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Leal AF, Herreno-Pachón AM, Benincore-Flórez E, Karunathilaka A, Tomatsu S. Current Strategies for Increasing Knock-In Efficiency in CRISPR/Cas9-Based Approaches. Int J Mol Sci 2024; 25:2456. [PMID: 38473704 PMCID: PMC10931195 DOI: 10.3390/ijms25052456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 02/15/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024] Open
Abstract
Since its discovery in 2012, the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) system has supposed a promising panorama for developing novel and highly precise genome editing-based gene therapy (GT) alternatives, leading to overcoming the challenges associated with classical GT. Classical GT aims to deliver transgenes to the cells via their random integration in the genome or episomal persistence into the nucleus through lentivirus (LV) or adeno-associated virus (AAV), respectively. Although high transgene expression efficiency is achieved by using either LV or AAV, their nature can result in severe side effects in humans. For instance, an LV (NCT03852498)- and AAV9 (NCT05514249)-based GT clinical trials for treating X-linked adrenoleukodystrophy and Duchenne Muscular Dystrophy showed the development of myelodysplastic syndrome and patient's death, respectively. In contrast with classical GT, the CRISPR/Cas9-based genome editing requires the homologous direct repair (HDR) machinery of the cells for inserting the transgene in specific regions of the genome. This sophisticated and well-regulated process is limited in the cell cycle of mammalian cells, and in turn, the nonhomologous end-joining (NHEJ) predominates. Consequently, seeking approaches to increase HDR efficiency over NHEJ is crucial. This manuscript comprehensively reviews the current alternatives for improving the HDR for CRISPR/Cas9-based GTs.
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Affiliation(s)
- Andrés Felipe Leal
- Nemours Children’s Health, Wilmington, DE 19803, USA; (A.F.L.); (A.M.H.-P.); (E.B.-F.); (A.K.)
- Institute for the Study of Inborn Errors of Metabolism, Faculty of Science, Pontificia Universidad Javeriana, Bogotá 110231, Colombia
| | - Angelica María Herreno-Pachón
- Nemours Children’s Health, Wilmington, DE 19803, USA; (A.F.L.); (A.M.H.-P.); (E.B.-F.); (A.K.)
- Faculty of Arts and Sciences, University of Delaware, Newark, DE 19716, USA
| | - Eliana Benincore-Flórez
- Nemours Children’s Health, Wilmington, DE 19803, USA; (A.F.L.); (A.M.H.-P.); (E.B.-F.); (A.K.)
| | - Amali Karunathilaka
- Nemours Children’s Health, Wilmington, DE 19803, USA; (A.F.L.); (A.M.H.-P.); (E.B.-F.); (A.K.)
- Faculty of Arts and Sciences, University of Delaware, Newark, DE 19716, USA
| | - Shunji Tomatsu
- Nemours Children’s Health, Wilmington, DE 19803, USA; (A.F.L.); (A.M.H.-P.); (E.B.-F.); (A.K.)
- Faculty of Arts and Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu 501-1194, Japan
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA 19144, USA
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Wang JH, Wu SJ, Li Y, Zhao Y, Liu ZM, Deng SL, Lian ZX. Improving the Efficiency of Precise Genome Editing with CRISPR/Cas9 to Generate Goats Overexpressing Human Butyrylcholinesterase. Cells 2023; 12:1818. [PMID: 37508483 PMCID: PMC10378061 DOI: 10.3390/cells12141818] [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: 05/02/2023] [Revised: 07/02/2023] [Accepted: 07/04/2023] [Indexed: 07/30/2023] Open
Abstract
The CRISPR/Cas9 system is widely used for genome editing in livestock production, although off-target effects can occur. It is the main method to produce genome-edited goats by somatic cell nuclear transfer (SCNT) of CRISPR/Cas9-mediated genome-edited primary goat fetal fibroblast cells (GFFs). Improving the double-strand break (DSB) efficiency of Cas9 in primary cells would improve the homologous repair (HR) efficiency. The low efficiency of HR remains a major hurdle in CRISPR/Cas9-mediated precise genome editing, increasing the work required to screen the genome-edited primary cell clones. In this study, we modified several essential parameters that affect the efficiency of the CRISPR/Cas9-mediated knock-in GFF cloning system, including establishing a high-efficiency transfection system for primary cells via nucleofection and optimizing homology arm (HA) length during HR. Here, we specifically inserted a recombinant human butyrylcholinesterase gene (rhBChE) into the goat fibroblast growth factor (FGF)-5 locus through the CRISPR/Cas9 system, thereby achieving simultaneous rhBChE insertion and FGF5 knock-out. First, this study introduced the Cas9, FGF5 knock-out small guide RNA, and rhBChE knock-in donors into GFFs by electroporation and obtained positive cell clones without off-target effects. Then, we demonstrated the expression of rhBChE in GFF clones and verified its function. Finally, we obtained a CRISPR/Cas9-mediated rhBChE-overexpression goat.
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Affiliation(s)
- Jia-Hao Wang
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
| | - Su-Jun Wu
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Yan Li
- Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing 100071, China;
| | - Yue Zhao
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Zhi-Mei Liu
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Shou-Long Deng
- NHC Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing 100021, China
| | - Zheng-Xing Lian
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
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Richardson C, Kelsh RN, J. Richardson R. New advances in CRISPR/Cas-mediated precise gene-editing techniques. Dis Model Mech 2023; 16:dmm049874. [PMID: 36847161 PMCID: PMC10003097 DOI: 10.1242/dmm.049874] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Over the past decade, CRISPR/Cas-based gene editing has become a powerful tool for generating mutations in a variety of model organisms, from Escherichia coli to zebrafish, rodents and large mammals. CRISPR/Cas-based gene editing effectively generates insertions or deletions (indels), which allow for rapid gene disruption. However, a large proportion of human genetic diseases are caused by single-base-pair substitutions, which result in more subtle alterations to protein function, and which require more complex and precise editing to recreate in model systems. Precise genome editing (PGE) methods, however, typically have efficiencies of less than a tenth of those that generate less-specific indels, and so there has been a great deal of effort to improve PGE efficiency. Such optimisations include optimal guide RNA and mutation-bearing donor DNA template design, modulation of DNA repair pathways that underpin how edits result from Cas-induced cuts, and the development of Cas9 fusion proteins that introduce edits via alternative mechanisms. In this Review, we provide an overview of the recent progress in optimising PGE methods and their potential for generating models of human genetic disease.
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Affiliation(s)
- Chris Richardson
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Robert N. Kelsh
- Department of Life Sciences, University of Bath, Bath BA2 7AY, UK
| | - Rebecca J. Richardson
- School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
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Li Y, Lian D, Wang J, Zhao Y, Li Y, Liu G, Wu S, Deng S, Du X, Lian Z. MDM2 antagonists promote CRISPR/Cas9-mediated precise genome editing in sheep primary cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:309-323. [PMID: 36726409 PMCID: PMC9883270 DOI: 10.1016/j.omtn.2022.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 12/31/2022] [Indexed: 01/04/2023]
Abstract
CRISPR-Cas9-mediated genome editing in sheep is of great use in both agricultural and biomedical applications. While targeted gene knockout by CRISPR-Cas9 through non-homologous end joining (NHEJ) has worked efficiently, the knockin efficiency via homology-directed repair (HDR) remains lower, which severely hampers the application of precise genome editing in sheep. Here, in sheep fetal fibroblasts (SFFs), we optimized several key parameters that affect HDR, including homology arm (HA) length and the amount of double-stranded DNA (dsDNA) repair template; we also observed synchronization of SFFs in G2/M phase could increase HDR efficiency. Besides, we identified three potent small molecules, RITA, Nutlin3, and CTX1, inhibitors of p53-MDM2 interaction, that caused activation of the p53 pathway, resulting in distinct G2/M cell-cycle arrest in response to DNA damage and improved CRISPR-Cas9-mediated HDR efficiency by 1.43- to 4.28-fold in SFFs. Furthermore, we demonstrated that genetic knockout of p53 could inhibit HDR in SFFs by suppressing the expression of several key factors involved in the HDR pathway, such as BRCA1 and RAD51. Overall, this study offers an optimized strategy for the usage of dsDNA repair template, more importantly, the application of MDM2 antagonists provides a simple and efficient strategy to promote CRISPR/Cas9-mediated precise genome editing in sheep primary cells.
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Affiliation(s)
- Yan Li
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China,State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China,Laboratory Animal Center of the Academy of Military Medical Sciences, Beijing 100071, China,These authors contributed equally
| | - Di Lian
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China,These authors contributed equally
| | - Jiahao Wang
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China,Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China,These authors contributed equally
| | - Yue Zhao
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Yao Li
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Guoshi Liu
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Sen Wu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shoulong Deng
- NHC Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing 100021, China,Corresponding author: Shoulong Deng, NHC Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, 5 Panjiayuannanli, Chaoyang District, Beijing 100021, China.
| | - Xuguang Du
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China,Corresponding author: Xuguang Du, State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
| | - Zhengxing Lian
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China,Corresponding author: Zhengxing Lian, Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, 2 Mingyuanxilu, Haidian District, Beijing 100193, China. .
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5
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Ahmad I. CRISPR/Cas9-A Promising Therapeutic Tool to Cure Blindness: Current Scenario and Future Prospects. Int J Mol Sci 2022; 23:11482. [PMID: 36232782 PMCID: PMC9569777 DOI: 10.3390/ijms231911482] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/24/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
CRISPR-based targeted genome editing is bringing revolutionary changes in the research arena of biological sciences. CRISPR/Cas9 has been explored as an efficient therapeutic tool for the treatment of genetic diseases. It has been widely used in ophthalmology research by using mouse models to correct pathogenic mutations in the eye stem cells. In recent studies, CRISPR/Cas9 has been used to correct a large number of mutations related to inherited retinal disorders. In vivo therapeutic advantages for retinal diseases have been successfully achieved in some rodents. Current advances in the CRISPR-based gene-editing domain, such as modified Cas variants and delivery approaches have optimized its application to treat blindness. In this review, recent progress and challenges of the CRISPR-Cas system have been discussed to cure blindness and its prospects.
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Affiliation(s)
- Irshad Ahmad
- Department of Bioengineering, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia; ; Tel.: +966-13-8608393
- Interdisciplinary Research Center for Membranes and Water Security, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
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Hillen AEJ, Hruzova M, Rothgangl T, Breur M, Bugiani M, van der Knaap MS, Schwank G, Heine VM. In vivo targeting of a variant causing vanishing white matter using CRISPR/Cas9. Mol Ther Methods Clin Dev 2022; 25:17-25. [PMID: 35317047 PMCID: PMC8917273 DOI: 10.1016/j.omtm.2022.02.006] [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: 08/27/2021] [Accepted: 02/19/2022] [Indexed: 11/17/2022]
Abstract
Vanishing white matter (VWM) is a leukodystrophy caused by recessive variants in subunits of eIF2B. At present, no curative treatment is available and patients often die at young age. Due to its monogenic nature, VWM is a promising candidate for the development of CRISPR/Cas9-mediated gene therapy. Here we tested a dual-AAV approach in VWM mice encoding CRISPR/Cas9 and a DNA donor template to correct a pathogenic variant in Eif2b5. We performed sequencing analysis to assess gene correction rates and examined effects on the VWM phenotype, including motor behavior. Sequence analysis demonstrated that over 90% of CRISPR/Cas9-induced edits at the targeted locus are insertion or deletion (indel) mutations, rather than precise corrections from the DNA donor template by homology-directed repair. Around half of the CRISPR/Cas9-treated animals died prematurely. VWM mice showed no improvement in motor skills, weight, or neurological scores at 7 months of age, and CRISPR/Cas9-treated controls displayed an induced VWM phenotype. In conclusion, CRISPR/Cas9-induced DNA double-strand breaks (DSBs) at the Eif2b5 locus did not lead to sufficient correction of the VWM variant. Moreover, indel formation in Eif2b5 induced an exacerbated VWM phenotype. Therefore, DSB-independent strategies like base- or prime editing might better suited for VWM correction.
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Affiliation(s)
- Anne E J Hillen
- Department of Pediatrics and Child Neurology, Emma Children's Hospital, Amsterdam Neuroscience, Amsterdam UMC, De Boelelaan 1117, 1081 Amsterdam, the Netherlands
| | - Martina Hruzova
- Department of Biology, Institute for Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Tanja Rothgangl
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Marjolein Breur
- Department of Pediatrics and Child Neurology, Emma Children's Hospital, Amsterdam Neuroscience, Amsterdam UMC, De Boelelaan 1117, 1081 Amsterdam, the Netherlands
| | - Marianna Bugiani
- Department of Pediatrics and Child Neurology, Emma Children's Hospital, Amsterdam Neuroscience, Amsterdam UMC, De Boelelaan 1117, 1081 Amsterdam, the Netherlands
| | - Marjo S van der Knaap
- Department of Pediatrics and Child Neurology, Emma Children's Hospital, Amsterdam Neuroscience, Amsterdam UMC, De Boelelaan 1117, 1081 Amsterdam, the Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, De Boelelaan 1085, 1081 Amsterdam, the Netherlands
| | - Gerald Schwank
- Department of Biology, Institute for Molecular Health Sciences, ETH Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Vivi M Heine
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, De Boelelaan 1085, 1081 Amsterdam, the Netherlands.,Department of Child and Adolescence Psychiatry, Emma Children's Hospital, Amsterdam Neuroscience, Amsterdam UMC, De Boelelaan 1085, 1081 Amsterdam, the Netherlands
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7
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Ali A, Xiao W, Babar ME, Bi Y. Double-Stranded Break Repair in Mammalian Cells and Precise Genome Editing. Genes (Basel) 2022; 13:genes13050737. [PMID: 35627122 PMCID: PMC9142082 DOI: 10.3390/genes13050737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/16/2022] Open
Abstract
In mammalian cells, double-strand breaks (DSBs) are repaired predominantly by error-prone non-homologous end joining (NHEJ), but less prevalently by error-free template-dependent homologous recombination (HR). DSB repair pathway selection is the bedrock for genome editing. NHEJ results in random mutations when repairing DSB, while HR induces high-fidelity sequence-specific variations, but with an undesirable low efficiency. In this review, we first discuss the latest insights into the action mode of NHEJ and HR in a panoramic view. We then propose the future direction of genome editing by virtue of these advancements. We suggest that by switching NHEJ to HR, full fidelity genome editing and robust gene knock-in could be enabled. We also envision that RNA molecules could be repurposed by RNA-templated DSB repair to mediate precise genetic editing.
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Affiliation(s)
- Akhtar Ali
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
- Department of Biotechnology, Virtual University of Pakistan, Lahore 54000, Pakistan
| | - Wei Xiao
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
| | - Masroor Ellahi Babar
- The University of Agriculture Dera Ismail Khan, Dera Ismail Khan 29220, Pakistan;
| | - Yanzhen Bi
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
- Correspondence: ; Tel.: +86-151-0714-8708
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Chen J, Li S, He Y, Li J, Xia L. An update on precision genome editing by homology-directed repair in plants. PLANT PHYSIOLOGY 2022; 188:1780-1794. [PMID: 35238390 PMCID: PMC8968426 DOI: 10.1093/plphys/kiac037] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/20/2022] [Indexed: 05/22/2023]
Abstract
Beneficial alleles derived from local landraces or related species, or even orthologs from other plant species, are often caused by differences of one or several single-nucleotide polymorphisms or indels in either the promoter region or the encoding region of a gene and often account for major differences in agriculturally important traits. Clustered regularly interspaced short palindromic repeats-associated endonuclease Cas9 system (CRISPR/Cas9)-mediated precision genome editing enables targeted allele replacement or insertion of flag or foreign genes at specific loci via homology-directed repair (HDR); however, HDR efficiency is low due to the intrinsic rare occurrence of HDR and insufficient DNA repair template in the proximity of a double-stranded break (DSB). Precise replacement of the targeted gene with elite alleles from landraces or relatives into a commercial variety through genome editing has been a holy grail in the crop genome editing field. In this update, we briefly summarize CRISPR/Cas-mediated HDR in plants. We describe diverse strategies to improve HDR efficiency by manipulating the DNA repair pathway, timing DSB induction, and donor delivery, and so on. Lastly, we outline open questions and challenges in HDR-mediated precision genome editing in both plant biological research and crop improvement.
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Affiliation(s)
- Jilin Chen
- Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China
- National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences/Hainan Yazhou Bay Seed Laboratory, Sanya 572024, China
| | - Shaoya Li
- Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China
| | - Yubing He
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Jingying Li
- Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China
- National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences/Hainan Yazhou Bay Seed Laboratory, Sanya 572024, China
| | - Lanqin Xia
- Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China
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9
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Bernard BE, Landmann E, Jeker LT, Schumann K. CRISPR/Cas-based Human T cell Engineering: Basic Research and Clinical Application. Immunol Lett 2022; 245:18-28. [DOI: 10.1016/j.imlet.2022.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/08/2022] [Accepted: 03/15/2022] [Indexed: 11/05/2022]
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10
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Feng S, Wang Z, Li A, Xie X, Liu J, Li S, Li Y, Wang B, Hu L, Yang L, Guo T. Strategies for High-Efficiency Mutation Using the CRISPR/Cas System. Front Cell Dev Biol 2022; 9:803252. [PMID: 35198566 PMCID: PMC8860194 DOI: 10.3389/fcell.2021.803252] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/22/2021] [Indexed: 12/15/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-associated systems have revolutionized traditional gene-editing tools and are a significant tool for ameliorating gene defects. Characterized by high target specificity, extraordinary efficiency, and cost-effectiveness, CRISPR/Cas systems have displayed tremendous potential for genetic manipulation in almost any organism and cell type. Despite their numerous advantages, however, CRISPR/Cas systems have some inherent limitations, such as off-target effects, unsatisfactory efficiency of delivery, and unwanted adverse effects, thereby resulting in a desire to explore approaches to address these issues. Strategies for improving the efficiency of CRISPR/Cas-induced mutations, such as reducing off-target effects, improving the design and modification of sgRNA, optimizing the editing time and the temperature, choice of delivery system, and enrichment of sgRNA, are comprehensively described in this review. Additionally, several newly emerging approaches, including the use of Cas variants, anti-CRISPR proteins, and mutant enrichment, are discussed in detail. Furthermore, the authors provide a deep analysis of the current challenges in the utilization of CRISPR/Cas systems and the future applications of CRISPR/Cas systems in various scenarios. This review not only serves as a reference for improving the maturity of CRISPR/Cas systems but also supplies practical guidance for expanding the applicability of this technology.
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Affiliation(s)
- Shuying Feng
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Zilong Wang
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Aifang Li
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Xin Xie
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Junjie Liu
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Shuxuan Li
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Yalan Li
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Baiyan Wang
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Lina Hu
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Lianhe Yang
- Medical College, Henan University of Chinese Medicine, Zhengzhou, China
| | - Tao Guo
- Department of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
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Rezazade Bazaz M, Dehghani H. From DNA break repair pathways to CRISPR/Cas-mediated gene knock-in methods. Life Sci 2022; 295:120409. [PMID: 35182556 DOI: 10.1016/j.lfs.2022.120409] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 12/11/2022]
Abstract
Various DNA breaks created via programmable CRISPR/Cas9 nuclease activity results in different intracellular DNA break repair pathways. Based on the cellular repair pathways, CRISPR-based gene knock-in methods can be categorized into two major strategies: 1) Homology-independent strategies which are targeted insertion events based on non-homologous end joining, and 2) Homology-dependent strategies which are targeted insertion events based on the homology-directed repair. This review elaborates on various gene knock-in methods in mammalian cells using the CRISPR/Cas9 system and in sync with DNA-break repair pathways. Gene knock-in methods are applied in functional genomics and gene therapy. To compensate or correct genetic defects, different CRISPR-based gene knock-in strategies can be used. Thus, researchers need to make a conscious decision about the most suitable knock-in method. For a successful gene-targeted insertion, some determinant factors should be considered like cell cycle, dominant DNA repair pathway, size of insertions, and donor properties. In this review, different aspects of each gene knock-in strategy are discussed to provide a framework for choosing the most appropriate gene knock-in method in different applications.
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Affiliation(s)
- Mahere Rezazade Bazaz
- Division of Biotechnology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran; Stem Cell Biology and Regenerative Medicine Research Group, Research Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hesam Dehghani
- Division of Biotechnology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran; Stem Cell Biology and Regenerative Medicine Research Group, Research Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran; Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.
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12
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Sun W, Liu H, Yin W, Qiao J, Zhao X, Liu Y. Strategies for Enhancing the Homology-directed Repair Efficiency of CRISPR-Cas Systems. CRISPR J 2022; 5:7-18. [PMID: 35076280 DOI: 10.1089/crispr.2021.0039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The CRISPR-Cas nuclease has emerged as a powerful genome-editing tool in recent years. The CRISPR-Cas system induces double-strand breaks that can be repaired via the non-homologous end joining or homology-directed repair (HDR) pathway. Compared to non-homologous end joining, HDR can be used for the treatment of incurable monogenetic diseases. Therefore, remarkable efforts have been dedicated to enhancing the efficacy of HDR. In this review, we summarize the currently used strategies for enhancing the HDR efficiency of CRISPR-Cas systems based on three factors: (1) regulation of the key factors in the DNA repair pathways, (2) modulation of the components in the CRISPR machinery, and (3) alteration of the intracellular environment around double-strand breaks. Representative cases and potential solutions for further improving HDR efficiency are also discussed, facilitating the development of new CRISPR technologies to achieve highly precise genetic manipulation in the future.
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Affiliation(s)
- Wenli Sun
- School of Life Science and Technology, Wuhan Polytechnic University, Hubei, People's Republic of China; Ltd., Hubei, People's Republic of China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Hubei, People's Republic of China; Ltd., Hubei, People's Republic of China
| | - Hui Liu
- Department of Hematology, Renmin Hospital of Wuhan University, Hubei, People's Republic of China; Ltd., Hubei, People's Republic of China
| | - Wenhao Yin
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Hubei, People's Republic of China; Ltd., Hubei, People's Republic of China
| | - Jie Qiao
- School of Life Science and Technology, Wuhan Polytechnic University, Hubei, People's Republic of China; Ltd., Hubei, People's Republic of China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Hubei, People's Republic of China; Ltd., Hubei, People's Republic of China
| | - Xueke Zhao
- State Key Laboratory of Esophageal Cancer Prevention and Treatment, Zhengzhou University, Henan, People's Republic of China; and Ltd., Hubei, People's Republic of China
| | - Yi Liu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Hubei, People's Republic of China; Ltd., Hubei, People's Republic of China.,BravoVax Co., Ltd., Hubei, People's Republic of China
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13
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Movahedi A, Wei H, Zhou X, Fountain JC, Chen ZH, Mu Z, Sun W, Zhang J, Li D, Guo B, Varshney RK, Yang L, Zhuge Q. Precise exogenous insertion and sequence replacements in poplar by simultaneous HDR overexpression and NHEJ suppression using CRISPR-Cas9. HORTICULTURE RESEARCH 2022; 9:uhac154. [PMID: 36133672 PMCID: PMC9478684 DOI: 10.1093/hr/uhac154] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 07/22/2022] [Accepted: 06/27/2022] [Indexed: 05/21/2023]
Abstract
CRISPR-mediated genome editing has become a powerful tool for the genetic modification of biological traits. However, developing an efficient, site-specific, gene knock-in system based on homology-directed DNA repair (HDR) remains a significant challenge in plants, especially in woody species like poplar. Here, we show that simultaneous inhibition of non-homologous end joining (NHEJ) recombination cofactor XRCC4 and overexpression of HDR enhancer factors CtIP and MRE11 can improve HDR efficiency for gene knock-in. Using this approach, the BleoR gene was integrated onto the 3' end of the MKK2 MAP kinase gene to generate a BleoR-MKK2 fusion protein. Based on fully edited nucleotides evaluated by TaqMan real-time PCR, the HDR-mediated knock-in efficiency was up to 48% when using XRCC4 silencing incorporated with a combination of CtIP and MRE11 overexpression compared with no HDR enhancement or NHEJ silencing. Furthermore, this combination of HDR enhancer overexpression and NHEJ repression also increased genome targeting efficiency and gave 7-fold fewer CRISPR-induced insertions and deletions (InDels), resulting in no functional effects on MKK2-based salt stress responses in poplar. Therefore, this approach may be useful not only in poplar and plants or crops but also in mammals for improving CRISPR-mediated gene knock-in efficiency.
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Affiliation(s)
| | - Hui Wei
- College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing 210037, China
| | | | | | - Zhong-Hua Chen
- School of Science, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
| | - Zhiying Mu
- College of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Weibo Sun
- College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing 210037, China
| | - Jiaxin Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210046, China
| | - Dawei Li
- College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics & Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing 210037, China
| | - Baozhu Guo
- USDA-ARS, Crop Genetics and Breeding Research Unit, Tifton, GA 31793, USA
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14
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Wimmer T, Bonthu D, Moeschl V, Kleekamp P, Thiel C, Lytvynchuk L, Ellinwood M, Stieger K. A Bioluminescence Resonance Energy Transfer-Based Reporter System: Characterization and Applications. CRISPR J 2021; 4:884-895. [PMID: 34847743 DOI: 10.1089/crispr.2021.0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Genome editing strategies and DNA repair research need powerful analytical tools. We generated a bioluminescence resonance energy transfer (BRET)-based reporter for the quantification of indel frequencies induced by DNA repair. The BRET reporter, expressed as a single molecule, consists of a mutated Renilla reniformis luciferase domain and a GFP2 domain separated by a shuttle-cloning box for the integration of any given endonuclease target sequence. The luciferase activity acts both as energy donor and as the internal standard, while the loss of GFP2 fluorescence acts as a reporter for the out-of-frame sequence alterations that result from the DNA repair via the non-homologous end joining/microhomology-mediated end joining DNA repair pathways of the endonuclease-mediated DNA double-strand break. This results in a decrease of the fluorescence/luminescence ratio. Employing this reporter in different experimental scenarios, using different cell lines and diseases targeted, we quantified the influence of both protein knockdown of DNA repair pathways as well as guide RNA mismatches on CRISPR-mediated nuclease activity and subsequent repair based on mutagenic repair on the reporter. In conclusion, we demonstrated this BRET-based reporter to be a robust and sensitive analytical tool for assessment of variety of different genome editing-based approaches.
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Affiliation(s)
- Tobias Wimmer
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Dileep Bonthu
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Vincent Moeschl
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Philip Kleekamp
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Christian Thiel
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Lyubomyr Lytvynchuk
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
| | | | - Knut Stieger
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
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15
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Kim SY, Kim GY, You HJ, Kang MJ. Relationship between DNA mismatch repair and CRISPR/Cas9-mediated knock-in in the bovine β-casein gene locus. Anim Biosci 2021; 35:126-137. [PMID: 34293843 PMCID: PMC8738927 DOI: 10.5713/ab.21.0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/16/2021] [Indexed: 11/27/2022] Open
Abstract
Objective Efficient gene editing technology is critical for successful knock-in in domestic animals. RAD51 recombinase (RAD51) gene plays an important role in strand invasion during homologous recombination (HR) in mammals, and is regulated by checkpoint kinase 1 (CHK1) and CHK2 genes, which are upstream elements of RAD51 recombinase (RAD51). In addition, mismatch repair (MMR) system is inextricably linked to HR-related pathways and regulates HR via heteroduplex rejection. Thus, the aim of this study was to investigate whether clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9)-mediated knock-in efficiency of human lactoferrin (hLF) knock-in vector in the bovine β-casein gene locus can be increased by suppressing DNA MMR-related genes (MSH2, MSH3, MSH6, MLH1, and PMS2) and overexpressing DNA double-strand break (DSB) repair-related genes (RAD51, CHK1, CHK2). Methods Bovine mammary epithelial (MAC-T) cells were transfected with a knock-in vector, RAD51, CHK1, or CHK2 overexpression vector and CRISPR/sgRNA expression vector to target the bovine β-casein gene locus, followed by treatment of the cells with CdCl2 for 24 hours. After 3 days of CdCl2 treatment, the knock-in efficiency was confirmed by polymerase chain reaction (PCR). The mRNA expression levels of DNA MMR-related and DNA DSB repair-related genes were assessed by quantitative real-time PCR (RT-qPCR). Results Treatment with CdCl2 decreased the mRNA expression of RAD51 and MMR-related genes but did not increase the knock-in efficiency in MAC-T cells. Also, the overexpression of DNA DSB repair-related genes in MAC-T cells did not significantly affect the mRNA expression of MMR-related genes and failed to increase the knock-in efficiency. Conclusion Treatment with CdCl2 inhibited the mRNA levels of RAD51 and DNA MMR-related genes in MAC-T cells. However, the function of MMR pathway in relation to HR may differ in various cell types or species.
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Affiliation(s)
- Seung-Yeon Kim
- Department of Animal Science, Chonnam National University, Gwangju 61186, Korea
| | - Ga-Yeon Kim
- Department of Animal Science, Chonnam National University, Gwangju 61186, Korea
| | - Hyeong-Ju You
- Department of Animal Science, Chonnam National University, Gwangju 61186, Korea
| | - Man-Jong Kang
- Department of Animal Science, Chonnam National University, Gwangju 61186, Korea
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16
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Gohil N, Bhattacharjee G, Lam NL, Perli SD, Singh V. CRISPR-Cas systems: Challenges and future prospects. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 180:141-151. [PMID: 33934835 DOI: 10.1016/bs.pmbts.2021.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The advancement gained over the past couple of decades in clustered regularly interspaced short palindromic repeats and CRISPR associated proteins (CRISPR-Cas) systems have revolutionized the field of synthetic biology, therapeutics, diagnostics and metabolic engineering. The technique has enabled the process of genome editing to be very precise, rapid, cost-effective and highly efficient which were the downfalls for the previously debuted zinc finger nucleases (ZFN) and transcription activator-like effector nucleases (TALEN) technologies. However, despite its great potential, challenges including off-target activity, method of delivery, ethical and regulatory issues still remain unresolved for the CRISPR-Cas systems. In this chapter, we present and point out the obstacles faced in implementation of the CRISPR-Cas system along with its future prospects.
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Affiliation(s)
- Nisarg Gohil
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India
| | - Gargi Bhattacharjee
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India
| | - Navya Lavina Lam
- The J. David Gladstone Institutes, San Francisco, CA, United States
| | - Samuel D Perli
- The J. David Gladstone Institutes, San Francisco, CA, United States
| | - Vijai Singh
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India.
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17
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Stinson BM, Loparo JJ. Repair of DNA Double-Strand Breaks by the Nonhomologous End Joining Pathway. Annu Rev Biochem 2021; 90:137-164. [PMID: 33556282 DOI: 10.1146/annurev-biochem-080320-110356] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA double-strand breaks pose a serious threat to genome stability. In vertebrates, these breaks are predominantly repaired by nonhomologous end joining (NHEJ), which pairs DNA ends in a multiprotein synaptic complex to promote their direct ligation. NHEJ is a highly versatile pathway that uses an array of processing enzymes to modify damaged DNA ends and enable their ligation. The mechanisms of end synapsis and end processing have important implications for genome stability. Rapid and stable synapsis is necessary to limit chromosome translocations that result from the mispairing of DNA ends. Furthermore, end processing must be tightly regulated to minimize mutations at the break site. Here, we review our current mechanistic understanding of vertebrate NHEJ, with a particular focus on end synapsis and processing.
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Affiliation(s)
- Benjamin M Stinson
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; ,
| | - Joseph J Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA; ,
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18
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Fu YW, Dai XY, Wang WT, Yang ZX, Zhao JJ, Zhang JP, Wen W, Zhang F, Oberg KC, Zhang L, Cheng T, Zhang XB. Dynamics and competition of CRISPR-Cas9 ribonucleoproteins and AAV donor-mediated NHEJ, MMEJ and HDR editing. Nucleic Acids Res 2021; 49:969-985. [PMID: 33398341 PMCID: PMC7826255 DOI: 10.1093/nar/gkaa1251] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Abstract
Investigations of CRISPR gene knockout editing profiles have contributed to enhanced precision of editing outcomes. However, for homology-directed repair (HDR) in particular, the editing dynamics and patterns in clinically relevant cells, such as human iPSCs and primary T cells, are poorly understood. Here, we explore the editing dynamics and DNA repair profiles after the delivery of Cas9-guide RNA ribonucleoprotein (RNP) with or without the adeno-associated virus serotype 6 (AAV6) as HDR donors in four cell types. We show that editing profiles have distinct differences among cell lines. We also reveal the kinetics of HDR mediated by the AAV6 donor template. Quantification of T50 (time to reach half of the maximum editing frequency) indicates that short indels (especially +A/T) occur faster than longer (>2 bp) deletions, while the kinetics of HDR falls between NHEJ (non-homologous end-joining) and MMEJ (microhomology-mediated end-joining). As such, AAV6-mediated HDR effectively outcompetes the longer MMEJ-mediated deletions but not NHEJ-mediated indels. Notably, a combination of small molecular compounds M3814 and Trichostatin A (TSA), which potently inhibits predominant NHEJ repairs, leads to a 3-fold increase in HDR efficiency.
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Affiliation(s)
- Ya-Wen Fu
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Xin-Yue Dai
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Wen-Tian Wang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Zhi-Xue Yang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Juan-Juan Zhao
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Jian-Ping Zhang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Wei Wen
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Feng Zhang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
| | - Kerby C Oberg
- Department of Pathology and Human Anatomy, Loma Linda University, Loma Linda, CA 92350, USA
| | - Lei Zhang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
- CAMS Key Laboratory of Gene Therapy for Blood Diseases, Tianjin 300020, China
- Tianjin Laboratory of Blood Disease Gene Therapy, Tianjin 300020, China
| | - Tao Cheng
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Tianjin 300020, China
- Department of Stem Cell & Regenerative Medicine, Peking Union Medical College, Tianjin 300020, China
| | - Xiao-Bing Zhang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
- Department of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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Wang L, Xu X, Teng M, Zhao G, Lei A. Coping with DNA Double-Strand Breaks via ATM Signaling Pathway in Bovine Oocytes. Int J Mol Sci 2020; 21:ijms21238892. [PMID: 33255251 PMCID: PMC7727702 DOI: 10.3390/ijms21238892] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/10/2020] [Accepted: 11/20/2020] [Indexed: 12/11/2022] Open
Abstract
As a common injury almost all cells face, DNA damage in oocytes—especially double-strand breaks (DSBs), which occur naturally during the first meiosis phase (meiosis I) due to synaptic complex separation—affects the fertilization ability of oocytes, instead of causing cancer (as in somatic cells). The mechanism of oocytes to effectively repair DSB damage has not yet been clearly studied, especially considering medically induced DSBs superimposed on naturally occurring DSBs in meiosis I. It was found that maturation rates decreased or increased, respectively corresponding with overexpression or interference of p21 in bovine oocytes. At the same time, the maturation rate of bovine oocytes decreased with a gradual increase in Zeocin dose, and the p21 expression in those immature oocytes changed significantly with the gradual increase in Zeocin dose (same as increased DSB intensity). Same as p21, the variation trend of ATM expression was consistent with the gradual increase in Zeocin dose. Furthermore, the oocytes demonstrated tolerance to DSBs during meiosis I, while the maturation rates decreased when the damage exceeded a certain threshold; according to which, it may be that ATM regulates the p53–p21 pathway to affect the completion of meiosis. In addition, nonhomologous recombination and cumulus cells are potentially involved in the process by which oocytes respond to DSB damage.
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Affiliation(s)
- Lili Wang
- Shaanxi Stem Cell Engineering and Technology Research Center, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China; (L.W.); (X.X.); (M.T.)
| | - Xiaolei Xu
- Shaanxi Stem Cell Engineering and Technology Research Center, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China; (L.W.); (X.X.); (M.T.)
| | - Mingming Teng
- Shaanxi Stem Cell Engineering and Technology Research Center, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China; (L.W.); (X.X.); (M.T.)
| | - Guimin Zhao
- Key Laboratory of Infection and Immunity of Shandong Province, Department of Immunology, School of Biomedical Sciences, Shandong University, Jinan 250012, China;
| | - Anmin Lei
- Shaanxi Stem Cell Engineering and Technology Research Center, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China; (L.W.); (X.X.); (M.T.)
- Correspondence: ; Tel./Fax: +86-029-87080068
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20
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Sun H, Li Q, Yin G, Ding X, Xie J. Ku70 and Ku80 participate in LPS-induced pro-inflammatory cytokines production in human macrophages and monocytes. Aging (Albany NY) 2020; 12:20432-20444. [PMID: 33109771 PMCID: PMC7655212 DOI: 10.18632/aging.103845] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/20/2020] [Indexed: 04/23/2023]
Abstract
In human macrophages and monocytes, lipopolysaccharide (LPS) induces nuclear factor kappa B (NFκB) activation and pro-inflammatory cytokines production. We tested the possible involvement of Ku70 and Ku80 in the process. In THP-1 macrophages and primary human peripheral blood mononuclear cells (PBMCs), shRNA-induced double knockdown of Ku70 and Ku80 potently inhibited LPS-induced production of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6). Additionally, we developed CRISPR/Cas-9 gene-editing methods to knockout both Ku70 and Ku80 in THP-1 cells and PBMCs. Double knockout (DKO) largely inhibited LPS-induced pro-inflammatory cytokines production. Conversely, in THP-1 cells exogenous overexpression of both Ku70 and Ku80 enhanced the pro-inflammatory cytokines production by LPS. Ku70 and Ku80 co-immunoprecipitated with p65-p52 NFκB complex in the nuclei of LPS-treated THP-1 cells. Significantly, LPS-induced NFκB activation was inhibited by Ku70 plus Ku80 double knockdown or DKO. It was however enhanced with Ku70 and Ku80 overexpression. Together, Ku70 and Ku80 promote LPS-induced NFκB activation and pro-inflammatory response in THP-1 cells and human PBMCs.
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Affiliation(s)
- Hong Sun
- Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Quan Li
- Center of Stomatology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Gang Yin
- Department of Orthopaedics, Wujin Hospital Affiliated to Jiangsu University and The Wujin Clinical College of Xuzhou Medical University, Changzhou, China
| | - Xi Ding
- Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jing Xie
- Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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21
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Yang H, Ren S, Yu S, Pan H, Li T, Ge S, Zhang J, Xia N. Methods Favoring Homology-Directed Repair Choice in Response to CRISPR/Cas9 Induced-Double Strand Breaks. Int J Mol Sci 2020; 21:E6461. [PMID: 32899704 PMCID: PMC7555059 DOI: 10.3390/ijms21186461] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/20/2020] [Accepted: 09/01/2020] [Indexed: 12/15/2022] Open
Abstract
Precise gene editing is-or will soon be-in clinical use for several diseases, and more applications are under development. The programmable nuclease Cas9, directed by a single-guide RNA (sgRNA), can introduce double-strand breaks (DSBs) in target sites of genomic DNA, which constitutes the initial step of gene editing using this novel technology. In mammals, two pathways dominate the repair of the DSBs-nonhomologous end joining (NHEJ) and homology-directed repair (HDR)-and the outcome of gene editing mainly depends on the choice between these two repair pathways. Although HDR is attractive for its high fidelity, the choice of repair pathway is biased in a biological context. Mammalian cells preferentially employ NHEJ over HDR through several mechanisms: NHEJ is active throughout the cell cycle, whereas HDR is restricted to S/G2 phases; NHEJ is faster than HDR; and NHEJ suppresses the HDR process. This suggests that definitive control of outcome of the programmed DNA lesioning could be achieved through manipulating the choice of cellular repair pathway. In this review, we summarize the DSB repair pathways, the mechanisms involved in choice selection based on DNA resection, and make progress in the research investigating strategies that favor Cas9-mediated HDR based on the manipulation of repair pathway choice to increase the frequency of HDR in mammalian cells. The remaining problems in improving HDR efficiency are also discussed. This review should facilitate the development of CRISPR/Cas9 technology to achieve more precise gene editing.
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Affiliation(s)
| | | | | | | | - Tingdong Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Disease, Collaborative Innovation Centers of Biological Products, School of Public Health, Xiamen University, Xiamen 361102, China; (H.Y.); (S.R.); (S.Y.); (H.P.); (J.Z.); (N.X.)
| | - Shengxiang Ge
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Disease, Collaborative Innovation Centers of Biological Products, School of Public Health, Xiamen University, Xiamen 361102, China; (H.Y.); (S.R.); (S.Y.); (H.P.); (J.Z.); (N.X.)
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22
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Uddin F, Rudin CM, Sen T. CRISPR Gene Therapy: Applications, Limitations, and Implications for the Future. Front Oncol 2020; 10:1387. [PMID: 32850447 PMCID: PMC7427626 DOI: 10.3389/fonc.2020.01387] [Citation(s) in RCA: 208] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 06/30/2020] [Indexed: 12/24/2022] Open
Abstract
A series of recent discoveries harnessing the adaptive immune system of prokaryotes to perform targeted genome editing is having a transformative influence across the biological sciences. The discovery of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) proteins has expanded the applications of genetic research in thousands of laboratories across the globe and is redefining our approach to gene therapy. Traditional gene therapy has raised some concerns, as its reliance on viral vector delivery of therapeutic transgenes can cause both insertional oncogenesis and immunogenic toxicity. While viral vectors remain a key delivery vehicle, CRISPR technology provides a relatively simple and efficient alternative for site-specific gene editing, obliviating some concerns raised by traditional gene therapy. Although it has apparent advantages, CRISPR/Cas9 brings its own set of limitations which must be addressed for safe and efficient clinical translation. This review focuses on the evolution of gene therapy and the role of CRISPR in shifting the gene therapy paradigm. We review the emerging data of recent gene therapy trials and consider the best strategy to move forward with this powerful but still relatively new technology.
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Affiliation(s)
- Fathema Uddin
- Department of Medicine, Thoracic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Charles M. Rudin
- Department of Medicine, Thoracic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, United States
- Weill Cornell Medicine, Cornell University, New York, NY, United States
| | - Triparna Sen
- Department of Medicine, Thoracic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, United States
- Weill Cornell Medicine, Cornell University, New York, NY, United States
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Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) is a precise genome manipulating tool that can produce targeted gene mutations in various cells and organisms. Although CRISPR/Cas9 can efficiently generate gene knockout, the gene knock-in (KI) efficiency mediated by homology-directed repair remains low, especially for large fragment integration. In this study, we established an efficient method for the CRISPR/Cas9-mediated integration of large transgene cassette, which carries salivary gland-expressed multiple digestion enzymes (≈ 20 kbp) in CEP112 locus in pig fetal fibroblasts (PFFs). Our results showed that using an optimal homology donor with a short and a long arm yielded the best CRISPR/Cas9-mediated KI efficiency in CEP112 locus, and the targeting efficiency in CEP112 locus was higher than in ROSA26 locus. The CEP112 KI cell lines were used as nuclear donors for somatic cell nuclear transfer to create genetically modified pigs. We found that KI pig (705) successfully expressed three microbial enzymes (β-glucanase, xylanase, and phytase) in salivary gland. This finding suggested that the CEP112 locus supports exogenous gene expression by a tissue-specific promoter. In summary, we successfully targeted CEP112 locus in pigs by using our optimal homology arm system and established a modified pig model for foreign digestion enzyme expression in the saliva.
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24
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Hong L, Gu T, He Y, Zhou C, Hu Q, Wang X, Zheng E, Huang S, Xu Z, Yang J, Yang H, Li Z, Liu D, Cai G, Wu Z. Genome-Wide Analysis of Circular RNAs Mediated ceRNA Regulation in Porcine Embryonic Muscle Development. Front Cell Dev Biol 2019; 7:289. [PMID: 31803743 PMCID: PMC6877547 DOI: 10.3389/fcell.2019.00289] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/05/2019] [Indexed: 12/19/2022] Open
Abstract
Many circular RNAs (circRNAs) have been discovered in various tissues and cell types in pig. However, the temporal expression pattern of circRNAs during porcine embryonic muscle development remains unclear. Here, we present a panorama view of circRNA expression in embryonic muscle development at 33-, 65-, and 90-days post-coitus (dpc) from Duroc pigs. An unbiased analysis reveals that more than 5,000 circRNAs specifically express in embryonic muscle development. The amount and complexity of circRNA expression is most pronounced in skeletal muscle at day 33 of gestation. Our circRNAs annotation analyses show that “hot-spot” genes produce multiple circRNA isoforms and RNA binding protein (RBPs) may regulate the biogenesis of circRNAs. Furthermore, we observed that host genes of differentially expressed circRNA across porcine muscle development are enriched in skeletal muscle function. A competing endogenous RNA (ceRNA) network analysis of circRNAs reveals that circRNAs regulate muscle gene expression by functioning as miRNA sponges. Finally, our experimental validation demonstrated that circTUT7 regulate the expression of HMG20B in a ceRNA mechanism. Our analyses show that circRNAs are dynamically expressed and interacting with muscle genes through ceRNA manner, suggesting their critical functions in embryonic skeletal muscle development.
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Affiliation(s)
- Linjun Hong
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Ting Gu
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yanjuan He
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Chen Zhou
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Qun Hu
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Xingwang Wang
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Enqin Zheng
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Sixiu Huang
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Zheng Xu
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Jie Yang
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Huaqiang Yang
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Zicong Li
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Dewu Liu
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Gengyuan Cai
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Zhenfang Wu
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
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25
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Tang XD, Gao F, Liu MJ, Fan QL, Chen DK, Ma WT. Methods for Enhancing Clustered Regularly Interspaced Short Palindromic Repeats/Cas9-Mediated Homology-Directed Repair Efficiency. Front Genet 2019; 10:551. [PMID: 31263478 PMCID: PMC6590329 DOI: 10.3389/fgene.2019.00551] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/24/2019] [Indexed: 12/26/2022] Open
Abstract
The evolution of organisms has provided a variety of mechanisms to maintain the integrity of its genome, but as damage occurs, DNA damage repair pathways are necessary to resolve errors. Among them, the DNA double-strand break repair pathway is highly conserved in eukaryotes, including mammals. Nonhomologous DNA end joining and homologous directed repair are two major DNA repair pathways that are synergistic or antagonistic. Clustered regularly interspaced short palindromic repeats genome editing techniques based on the nonhomologous DNA end joining repair pathway have been used to generate highly efficient insertions or deletions of variable-sized genes but are error-prone and inaccurate. By combining the homology-directed repair pathway with clustered regularly interspaced short palindromic repeats cleavage, more precise genome editing via insertion or deletion of the desired fragment can be performed. However, homologous directed repair is not efficient and needs further improvement. Here, we describe several ways to improve the efficiency of homologous directed repair by regulating the cell cycle, expressing key proteins involved in homologous recombination and selecting appropriate donor DNA.
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Affiliation(s)
- Xi-Dian Tang
- Veterinary Immunology Laboratory, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, China
| | - Fei Gao
- Veterinary Immunology Laboratory, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, China
| | - Ming-Jie Liu
- Veterinary Immunology Laboratory, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, China
| | - Qin-Lei Fan
- China Animal Health and Epidemiology Center, Qingdao, China
| | - De-Kun Chen
- Veterinary Immunology Laboratory, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, China
| | - Wen-Tao Ma
- Veterinary Immunology Laboratory, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, China
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26
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Liu M, Rehman S, Tang X, Gu K, Fan Q, Chen D, Ma W. Methodologies for Improving HDR Efficiency. Front Genet 2019; 9:691. [PMID: 30687381 PMCID: PMC6338032 DOI: 10.3389/fgene.2018.00691] [Citation(s) in RCA: 185] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/11/2018] [Indexed: 12/26/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) is a precise genome manipulating technology that can be programmed to induce double-strand break (DSB) in the genome wherever needed. After nuclease cleavage, DSBs can be repaired by non-homologous end joining (NHEJ) or homology-directed repair (HDR) pathway. For producing targeted gene knock-in or other specific mutations, DSBs should be repaired by the HDR pathway. While NHEJ can cause various length insertions/deletion mutations (indels), which can lead the targeted gene to lose its function by shifting the open reading frame (ORF). Furthermore, HDR has low efficiency compared with the NHEJ pathway. In order to modify the gene precisely, numerous methods arose by inhibiting NHEJ or enhancing HDR, such as chemical modulation, synchronized expression, and overlapping homology arm. Here we focus on the efficiency and other considerations of these methodologies.
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Affiliation(s)
- Mingjie Liu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Saad Rehman
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Xidian Tang
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Kui Gu
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Qinlei Fan
- China Animal Health and Epidemiology Center, Qingdao, China
| | - Dekun Chen
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Wentao Ma
- College of Veterinary Medicine, Northwest A&F University, Xianyang, China
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