49 761 270 34800, Fax: + 49 761 270 37900, E-Mail:
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43
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de Lange O, Schandry N, Wunderlich M, Berendzen KW, Lahaye T. Exploiting the sequence diversity of TALE-like repeats to vary the strength of dTALE-promoter interactions. Synth Biol (Oxf) 2017; 2:ysx004. [PMID: 32995505 PMCID: PMC7445789 DOI: 10.1093/synbio/ysx004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 06/13/2017] [Accepted: 06/16/2017] [Indexed: 11/13/2022] Open
Abstract
Designer transcription activator-like effectors (dTALEs) are programmable transcription factors used to regulate user-defined promoters. The TALE DNA-binding domain is a tandem series of amino acid repeats that each bind one DNA base. Each repeat is 33-35 amino acids long. A residue in the center of each repeat is responsible for defining DNA base specificity and is referred to as the base specificying residue (BSR). Other repeat residues are termed non-BSRs and can contribute to TALE DNA affinity in a non-base-specific manner. Previous dTALE engineering efforts have focused on BSRs. Non-BSRs have received less attention, perhaps because there is almost no non-BSR sequence diversity in natural TALEs. However, more sequence diverse, TALE-like proteins are found in diverse bacterial clades. Here, we show that natural non-BSR sequence diversity of TALEs and TALE-likes can be used to modify DNA-binding strength in a new form of dTALE repeat array that we term variable sequence TALEs (VarSeTALEs). We generated VarSeTALE repeat modules through random assembly of repeat sequences from different origins, while holding BSR composition, and thus base preference, constant. We used two different VarSeTALE design approaches combing either whole repeats from different TALE-like sources (inter-repeat VarSeTALEs) or repeat subunits corresponding to secondary structural elements (intra-repeat VarSeTALEs). VarSeTALE proteins were assayed in bacteria, plant protoplasts and leaf tissues. In each case, VarSeTALEs activated or repressed promoters with a range of activities. Our results indicate that natural non-BSR diversity can be used to diversify the binding strengths of dTALE repeat arrays while keeping target sequences constant.
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Affiliation(s)
- Orlando de Lange
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universitat Tübingen, Tübingen, Germany
- Department of Electrical Engineering, University of Washington, Seattle, WA, USA
| | - Niklas Schandry
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universitat Tübingen, Tübingen, Germany
| | - Markus Wunderlich
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universitat Tübingen, Tübingen, Germany
| | - Kenneth Wayne Berendzen
- ZMBP Central Facilities, Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Thomas Lahaye
- Department of General Genetics, Center for Plant Molecular Biology (ZMBP), Eberhard Karls Universitat Tübingen, Tübingen, Germany
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44
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Gaj T, Sirk SJ, Shui SL, Liu J. Genome-Editing Technologies: Principles and Applications. Cold Spring Harb Perspect Biol 2016; 8:cshperspect.a023754. [PMID: 27908936 DOI: 10.1101/cshperspect.a023754] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Targeted nucleases have provided researchers with the ability to manipulate virtually any genomic sequence, enabling the facile creation of isogenic cell lines and animal models for the study of human disease, and promoting exciting new possibilities for human gene therapy. Here we review three foundational technologies-clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9), transcription activator-like effector nucleases (TALENs), and zinc-finger nucleases (ZFNs). We discuss the engineering advances that facilitated their development and highlight several achievements in genome engineering that were made possible by these tools. We also consider artificial transcription factors, illustrating how this technology can complement targeted nucleases for synthetic biology and gene therapy.
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Affiliation(s)
- Thomas Gaj
- Department of Bioengineering, University of California, Berkeley, California 94720
| | - Shannon J Sirk
- Department of Chemical Engineering, Stanford University, Stanford, California 94305
| | - Sai-Lan Shui
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Jia Liu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
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45
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Hendriks WT, Warren CR, Cowan CA. Genome Editing in Human Pluripotent Stem Cells: Approaches, Pitfalls, and Solutions. Cell Stem Cell 2016; 18:53-65. [PMID: 26748756 DOI: 10.1016/j.stem.2015.12.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Human pluripotent stem cells (hPSCs) with knockout or mutant alleles can be generated using custom-engineered nucleases. Transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 nucleases are the most commonly employed technologies for editing hPSC genomes. In this Protocol Review, we provide a brief overview of custom-engineered nucleases in the context of gene editing in hPSCs with a focus on the application of TALENs and CRISPR/Cas9. We will highlight the advantages and disadvantages of each method and discuss theoretical and technical considerations for experimental design.
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Affiliation(s)
- William T Hendriks
- The Collaborative Center for X-Linked Dystonia Parkinsonism, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA; Harvard Brain Science Initiative, Harvard Medical School, Boston, MA 02114, USA
| | - Curtis R Warren
- Department of Stem Cell and Regenerative Biology, Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Chad A Cowan
- Department of Stem Cell and Regenerative Biology, Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA; Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.
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46
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Yu KR, Natanson H, Dunbar CE. Gene Editing of Human Hematopoietic Stem and Progenitor Cells: Promise and Potential Hurdles. Hum Gene Ther 2016; 27:729-740. [PMID: 27483988 DOI: 10.1089/hum.2016.107] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hematopoietic stem and progenitor cells (HSPCs) have great therapeutic potential because of their ability to both self-renew and differentiate. It has been proposed that, given their unique properties, a small number of genetically modified HSPCs could accomplish lifelong, corrective reconstitution of the entire hematopoietic system in patients with various hematologic disorders. Scientists have demonstrated that gene addition therapies-targeted to HSPCs and using integrating retroviral vectors-possess clear clinical benefits in multiple diseases, among them immunodeficiencies, storage disorders, and hemoglobinopathies. Scientists attempting to develop clinically relevant gene therapy protocols have, however, encountered a number of unexpected hurdles because of their incomplete knowledge of target cells, genomic control, and gene transfer technologies. Targeted gene-editing technologies using engineered nucleases such as ZFN, TALEN, and/or CRISPR/Cas9 RGEN show great clinical promise, allowing for the site-specific correction of disease-causing mutations-a process with important applications in autosomal dominant or dominant-negative genetic disorders. The relative simplicity of the CRISPR/Cas9 system, in particular, has sparked an exponential increase in the scientific community's interest in and use of these gene-editing technologies. In this minireview, we discuss the specific applications of gene-editing technologies in human HSPCs, as informed by prior experience with gene addition strategies. HSPCs are desirable but challenging targets; the specific mechanisms these cells evolved to protect themselves from DNA damage render them potentially more susceptible to oncogenesis, especially given their ability to self-renew and their long-term proliferative potential. We further review scientists' experience with gene-editing technologies to date, focusing on strategies to move these techniques toward implementation in safe and effective clinical trials.
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Affiliation(s)
- Kyung-Rok Yu
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Hannah Natanson
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Cynthia E Dunbar
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
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47
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Rathi P, Maurer S, Kubik G, Summerer D. Isolation of Human Genomic DNA Sequences with Expanded Nucleobase Selectivity. J Am Chem Soc 2016; 138:9910-8. [PMID: 27429302 DOI: 10.1021/jacs.6b04807] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the direct isolation of user-defined DNA sequences from the human genome with programmable selectivity for both canonical and epigenetic nucleobases. This is enabled by the use of engineered transcription-activator-like effectors (TALEs) as DNA major groove-binding probes in affinity enrichment. The approach provides the direct quantification of 5-methylcytosine (5mC) levels at single genomic nucleotide positions in a strand-specific manner. We demonstrate the simple, multiplexed typing of a variety of epigenetic cancer biomarker 5mC with custom TALE mixes. Compared to antibodies as the most widely used affinity probes for 5mC analysis, i.e., employed in the methylated DNA immunoprecipitation (MeDIP) protocol, TALEs provide superior sensitivity, resolution and technical ease. We engineer a range of size-reduced TALE repeats and establish full selectivity profiles for their binding to all five human cytosine nucleobases. These provide insights into their nucleobase recognition mechanisms and reveal the ability of TALEs to isolate genomic target sequences with selectivity for single 5-hydroxymethylcytosine and, in combination with sodium borohydride reduction, single 5-formylcytosine nucleobases.
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Affiliation(s)
- Preeti Rathi
- Department of Chemistry and Chemical Biology, Technical University of Dortmund , Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Sara Maurer
- Department of Chemistry and Chemical Biology, Technical University of Dortmund , Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Grzegorz Kubik
- Department of Chemistry and Chemical Biology, Technical University of Dortmund , Otto-Hahn-Str. 6, 44227 Dortmund, Germany
| | - Daniel Summerer
- Department of Chemistry and Chemical Biology, Technical University of Dortmund , Otto-Hahn-Str. 6, 44227 Dortmund, Germany
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48
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Lin J, Musunuru K. Genome engineering tools for building cellular models of disease. FEBS J 2016; 283:3222-31. [PMID: 27218233 DOI: 10.1111/febs.13763] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 05/16/2016] [Accepted: 05/21/2016] [Indexed: 12/18/2022]
Abstract
With the recent development of methods for genome editing of human pluripotent stem cells, study of the genetic basis of human diseases has been rapidly advancing. Genome-edited differentiated stem cells have provided new and more accurate insights into genomic underpinnings of diseases for which there have not been adequate treatments, and moving toward clinical application of genome editing holds great promise for acceleration of therapeutic translation. Here, we review recent advances in genome-editing technologies and their application to human biology in disease modeling and beyond.
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Affiliation(s)
- Jennie Lin
- Renal, Electrolyte, and Hypertension Division, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Kiran Musunuru
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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49
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Tan W, Proudfoot C, Lillico SG, Whitelaw CBA. Gene targeting, genome editing: from Dolly to editors. Transgenic Res 2016; 25:273-87. [PMID: 26847670 PMCID: PMC4882362 DOI: 10.1007/s11248-016-9932-x] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/06/2016] [Indexed: 12/25/2022]
Abstract
One of the most powerful strategies to investigate biology we have as scientists, is the ability to transfer genetic material in a controlled and deliberate manner between organisms. When applied to livestock, applications worthy of commercial venture can be devised. Although initial methods used to generate transgenic livestock resulted in random transgene insertion, the development of SCNT technology enabled homologous recombination gene targeting strategies to be used in livestock. Much has been accomplished using this approach. However, now we have the ability to change a specific base in the genome without leaving any other DNA mark, with no need for a transgene. With the advent of the genome editors this is now possible and like other significant technological leaps, the result is an even greater diversity of possible applications. Indeed, in merely 5 years, these 'molecular scissors' have enabled the production of more than 300 differently edited pigs, cattle, sheep and goats. The advent of genome editors has brought genetic engineering of livestock to a position where industry, the public and politicians are all eager to see real use of genetically engineered livestock to address societal needs. Since the first transgenic livestock reported just over three decades ago the field of livestock biotechnology has come a long way-but the most exciting period is just starting.
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Affiliation(s)
- Wenfang Tan
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG UK
| | - Chris Proudfoot
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG UK
| | - Simon G. Lillico
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG UK
| | - C. Bruce A. Whitelaw
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG UK
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50
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Abstract
Transcription activator-like effector nucleases (TALENs) are one of several types of programmable, engineered nucleases that bind and cleave specific DNA sequences. Cellular machinery repairs the cleaved DNA by introducing indels. In this review, we emphasize the potential, explore progress, and identify challenges in using TALENs as a therapeutic tool to treat HIV infection. TALENs have less off-target editing and can be more effective at tolerating HIV escape mutations than CRISPR/Cas-9. Scientists have explored TALEN-mediated editing of host genes such as viral entry receptors (CCR5 and CXCR4) and a protein involved in proviral integration (LEDGF/p75). Viral targets include the proviral DNA, particularly focused on the long terminal repeats. Major challenges with translating gene therapy from bench to bedside are improving cleavage efficiency and delivery, while minimizing off-target editing, cytotoxicity, and immunogenicity. However, rapid improvements in TALEN technology are enhancing cleavage efficiency and specificity. Therapeutic testing in animal models of HIV infection will help determine whether TALENs are a viable HIV treatment therapy. TALENs or other engineered nucleases could shift the therapeutic paradigm from life-long antiretroviral therapy toward eradication of HIV infection.
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