1
|
Trost H, Lopezcolorado FW, Merkell A, Stark JM. Functions of PMS2 and MLH1 important for regulation of divergent repeat-mediated deletions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.05.606388. [PMID: 39149360 PMCID: PMC11326157 DOI: 10.1101/2024.08.05.606388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Repeat-mediated deletions (RMDs) are a type of deletion rearrangement that utilizes two repetitive elements to bridge a DNA double-strand break (DSB) that leads to loss of the intervening sequence and one of the repeats. Sequence divergence between repeats causes RMD suppression and indeed this divergence must be resolved in the RMD products. The mismatch repair factor, MLH1, was shown to be critical for both RMD suppression and a polarity of sequence divergence resolution in RMDs. Here, we sought to study the interrelationship between these two aspects of RMD regulation (i.e., RMD suppression and polar divergence resolution), by examining several mutants of MLH1 and its binding partner PMS2. To begin with, we show that PMS2 is also critical for both RMD suppression and polar resolution of sequence divergence in RMD products. Then, with six mutants of the MLH1-PMS2 heterodimer, we found several different patterns: three mutants showed defects in both functions, one mutant showed loss of RMD suppression but not polar divergence resolution, whereas another mutant showed the opposite, and finally one mutant showed loss of RMD suppression but had a complex effect on polar divergence resolution. These findings indicate that RMD suppression vs. polar resolution of sequence divergence are distinct functions of MLH1-PMS2.
Collapse
Affiliation(s)
- Hannah Trost
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA
| | - Felicia Wednesday Lopezcolorado
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA
| | - Arianna Merkell
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA
| | - Jeremy M. Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA
| |
Collapse
|
2
|
Saito S, Adachi N. Characterization and regulation of cell cycle-independent noncanonical gene targeting. Nat Commun 2024; 15:5044. [PMID: 38890315 PMCID: PMC11189520 DOI: 10.1038/s41467-024-49385-9] [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: 11/22/2023] [Accepted: 06/04/2024] [Indexed: 06/20/2024] Open
Abstract
Homology-dependent targeted DNA integration, generally referred to as gene targeting, provides a powerful tool for precise genome modification; however, its fundamental mechanisms remain poorly understood in human cells. Here we reveal a noncanonical gene targeting mechanism that does not rely on the homologous recombination (HR) protein Rad51. This mechanism is suppressed by Rad52 inhibition, suggesting the involvement of single-strand annealing (SSA). The SSA-mediated gene targeting becomes prominent when DSB repair by HR or end-joining pathways is defective and does not require isogenic DNA, permitting 5% sequence divergence. Intriguingly, loss of Msh2, loss of BLM, and induction of a target-site DNA break all significantly and synergistically enhance SSA-mediated targeted integration. Most notably, SSA-mediated integration is cell cycle-independent, occurring in the G1 phase as well. Our findings provide unequivocal evidence for Rad51-independent targeted integration and unveil multiple mechanisms to regulate SSA-mediated targeted as well as random integration.
Collapse
Affiliation(s)
- Shinta Saito
- Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Yokohama, 236-0027, Japan
| | - Noritaka Adachi
- Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Yokohama, 236-0027, Japan.
| |
Collapse
|
3
|
Sapède E, Sugawara N, Tyers RG, Nakajima Y, Afreen MF, Romero Escobar J, Haber JE. Nonhomologous tails direct heteroduplex rejection and mismatch correction during single-strand annealing in Saccharomyces cerevisiae. PLoS Genet 2024; 20:e1010527. [PMID: 38315739 PMCID: PMC10868807 DOI: 10.1371/journal.pgen.1010527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/15/2024] [Accepted: 12/28/2023] [Indexed: 02/07/2024] Open
Abstract
Single-strand annealing (SSA) is initiated when a double strand break (DSB) occurs between two flanking repeated sequences, resulting in a deletion that leaves a single copy of the repeat. We studied budding yeast strains carrying two 200-bp URA3 sequences separated by 2.6 kb of spacer DNA (phage lambda) in which a site-specific DSB can be created by HO or Cas9 endonucleases. Repeat-mediated deletion requires removal of long 3'-ended single-stranded tails (flaps) by Rad1-Rad10 with the assistance of Msh2-Msh3, Saw1 and Slx4. A natural 3% divergence of unequally spaced heterologies between these repeats (designated F and A) causes a significant reduction in the frequency of SSA repair. This decrease is caused by heteroduplex rejection in which mismatches (MMs) in the annealed intermediate are recognized by the MutS (Msh2 and Msh6) components of the MM repair (MMR) pathway coupled to unwinding of the duplex by the Sgs1-Rmi1-Top3 helicase. MutL homologs, Mlh1-Pms1 (MutL), are not required for rejection but play their expected role in mismatch correction. Remarkably, heteroduplex rejection is very low in strains where the divergent repeats were immediately adjacent (Tailless strains) and the DSB was induced by Cas9. These results suggest that the presence of nonhomologous tails strongly stimulates heteroduplex rejection in SSA. DNA sequencing analysis of SSA products from the FA Tailed strain showed a gradient of correction favoring the sequence opposite each 3' end of the annealed strand. Mismatches located in the center of the repair intermediate were corrected by Msh2-Msh6 mediated mismatch correction, while correction of MMs at the extremity of the SSA intermediate often appears to use a different mechanism, possibly by 3' nonhomologous tail removal that includes part of the homologous sequence. In contrast, in FA Tailless strains there was a uniform repair of the MMs across the repeat. A distinctive pattern of correction was found in the absence of MSH2, in both Tailed and Tailless strains, different from the spectrum seen in a msh3Δ msh6Δ double mutant. Previous work has shown that SSA is Rad51-independent but dependent on the strand annealing activity of Rad52. However Rad52 becomes dispensable in a Tailless construct where the DSB is induced by Cas9 or in transformation of a plasmid where SSA occurs in the absence of nonhomologous tails.
Collapse
Affiliation(s)
- Elena Sapède
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Neal Sugawara
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Randall G. Tyers
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Yuko Nakajima
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Mosammat Faria Afreen
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Jesselin Romero Escobar
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - James E. Haber
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| |
Collapse
|
4
|
Mendez-Dorantes C, Burns KH. LINE-1 retrotransposition and its deregulation in cancers: implications for therapeutic opportunities. Genes Dev 2023; 37:948-967. [PMID: 38092519 PMCID: PMC10760644 DOI: 10.1101/gad.351051.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Long interspersed element 1 (LINE-1) is the only protein-coding transposon that is active in humans. LINE-1 propagates in the genome using RNA intermediates via retrotransposition. This activity has resulted in LINE-1 sequences occupying approximately one-fifth of our genome. Although most copies of LINE-1 are immobile, ∼100 copies are retrotransposition-competent. Retrotransposition is normally limited via epigenetic silencing, DNA repair, and other host defense mechanisms. In contrast, LINE-1 overexpression and retrotransposition are hallmarks of cancers. Here, we review mechanisms of LINE-1 regulation and how LINE-1 may promote genetic heterogeneity in tumors. Finally, we discuss therapeutic strategies to exploit LINE-1 biology in cancers.
Collapse
Affiliation(s)
- Carlos Mendez-Dorantes
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kathleen H Burns
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| |
Collapse
|
5
|
Hou Z, Xu Z, Wu M, Ma L, Sui L, Bian P, Wang T. Enhancement of Repeat-Mediated Deletion Rearrangement Induced by Particle Irradiation in a RecA-Dependent Manner in Escherichia coli. BIOLOGY 2023; 12:1406. [PMID: 37998005 PMCID: PMC10669199 DOI: 10.3390/biology12111406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 10/30/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023]
Abstract
Repeat-mediated deletion (RMD) rearrangement is a major source of genome instability and can be deleterious to the organism, whereby the intervening sequence between two repeats is deleted along with one of the repeats. RMD rearrangement is likely induced by DNA double-strand breaks (DSBs); however, it is unclear how the complexity of DSBs influences RMD rearrangement. Here, a transgenic Escherichia coli strain K12 MG1655 with a lacI repeat-controlled amp activation was used while taking advantage of particle irradiation, such as proton and carbon irradiation, to generate different complexities of DSBs. Our research confirmed the enhancement of RMD under proton and carbon irradiation and revealed a positive correlation between RMD enhancement and LET. In addition, RMD enhancement could be suppressed by an intermolecular homologous sequence, which was regulated by its composition and length. Meanwhile, RMD enhancement was significantly stimulated by exogenous λ-Red recombinase. Further results investigating its mechanisms showed that the enhancement of RMD, induced by particle irradiation, occurred in a RecA-dependent manner. Our finding has a significant impact on the understanding of RMD rearrangement and provides some clues for elucidating the repair process and possible outcomes of complex DNA damage.
Collapse
Affiliation(s)
- Zhiyang Hou
- Teaching and Research Section of Nuclear Medicine, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China; (Z.H.); (Z.X.); (M.W.); (P.B.)
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Science Island Branch, Graduate School of USTC, Hefei 230026, China
| | - Zelin Xu
- Teaching and Research Section of Nuclear Medicine, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China; (Z.H.); (Z.X.); (M.W.); (P.B.)
| | - Mengying Wu
- Teaching and Research Section of Nuclear Medicine, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China; (Z.H.); (Z.X.); (M.W.); (P.B.)
| | - Liqiu Ma
- Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413, China;
- National Innovation Center of Radiation Application, Beijing 102413, China
| | - Li Sui
- Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413, China;
- National Innovation Center of Radiation Application, Beijing 102413, China
| | - Po Bian
- Teaching and Research Section of Nuclear Medicine, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China; (Z.H.); (Z.X.); (M.W.); (P.B.)
| | - Ting Wang
- Teaching and Research Section of Nuclear Medicine, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China; (Z.H.); (Z.X.); (M.W.); (P.B.)
| |
Collapse
|
6
|
Trost H, Merkell A, Lopezcolorado FW, Stark J. Resolution of sequence divergence for repeat-mediated deletions shows a polarity that is mediated by MLH1. Nucleic Acids Res 2023; 51:650-667. [PMID: 36620890 PMCID: PMC9881173 DOI: 10.1093/nar/gkac1240] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/07/2022] [Accepted: 01/04/2023] [Indexed: 01/10/2023] Open
Abstract
Repeat-mediated deletions (RMDs) are a type of chromosomal rearrangement between two homologous sequences that causes loss of the sequence between the repeats, along with one of the repeats. Sequence divergence between repeats suppresses RMDs; the mechanisms of such suppression and of resolution of the sequence divergence remains poorly understood. We identified RMD regulators using a set of reporter assays in mouse cells that test two key parameters: repeat sequence divergence and the distances between one repeat and the initiating chromosomal break. We found that the mismatch repair factor MLH1 suppresses RMDs with sequence divergence in the same pathway as MSH2 and MSH6, and which is dependent on residues in MLH1 and its binding partner PMS2 that are important for nuclease activity. Additionally, we found that the resolution of sequence divergence in the RMD product has a specific polarity, where divergent bases that are proximal to the chromosomal break end are preferentially removed. Moreover, we found that the domain of MLH1 that forms part of the MLH1-PMS2 endonuclease is important for polarity of resolution of sequence divergence. We also identified distinctions between MLH1 versus TOP3α in regulation of RMDs. We suggest that MLH1 suppresses RMDs with sequence divergence, while also promoting directional resolution of sequence divergence in the RMD product.
Collapse
Affiliation(s)
- Hannah Trost
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Arianna Merkell
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | | | - Jeremy M Stark
- To whom correspondence should be addressed. Tel: +1 626 218-6346; Fax: +1 626 218 8892;
| |
Collapse
|
7
|
Discovery of a Novel Bloom's Syndrome Protein (BLM) Inhibitor Suppressing Growth and Metastasis of Prostate Cancer. Int J Mol Sci 2022; 23:ijms232314798. [PMID: 36499126 PMCID: PMC9736344 DOI: 10.3390/ijms232314798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 12/03/2022] Open
Abstract
Prostate cancer (PCa) is a common cancer and a major cause of cancer-related death worldwide in men, necessitating novel targets for cancer therapy. High expression of Bloom's syndrome protein (BLM) helicase is associated with the occurrence and development of PCa. Therefore, the identification and development of new BLM inhibitors may be a new direction for the treatment of PCa. Here, we identified a novel inhibitor by molecular docking and put it to systematic evaluation via various experiments, AO/854, which acted as a competitive inhibitor that blocked the BLM-DNA interaction. Cellular evaluation indicated that AO/854-suppressed tumor growth and metastasis in PC3 cells by enhancing DNA damage, phosphorylating Chk1/Chk2, and altering the p53 signaling pathway. Collectively, the study highlights the potential of BLM as a therapeutic target in PCa and reveals a distinct mechanism by which AO/854 competitively inhibits the function of BLM.
Collapse
|
8
|
Ping X, Stark JM. O-GlcNAc transferase is important for homology-directed repair. DNA Repair (Amst) 2022; 119:103394. [PMID: 36095925 PMCID: PMC9884008 DOI: 10.1016/j.dnarep.2022.103394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/11/2022] [Accepted: 09/01/2022] [Indexed: 01/31/2023]
Abstract
O-Linked β-N-acetylglucosamine glycosylation (O-GlcNAcylation) to serine or threonine residues is a reversible and dynamic post-translational modification. O-GlcNAc transferase (OGT) is the only enzyme for O-GlcNAcylation, and is a potential cancer therapeutic target in combination with clastogenic (i.e., chromosomal breaking) therapeutics. Thus, we sought to examine the influence of O-GlcNAcylation on chromosomal break repair. Using a set of DNA double strand break (DSB) reporter assays, we found that the depletion of OGT, and its inhibition with a small molecule each caused a reduction in repair pathways that involve use of homology: RAD51-dependent homology-directed repair (HDR), and single strand annealing. In contrast, such OGT disruption did not obviously affect chromosomal break end joining, and furthermore caused an increase in homology-directed gene targeting. Such disruption in OGT also caused a reduction in clonogenic survival, as well as modifications to cell cycle profiles, particularly an increase in G1-phase cells. We also examined intermediate steps of HDR, finding no obvious effects on an assay for DSB end resection, nor for RAD51 recruitment into ionizing radiation induced foci (IRIF) in proliferating cells. However, we also found that the influence of OGT on HDR and homology-directed gene targeting were dependent on RAD52, and that OGT is important for RAD52 IRIF in proliferating cells. Thus, we suggest that OGT is important for regulation of HDR that is partially linked to RAD52 function.
Collapse
Affiliation(s)
- Xiaoli Ping
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, CA 91010, USA
| | - Jeremy M. Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, CA 91010, USA,Correspondence should be addressed to J.M.S:, Phone: 626-218-6346, Fax: 626-301-8892,
| |
Collapse
|
9
|
Li E, Xia M, Du Y, Long K, Ji F, Pan F, He L, Hu Z, Guo Z. METTL3 promotes homologous recombination repair and modulates chemotherapeutic response in breast cancer by regulating the EGF/Rad51 axis. eLife 2022; 11:75231. [PMID: 35502895 PMCID: PMC9094751 DOI: 10.7554/elife.75231] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
METTL3 and N6-methyladenosine (m6A) are involved in many types of biological and pathological processes, including DNA repair. However, the function and mechanism of METTL3 in DNA repair and chemotherapeutic response remain largely unknown. In present study, we identified that METTL3 participates in the regulation of homologous recombination repair (HR), which further influences chemotherapeutic response in both MCF-7 and MDA-MB-231 breast cancer (BC) cells. Knockdown of METTL3 sensitized these BC cells to Adriamycin (ADR; also named as doxorubicin) treatment and increased accumulation of DNA damage. Mechanically, we demonstrated that inhibition of METTL3 impaired HR efficiency and increased ADR-induced DNA damage by regulating m6A modification of EGF/RAD51 axis. METTL3 promoted EGF expression through m6A modification, which further upregulated RAD51 expression, resulting in enhanced HR activity. We further demonstrated that the m6A 'reader', YTHDC1, bound to the m6A modified EGF transcript and promoted EGF synthesis, which enhanced HR and cell survival during ADR treatment in breast cancer cells. Our findings reveal a pivotal mechanism of METTL3-mediated HR and chemotherapeutic drug response, which may contribute to cancer therapy.
Collapse
Affiliation(s)
- Enjie Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Mingyue Xia
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Yu Du
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Kaili Long
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Feng Ji
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Feiyan Pan
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Lingfeng He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Zhigang Hu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing, China
| |
Collapse
|
10
|
A POLD3/BLM dependent pathway handles DSBs in transcribed chromatin upon excessive RNA:DNA hybrid accumulation. Nat Commun 2022; 13:2012. [PMID: 35440629 PMCID: PMC9019021 DOI: 10.1038/s41467-022-29629-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 03/25/2022] [Indexed: 12/03/2022] Open
Abstract
Transcriptionally active loci are particularly prone to breakage and mounting evidence suggests that DNA Double-Strand Breaks arising in active genes are handled by a dedicated repair pathway, Transcription-Coupled DSB Repair (TC-DSBR), that entails R-loop accumulation and dissolution. Here, we uncover a function for the Bloom RecQ DNA helicase (BLM) in TC-DSBR in human cells. BLM is recruited in a transcription dependent-manner at DSBs where it fosters resection, RAD51 binding and accurate Homologous Recombination repair. However, in an R-loop dissolution-deficient background, we find that BLM promotes cell death. We report that upon excessive RNA:DNA hybrid accumulation, DNA synthesis is enhanced at DSBs, in a manner that depends on BLM and POLD3. Altogether our work unveils a role for BLM at DSBs in active chromatin, and highlights the toxic potential of RNA:DNA hybrids that accumulate at transcription-associated DSBs. DNA Double Strand breaks in transcriptionally active loci (TC-DSBs) undergo a dedicated repair pathway. Here, the authors show that excessive RNA:DNA hybrid accumulation at TC-DSBs elicits POLD3/BLM-dependent DNA synthesis that induces cell toxicity.
Collapse
|
11
|
Qi M, Stenson PD, Ball EV, Tainer JA, Bacolla A, Kehrer-Sawatzki H, Cooper DN, Zhao H. Distinct sequence features underlie microdeletions and gross deletions in the human genome. Hum Mutat 2021; 43:328-346. [PMID: 34918412 PMCID: PMC9069542 DOI: 10.1002/humu.24314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/02/2021] [Accepted: 12/14/2021] [Indexed: 11/18/2022]
Abstract
Microdeletions and gross deletions are important causes (~20%) of human inherited disease and their genomic locations are strongly influenced by the local DNA sequence environment. This notwithstanding, no study has systematically examined their underlying generative mechanisms. Here, we obtained 42,098 pathogenic microdeletions and gross deletions from the Human Gene Mutation Database (HGMD) that together form a continuum of germline deletions ranging in size from 1 to 28,394,429 bp. We analyzed the DNA sequence within 1 kb of the breakpoint junctions and found that the frequencies of non‐B DNA‐forming repeats, GC‐content, and the presence of seven of 78 specific sequence motifs in the vicinity of pathogenic deletions correlated with deletion length for deletions of length ≤30 bp. Further, we found that the presence of DR, GQ, and STR repeats is important for the formation of longer deletions (>30 bp) but not for the formation of shorter deletions (≤30 bp) while significantly (χ2, p < 2E−16) more microhomologies were identified flanking short deletions than long deletions (length >30 bp). We provide evidence to support a functional distinction between microdeletions and gross deletions. Finally, we propose that a deletion length cut‐off of 25–30 bp may serve as an objective means to functionally distinguish microdeletions from gross deletions.
Collapse
Affiliation(s)
- Mengling Qi
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, China
| | - Peter D Stenson
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Edward V Ball
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - John A Tainer
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Albino Bacolla
- Departments of Cancer Biology and of Molecular and Cellular Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | | | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Huiying Zhao
- Department of Medical Research Center, Sun Yat-sen Memorial Hospital; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangzhou, China
| |
Collapse
|
12
|
Vu TV, Das S, Nguyen CC, Kim J, Kim JY. Single-strand annealing: Molecular mechanisms and potential applications in CRISPR-Cas-based precision genome editing. Biotechnol J 2021; 17:e2100413. [PMID: 34846104 DOI: 10.1002/biot.202100413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/22/2021] [Accepted: 11/29/2021] [Indexed: 12/24/2022]
Abstract
BACKGROUND Spontaneous double-stranded DNA breaks (DSBs) frequently occur within the genome of all living organisms and must be well repaired for survival. Recently, more important roles of the DSB repair pathways that were previously thought to be minor pathways, such as single-strand annealing (SSA), have been shown. Nevertheless, the biochemical mechanisms and applications of the SSA pathway in genome editing have not been updated. PURPOSE AND SCOPE Understanding the molecular mechanism of SSA is important to design potential applications in gene editing. This review provides insights into the recent progress of SSA studies and establishes a model for their potential applications in precision genome editing. SUMMARY AND CONCLUSION The SSA mechanism involved in DNA DSB repair appears to be activated by a complex signaling cascade starting with broken end sensing and 5'-3' resection to reveal homologous repeats on the 3' ssDNA overhangs that flank the DSB. Annealing the repeats would help to amend the discontinuous ends and restore the intact genome, resulting in the missing of one repeat and the intervening sequence between the repeats. We proposed a model for CRISPR-Cas-based precision insertion or replacement of DNA fragments to take advantage of the characteristics. The proposed model can add a tool to extend the choice for precision gene editing. Nevertheless, the model needs to be experimentally validated and optimized with SSA-favorable conditions for practical applications.
Collapse
Affiliation(s)
- Tien Van Vu
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea.,National Key Laboratory for Plant Cell Biotechnology, Agricultural Genetics Institute, Bac Tu Liem, Hanoi, Vietnam
| | - Swati Das
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Cam Chau Nguyen
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Jihae Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Jae-Yean Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea.,Division of Life Science, Gyeongsang National University, Jinju, Republic of Korea
| |
Collapse
|
13
|
Rall-Scharpf M, Friedl TWP, Biechonski S, Denkinger M, Milyavsky M, Wiesmüller L. Sex-specific differences in DNA double-strand break repair of cycling human lymphocytes during aging. Aging (Albany NY) 2021; 13:21066-21089. [PMID: 34506302 PMCID: PMC8457596 DOI: 10.18632/aging.203519] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/10/2021] [Indexed: 12/15/2022]
Abstract
The gender gap in life expectancy and cancer incidence suggests differences in the aging process between the sexes. Genomic instability has been recognized as a key factor in aging, but little is known about sex-specific differences. Therefore, we analyzed DNA double-strand break (DSB) repair in cycling human peripheral blood lymphocytes (PBL) from male and female donors of different age. Reporter-based DSB repair analyses revealed differential regulation of pathway usage in PBL from male and female donors with age: Non-homologous end joining (NHEJ) was inversely regulated in men and women; the activity of pathways requiring end processing and strand annealing steps such as microhomology-mediated end joining (MMEJ) declined with age in women but not in men. Screening candidate proteins identified the NHEJ protein KU70 as well as the end resection regulatory factors ATM and BLM showing reduced expression during aging in women. Consistently, the regulatory factor BLM contributed to the MMEJ proficiency in young but not in old women as demonstrated by knockdown analysis. In conclusion, we show that DSB repair is subject to changes upon aging and age-related changes in DSB repair are distinct in men and women.
Collapse
Affiliation(s)
| | - Thomas W P Friedl
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Shahar Biechonski
- Department of Pathology, Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel
| | - Michael Denkinger
- Institute for Geriatric Research Unit, Agaplesion Bethesda Hospital, Ulm University, Ulm, Germany
| | - Michael Milyavsky
- Department of Pathology, Sackler Faculty of Medicine, Tel Aviv University, Tel-Aviv, Israel
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| |
Collapse
|
14
|
Al-Zain AM, Symington LS. The dark side of homology-directed repair. DNA Repair (Amst) 2021; 106:103181. [PMID: 34311272 DOI: 10.1016/j.dnarep.2021.103181] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/16/2021] [Accepted: 07/16/2021] [Indexed: 10/20/2022]
Abstract
DNA double strand breaks (DSB) are cytotoxic lesions that can lead to genome rearrangements and genomic instability, which are hallmarks of cancer. The two main DSB repair pathways are non-homologous end joining and homologous recombination (HR). While HR is generally highly accurate, it has the potential for rearrangements that occur directly or through intermediates generated during the repair process. Whole genome sequencing of cancers has revealed numerous types of structural rearrangement signatures that are often indicative of repair mediated by sequence homology. However, it can be challenging to delineate repair mechanisms from sequence analysis of rearrangement end products from cancer genomes, or even model systems, because the same rearrangements can be generated by different pathways. Here, we review homology-directed repair pathways and their consequences. Exploring those pathways can lead to a greater understanding of rearrangements that occur in cancer cells.
Collapse
Affiliation(s)
- Amr M Al-Zain
- Program in Biological Sciences, Columbia University, New York, NY, 10027, United States; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, United States
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY, 10032, United States; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, 10032, United States.
| |
Collapse
|
15
|
Morales ME, Kaul T, Walker J, Everett C, White T, Deininger P. Altered DNA repair creates novel Alu/Alu repeat-mediated deletions. Hum Mutat 2021; 42:600-613. [PMID: 33675284 PMCID: PMC8068675 DOI: 10.1002/humu.24193] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/25/2021] [Accepted: 02/24/2021] [Indexed: 12/21/2022]
Abstract
Alu elements are the most abundant source of nonallelic homology that influences genetic instability in the human genome. When there is a DNA double-stranded break, the Alu element's high copy number, moderate length and distance and mismatch between elements uniquely influence recombination processes. We utilize a reporter-gene assay to show the complex influence of Alu mismatches on Alu-related repeat-mediated deletions (RMDs). The Alu/Alu heteroduplex intermediate can result in a nonallelic homologous recombination (HR). Alternatively, the heteroduplex can result in various DNA breaks around the Alu elements caused by competing nucleases. These breaks can undergo Alt-nonhomologous end joining to cause deletions focused around the Alu elements. Formation of these heteroduplex intermediates is largely RAD52 dependent. Cells with low ERCC1 levels utilize more of these alternatives resolutions, while cells with MSH2 defects tend to have more RMDs with a specific increase in the HR events. Therefore, Alu elements are expected to create different forms of deletions in various cancers depending on a number of these DNA repair defects.
Collapse
Affiliation(s)
- Maria E Morales
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - Tiffany Kaul
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - JaNiece Walker
- Department of Biology, Xavier University, New Orleans, Louisiana, USA
| | - Chelsea Everett
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - Travis White
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA.,Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Prescott Deininger
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA.,Department of Epidemiology, Tulane University, New Orleans, Louisiana, USA
| |
Collapse
|
16
|
Shorrocks AMK, Jones SE, Tsukada K, Morrow CA, Belblidia Z, Shen J, Vendrell I, Fischer R, Kessler BM, Blackford AN. The Bloom syndrome complex senses RPA-coated single-stranded DNA to restart stalled replication forks. Nat Commun 2021; 12:585. [PMID: 33500419 PMCID: PMC7838300 DOI: 10.1038/s41467-020-20818-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 12/22/2020] [Indexed: 01/30/2023] Open
Abstract
The Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1 and RMI2 to form the BTR complex, which dissolves double Holliday junctions to produce non-crossover homologous recombination (HR) products. BLM also promotes DNA-end resection, restart of stalled replication forks, and processing of ultra-fine DNA bridges in mitosis. How these activities of the BTR complex are regulated in cells is still unclear. Here, we identify multiple conserved motifs within the BTR complex that interact cooperatively with the single-stranded DNA (ssDNA)-binding protein RPA. Furthermore, we demonstrate that RPA-binding is required for stable BLM recruitment to sites of DNA replication stress and for fork restart, but not for its roles in HR or mitosis. Our findings suggest a model in which the BTR complex contains the intrinsic ability to sense levels of RPA-ssDNA at replication forks, which controls BLM recruitment and activation in response to replication stress.
Collapse
Affiliation(s)
- Ann-Marie K Shorrocks
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Samuel E Jones
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Kaima Tsukada
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
- Department of Transdisciplinary Science and Engineering, School of Environment and Society, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Carl A Morrow
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Zoulikha Belblidia
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Johanna Shen
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, 06520, USA
| | - Iolanda Vendrell
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Roman Fischer
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Benedikt M Kessler
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ, UK
| | - Andrew N Blackford
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK.
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK.
| |
Collapse
|