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Balzano E, Pelliccia F, Giunta S. Genome (in)stability at tandem repeats. Semin Cell Dev Biol 2020; 113:97-112. [PMID: 33109442 DOI: 10.1016/j.semcdb.2020.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/26/2020] [Accepted: 10/10/2020] [Indexed: 12/12/2022]
Abstract
Repeat sequences account for over half of the human genome and represent a significant source of variation that underlies physiological and pathological states. Yet, their study has been hindered due to limitations in short-reads sequencing technology and difficulties in assembly. A important category of repetitive DNA in the human genome is comprised of tandem repeats (TRs), where repetitive units are arranged in a head-to-tail pattern. Compared to other regions of the genome, TRs carry between 10 and 10,000 fold higher mutation rate. There are several mutagenic mechanisms that can give rise to this propensity toward instability, but their precise contribution remains speculative. Given the high degree of homology between these sequences and their arrangement in tandem, once damaged, TRs have an intrinsic propensity to undergo aberrant recombination with non-allelic exchange and generate harmful rearrangements that may undermine the stability of the entire genome. The dynamic mutagenesis at TRs has been found to underlie individual polymorphism associated with neurodegenerative and neuromuscular disorders, as well as complex genetic diseases like cancer and diabetes. Here, we review our current understanding of the surveillance and repair mechanisms operating within these regions, and we describe how alterations in these protective processes can readily trigger mutational signatures found at TRs, ultimately resulting in the pathological correlation between TRs instability and human diseases. Finally, we provide a viewpoint to counter the detrimental effects that TRs pose in light of their selection and conservation, as important drivers of human evolution.
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Affiliation(s)
- Elisa Balzano
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy
| | - Franca Pelliccia
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy
| | - Simona Giunta
- The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy.
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Zablotskaya A, Van Esch H, Verstrepen KJ, Froyen G, Vermeesch JR. Mapping the landscape of tandem repeat variability by targeted long read single molecule sequencing in familial X-linked intellectual disability. BMC Med Genomics 2018; 11:123. [PMID: 30567555 PMCID: PMC6299999 DOI: 10.1186/s12920-018-0446-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 12/06/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The etiology of more than half of all patients with X-linked intellectual disability remains elusive, despite array-based comparative genomic hybridization, whole exome or genome sequencing. Since short read massive parallel sequencing approaches do not allow the detection of larger tandem repeat expansions, we hypothesized that such expansions could be a hidden cause of X-linked intellectual disability. METHODS We selectively captured over 1800 tandem repeats on the X chromosome and characterized them by long read single molecule sequencing in 3 families with idiopathic X-linked intellectual disability. RESULTS In male DNA samples, full tandem repeat length sequences were obtained for 88-93% of the targets and up to 99.6% of the repeats with a moderate guanine-cytosine content. Read length and analysis pipeline allow to detect cases of > 900 bp tandem repeat expansion. In one family, one repeat expansion co-occurs with down-regulation of the neighboring MIR222 gene. This gene has previously been implicated in intellectual disability and is apparently linked to FMR1 and NEFH overexpression associated with neurological disorders. CONCLUSIONS This study demonstrates the power of single molecule sequencing to measure tandem repeat lengths and detect expansions, and suggests that tandem repeat mutations may be a hidden cause of X-linked intellectual disability.
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Affiliation(s)
- Alena Zablotskaya
- Department of Human Genetics and Center for Human Genetics, Laboratory for Cytogenetics and Genome Research, University Hospitals Leuven, KU Leuven, O&N I Herestraat 49 - box 606, 3000, Leuven, Belgium
| | - Hilde Van Esch
- Department of Human Genetics and Center for Human Genetics, Laboratory for Genetics of Cognition, University Hospitals Leuven, KU Leuven, O&N I Herestraat 49 - box 606, 3000, Leuven, Belgium
| | - Kevin J Verstrepen
- VIB Center for Microbiology and CMPG Lab for Genetics and Genomics, KU Leuven, Gaston Geenslaan 1 - box 2471, 3001, Leuven, Belgium
| | - Guy Froyen
- Clinical Biology, Laboratory for Molecular Diagnostics, Jessa Hospital, Stadsomvaart 11, 3500, Hasselt, Belgium
| | - Joris R Vermeesch
- Department of Human Genetics and Center for Human Genetics, Laboratory for Cytogenetics and Genome Research, University Hospitals Leuven, KU Leuven, O&N I Herestraat 49 - box 606, 3000, Leuven, Belgium.
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Liu Z, Hui Y, Shi L, Chen Z, Xu X, Chi L, Fan B, Fang Y, Liu Y, Ma L, Wang Y, Xiao L, Zhang Q, Jin G, Liu L, Zhang X. Efficient CRISPR/Cas9-Mediated Versatile, Predictable, and Donor-Free Gene Knockout in Human Pluripotent Stem Cells. Stem Cell Reports 2016; 7:496-507. [PMID: 27594587 PMCID: PMC5032288 DOI: 10.1016/j.stemcr.2016.07.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/28/2016] [Accepted: 07/28/2016] [Indexed: 11/17/2022] Open
Abstract
Loss-of-function studies in human pluripotent stem cells (hPSCs) require efficient methodologies for lesion of genes of interest. Here, we introduce a donor-free paired gRNA-guided CRISPR/Cas9 knockout strategy (paired-KO) for efficient and rapid gene ablation in hPSCs. Through paired-KO, we succeeded in targeting all genes of interest with high biallelic targeting efficiencies. More importantly, during paired-KO, the cleaved DNA was repaired mostly through direct end joining without insertions/deletions (precise ligation), and thus makes the lesion product predictable. The paired-KO remained highly efficient for one-step targeting of multiple genes and was also efficient for targeting of microRNA, while for long non-coding RNA over 8 kb, cleavage of a short fragment of the core promoter region was sufficient to eradicate downstream gene transcription. This work suggests that the paired-KO strategy is a simple and robust system for loss-of-function studies for both coding and non-coding genes in hPSCs.
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Affiliation(s)
- Zhongliang Liu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Yi Hui
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, China
| | - Lei Shi
- College of Animal Science and Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Zhenyu Chen
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Xiangjie Xu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Liankai Chi
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Beibei Fan
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Yujiang Fang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Yang Liu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Lin Ma
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Yiran Wang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Lei Xiao
- College of Animal Science and Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Quanbin Zhang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China
| | - Guohua Jin
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, Jiangsu 226001, China.
| | - Ling Liu
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China; Tongji University Advanced Institute of Translational Medicine, Tongji University School of Medicine, 1239 Siping Road, Shanghai 200092, China.
| | - Xiaoqing Zhang
- Shanghai Tenth People's Hospital, and Neuroregeneration Key Laboratory of Shanghai Universities, Tongji University School of Medicine, Shanghai 200092, China; Tongji University Advanced Institute of Translational Medicine, Tongji University School of Medicine, 1239 Siping Road, Shanghai 200092, China; The Collaborative Innovation Center for Brain Science, Tongji University, Shanghai 200092, China.
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