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Panda S, Roychowdhury T, Dutta A, Chakraborty S, Das T, Chatterjee S. ALTering Cancer by Triggering Telomere Replication Stress through the Stabilization of Promoter G-Quadruplex in SMARCAL1. ACS Chem Biol 2024. [PMID: 38959478 DOI: 10.1021/acschembio.4c00285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Most of the human cancers are dependent on telomerase to extend the telomeres. But ∼10% of all cancers use a telomerase-independent, homologous recombination mediated pathway called alternative lengthening of telomeres (ALT). Due to the poor prognosis, ALT status is not being considered yet in the diagnosis of cancer. No such specific treatment is available to date for ALT positive cancers. ALT positive cancers are dependent on replication stress to deploy DNA repair pathways to the telomeres to execute homologous recombination mediated telomere extension. SMARCAL1 (SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily A-like 1) is associated with the ALT telomeres to resolve replication stress thus providing telomere stability. Thus, the dependency on replication stress regulatory factors like SMARCAL1 made it a suitable therapeutic target for the treatment of ALT positive cancers. In this study, we found a significant downregulation of SMARCAL1 expression by stabilizing the G-quadruplex (G4) motif found in the promoter of SMARCAL1 by potent G4 stabilizers, like TMPyP4 and BRACO-19. SMARCAL1 downregulation led toward the increased localization of PML (promyelocytic leukemia) bodies in ALT telomeres and triggered the formation of APBs (ALT-associated promyelocytic leukemia bodies) in ALT positive cell lines, increasing telomere replication stress and DNA damage at a genomic level. Induction of replication stress and hyper-recombinogenic phenotype in ALT positive cells mediated by G4 stabilizing molecules already highlighted their possible application as a new therapeutic window to target ALT positive tumors. In accordance with this, our study will also provide a valuable insight toward the development of G4-based ALT therapeutics targeting SMARCAL1.
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Affiliation(s)
- Suman Panda
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
| | - Tanaya Roychowdhury
- Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, New York 10065, United States of America
| | - Anindya Dutta
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
| | - Sourio Chakraborty
- Division of Molecular Medicine, Centenary Campus, Bose Institute, P-1/12 C.I.T. Scheme VII-M, Kolkata 700054, India
| | - Tanya Das
- Division of Molecular Medicine, Centenary Campus, Bose Institute, P-1/12 C.I.T. Scheme VII-M, Kolkata 700054, India
| | - Subhrangsu Chatterjee
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
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Zhou H, Xie C, Xie Y, He Y, Chen Y, Zhang C, Zhang Y, Zhao Y, Liu H. UBQLN1 deficiency mediates telomere shortening and IPF through interacting with RPA1. PLoS Genet 2023; 19:e1010856. [PMID: 37463174 PMCID: PMC10381042 DOI: 10.1371/journal.pgen.1010856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 07/03/2023] [Indexed: 07/20/2023] Open
Abstract
Premature telomere shortening is a known factor correlated to idiopathic pulmonary fibrosis (IPF) occurrence, which is a chronic, progressive, age-related disease with high mortality. The etiology of IPF is still unknown. Here, we found that UBQLN1 plays a key role in telomere length maintenance and is potentially relevant to IPF. UBQLN1 involves in DNA replication by interacting with RPA1 and shuttling it off from the replication fork. The deficiency of UBQLN1 retains RPA1 at replication fork, hinders replication and thus causes cell cycle arrest and genome instability. Especially at telomere regions of the genome, where more endogenous replication stress exists because of G rich sequences, UBQLN1 depletion leads to rapid telomere shortening in HeLa cells. It revealed that UBQLN1 depletion also shortens telomere length at mouse lung and accelerates mouse lung fibrosis. In addition, the UBQLN1 expression level in IPF patients is downregulated and correlated to poor prognosis. Altogether, these results uncover a new role of UBQLN1 in ensuring DNA replication and maintaining telomere stability, which may shed light on IPF pathogenesis and prevention.
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Affiliation(s)
- Haoxian Zhou
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- Department of Cardiology, Guangdong Provincial Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China
| | - Chen Xie
- Cardiovascular Department, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yujie Xie
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yunru He
- Center for Translational Medicine, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yanlian Chen
- Cardiovascular Department, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Canfeng Zhang
- Center for Translational Medicine, Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yan Zhang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yong Zhao
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Haiying Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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3
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Abu-Libdeh B, Jhujh SS, Dhar S, Sommers JA, Datta A, Longo GM, Grange LJ, Reynolds JJ, Cooke SL, McNee GS, Hollingworth R, Woodward BL, Ganesh AN, Smerdon SJ, Nicolae CM, Durlacher-Betzer K, Molho-Pessach V, Abu-Libdeh A, Meiner V, Moldovan GL, Roukos V, Harel T, Brosh RM, Stewart GS. RECON syndrome is a genome instability disorder caused by mutations in the DNA helicase RECQL1. J Clin Invest 2022; 132:147301. [PMID: 35025765 PMCID: PMC8884905 DOI: 10.1172/jci147301] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Despite being the first homolog of the bacterial RecQ helicase to be identified in humans, the function of RECQL1 remains poorly characterized. Furthermore, unlike other members of the human RECQ family of helicases, mutations in RECQL1 have not been associated with a genetic disease. Here, we identify 2 families with a genome instability disorder that we have named RECON (RECql ONe) syndrome, caused by biallelic mutations in the RECQL gene. The affected individuals had short stature, progeroid facial features, a hypoplastic nose, xeroderma, and skin photosensitivity and were homozygous for the same missense mutation in RECQL1 (p.Ala459Ser), located within its zinc binding domain. Biochemical analysis of the mutant RECQL1 protein revealed that the p.A459S missense mutation compromised its ATPase, helicase, and fork restoration activity, while its capacity to promote single-strand DNA annealing was largely unaffected. At the cellular level, this mutation in RECQL1 gave rise to a defect in the ability to repair DNA damage induced by exposure to topoisomerase poisons and a failure of DNA replication to progress efficiently in the presence of abortive topoisomerase lesions. Taken together, RECQL1 is the fourth member of the RecQ family of helicases to be associated with a human genome instability disorder.
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Affiliation(s)
- Bassam Abu-Libdeh
- Department of Pediatrics & Genetics, Makassed Hospital & Al-Quds Medical School, Jerusalem, Israel
| | - Satpal S Jhujh
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Srijita Dhar
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Canada
| | - Joshua A Sommers
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Canada
| | - Arindam Datta
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Canada
| | - Gabriel Mc Longo
- Institute of Molecular Biology, Institute of Molecular Biology, Mainz, Germany
| | - Laura J Grange
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - John J Reynolds
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Sophie L Cooke
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Gavin S McNee
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Robert Hollingworth
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Beth L Woodward
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Anil N Ganesh
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Stephen J Smerdon
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Claudia M Nicolae
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, United States of America
| | | | - Vered Molho-Pessach
- Department of Dermatology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Abdulsalam Abu-Libdeh
- Department of Pediatrics & Genetics, Makassed Hospital & Al-Quds Medical School, Jerusalem, Israel
| | - Vardiella Meiner
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, United States of America
| | - Vassilis Roukos
- Institute of Molecular Biology, Institute of Molecular Biology, Mainz, Germany
| | - Tamar Harel
- Faculty of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Robert M Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Canada
| | - Grant S Stewart
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
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Vicari MR, Bruschi DP, Cabral-de-Mello DC, Nogaroto V. Telomere organization and the interstitial telomeric sites involvement in insects and vertebrates chromosome evolution. Genet Mol Biol 2022; 45:e20220071. [DOI: 10.1590/1678-4685-gmb-2022-0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 09/24/2022] [Indexed: 11/16/2022] Open
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Comprehensive germline genomic profiles of children, adolescents and young adults with solid tumors. Nat Commun 2020; 11:2206. [PMID: 32371905 PMCID: PMC7200683 DOI: 10.1038/s41467-020-16067-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 04/08/2020] [Indexed: 02/07/2023] Open
Abstract
Compared to adult carcinomas, there is a paucity of targeted treatments for solid tumors in children, adolescents, and young adults (C-AYA). The impact of germline genomic signatures has implications for heritability, but its impact on targeted therapies has not been fully appreciated. Performing variant-prioritization analysis on germline DNA of 1,507 C-AYA patients with solid tumors, we show 12% of these patients carrying germline pathogenic and/or likely pathogenic variants (P/LP) in known cancer-predisposing genes (KCPG). An additional 61% have germline pathogenic variants in non-KCPG genes, including PRKN, SMARCAL1, SMAD7, which we refer to as candidate genes. Despite germline variants in a broad gene spectrum, pathway analysis leads to top networks centering around p53. Our drug-target analysis shows 1/3 of patients with germline P/LP variants have at least one druggable alteration, while more than half of them are from our candidate gene group, which would otherwise go unidentified in routine clinical care. Targeted therapies for solid tumors in children, adolescents, and young adults (C-AYA) lag behind that of adult carcinomas. Here, the authors study the germline genomic signatures of 1,507 C-AYA patients with solid tumors and find pathogenic/likely pathogenic germline variants in diverse genes of which 1/3 of these alterations are druggable.
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Aksenova AY, Mirkin SM. At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences. Genes (Basel) 2019; 10:genes10020118. [PMID: 30764567 PMCID: PMC6410037 DOI: 10.3390/genes10020118] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023] Open
Abstract
Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.
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Affiliation(s)
- Anna Y Aksenova
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia.
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02421, USA.
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Zhang T, Zhang Z, Shengzhao G, Li X, Liu H, Zhao Y. Strand break-induced replication fork collapse leads to C-circles, C-overhangs and telomeric recombination. PLoS Genet 2019; 15:e1007925. [PMID: 30716077 PMCID: PMC6382176 DOI: 10.1371/journal.pgen.1007925] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 02/20/2019] [Accepted: 01/01/2019] [Indexed: 12/16/2022] Open
Abstract
Telomerase-independent ALT (alternative lengthening of telomeres) cells are characterized by high frequency of telomeric homologous recombination (HR), C-rich extrachromosomal circles (C-circles) and C-rich terminal 5' overhangs (C-overhangs). However, underlying mechanism is poorly understood. Here, we show that both C-circle and C-overhang form when replication fork collapse is induced by strand break at telomeres. We find that endogenous DNA break predominantly occur on C-rich strand of telomeres in ALT cells, resulting in high frequency of replication fork collapse. While collapsed forks could be rescued by replication fork regression leading to telomeric homologous recombination, those unresolved are converted to C-circles and C-overhang at lagging and leading synthesized strand, respectively. Meanwhile, multiple hallmarks of ALT are provoked, suggesting that strand break-induced replication stress underlies ALT. These findings provide a molecular basis underlying telomeric HR and biogenesis of C-circle and C-overhang, thus implicating the specific mechanism to resolve strand break-induced replication defect at telomeres in ALT cells. 10 to 15% human cancers utilize telomerase-independent alternative lengthening of telomeres (ALT) to maintain their telomere length. Unexpectedly, we find that endogenous C-strand breaks predominantly exist in telomeres of ALT cells, which induce high frequency of replication fork collapse. While collapsed fork triggers fork regression machinery to restart the replication, leading to telomeric homologous recombination; those unresolved are converted to C-circle and C-overhang. These findings suggest that the formation of C-circle and C-overhang represents a unique manner for ALT cells to prevent chromosome instability induced by replication defect at telomeres. Moreover, multiple hallmarks of ALT are provoked during this process, demonstrating that DNA strand break at telomeres underlies ALT mechanism.
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Affiliation(s)
- Tianpeng Zhang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Zepeng Zhang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Gong Shengzhao
- School of Chemical Engineering and Technology, Guangdong Engineering Technical Research Center for Green Household Chemicals, Guangdong Industry Technical College, Guangzhou, P.R.China
| | - Xiaocui Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Haiying Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Yong Zhao
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China
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8
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Yang B, Xu X, Russell L, Sullenberger MT, Yanowitz JL, Maine EM. A DNA repair protein and histone methyltransferase interact to promote genome stability in the Caenorhabditis elegans germ line. PLoS Genet 2019; 15:e1007992. [PMID: 30794539 PMCID: PMC6402707 DOI: 10.1371/journal.pgen.1007992] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 03/06/2019] [Accepted: 01/28/2019] [Indexed: 12/29/2022] Open
Abstract
Histone modifications regulate gene expression and chromosomal events, yet how histone-modifying enzymes are targeted is poorly understood. Here we report that a conserved DNA repair protein, SMRC-1, associates with MET-2, the C. elegans histone methyltransferase responsible for H3K9me1 and me2 deposition. We used molecular, genetic, and biochemical methods to investigate the biological role of SMRC-1 and to explore its relationship with MET-2. SMRC-1, like its mammalian ortholog SMARCAL1, provides protection from DNA replication stress. SMRC-1 limits accumulation of DNA damage and promotes germline and embryonic viability. MET-2 and SMRC-1 localize to mitotic and meiotic germline nuclei, and SMRC-1 promotes an increase in MET-2 abundance in mitotic germline nuclei upon replication stress. In the absence of SMRC-1, germline H3K9me2 generally decreases after multiple generations at high culture temperature. Genetic data are consistent with MET-2 and SMRC-1 functioning together to limit replication stress in the germ line and in parallel to promote other germline processes. We hypothesize that loss of SMRC-1 activity causes chronic replication stress, in part because of insufficient recruitment of MET-2 to nuclei.
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Affiliation(s)
- Bing Yang
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| | - Xia Xu
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| | - Logan Russell
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | | | - Judith L. Yanowitz
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Eleanor M. Maine
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
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Abstract
A large number of SNF2 family, DNA and ATP-dependent motor proteins are needed during transcription, DNA replication, and DNA repair to manipulate protein-DNA interactions and change DNA structure. SMARCAL1, ZRANB3, and HLTF are three related members of this family with specialized functions that maintain genome stability during DNA replication. These proteins are recruited to replication forks through protein-protein interactions and bind DNA using both their motor and substrate recognition domains (SRDs). The SRD provides specificity to DNA structures like forks and junctions and confers DNA remodeling activity to the motor domains. Remodeling reactions include fork reversal and branch migration to promote fork stabilization, template switching, and repair. Regulation ensures these powerful activities remain controlled and restricted to damaged replication forks. Inherited mutations in SMARCAL1 cause a severe developmental disorder and mutations in ZRANB3 and HLTF are linked to cancer illustrating the importance of these enzymes in ensuring complete and accurate DNA replication. In this review, we examine how these proteins function, concentrating on their common and unique attributes and regulatory mechanisms.
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Affiliation(s)
- Lisa A Poole
- a Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , TN , USA
| | - David Cortez
- a Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , TN , USA
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Lugli N, Sotiriou SK, Halazonetis TD. The role of SMARCAL1 in replication fork stability and telomere maintenance. DNA Repair (Amst) 2017. [PMID: 28623093 DOI: 10.1016/j.dnarep.2017.06.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
SMARCAL1 (SWI/SNF Related, Matrix Associated, Actin Dependent Regulator Of Chromatin, Subfamily A-Like 1), also known as HARP, is an ATP-dependent annealing helicase that stabilizes replication forks during DNA damage. Mutations in this gene are the cause of Schimke immune-osseous dysplasia (SIOD), an autosomal recessive disorder characterized by T-cell immunodeficiency and growth dysfunctions. In this review, we summarize the main roles of SMARCAL1 in DNA repair, telomere maintenance and replication fork stability in response to DNA replication stress.
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Affiliation(s)
- Natalia Lugli
- Department of Molecular Biology, University of Geneva, Switzerland
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Azeroglu B, Leach DRF. RecG controls DNA amplification at double-strand breaks and arrested replication forks. FEBS Lett 2017; 591:1101-1113. [PMID: 28155219 PMCID: PMC5412681 DOI: 10.1002/1873-3468.12583] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 01/13/2017] [Accepted: 01/28/2017] [Indexed: 12/16/2022]
Abstract
DNA amplification is a powerful mutational mechanism that is a hallmark of cancer and drug resistance. It is therefore important to understand the fundamental pathways that cells employ to avoid over‐replicating sections of their genomes. Recent studies demonstrate that, in the absence of RecG, DNA amplification is observed at sites of DNA double‐strand break repair (DSBR) and of DNA replication arrest that are processed to generate double‐strand ends. RecG also plays a role in stabilising joint molecules formed during DSBR. We propose that RecG prevents a previously unrecognised mechanism of DNA amplification that we call reverse‐restart, which generates DNA double‐strand ends from incorrect loading of the replicative helicase at D‐loops formed by recombination, and at arrested replication forks.
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Affiliation(s)
- Benura Azeroglu
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, UK
| | - David R F Leach
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, UK
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