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Xu Y, Jiao Y, Liu C, Miao R, Liu C, Wang Y, Ma C, Liu J. R-loop and diseases: the cell cycle matters. Mol Cancer 2024; 23:84. [PMID: 38678239 PMCID: PMC11055327 DOI: 10.1186/s12943-024-02000-3] [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: 02/11/2024] [Accepted: 04/13/2024] [Indexed: 04/29/2024] Open
Abstract
The cell cycle is a crucial biological process that is involved in cell growth, development, and reproduction. It can be divided into G1, S, G2, and M phases, and each period is closely regulated to ensure the production of two similar daughter cells with the same genetic material. However, many obstacles influence the cell cycle, including the R-loop that is formed throughout this process. R-loop is a triple-stranded structure, composed of an RNA: DNA hybrid and a single DNA strand, which is ubiquitous in organisms from bacteria to mammals. The existence of the R-loop has important significance for the regulation of various physiological processes. However, aberrant accumulation of R-loop due to its limited resolving ability will be detrimental for cells. For example, DNA damage and genomic instability, caused by the R-loop, can activate checkpoints in the cell cycle, which in turn induce cell cycle arrest and cell death. At present, a growing number of factors have been proven to prevent or eliminate the accumulation of R-loop thereby avoiding DNA damage and mutations. Therefore, we need to gain detailed insight into the R-loop resolution factors at different stages of the cell cycle. In this review, we review the current knowledge of factors that play a role in resolving the R-loop at different stages of the cell cycle, as well as how mutations of these factors lead to the onset and progression of diseases.
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Affiliation(s)
- Yuqin Xu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Yue Jiao
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chengbin Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Rui Miao
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chunyan Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Yilong Wang
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chunming Ma
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Jiao Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China.
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2
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Bhattacharjee R, Jolly LA, Corbett MA, Wee IC, Rao SR, Gardner AE, Ritchie T, van Hugte EJH, Ciptasari U, Piltz S, Noll JE, Nazri N, van Eyk CL, White M, Fornarino D, Poulton C, Baynam G, Collins-Praino LE, Snel MF, Nadif Kasri N, Hemsley KM, Thomas PQ, Kumar R, Gecz J. Compromised transcription-mRNA export factor THOC2 causes R-loop accumulation, DNA damage and adverse neurodevelopment. Nat Commun 2024; 15:1210. [PMID: 38331934 PMCID: PMC10853216 DOI: 10.1038/s41467-024-45121-5] [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: 06/16/2023] [Accepted: 01/15/2024] [Indexed: 02/10/2024] Open
Abstract
We implicated the X-chromosome THOC2 gene, which encodes the largest subunit of the highly-conserved TREX (Transcription-Export) complex, in a clinically complex neurodevelopmental disorder with intellectual disability as the core phenotype. To study the molecular pathology of this essential eukaryotic gene, we generated a mouse model based on a hypomorphic Thoc2 exon 37-38 deletion variant of a patient with ID, speech delay, hypotonia, and microcephaly. The Thoc2 exon 37-38 deletion male (Thoc2Δ/Y) mice recapitulate the core phenotypes of THOC2 syndrome including smaller size and weight, and significant deficits in spatial learning, working memory and sensorimotor functions. The Thoc2Δ/Y mouse brain development is significantly impacted by compromised THOC2/TREX function resulting in R-loop accumulation, DNA damage and consequent cell death. Overall, we suggest that perturbed R-loop homeostasis, in stem cells and/or differentiated cells in mice and the patient, and DNA damage-associated functional alterations are at the root of THOC2 syndrome.
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Affiliation(s)
- Rudrarup Bhattacharjee
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Lachlan A Jolly
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
- School of Biomedicine, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Mark A Corbett
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Ing Chee Wee
- Discipline of Anatomy and Pathology, School of Biomedicine, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Sushma R Rao
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Proteomics, Metabolomics and MS-imaging Core Facility, South Australian Health and Medical Research Institute, and Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Alison E Gardner
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Tarin Ritchie
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Eline J H van Hugte
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, 6500, HB, the Netherlands
| | - Ummi Ciptasari
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, 6500, HB, the Netherlands
| | - Sandra Piltz
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
- School of Biomedicine, The University of Adelaide, Adelaide, SA, 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Jacqueline E Noll
- School of Biomedicine, Faculty of Health and Medical Sciences, University of Adelaide and Precision Cancer Medicine Theme, Solid Tumour Program, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Nazzmer Nazri
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Childhood Dementia Research Group, College of Medicine and Public Health, Flinders Health & Medical Research Institute, Flinders University, Bedford Park, Adelaide, SA, 5042, Australia
| | - Clare L van Eyk
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Melissa White
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
- School of Biomedicine, The University of Adelaide, Adelaide, SA, 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Dani Fornarino
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Cathryn Poulton
- Undiagnosed Diseases Program, Genetic Services of WA, King Edward Memorial Hospital, Subiaco, WA, 6008, Australia
| | - Gareth Baynam
- Undiagnosed Diseases Program, Genetic Services of WA, King Edward Memorial Hospital, Subiaco, WA, 6008, Australia
- Western Australian Register of Developmental Anomalies, King Edward Memorial Hospital, Subiaco, WA, 6008, Australia
- Rare Care Centre, Perth Children's Hospital, Nedlands, WA, 6009, Australia
| | - Lyndsey E Collins-Praino
- Discipline of Anatomy and Pathology, School of Biomedicine, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Marten F Snel
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Proteomics, Metabolomics and MS-imaging Core Facility, South Australian Health and Medical Research Institute, and Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Nael Nadif Kasri
- Department of Human Genetics, Radboudumc, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, 6500, HB, the Netherlands
| | - Kim M Hemsley
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Childhood Dementia Research Group, College of Medicine and Public Health, Flinders Health & Medical Research Institute, Flinders University, Bedford Park, Adelaide, SA, 5042, Australia
| | - Paul Q Thomas
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
- School of Biomedicine, The University of Adelaide, Adelaide, SA, 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Raman Kumar
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Jozef Gecz
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.
- Robinson Research Institute, The University of Adelaide, Adelaide, SA, 5005, Australia.
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Kim S, Shin WH, Kang Y, Kim H, Lee JY. Direct visualization of replication and R-loop collision using single-molecule imaging. Nucleic Acids Res 2024; 52:259-273. [PMID: 37994723 PMCID: PMC10783495 DOI: 10.1093/nar/gkad1101] [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: 07/25/2023] [Revised: 10/12/2023] [Accepted: 11/06/2023] [Indexed: 11/24/2023] Open
Abstract
R-loops are three-stranded nucleic acid structures that can cause replication stress by blocking replication fork progression. However, the detailed mechanism underlying the collision of DNA replication forks and R-loops remains elusive. To investigate how R-loops induce replication stress, we use single-molecule fluorescence imaging to directly visualize the collision of replicating Phi29 DNA polymerase (Phi29 DNAp), the simplest replication system, and R-loops. We demonstrate that a single R-loop can block replication, and the blockage is more pronounced when an RNA-DNA hybrid is on the non-template strand. We show that this asymmetry results from secondary structure formation on the non-template strand, which impedes the progression of Phi29 DNAp. We also show that G-quadruplex formation on the displaced single-stranded DNA in an R-loop enhances the replication stalling. Moreover, we observe the collision between Phi29 DNAp and RNA transcripts synthesized by T7 RNA polymerase (T7 RNAp). RNA transcripts cause more stalling because of the presence of T7 RNAp. Our work provides insights into how R-loops impede DNA replication at single-molecule resolution.
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Affiliation(s)
- Subin Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Woo Hee Shin
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Yujin Kang
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Hongtae Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Ja Yil Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
- Institute of Basic Science Center for Genomic Integrity, Ulsan 44919, Republic of Korea
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Jiang Y, Huang F, Chen L, Gu JH, Wu YW, Jia MY, Lin Z, Zhou Y, Li YC, Yu C, Tong MH, Shen L, Fan HY, Sha QQ. Genome-wide map of R-loops reveals its interplay with transcription and genome integrity during germ cell meiosis. J Adv Res 2023; 51:45-57. [PMID: 36396044 PMCID: PMC10491972 DOI: 10.1016/j.jare.2022.10.016] [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: 05/09/2022] [Revised: 08/14/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022] Open
Abstract
INTRODUCTION The R-loop is a naturally formed three-strand nucleic acid structure that recently has been reported to participate in multiple biological processes and helped answer some previously unexplained scientific questions. Meiosis process involves multiple chromatin-related events such as DNA double-stranded breaks (DSB) formation, repairing and transcriptional dynamics. OBJECTIVES Explore the regulatory roles and physiological functions of R-loops in the mammalian meiosis process. METHODS In our study, using genome-wide S9.6 CUT & Tag seq, we first mapped the genomic distribution and dynamic changes of R-loop during the meiotic process in mice, from spermatogonia to secondary spermatocytes. And we further explore the role of R-loop in physiological conditions by constructing conditional knockout mice of Rnaseh1, which deleted the R-loop endonuclease before meiosis entry. RESULTS R-loop predominantly distributes at promoter-related regions and varies across different meiotic stages. By joint analysis with the corresponding transcriptome, we found that the R-loop was closely related to transcription during the meiotic process. The high frequency of promoter-related R-loop in meiotic cells is usually accompanied by high transcription activity, and we further verified this in the leptotene/zygotene to the pachytene transition process. Moreover, the lack of RNase H1 caused sterility in male mice with R-loop accumulation and abnormal DSB repair in spermatocytes. Further analysis showed that abnormal R-loop accumulation in the leptotene/zygotene stages influenced transcriptional regulation in the pachytene stage. CONCLUSION The mutual regulation of the R-loop and transcription plays an essential role in spermatogenesis. And R-loop is also important for the normal repair process of DSB during meiosis.
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Affiliation(s)
- Yu Jiang
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Fei Huang
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Lu Chen
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jia-Hui Gu
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yun-Wen Wu
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Meng-Yan Jia
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhen Lin
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yong Zhou
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317 Guangzhou, China
| | - Yan-Chu Li
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317 Guangzhou, China
| | - Chao Yu
- Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ming-Han Tong
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Li Shen
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| | - Heng-Yu Fan
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| | - Qian-Qian Sha
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317 Guangzhou, China.
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Saha S, Pommier Y. R-loops, type I topoisomerases and cancer. NAR Cancer 2023; 5:zcad013. [PMID: 37600974 PMCID: PMC9984992 DOI: 10.1093/narcan/zcad013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/18/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
R-loops are abundant and dynamic structures ubiquitously present in human cells both in the nuclear and mitochondrial genomes. They form in cis in the wake of transcription complexes and in trans apart from transcription complexes. In this review, we focus on the relationship between R-loops and topoisomerases, and cancer genomics and therapies. We summarize the topological parameters associated with the formation and resolution of R-loops, which absorb and release high levels of genomic negative supercoiling (Sc-). We review the deleterious consequences of excessive R-loops and rationalize how human type IA (TOP3B) and type IB (TOP1) topoisomerases regulate and resolve R-loops in coordination with helicase and RNase H enzymes. We also review the drugs (topoisomerase inhibitors, splicing inhibitors, G4 stabilizing ligands) and cancer predisposing genes (BRCA1/2, transcription, and splicing genes) known to induce R-loops, and whether stabilizing R-loops and thereby inducing genomic damage can be viewed as a strategy for cancer treatment.
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Affiliation(s)
- Sourav Saha
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Yves Pommier
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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Sun B, Sherrin M, Roy R. Unscheduled epigenetic modifications cause genome instability and sterility through aberrant R-loops following starvation. Nucleic Acids Res 2022; 51:84-98. [PMID: 36504323 PMCID: PMC9841415 DOI: 10.1093/nar/gkac1155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
During starvation, organisms modify both gene expression and metabolism to adjust to the energy stress. We previously reported that Caenorhabditis elegans lacing AMP-activated protein kinase (AMPK) exhibit transgenerational reproductive defects associated with abnormally elevated trimethylated histone H3 at lysine 4 (H3K4me3) levels in the germ line following recovery from acute starvation. Here, we show that these H3K4me3 marks are significantly increased at promoters, driving aberrant transcription elongation resulting in the accumulation of R-loops in starved AMPK mutants. DNA-RNA immunoprecipitation followed by high-throughput sequencing (DRIP-seq) analysis demonstrated that a significant proportion of the genome was affected by R-loop formation. This was most pronounced in the promoter-transcription start site regions of genes, in which the chromatin was modified by H3K4me3. Like H3K4me3, the R-loops were also found to be heritable, likely contributing to the transgenerational reproductive defects typical of these mutants following starvation. Strikingly, AMPK mutant germ lines show considerably more RAD-51 (the RecA recombinase) foci at sites of R-loop formation, potentially sequestering them from their roles at meiotic breaks or at sites of induced DNA damage. Our study reveals a previously unforeseen role of AMPK in maintaining genome stability following starvation. The downstream effects of R-loops on DNA damage sensitivity and germline stem cell integrity may account for inappropriate epigenetic modification that occurs in numerous human disorders, including various cancers.
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Affiliation(s)
- Bing Sun
- To whom correspondence should be addressed.
| | - McLean Sherrin
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Richard Roy
- Correspondence may also be addressed to Richard Roy. Tel: +1 514 398 6437;
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7
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Li X, Wang L, Liu X, Zheng Z, Kong D. Cellular regulation and stability of DNA replication forks in eukaryotic cells. DNA Repair (Amst) 2022; 120:103418. [DOI: 10.1016/j.dnarep.2022.103418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/03/2022] [Accepted: 10/07/2022] [Indexed: 11/03/2022]
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R-Loop Formation in Meiosis: Roles in Meiotic Transcription-Associated DNA Damage. EPIGENOMES 2022; 6:epigenomes6030026. [PMID: 36135313 PMCID: PMC9498298 DOI: 10.3390/epigenomes6030026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/24/2022] [Accepted: 08/20/2022] [Indexed: 11/16/2022] Open
Abstract
Meiosis is specialized cell division during gametogenesis that produces genetically unique gametes via homologous recombination. Meiotic homologous recombination entails repairing programmed 200–300 DNA double-strand breaks generated during the early prophase. To avoid interference between meiotic gene transcription and homologous recombination, mammalian meiosis is thought to employ a strategy of exclusively transcribing meiotic or post-meiotic genes before their use. Recent studies have shown that R-loops, three-stranded DNA/RNA hybrid nucleotide structures formed during transcription, play a crucial role in transcription and genome integrity. Although our knowledge about the function of R-loops during meiosis is limited, recent findings in mouse models have suggested that they play crucial roles in meiosis. Given that defective formation of an R-loop can cause abnormal transcription and transcription-coupled DNA damage, the precise regulatory network of R-loops may be essential in vivo for the faithful progression of mammalian meiosis and gametogenesis.
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Riera-Escamilla A, Vockel M, Nagirnaja L, Xavier MJ, Carbonell A, Moreno-Mendoza D, Pybus M, Farnetani G, Rosta V, Cioppi F, Friedrich C, Oud MS, van der Heijden GW, Soave A, Diemer T, Ars E, Sánchez-Curbelo J, Kliesch S, O’Bryan MK, Ruiz-Castañe E, Azorín F, Veltman JA, Aston KI, Conrad DF, Tüttelmann F, Krausz C. Large-scale analyses of the X chromosome in 2,354 infertile men discover recurrently affected genes associated with spermatogenic failure. Am J Hum Genet 2022; 109:1458-1471. [PMID: 35809576 PMCID: PMC9388793 DOI: 10.1016/j.ajhg.2022.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 06/13/2022] [Indexed: 02/06/2023] Open
Abstract
Although the evolutionary history of the X chromosome indicates its specialization in male fitness, its role in spermatogenesis has largely been unexplored. Currently only three X chromosome genes are considered of moderate-definitive diagnostic value. We aimed to provide a comprehensive analysis of all X chromosome-linked protein-coding genes in 2,354 azoospermic/cryptozoospermic men from four independent cohorts. Genomic data were analyzed and compared with data in normozoospermic control individuals and gnomAD. While updating the clinical significance of known genes, we propose 21 recurrently mutated genes strongly associated with and 34 moderately associated with azoospermia/cryptozoospermia not previously linked to male infertility (novel). The most frequently affected prioritized gene, RBBP7, was found mutated in ten men across all cohorts, and our functional studies in Drosophila support its role in germ stem cell maintenance. Collectively, our study represents a significant step towards the definition of the missing genetic etiology in idiopathic severe spermatogenic failure and significantly reduces the knowledge gap of X-linked genetic causes of azoospermia/cryptozoospermia contributing to the development of future diagnostic gene panels.
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Affiliation(s)
- Antoni Riera-Escamilla
- Andrology Department, Fundació Puigvert, Universitat Autònoma de Barcelona, Instituto de Investigaciones Biomédicas Sant Pau, Barcelona, 08025 Catalonia, Spain
| | - Matthias Vockel
- Institute of Human Genetics, University of Münster, Vesaliusweg 12-14, 48149 Münster, Germany
| | - Liina Nagirnaja
- Division of Genetics, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA
| | - Miguel J. Xavier
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Albert Carbonell
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 4, Barcelona, 08028 Catalonia, Spain,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Baldiri Reixac, 10, Barcelona, 08028 Catalonia, Spain
| | - Daniel Moreno-Mendoza
- Andrology Department, Fundació Puigvert, Universitat Autònoma de Barcelona, Instituto de Investigaciones Biomédicas Sant Pau, Barcelona, 08025 Catalonia, Spain,Department of Urology, Hospital del Oriente de Asturias, Arriondas, 33540 Asturias, Spain
| | - Marc Pybus
- Molecular Biology Laboratory, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau, Universitat Autònoma de Barcelona, Barcelona, 08025 Catalonia, Spain
| | - Ginevra Farnetani
- Department of Biomedical, Experimental and Clinical Sciences Mario Serio, University of Florence, Florence 50139, Italy
| | - Viktoria Rosta
- Department of Biomedical, Experimental and Clinical Sciences Mario Serio, University of Florence, Florence 50139, Italy
| | - Francesca Cioppi
- Department of Biomedical, Experimental and Clinical Sciences Mario Serio, University of Florence, Florence 50139, Italy
| | - Corinna Friedrich
- Institute of Reproductive Genetics, University of Münster, Vesaliusweg 12-14, 48149 Münster, Germany
| | - Manon S. Oud
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen 6525, the Netherlands
| | | | - Armin Soave
- Department of Urology, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Thorsten Diemer
- Clinic for Urology, Paediatric Urology and Andrology, Justus Liebig University, Gießen 35392, Germany
| | - Elisabet Ars
- Molecular Biology Laboratory, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau, Universitat Autònoma de Barcelona, Barcelona, 08025 Catalonia, Spain
| | - Josvany Sánchez-Curbelo
- Andrology Department, Fundació Puigvert, Universitat Autònoma de Barcelona, Instituto de Investigaciones Biomédicas Sant Pau, Barcelona, 08025 Catalonia, Spain
| | - Sabine Kliesch
- Centre of Reproductive Medicine and Andrology, Department of Clinical and Surgical Andrology, University Hospital Münster, Münster 48149, Germany
| | - Moira K. O’Bryan
- The School of BioScience that the Bio21 Institute, The Faculty of Science, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Eduard Ruiz-Castañe
- Andrology Department, Fundació Puigvert, Universitat Autònoma de Barcelona, Instituto de Investigaciones Biomédicas Sant Pau, Barcelona, 08025 Catalonia, Spain
| | | | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, CSIC, Baldiri Reixac, 4, Barcelona, 08028 Catalonia, Spain,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Baldiri Reixac, 10, Barcelona, 08028 Catalonia, Spain
| | - Joris A. Veltman
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Kenneth I. Aston
- Andrology and IVF Laboratories, Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Donald F. Conrad
- Division of Genetics, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA,Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Frank Tüttelmann
- Institute of Reproductive Genetics, University of Münster, Vesaliusweg 12-14, 48149 Münster, Germany
| | - Csilla Krausz
- Department of Biomedical, Experimental and Clinical Sciences Mario Serio, University of Florence, Florence 50139, Italy,Corresponding author
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10
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Hicks T, Koury E, McCabe C, Williams C, Crahan C, Smolikove S. R-loop-induced irreparable DNA damage evades checkpoint detection in the C. elegans germline. Nucleic Acids Res 2022; 50:8041-8059. [PMID: 35871299 PMCID: PMC9371901 DOI: 10.1093/nar/gkac621] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/28/2022] [Accepted: 07/18/2022] [Indexed: 11/24/2022] Open
Abstract
Accumulation of DNA–RNA hybrids in the form of R-loops can result in replication–transcription conflict that leads to the formation of DNA double strand breaks (DSBs). Using null mutants for the two Caenorhabditis elegans genes encoding for RNaseH1 and RNaseH2, we identify novel effects of R-loop accumulation in the germline. R-loop accumulation leads, as expected, to replication stress, followed by the formation of DSBs. A subset of these DSBs are irreparable. However, unlike irreparable DSBs generated in other systems, which trigger permanent cell cycle arrest, germline irreparable DSBs are propagated to oocytes. Despite DNA damage checkpoint activation in the stem cell niche, the signaling cannot be sustained and nuclei with irreparable DNA damage progress into meiosis. Moreover, unlike other forms of DNA damage that increase germline apoptosis, R-loop-generated DSBs remain undetected by the apoptotic checkpoint. This coincides with attenuation of ATM/ATR signaling in mid-to-late meiotic prophase I. These data altogether indicate that in the germline, DSBs that are generated by R-loops can lead to irreparable DSBs that evade cellular machineries designed for damage recognition. These studies implicate germline R-loops as an especially dangerous driver of germline mutagenesis.
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Affiliation(s)
- Tara Hicks
- Department of Biology, The University of Iowa , IA City, IA 52242, USA
| | - Emily Koury
- Department of Biology, The University of Iowa , IA City, IA 52242, USA
| | - Caleb McCabe
- Department of Biology, The University of Iowa , IA City, IA 52242, USA
| | - Cameron Williams
- Department of Biology, The University of Iowa , IA City, IA 52242, USA
| | - Caroline Crahan
- Department of Biology, The University of Iowa , IA City, IA 52242, USA
| | - Sarit Smolikove
- Department of Biology, The University of Iowa , IA City, IA 52242, USA
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11
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Saha S, Yang X, Huang SYN, Agama K, Baechler SA, Sun Y, Zhang H, Saha LK, Su S, Jenkins LM, Wang W, Pommier Y. Resolution of R-loops by topoisomerase III-β (TOP3B) in coordination with the DEAD-box helicase DDX5. Cell Rep 2022; 40:111067. [PMID: 35830799 PMCID: PMC10575568 DOI: 10.1016/j.celrep.2022.111067] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/20/2022] [Accepted: 06/16/2022] [Indexed: 11/16/2022] Open
Abstract
The present study demonstrates how TOP3B is involved in resolving R-loops. We observed elevated R-loops in TOP3B knockout cells (TOP3BKO), which are suppressed by TOP3B transfection. R-loop-inducing agents, the topoisomerase I inhibitor camptothecin, and the splicing inhibitor pladienolide-B also induce higher R-loops in TOP3BKO cells. Camptothecin- and pladienolide-B-induced R-loops are concurrent with the induction of TOP3B cleavage complexes (TOP3Bccs). RNA/DNA hybrid IP-western blotting show that TOP3B is physically associated with R-loops. Biochemical assays using recombinant TOP3B and oligonucleotides mimicking R-loops show that TOP3B cleaves the single-stranded DNA displaced by the R-loop RNA-DNA duplex. IP-mass spectrometry and IP-western experiments reveal that TOP3B interacts with the R-loop helicase DDX5 independently of TDRD3. Finally, we demonstrate that DDX5 and TOP3B are epistatic in resolving R-loops in a pathway parallel with senataxin. We propose a decatenation model for R-loop resolution by TOP3B-DDX5 protecting cells from R-loop-induced damage.
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Affiliation(s)
- Sourav Saha
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Xi Yang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Shar-Yin Naomi Huang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Keli Agama
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Simone Andrea Baechler
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Yilun Sun
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Hongliang Zhang
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Liton Kumar Saha
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Shuaikun Su
- Laboratory of Genetics and Genomics, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Lisa M Jenkins
- Collaborative Protein Technology Resource, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Weidong Wang
- Laboratory of Genetics and Genomics, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Yves Pommier
- Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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12
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Kamp JA, Lemmens BBLG, Romeijn RJ, González-Prieto R, Olsen J, Vertegaal ACO, van Schendel R, Tijsterman M. THO complex deficiency impairs DNA double-strand break repair via the RNA surveillance kinase SMG-1. Nucleic Acids Res 2022; 50:6235-6250. [PMID: 35670662 PMCID: PMC9226523 DOI: 10.1093/nar/gkac472] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 05/11/2022] [Accepted: 06/02/2022] [Indexed: 12/25/2022] Open
Abstract
The integrity and proper expression of genomes are safeguarded by DNA and RNA surveillance pathways. While many RNA surveillance factors have additional functions in the nucleus, little is known about the incidence and physiological impact of converging RNA and DNA signals. Here, using genetic screens and genome-wide analyses, we identified unforeseen SMG-1-dependent crosstalk between RNA surveillance and DNA repair in living animals. Defects in RNA processing, due to viable THO complex or PNN-1 mutations, induce a shift in DNA repair in dividing and non-dividing tissues. Loss of SMG-1, an ATM/ATR-like kinase central to RNA surveillance by nonsense-mediated decay (NMD), restores DNA repair and radio-resistance in THO-deficient animals. Mechanistically, we find SMG-1 and its downstream target SMG-2/UPF1, but not NMD per se, to suppress DNA repair by non-homologous end-joining in favour of single strand annealing. We postulate that moonlighting proteins create short-circuits in vivo, allowing aberrant RNA to redirect DNA repair.
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Affiliation(s)
| | | | - Ron J Romeijn
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Román González-Prieto
- Department of Cell & Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
| | - Jesper V Olsen
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Alfred C O Vertegaal
- Department of Cell & Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
| | - Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
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13
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Abstract
RNase H1 has become an essential tool to uncover the physiological and pathological roles of R-loops, three-stranded structures consisting of and RNA-DNA hybrid opposite to a single DNA strand (ssDNA). RNase H1 degrades the RNA portion of the R-loops returning the two DNA strands to double-stranded form (dsDNA). Overexpression of RNase H1 in different systems has helped to address the questions of where R-loops are located, their abundance, and mechanisms of formation, stability, and degradation. In this chapter we review multiple studies that used RNase H1 as an instrument to investigate R-loops multiple functions and their relevance in health and diseases.
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Affiliation(s)
- Susana M Cerritelli
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Kiran Sakhuja
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Robert J Crouch
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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14
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RNA-DNA hybrids regulate meiotic recombination. Cell Rep 2021; 37:110097. [PMID: 34879269 DOI: 10.1016/j.celrep.2021.110097] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 07/26/2021] [Accepted: 11/14/2021] [Indexed: 01/07/2023] Open
Abstract
RNA-DNA hybrids are often associated with genome instability and also function as a cellular regulator in many biological processes. In this study, we show that accumulated RNA-DNA hybrids cause multiple defects in budding yeast meiosis, including decreased sporulation efficiency and spore viability. Further analysis shows that these RNA-DNA hybrid foci colocalize with RPA/Rad51 foci on chromosomes. The efficient formation of RNA-DNA hybrid foci depends on Rad52 and ssDNA ends of meiotic DNA double-strand breaks (DSBs), and their number is correlated with DSB frequency. Interestingly, RNA-DNA hybrid foci and recombination foci show similar dynamics. The excessive accumulation of RNA-DNA hybrids around DSBs competes with Rad51/Dmc1, impairs homolog bias, and decreases crossover and noncrossover recombination. Furthermore, precocious removal of RNA-DNA hybrids by RNase H1 overexpression also impairs meiotic recombination similarly. Taken together, our results demonstrate that RNA-DNA hybrids form at ssDNA ends of DSBs to actively regulate meiotic recombination.
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15
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Zheleva A, Camino LP, Fernández-Fernández N, García-Rubio M, Askjaer P, García-Muse T, Aguilera A. THSC/TREX-2 deficiency causes replication stress and genome instability in Caenorhabditis elegans. J Cell Sci 2021; 134:jcs258435. [PMID: 34553761 PMCID: PMC10658913 DOI: 10.1242/jcs.258435] [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: 01/19/2021] [Accepted: 09/11/2021] [Indexed: 11/20/2022] Open
Abstract
Transcription is an essential process of DNA metabolism, yet it makes DNA more susceptible to DNA damage. THSC/TREX-2 is a conserved eukaryotic protein complex with a key role in mRNP biogenesis and maturation that prevents genome instability. One source of such instability is linked to transcription, as shown in yeast and human cells, but the underlying mechanism and whether this link is universal is still unclear. To obtain further insight into the putative role of the THSC/TREX-2 complex in genome integrity, we have used Caenorhabditis elegans mutants of the thp-1 and dss-1 components of THSC/TREX-2. These mutants show similar defective meiosis, DNA damage accumulation and activation of the DNA damage checkpoint. However, they differ from each other regarding replication defects, as determined by measuring dUTP incorporation in the germline. Interestingly, this specific thp-1 mutant phenotype can be partially rescued by overexpression of RNase H. Furthermore, both mutants show a mild increase in phosphorylation of histone H3 at Ser10 (H3S10P), a mark previously shown to be linked to DNA-RNA hybrid-mediated genome instability. These data support the view that both THSC/TREX-2 factors prevent transcription-associated DNA damage derived from DNA-RNA hybrid accumulation by separate means.
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Affiliation(s)
- Angelina Zheleva
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Lola P. Camino
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Nuria Fernández-Fernández
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - María García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Peter Askjaer
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Tatiana García-Muse
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
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16
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Stein RE, Nauerth BH, Binmöller L, Zühl L, Loreth A, Reinert M, Ibberson D, Schmidt A. RH17 restricts reproductive fate and represses autonomous seed coat development in sexual Arabidopsis. Development 2021; 148:272091. [PMID: 34495331 DOI: 10.1242/dev.198739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 08/31/2021] [Indexed: 12/13/2022]
Abstract
Plant sexual and asexual reproduction through seeds (apomixis) is tightly controlled by complex gene regulatory programs, which are not yet fully understood. Recent findings suggest that RNA helicases are required for plant germline development. This resembles their crucial roles in animals, where they are involved in controlling gene activity and the maintenance of genome integrity. Here, we identified previously unknown roles of Arabidopsis RH17 during reproductive development. Interestingly, RH17 is involved in repression of reproductive fate and of elements of seed development in the absence of fertilization. In lines carrying a mutant rh17 allele, development of supernumerary reproductive cell lineages in the female flower tissues (ovules) was observed, occasionally leading to formation of two embryos per seed. Furthermore, seed coat, and putatively also endosperm development, frequently initiated autonomously. Such induction of several features phenocopying distinct elements of apomixis by a single mutation is unusual and suggests that RH17 acts in regulatory control of plant reproductive development. Furthermore, an in-depth understanding of its action might be of use for agricultural applications.
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Affiliation(s)
- Ron Eric Stein
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Berit Helge Nauerth
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Laura Binmöller
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Luise Zühl
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Anna Loreth
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Maximilian Reinert
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Im Neuenheimer Feld 267, D-69120, Heidelberg, Germany
| | - Anja Schmidt
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
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17
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Molinaro C, Martoriati A, Cailliau K. Proteins from the DNA Damage Response: Regulation, Dysfunction, and Anticancer Strategies. Cancers (Basel) 2021; 13:3819. [PMID: 34359720 PMCID: PMC8345162 DOI: 10.3390/cancers13153819] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 12/21/2022] Open
Abstract
Cells respond to genotoxic stress through a series of complex protein pathways called DNA damage response (DDR). These monitoring mechanisms ensure the maintenance and the transfer of a correct genome to daughter cells through a selection of DNA repair, cell cycle regulation, and programmed cell death processes. Canonical or non-canonical DDRs are highly organized and controlled to play crucial roles in genome stability and diversity. When altered or mutated, the proteins in these complex networks lead to many diseases that share common features, and to tumor formation. In recent years, technological advances have made it possible to benefit from the principles and mechanisms of DDR to target and eliminate cancer cells. These new types of treatments are adapted to the different types of tumor sensitivity and could benefit from a combination of therapies to ensure maximal efficiency.
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Affiliation(s)
| | | | - Katia Cailliau
- Univ. Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France; (C.M.); (A.M.)
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18
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Crossley MP, Brickner JR, Song C, Zar SMT, Maw SS, Chédin F, Tsai MS, Cimprich KA. Catalytically inactive, purified RNase H1: A specific and sensitive probe for RNA-DNA hybrid imaging. J Cell Biol 2021; 220:212458. [PMID: 34232287 PMCID: PMC8266564 DOI: 10.1083/jcb.202101092] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/24/2021] [Accepted: 06/07/2021] [Indexed: 12/17/2022] Open
Abstract
R-loops are three-stranded nucleic acid structures with both physiological and pathological roles in cells. R-loop imaging generally relies on detection of the RNA-DNA hybrid component of these structures using the S9.6 antibody. We show that the use of this antibody for imaging can be problematic because it readily binds to double-stranded RNA (dsRNA) in vitro and in vivo, giving rise to nonspecific signal. In contrast, purified, catalytically inactive human RNase H1 tagged with GFP (GFP-dRNH1) is a more specific reagent for imaging RNA-DNA hybrids. GFP-dRNH1 binds strongly to RNA-DNA hybrids but not to dsRNA oligonucleotides in fixed human cells and is not susceptible to binding endogenous RNA. Furthermore, we demonstrate that purified GFP-dRNH1 can be applied to fixed cells to detect hybrids after their induction, thereby bypassing the need for cell line engineering. GFP-dRNH1 therefore promises to be a versatile tool for imaging and quantifying RNA-DNA hybrids under a wide range of conditions.
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Affiliation(s)
- Magdalena P Crossley
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Joshua R Brickner
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Chenlin Song
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Su Mon Thin Zar
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Su S Maw
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Frédéric Chédin
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, Davis, CA
| | - Miaw-Sheue Tsai
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
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19
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San Martin Alonso M, Noordermeer S. Untangling the crosstalk between BRCA1 and R-loops during DNA repair. Nucleic Acids Res 2021; 49:4848-4863. [PMID: 33755171 PMCID: PMC8136775 DOI: 10.1093/nar/gkab178] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/25/2021] [Accepted: 03/04/2021] [Indexed: 01/13/2023] Open
Abstract
R-loops are RNA:DNA hybrids assembled during biological processes but are also linked to genetic instability when formed out of their natural context. Emerging evidence suggests that the repair of DNA double-strand breaks requires the formation of a transient R-loop, which eventually must be removed to guarantee a correct repair process. The multifaceted BRCA1 protein has been shown to be recruited at this specific break-induced R-loop, and it facilitates mechanisms in order to regulate R-loop removal. In this review, we discuss the different potential roles of BRCA1 in R-loop homeostasis during DNA repair and how these processes ensure faithful DSB repair.
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Affiliation(s)
- Marta San Martin Alonso
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Sylvie M Noordermeer
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
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20
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Brüning JG, Marians KJ. Replisome bypass of transcription complexes and R-loops. Nucleic Acids Res 2020; 48:10353-10367. [PMID: 32926139 PMCID: PMC7544221 DOI: 10.1093/nar/gkaa741] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 12/16/2022] Open
Abstract
The vast majority of the genome is transcribed by RNA polymerases. G+C-rich regions of the chromosomes and negative superhelicity can promote the invasion of the DNA by RNA to form R-loops, which have been shown to block DNA replication and promote genome instability. However, it is unclear whether the R-loops themselves are sufficient to cause this instability or if additional factors are required. We have investigated replisome collisions with transcription complexes and R-loops using a reconstituted bacterial DNA replication system. RNA polymerase transcription complexes co-directionally oriented with the replication fork were transient blockages, whereas those oriented head-on were severe, stable blockages. On the other hand, replisomes easily bypassed R-loops on either template strand. Replication encounters with R-loops on the leading-strand template (co-directional) resulted in gaps in the nascent leading strand, whereas lagging-strand template R-loops (head-on) had little impact on replication fork progression. We conclude that whereas R-loops alone can act as transient replication blocks, most genome-destabilizing replication fork stalling likely occurs because of proteins bound to the R-loops.
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Affiliation(s)
- Jan-Gert Brüning
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kenneth J Marians
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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21
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Abstract
Physiological and pathological roles for R-loop structures continue to be discovered, and studies suggest that R-loops could contribute to human disease. R-loops are nucleic acid structures characterized by a DNA:RNA hybrid and displaced single-stranded DNA that occur in connection with transcription. R-loops form naturally and have been shown to be important for a number of physiological processes such as mitochondrial replication initiation, class switch recombination, DNA repair, modulating DNA topology, and regulation of gene expression. However, subsets of R-loops or persistent R-loops lead to DNA breaks, chromosome rearrangement, and genome instability. In addition, R-loops have been linked to human diseases, specifically neurological disorders and cancer. Of the large amount of research produced recently on R-loops, this review covers evidence for R-loop involvement in normal cellular physiology and pathophysiology, as well as describing factors that contribute to R-loop regulation.
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Affiliation(s)
- Ryan Patrick Mackay
- Department of Molecular and Cellular Physiology and Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA
| | - Qinqin Xu
- Department of Otolaryngology - Head & Neck Surgery, Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA
| | - Paul M Weinberger
- Department of Molecular and Cellular Physiology and Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA.,Department of Otolaryngology - Head & Neck Surgery, Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA
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22
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Luna R, Rondón AG, Pérez-Calero C, Salas-Armenteros I, Aguilera A. The THO Complex as a Paradigm for the Prevention of Cotranscriptional R-Loops. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:105-114. [PMID: 32493765 DOI: 10.1101/sqb.2019.84.039594] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Different proteins associate with the nascent RNA and the RNA polymerase (RNAP) to catalyze the transcription cycle and RNA export. If these processes are not properly controlled, the nascent RNA can thread back and hybridize to the DNA template forming R-loops capable of stalling replication, leading to DNA breaks. Given the transcriptional promiscuity of the genome, which leads to large amounts of RNAs from mRNAs to different types of ncRNAs, these can become a major threat to genome integrity if they form R-loops. Consequently, cells have evolved nuclear factors to prevent this phenomenon that includes THO, a conserved eukaryotic complex acting in transcription elongation and RNA processing and export that upon inactivation causes genome instability linked to R-loop accumulation. We revise and discuss here the biological relevance of THO and a number of RNA helicases, including the THO partner UAP56/DDX39B, as a paradigm of the cellular mechanisms of cotranscriptional R-loop prevention.
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Affiliation(s)
- Rosa Luna
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Ana G Rondón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Carmen Pérez-Calero
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Irene Salas-Armenteros
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
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23
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Zhou X, Liu X, Zhang G, Zhang Q, Chen H, Wang Y, Fang F, Sun J. Knockdown THOC2 suppresses the proliferation and invasion of melanoma. Bioengineered 2020; 10:635-645. [PMID: 31680623 PMCID: PMC7567448 DOI: 10.1080/21655979.2019.1685727] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Melanoma is a potentially fatal form of skin cancer with great metastatic potential. THOC2 plays a vital role in human biological progression, however, the roles of THOC2 in melanoma tumorigenesis are still unknown. In the present study, our data demonstrated that THOC2 expression was significantly increased in melanoma tissues, and high THOC2 expression was associated with poor overall survival of melanoma patients. THOC2 reduction repressed melanoma cell proliferation and invasion, and induced cell apoptosis in vitro. Microarray data revealed that the cAMP signaling pathway was significantly downregulated in A375 cells transfected with si-THOC2, which was further confirmed by RT-qPCR and bioinformatics analysis. In conclusion, our data indicated that THOC2 might act as an oncogene in melanoma progression through cAMP signaling pathway regulation, which may offer a therapeutic target for melanoma treatment.
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Affiliation(s)
- Xiaowei Zhou
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, P.R.China
| | - Xing Liu
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, P.R.China
| | - Guoqiang Zhang
- Department of Dermatology, The 1th Hospital of Hebei Medical University, Shijiazhuang, P.R.China
| | - Qian Zhang
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, P.R.China
| | - Hao Chen
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, P.R.China
| | - Yan Wang
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, P.R.China
| | - Fang Fang
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, P.R.China
| | - Jianfang Sun
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, P.R.China
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24
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Katahira J, Senokuchi K, Hieda M. Human THO maintains the stability of repetitive DNA. Genes Cells 2020; 25:334-342. [PMID: 32065701 DOI: 10.1111/gtc.12760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 01/31/2023]
Abstract
The evolutionarily conserved multiprotein complex THO/TREX is required for pre-mRNA processing, mRNA export and the maintenance of genome stability. In this study, we analyzed the genome-wide distribution of human THOC7, a component of human THO, by chromatin immunoprecipitation sequencing. The analysis revealed that human THOC7 occupies repetitive sequences, which include microsatellite repeats in genic and intergenic regions and telomeric repeats. The majority of the THOC7 ChIP peaks overlapped with those of the elongating form of RNA polymerase II and R-loops, indicating that THOC7 accumulates in transcriptionally active repeat regions. Knocking down THOC5, an RNA-binding component of human THO, by siRNA induced the accumulation of γH2AX in the repeat regions. We also observed an aberration in the telomeres in the THOC5-depleted condition. These results suggest that human THO restrains the transcription-associated instability of repeat regions in the human genome.
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Affiliation(s)
- Jun Katahira
- Laboratory of Cellular and Molecular Biology, Department of Veterinary Sciences, Osaka Prefecture University, Izumisano, Japan
| | - Kohei Senokuchi
- Laboratory of Cellular and Molecular Biology, Department of Veterinary Sciences, Osaka Prefecture University, Izumisano, Japan
| | - Miki Hieda
- Graduate School of Health Sciences, Ehime Prefectural University of Health Sciences, Iyo-gun, Japan
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25
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Amparo C, Clark J, Bedell V, Murata-Collins JL, Martella M, Pichiorri F, Warner EF, Abdelhamid MAS, Waller ZAE, Smith SS. Duplex DNA from Sites of Helicase-Polymerase Uncoupling Links Non-B DNA Structure Formation to Replicative Stress. Cancer Genomics Proteomics 2020; 17:101-115. [PMID: 32108033 DOI: 10.21873/cgp.20171] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/25/2020] [Accepted: 01/27/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Replication impediments can produce helicase-polymerase uncoupling allowing lagging strand synthesis to continue for as much as 6 kb from the site of the impediment. MATERIALS AND METHODS We developed a cloning procedure designed to recover fragments from lagging strand near the helicase halt site. RESULTS A total of 62% of clones from a p53-deficient tumor cell line (PC3) and 33% of the clones from a primary cell line (HPS-19I) were within 5 kb of a G-quadruplex forming sequence. Analyses of a RACK7 gene sequence, that was cloned multiple times from the PC3 line, revealed multiple deletions in region about 1 kb from the cloned region that was present in a non-B conformation. Sequences from the region formed G-quadruplex and i-motif structures under physiological conditions. CONCLUSION Defects in components of non-B structure suppression systems (e.g. p53 helicase targeting) promote replication-linked damage selectively targeted to sequences prone to G-quadruplex and i-motif formation.
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Affiliation(s)
- Camille Amparo
- Division of Urology, City of Hope National Medical Center, Duarte, CA, U.S.A.,Beckman Research Institute, City of Hope, Duarte, CA, U.S.A
| | - Jarrod Clark
- Division of Urology, City of Hope National Medical Center, Duarte, CA, U.S.A.,Beckman Research Institute, City of Hope, Duarte, CA, U.S.A
| | - Victoria Bedell
- Division of Cytogenetics, City of Hope National Medical Center, Duarte, CA, U.S.A
| | | | - Marianna Martella
- Judy and Bernard Briskin Center for Multiple Myeloma Research, City of Hope National Medical Center, Duarte, CA, U.S.A.,Hematological Malignancies and Translational Science, City of Hope National Medical Center, Duarte, CA, U.S.A
| | - Flavia Pichiorri
- Judy and Bernard Briskin Center for Multiple Myeloma Research, City of Hope National Medical Center, Duarte, CA, U.S.A.,Hematological Malignancies and Translational Science, City of Hope National Medical Center, Duarte, CA, U.S.A
| | - Emily F Warner
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, U.K
| | | | - Zoë A E Waller
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, U.K
| | - Steven S Smith
- Beckman Research Institute, City of Hope, Duarte, CA, U.S.A. .,Hematological Malignancies and Translational Science, City of Hope National Medical Center, Duarte, CA, U.S.A
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26
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Gómez-González B, Barroso S, Herrera-Moyano E, Aguilera A. Spontaneous DNA-RNA hybrids: differential impacts throughout the cell cycle. Cell Cycle 2020; 19:525-531. [PMID: 32065022 DOI: 10.1080/15384101.2020.1728015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
A large body of research supports that transcription plays a major role among the many sources of replicative stress contributing to genome instability. It is therefore not surprising that the DNA damage response has a role in the prevention of transcription-induced threatening events such as the formation of DNA-RNA hybrids, as we have recently found through an siRNA screening. Three major DDR pathways were defined to participate in the protection against DNA-RNA hybrids: ATM/CHK2, ATR/CHK1 and Postreplication Repair (PRR). Based on these observations, we envision different scenarios of DNA-RNA hybridization and their consequent DNA damage.
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Affiliation(s)
- Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Sonia Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Emilia Herrera-Moyano
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
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27
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Chiang HC, Zhang X, Li J, Zhao X, Chen J, Wang HTH, Jatoi I, Brenner A, Hu Y, Li R. BRCA1-associated R-loop affects transcription and differentiation in breast luminal epithelial cells. Nucleic Acids Res 2019; 47:5086-5099. [PMID: 30982901 PMCID: PMC6547407 DOI: 10.1093/nar/gkz262] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 03/06/2019] [Accepted: 04/01/2019] [Indexed: 12/17/2022] Open
Abstract
BRCA1-associated basal-like breast cancer originates from luminal progenitor cells. Breast epithelial cells from cancer-free BRCA1 mutation carriers are defective in luminal differentiation. However, how BRCA1 deficiency leads to lineage-specific differentiation defect is not clear. BRCA1 is implicated in resolving R-loops, DNA-RNA hybrid structures associated with genome instability and transcriptional regulation. We recently showed that R-loops are preferentially accumulated in breast luminal epithelial cells of BRCA1 mutation carriers. Here, we interrogate the impact of a BRCA1 mutation-associated R-loop located in a putative transcriptional enhancer upstream of the ERα-encoding ESR1 gene. Genetic ablation confirms the relevance of this R-loop-containing region to enhancer-promoter interactions and transcriptional activation of the corresponding neighboring genes, including ESR1, CCDC170 and RMND1. BRCA1 knockdown in ERα+ luminal breast cancer cells increases intensity of this R-loop and reduces transcription of its neighboring genes. The deleterious effect of BRCA1 depletion on transcription is mitigated by ectopic expression of R-loop-removing RNase H1. Furthermore, RNase H1 overexpression in primary breast cells from BRCA1 mutation carriers results in a shift from luminal progenitor cells to mature luminal cells. Our findings suggest that BRCA1-dependent R-loop mitigation contributes to luminal cell-specific transcription and differentiation, which could in turn suppress BRCA1-associated tumorigenesis.
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Affiliation(s)
- Huai-Chin Chiang
- Department of Biochemistry & Molecular Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
| | - Xiaowen Zhang
- Department of Biochemistry & Molecular Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
| | - Jingwei Li
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Xiayan Zhao
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jerry Chen
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Howard T-H Wang
- Department of Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Ismail Jatoi
- Department of Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Andrew Brenner
- Department of Medicine, The Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Yanfen Hu
- Department of Anatomy & Cell Biology, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
| | - Rong Li
- Department of Biochemistry & Molecular Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC 20037, USA
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28
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Saha A, Nanavaty VP, Li B. Telomere and Subtelomere R-loops and Antigenic Variation in Trypanosomes. J Mol Biol 2019; 432:4167-4185. [PMID: 31682833 DOI: 10.1016/j.jmb.2019.10.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/02/2019] [Accepted: 10/21/2019] [Indexed: 12/12/2022]
Abstract
Trypanosoma brucei is a kinetoplastid parasite that causes African trypanosomiasis, which is fatal if left untreated. T. brucei regularly switches its major surface antigen, VSG, to evade the host immune responses. VSGs are exclusively expressed from subtelomeric expression sites (ESs) where VSG genes are flanked by upstream 70 bp repeats and downstream telomeric repeats. The telomere downstream of the active VSG is transcribed into a long-noncoding RNA (TERRA), which forms RNA:DNA hybrids (R-loops) with the telomeric DNA. At an elevated level, telomere R-loops cause more telomeric and subtelomeric double-strand breaks (DSBs) and increase VSG switching rate. In addition, stabilized R-loops are observed at the 70 bp repeats and immediately downstream of ES-linked VSGs in RNase H defective cells, which also have an increased amount of subtelomeric DSBs and more frequent VSG switching. Although subtelomere plasticity is expected to be beneficial to antigenic variation, severe defects in subtelomere integrity and stability increase cell lethality. Therefore, regulation of the telomere and 70 bp repeat R-loop levels is important for the balance between antigenic variation and cell fitness in T. brucei. In addition, the high level of the active ES transcription favors accumulation of R-loops at the telomere and 70 bp repeats, providing an intrinsic mechanism for local DSB formation, which is a strong inducer of VSG switching.
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Affiliation(s)
- Arpita Saha
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Vishal P Nanavaty
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA; Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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29
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Barroso S, Herrera‐Moyano E, Muñoz S, García‐Rubio M, Gómez‐González B, Aguilera A. The DNA damage response acts as a safeguard against harmful DNA-RNA hybrids of different origins. EMBO Rep 2019; 20:e47250. [PMID: 31338941 PMCID: PMC6726908 DOI: 10.15252/embr.201847250] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/14/2022] Open
Abstract
Despite playing physiological roles in specific situations, DNA-RNA hybrids threat genome integrity. To investigate how cells do counteract spontaneous DNA-RNA hybrids, here we screen an siRNA library covering 240 human DNA damage response (DDR) genes and select siRNAs causing DNA-RNA hybrid accumulation and a significant increase in hybrid-dependent DNA breakage. We identify post-replicative repair and DNA damage checkpoint factors, including those of the ATM/CHK2 and ATR/CHK1 pathways. Thus, spontaneous DNA-RNA hybrids are likely a major source of replication stress, but they can also accumulate and menace genome integrity as a consequence of unrepaired DSBs and post-replicative ssDNA gaps in normal cells. We show that DNA-RNA hybrid accumulation correlates with increased DNA damage and chromatin compaction marks. Our results suggest that different mechanisms can lead to DNA-RNA hybrids with distinct consequences for replication and DNA dynamics at each cell cycle stage and support the conclusion that DNA-RNA hybrids are a common source of spontaneous DNA damage that remains unsolved under a deficient DDR.
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Affiliation(s)
- Sonia Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa‐CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
| | - Emilia Herrera‐Moyano
- Centro Andaluz de Biología Molecular y Medicina Regenerativa‐CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
| | - Sergio Muñoz
- Centro Andaluz de Biología Molecular y Medicina Regenerativa‐CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
| | - María García‐Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa‐CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
| | - Belén Gómez‐González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa‐CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa‐CABIMERUniversidad de Sevilla‐CSIC‐Universidad Pablo de OlavideSevilleSpain
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30
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Abstract
Transcription is a source of genome instability that stimulates mutation and recombination. Part of the damage produced by transcription is mediated by R-loops, non-B DNA structures that normally form by the re-annealing of the nascent RNA with the template DNA outside the catalytic center of the RNA polymerase, displacing the non-template strand. Recent discoveries have revealed that R-loops might not be harmful by themselves. Instead, chromatin compaction triggered by these structures seems necessary, as deduced from the histone modifications frequently found associated with harmful R-loops. Remarkably, hybrids may also become harmful if stabilized by specific RNA binding proteins, one example of which is the yeast Yra1. We discuss here the possible mechanisms by which cells may stabilize R-loops and the consequences on transcription-replication conflicts and telomere homeostasis.
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Affiliation(s)
- Ana G Rondón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092, Seville, Spain.
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31
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Genome-wide Map of R-Loop-Induced Damage Reveals How a Subset of R-Loops Contributes to Genomic Instability. Mol Cell 2018; 71:487-497.e3. [PMID: 30078723 DOI: 10.1016/j.molcel.2018.06.037] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/23/2018] [Accepted: 06/22/2018] [Indexed: 01/04/2023]
Abstract
DNA-RNA hybrids associated with R-loops promote DNA damage and genomic instability. The capacity of hybrids at different genomic sites to cause DNA damage was not known, and the mechanisms leading from hybrid to damage were poorly understood. Here, we adopt a new strategy to map and characterize the sites of hybrid-induced damage genome-wide in budding yeast. We show that hybrid removal is essential for life because persistent hybrids cause irreparable DNA damage and cell death. We identify that a subset of hybrids is prone to cause damage, and the chromosomal context of hybrids dramatically impacts their ability to induce damage. Furthermore, persistent hybrids affect the repair pathway, generating large regions of single-stranded DNA (ssDNA) by two distinct mechanisms, likely resection and re-replication. These damaged regions may act as potential precursors to gross chromosomal rearrangements like deletions and duplications that are associated with R-loops and cancers.
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32
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García-Rubio M, Aguilera P, Lafuente-Barquero J, Ruiz JF, Simon MN, Geli V, Rondón AG, Aguilera A. Yra1-bound RNA-DNA hybrids cause orientation-independent transcription-replication collisions and telomere instability. Genes Dev 2018; 32:965-977. [PMID: 29954833 PMCID: PMC6075034 DOI: 10.1101/gad.311274.117] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 05/16/2018] [Indexed: 12/25/2022]
Abstract
R loops are an important source of genome instability, largely due to their negative impact on replication progression. Yra1/ALY is an abundant RNA-binding factor conserved from yeast to humans and required for mRNA export, but its excess causes lethality and genome instability. Here, we show that, in addition to ssDNA and ssRNA, Yra1 binds RNA-DNA hybrids in vitro and, when artificially overexpressed, can be recruited to chromatin in an RNA-DNA hybrid-dependent manner, stabilizing R loops and converting them into replication obstacles in vivo. Importantly, an excess of Yra1 increases R-loop-mediated genome instability caused by transcription-replication collisions regardless of whether they are codirectional or head-on. It also induces telomere shortening in telomerase-negative cells and accelerates senescence, consistent with a defect in telomere replication. Our results indicate that RNA-DNA hybrids form transiently in cells regardless of replication and, after stabilization by excess Yra1, compromise genome integrity, in agreement with a two-step model of R-loop-mediated genome instability. This work opens new perspectives to understand transcription-associated genome instability in repair-deficient cells, including tumoral cells.
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Affiliation(s)
- María García-Rubio
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Paula Aguilera
- Marseille Cancer Research Center (CRCM), U1068, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR7258, Centre National de la Recherche Scientifique (CNRS), Aix Marseille University, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 13273 Marseille, France
| | - Juan Lafuente-Barquero
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - José F Ruiz
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Marie-Noelle Simon
- Marseille Cancer Research Center (CRCM), U1068, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR7258, Centre National de la Recherche Scientifique (CNRS), Aix Marseille University, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 13273 Marseille, France
| | - Vincent Geli
- Marseille Cancer Research Center (CRCM), U1068, Institut National de la Santé et de la Recherche Médicale (INSERM), UMR7258, Centre National de la Recherche Scientifique (CNRS), Aix Marseille University, Institut Paoli-Calmettes, Equipe Labellisée Ligue, 13273 Marseille, France
| | - Ana G Rondón
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Pablo de Olavide, 41092 Seville, Spain
| | - Andrés Aguilera
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Pablo de Olavide, 41092 Seville, Spain
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33
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Zhao H, Zhu M, Limbo O, Russell P. RNase H eliminates R-loops that disrupt DNA replication but is nonessential for efficient DSB repair. EMBO Rep 2018; 19:embr.201745335. [PMID: 29622660 DOI: 10.15252/embr.201745335] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 03/02/2018] [Accepted: 03/09/2018] [Indexed: 12/12/2022] Open
Abstract
In Saccharomyces cerevisiae, genome stability depends on RNases H1 and H2, which remove ribonucleotides from DNA and eliminate RNA-DNA hybrids (R-loops). In Schizosaccharomyces pombe, RNase H enzymes were reported to process RNA-DNA hybrids produced at a double-strand break (DSB) generated by I-PpoI meganuclease. However, it is unclear if RNase H is generally required for efficient DSB repair in fission yeast, or whether it has other genome protection roles. Here, we show that S. pombe rnh1∆ rnh201∆ cells, which lack the RNase H enzymes, accumulate R-loops and activate DNA damage checkpoints. Their viability requires critical DSB repair proteins and Mus81, which resolves DNA junctions formed during repair of broken replication forks. "Dirty" DSBs generated by ionizing radiation, as well as a "clean" DSB at a broken replication fork, are efficiently repaired in the absence of RNase H. RNA-DNA hybrids are not detected at a reparable DSB formed by fork collapse. We conclude that unprocessed R-loops collapse replication forks in rnh1∆ rnh201∆ cells, but RNase H is not generally required for efficient DSB repair.
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Affiliation(s)
- Hongchang Zhao
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Min Zhu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Oliver Limbo
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Paul Russell
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
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34
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Colombo CV, Trovesi C, Menin L, Longhese MP, Clerici M. The RNA binding protein Npl3 promotes resection of DNA double-strand breaks by regulating the levels of Exo1. Nucleic Acids Res 2017; 45:6530-6545. [PMID: 28472517 PMCID: PMC5499764 DOI: 10.1093/nar/gkx347] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/21/2017] [Indexed: 12/29/2022] Open
Abstract
Eukaryotic cells preserve genome integrity upon DNA damage by activating a signaling network that promotes DNA repair and controls cell cycle progression. One of the most severe DNA damage is the DNA double-strand break (DSB), whose 5΄ ends can be nucleolitically resected by multiple nucleases to create 3΄-ended single-stranded DNA tails that trigger DSB repair by homologous recombination. Here, we identify the Saccharomyces cerevisiae RNA binding protein Npl3 as a new player in DSB resection. Npl3 is related to both the metazoan serine-arginine-rich and the heterogeneous nuclear ribonucleo-proteins. NPL3 deletion impairs the generation of long ssDNA tails at the DSB ends, whereas it does not exacerbate the resection defect of exo1Δ cells. Furthermore, either the lack of Npl3 or the inactivation of its RNA-binding domains causes decrease of the exonuclease Exo1 protein levels as well as generation of unusual and extended EXO1 RNA species. These findings, together with the observation that EXO1 overexpression partially suppresses the resection defect of npl3Δ cells, indicate that Npl3 participates in DSB resection by promoting the proper biogenesis of EXO1 mRNA.
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Affiliation(s)
- Chiara Vittoria Colombo
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy
| | - Camilla Trovesi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy
| | - Luca Menin
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy
| | - Michela Clerici
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy
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35
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Zeller P, Gasser SM. The Importance of Satellite Sequence Repression for Genome Stability. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2017; 82:15-24. [PMID: 29133300 DOI: 10.1101/sqb.2017.82.033662] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Up to two-thirds of eukaryotic genomes consist of repetitive sequences, which include both transposable elements and tandemly arranged simple or satellite repeats. Whereas extensive progress has been made toward understanding the danger of and control over transposon expression, only recently has it been recognized that DNA damage can arise from satellite sequence transcription. Although the structural role of satellite repeats in kinetochore function and end protection has long been appreciated, it has now become clear that it is not only these functions that are compromised by elevated levels of transcription. RNA from simple repeat sequences can compromise replication fork stability and genome integrity, thus compromising germline viability. Here we summarize recent discoveries on how cells control the transcription of repeat sequence and the dangers that arise from their expression. We propose that the link between the DNA damage response and the transcriptional silencing machinery may help a cell or organism recognize foreign DNA insertions into an evolving genome.
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Affiliation(s)
- Peter Zeller
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
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36
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Man L, Lekovich J, Rosenwaks Z, Gerhardt J. Fragile X-Associated Diminished Ovarian Reserve and Primary Ovarian Insufficiency from Molecular Mechanisms to Clinical Manifestations. Front Mol Neurosci 2017; 10:290. [PMID: 28955201 PMCID: PMC5600956 DOI: 10.3389/fnmol.2017.00290] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 08/28/2017] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS), is caused by a loss-of-function mutation in the FMR1 gene located on the X-chromosome, which leads to the most common cause of inherited intellectual disability in males and the leading single-gene defect associated with autism. A full mutation (FM) is represented by more than 200 CGG repeats within the FMR1 gene, resulting in FXS. A FM is inherited from women carrying a FM or a premutation (PM; 55–200 CGG repeats) allele. PM is associated with phenotypes distinct from those associated with FM. Some manifestations of the PM are unique; fragile-X-associated tremor/ataxia syndrome (FXTAS), and fragile-X-associated primary ovarian insufficiency (FXPOI), while others tend to be non-specific such as intellectual disability. In addition, women carrying a PM may suffer from subfertility or infertility. There is a need to elucidate whether the impairment of ovarian function found in PM carriers arises during the primordial germ cell (PGC) development stage, or due to a rapidly diminishing oocyte pool throughout life or even both. Due to the possibility of expansion into a FM in the next generation, and other ramifications, carrying a PM can have an enormous impact on one’s life; therefore, preconception counseling for couples carrying the PM is of paramount importance. In this review, we will elaborate on the clinical manifestations in female PM carriers and propose the definition of fragile-X-associated diminished ovarian reserve (FXDOR), then we will review recent scientific findings regarding possible mechanisms leading to FXDOR and FXPOI. Lastly, we will discuss counseling, preventative measures and interventions available for women carrying a PM regarding different aspects of their reproductive life, fertility treatment, pregnancy, prenatal testing, contraception and fertility preservation options.
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Affiliation(s)
- Limor Man
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jovana Lekovich
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Zev Rosenwaks
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jeannine Gerhardt
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
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37
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Hamperl S, Bocek MJ, Saldivar JC, Swigut T, Cimprich KA. Transcription-Replication Conflict Orientation Modulates R-Loop Levels and Activates Distinct DNA Damage Responses. Cell 2017; 170:774-786.e19. [PMID: 28802045 DOI: 10.1016/j.cell.2017.07.043] [Citation(s) in RCA: 388] [Impact Index Per Article: 55.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 05/09/2017] [Accepted: 07/25/2017] [Indexed: 12/19/2022]
Abstract
Conflicts between transcription and replication are a potent source of DNA damage. Co-transcriptional R-loops could aggravate such conflicts by creating an additional barrier to replication fork progression. Here, we use a defined episomal system to investigate how conflict orientation and R-loop formation influence genome stability in human cells. R-loops, but not normal transcription complexes, induce DNA breaks and orientation-specific DNA damage responses during conflicts with replication forks. Unexpectedly, the replisome acts as an orientation-dependent regulator of R-loop levels, reducing R-loops in the co-directional (CD) orientation but promoting their formation in the head-on (HO) orientation. Replication stress and deregulated origin firing increase the number of HO collisions leading to genome-destabilizing R-loops. Our findings connect DNA replication to R-loop homeostasis and suggest a mechanistic basis for genome instability resulting from deregulated DNA replication, observed in cancer and other disease states.
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Affiliation(s)
- Stephan Hamperl
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael J Bocek
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joshua C Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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38
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Aguilera A, Gómez-González B. DNA-RNA hybrids: the risks of DNA breakage during transcription. Nat Struct Mol Biol 2017; 24:439-443. [PMID: 28471430 DOI: 10.1038/nsmb.3395] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/05/2017] [Indexed: 12/28/2022]
Abstract
Although R loops can occur at different genomic locations, the factors that determine their formation and frequency remain unclear. Emerging evidence indicates that DNA breaks stimulate DNA-RNA hybrid formation. Here, we discuss the possibility that formation of hybrids may be an inevitable risk of DNA breaks that occur within actively transcribed regions. While such hybrids must be removed to permit repair, their potential role as repair intermediates remains to be established.
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Affiliation(s)
- Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
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Bhatia V, Herrera-Moyano E, Aguilera A, Gómez-González B. The Role of Replication-Associated Repair Factors on R-Loops. Genes (Basel) 2017; 8:E171. [PMID: 28653981 PMCID: PMC5541304 DOI: 10.3390/genes8070171] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 12/12/2022] Open
Abstract
The nascent RNA can reinvade the DNA double helix to form a structure termed the R-loop, where a single-stranded DNA (ssDNA) is accompanied by a DNA-RNA hybrid. Unresolved R-loops can impede transcription and replication processes and lead to genomic instability by a mechanism still not fully understood. In this sense, a connection between R-loops and certain chromatin markers has been reported that might play a key role in R-loop homeostasis and genome instability. To counteract the potential harmful effect of R-loops, different conserved messenger ribonucleoprotein (mRNP) biogenesis and nuclear export factors prevent R-loop formation, while ubiquitously-expressed specific ribonucleases and DNA-RNA helicases resolve DNA-RNA hybrids. However, the molecular events associated with R-loop sensing and processing are not yet known. Given that R-loops hinder replication progression, it is plausible that some DNA replication-associated factors contribute to dissolve R-loops or prevent R-loop mediated genome instability. In support of this, R-loops accumulate in cells depleted of the BRCA1, BRCA2 or the Fanconi anemia (FA) DNA repair factors, indicating that they play an active role in R-loop dissolution. In light of these results, we review our current view of the role of replication-associated DNA repair pathways in preventing the harmful consequences of R-loops.
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Affiliation(s)
- Vaibhav Bhatia
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Av. Américo Vespucio 24, 41092 Seville, Spain.
| | - Emilia Herrera-Moyano
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Av. Américo Vespucio 24, 41092 Seville, Spain.
| | - Andrés Aguilera
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Av. Américo Vespucio 24, 41092 Seville, Spain.
| | - Belén Gómez-González
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Av. Américo Vespucio 24, 41092 Seville, Spain.
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40
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Richard P, Manley JL. R Loops and Links to Human Disease. J Mol Biol 2016; 429:3168-3180. [PMID: 27600412 DOI: 10.1016/j.jmb.2016.08.031] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/26/2016] [Accepted: 08/31/2016] [Indexed: 12/13/2022]
Abstract
Aberrant R-loop structures are increasingly being realized as an important contributor to human disease. R loops, which are mainly co-transcriptional, abundant RNA/DNA hybrids, form naturally and can indeed be beneficial for transcription regulation at certain loci. However, their unwanted persistence elsewhere or in particular situations can lead to DNA double-strand breaks, chromosome rearrangements, and hypermutation, which are all sources of genomic instability. Mutations in genes involved in R-loop resolution or mutations leading to R-loop formation at specific genes affect the normal physiology of the cell. We discuss here the examples of diseases for which a link with R loops has been described, as well as how disease-causing mutations might participate in the development and/or progression of diseases that include repeat-associated conditions, other neurological disorders, and cancers.
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Affiliation(s)
- Patricia Richard
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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41
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Epshtein A, Potenski CJ, Klein HL. Increased Spontaneous Recombination in RNase H2-Deficient Cells Arises From Multiple Contiguous rNMPs and Not From Single rNMP Residues Incorporated by DNA Polymerase Epsilon. MICROBIAL CELL 2016; 3:248-254. [PMID: 28203566 PMCID: PMC5305187 DOI: 10.15698/mic2016.06.506] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ribonucleotides can become embedded in DNA from insertion by DNA polymerases,
failure to remove Okazaki fragment primers, R-loops that can prime replication,
and RNA/cDNA-mediated recombination. RNA:DNA hybrids are removed by RNase H
enzymes. Single rNMPs in DNA are removed by RNase H2 and if they remain on the
leading strand, can lead to mutagenesis in a Top1-dependent pathway. rNMPs in
DNA can also stimulate genome instability, among which are homologous
recombination gene conversion events. We previously found that, similar to the
rNMP-stimulated mutagenesis, rNMP-stimulated recombination was also
Top1-dependent. However, in contrast to mutagenesis, we report here that
recombination is not stimulated by rNMPs incorporated by the replicative
polymerase epsilon. Instead, recombination seems to be stimulated by multiple
contiguous rNMPs, which may arise from R-loops or replication priming
events.
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Affiliation(s)
- Anastasiya Epshtein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | | | - Hannah L Klein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
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42
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Affiliation(s)
- Hélène Gaillard
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, Sevilla 41092, Spain; ,
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, Sevilla 41092, Spain; ,
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43
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Gavaldá S, Santos-Pereira JM, García-Rubio ML, Luna R, Aguilera A. Excess of Yra1 RNA-Binding Factor Causes Transcription-Dependent Genome Instability, Replication Impairment and Telomere Shortening. PLoS Genet 2016; 12:e1005966. [PMID: 27035147 PMCID: PMC4818039 DOI: 10.1371/journal.pgen.1005966] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 03/09/2016] [Indexed: 11/19/2022] Open
Abstract
Yra1 is an essential nuclear factor of the evolutionarily conserved family of hnRNP-like export factors that when overexpressed impairs mRNA export and cell growth. To investigate further the relevance of proper Yra1 stoichiometry in the cell, we overexpressed Yra1 by transforming yeast cells with YRA1 intron-less constructs and analyzed its effect on gene expression and genome integrity. We found that YRA1 overexpression induces DNA damage and leads to a transcription-associated hyperrecombination phenotype that is mediated by RNA:DNA hybrids. In addition, it confers a genome-wide replication retardation as seen by reduced BrdU incorporation and accumulation of the Rrm3 helicase. In addition, YRA1 overexpression causes a cell senescence-like phenotype and telomere shortening. ChIP-chip analysis shows that overexpressed Yra1 is loaded to transcribed chromatin along the genome and to Y’ telomeric regions, where Rrm3 is also accumulated, suggesting an impairment of telomere replication. Our work not only demonstrates that a proper stoichiometry of the Yra1 mRNA binding and export factor is required to maintain genome integrity and telomere homeostasis, but suggests that the cellular imbalance between transcribed RNA and specific RNA-binding factors may become a major cause of genome instability mediated by co-transcriptional replication impairment. Yra1 is an essential nuclear RNA-binding protein that plays a role in mRNA export in Saccharomyces cerevisiae. The cellular levels of Yra1 are tightly auto-regulated by splicing of an unusual intron in its pre-mRNA, removal of which causes Yra1 overexpression that results in a dominant-negative growth defect and mRNA export defect. We wondered whether or not YRA1 overexpression has an effect on genome integrity that could explain the loss of cell viability. Our analyses reveal that YRA1 overexpression causes DNA damage, confers a hyperrecombination phenotype that depends on transcription and that is mediated by RNA:DNA hybrids. YRA1 overexpression also leads to a cell senescence-like phenotype and telomere shortening. We show by ChIP-chip analysis that Yra1 binds to active chromatin and Y’ telomeric regions when it is overexpressed, in agreement with a possible role of this mRNP factor in the maintenance of telomere integrity. Our data indicate that YRA1 overexpression correlates with replication impairment as inferred by the reduction of BrdU incorporation and the increase of Rrm3 recruitment, a helicase involved in replication fork progression, at transcribed genes and Y’ regions. We conclude that the stoichiometry of specific RNA-binding factors such as Yra1 at telomeres is critical for genome integrity and for preventing transcription-replication conflicts.
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Affiliation(s)
- Sandra Gavaldá
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
| | - José M. Santos-Pereira
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
| | - María L. García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
| | - Rosa Luna
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
- * E-mail: (AA); (RL)
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
- * E-mail: (AA); (RL)
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44
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Muñoz S, Méndez J. DNA replication stress: from molecular mechanisms to human disease. Chromosoma 2016; 126:1-15. [PMID: 26797216 DOI: 10.1007/s00412-016-0573-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 01/04/2016] [Accepted: 01/05/2016] [Indexed: 12/29/2022]
Abstract
The genome of proliferating cells must be precisely duplicated in each cell division cycle. Chromosomal replication entails risks such as the possibility of introducing breaks and/or mutations in the genome. Hence, DNA replication requires the coordinated action of multiple proteins and regulatory factors, whose deregulation causes severe developmental diseases and predisposes to cancer. In recent years, the concept of "replicative stress" (RS) has attracted much attention as it impinges directly on genomic stability and offers a promising new avenue to design anticancer therapies. In this review, we summarize recent progress in three areas: (1) endogenous and exogenous factors that contribute to RS, (2) molecular mechanisms that mediate the cellular responses to RS, and (3) the large list of diseases that are directly or indirectly linked to RS.
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Affiliation(s)
- Sergio Muñoz
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, E-28029, Madrid, Spain
| | - Juan Méndez
- DNA Replication Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro 3, E-28029, Madrid, Spain.
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45
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Santos-Pereira JM, Aguilera A. R loops: new modulators of genome dynamics and function. Nat Rev Genet 2015; 16:583-97. [PMID: 26370899 DOI: 10.1038/nrg3961] [Citation(s) in RCA: 528] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
R loops are nucleic acid structures composed of an RNA-DNA hybrid and a displaced single-stranded DNA. Recently, evidence has emerged that R loops occur more often in the genome and have greater physiological relevance, including roles in transcription and chromatin structure, than was previously predicted. Importantly, however, R loops are also a major threat to genome stability. For this reason, several DNA and RNA metabolism factors prevent R-loop formation in cells. Dysfunction of these factors causes R-loop accumulation, which leads to replication stress, genome instability, chromatin alterations or gene silencing, phenomena that are frequently associated with cancer and a number of genetic diseases. We review the current knowledge of the mechanisms controlling R loops and their putative relationship with disease.
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Affiliation(s)
- José M Santos-Pereira
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Seville 41092, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Av. Américo Vespucio s/n, Seville 41092, Spain
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46
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Kumar R, Corbett MA, van Bon BWM, Woenig JA, Weir L, Douglas E, Friend KL, Gardner A, Shaw M, Jolly LA, Tan C, Hunter MF, Hackett A, Field M, Palmer EE, Leffler M, Rogers C, Boyle J, Bienek M, Jensen C, Van Buggenhout G, Van Esch H, Hoffmann K, Raynaud M, Zhao H, Reed R, Hu H, Haas SA, Haan E, Kalscheuer VM, Gecz J. THOC2 Mutations Implicate mRNA-Export Pathway in X-Linked Intellectual Disability. Am J Hum Genet 2015; 97:302-10. [PMID: 26166480 DOI: 10.1016/j.ajhg.2015.05.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/27/2015] [Indexed: 11/30/2022] Open
Abstract
Export of mRNA from the cell nucleus to the cytoplasm is essential for protein synthesis, a process vital to all living eukaryotic cells. mRNA export is highly conserved and ubiquitous. Mutations affecting mRNA and mRNA processing or export factors, which cause aberrant retention of mRNAs in the nucleus, are thus emerging as contributors to an important class of human genetic disorders. Here, we report that variants in THOC2, which encodes a subunit of the highly conserved TREX mRNA-export complex, cause syndromic intellectual disability (ID). Affected individuals presented with variable degrees of ID and commonly observed features included speech delay, elevated BMI, short stature, seizure disorders, gait disturbance, and tremors. X chromosome exome sequencing revealed four missense variants in THOC2 in four families, including family MRX12, first ascertained in 1971. We show that two variants lead to decreased stability of THOC2 and its TREX-complex partners in cells derived from the affected individuals. Protein structural modeling showed that the altered amino acids are located in the RNA-binding domains of two complex THOC2 structures, potentially representing two different intermediate RNA-binding states of THOC2 during RNA transport. Our results show that disturbance of the canonical molecular pathway of mRNA export is compatible with life but results in altered neuronal development with other comorbidities.
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MESH Headings
- Active Transport, Cell Nucleus/genetics
- Amino Acid Sequence
- Base Sequence
- Chromosomes, Human, X/genetics
- Humans
- Mental Retardation, X-Linked/genetics
- Mental Retardation, X-Linked/pathology
- Models, Molecular
- Molecular Sequence Data
- Mutation, Missense/genetics
- Pedigree
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/genetics
- Sequence Analysis, DNA
- Syndrome
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Affiliation(s)
- Raman Kumar
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Mark A Corbett
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Bregje W M van Bon
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia; Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands
| | - Joshua A Woenig
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Lloyd Weir
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Evelyn Douglas
- Genetics and Molecular Pathology, SA Pathology, North Adelaide, SA 5006, Australia
| | - Kathryn L Friend
- Genetics and Molecular Pathology, SA Pathology, North Adelaide, SA 5006, Australia
| | - Alison Gardner
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Marie Shaw
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Lachlan A Jolly
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Chuan Tan
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia
| | - Matthew F Hunter
- Monash Genetics, Monash Medical Centre, Clayton, VIC 3168, Australia; Department of Paediatrics, Monash University, Clayton, VIC 3168, Australia
| | - Anna Hackett
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW 2298, Australia
| | - Michael Field
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW 2298, Australia
| | - Elizabeth E Palmer
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW 2298, Australia
| | - Melanie Leffler
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW 2298, Australia
| | - Carolyn Rogers
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW 2298, Australia
| | - Jackie Boyle
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW 2298, Australia
| | - Melanie Bienek
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Corinna Jensen
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | | | - Hilde Van Esch
- Center for Human Genetics, University Hospitals Leuven, Leuven 3000, Belgium
| | - Katrin Hoffmann
- Institute of Human Genetics, Martin Luther University Halle-Wittenberg, Magdeburger Strasse 2, 06112 Halle (Saale), Germany
| | - Martine Raynaud
- INSERM U930, Imaging and Brain, François-Rabelais University, 37000 Tours, France; INSERM U930, Service de Génétique, Centre Hospitalier Régional Universitaire, 37000 Tours, France
| | - Huiying Zhao
- QIMR Berghofer Medical Research Institute, Brisbane, QLD 4029, Australia
| | - Robin Reed
- Department of Cell Biology, Harvard Medical School, Harvard University, Boston, MA 02115, USA
| | - Hao Hu
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Stefan A Haas
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Eric Haan
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia; South Australian Clinical Genetics Service, SA Pathology, North Adelaide, SA 5006, Australia
| | - Vera M Kalscheuer
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Jozef Gecz
- School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, SA 5000, Australia; School of Molecular and Biomedical Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
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47
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Role for RNA:DNA hybrids in origin-independent replication priming in a eukaryotic system. Proc Natl Acad Sci U S A 2015; 112:5779-84. [PMID: 25902524 DOI: 10.1073/pnas.1501769112] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA replication initiates at defined replication origins along eukaryotic chromosomes, ensuring complete genome duplication within a single S-phase. A key feature of replication origins is their ability to control the onset of DNA synthesis mediated by DNA polymerase-α and its intrinsic RNA primase activity. Here, we describe a novel origin-independent replication process that is mediated by transcription. RNA polymerase I transcription constraints lead to persistent RNA:DNA hybrids (R-loops) that prime replication in the ribosomal DNA locus. Our results suggest that eukaryotic genomes have developed tools to prevent R-loop-mediated replication events that potentially contribute to copy number variation, particularly relevant to carcinogenesis.
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Felipe-Abrio I, Lafuente-Barquero J, García-Rubio ML, Aguilera A. RNA polymerase II contributes to preventing transcription-mediated replication fork stalls. EMBO J 2014; 34:236-50. [PMID: 25452497 DOI: 10.15252/embj.201488544] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Transcription is a major contributor to genome instability. A main cause of transcription-associated instability relies on the capacity of transcription to stall replication. However, we know little of the possible role, if any, of the RNA polymerase (RNAP) in this process. Here, we analyzed 4 specific yeast RNAPII mutants that show different phenotypes of genetic instability including hyper-recombination, DNA damage sensitivity and/or a strong dependency on double-strand break repair functions for viability. Three specific alleles of the RNAPII core, rpb1-1, rpb1-S751F and rpb9∆, cause a defect in replication fork progression, compensated for by additional origin firing, as the main action responsible for instability. The transcription elongation defects of rpb1-S751F and rpb9∆ plus our observation that rpb1-1 causes RNAPII retention on chromatin suggest that RNAPII could participate in facilitating fork progression upon a transcription-replication encounter. Our results imply that the RNAPII or ancillary factors actively help prevent transcription-associated genome instability.
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Affiliation(s)
- Irene Felipe-Abrio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
| | - Juan Lafuente-Barquero
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
| | - María L García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla, Seville, Spain
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Kim HM, Colaiácovo MP. ZTF-8 interacts with the 9-1-1 complex and is required for DNA damage response and double-strand break repair in the C. elegans germline. PLoS Genet 2014; 10:e1004723. [PMID: 25329393 PMCID: PMC4199516 DOI: 10.1371/journal.pgen.1004723] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/29/2014] [Indexed: 11/19/2022] Open
Abstract
Germline mutations in DNA repair genes are linked to tumor progression. Furthermore, failure in either activating a DNA damage checkpoint or repairing programmed meiotic double-strand breaks (DSBs) can impair chromosome segregation. Therefore, understanding the molecular basis for DNA damage response (DDR) and DSB repair (DSBR) within the germline is highly important. Here we define ZTF-8, a previously uncharacterized protein conserved from worms to humans, as a novel factor involved in the repair of both mitotic and meiotic DSBs as well as in meiotic DNA damage checkpoint activation in the C. elegans germline. ztf-8 mutants exhibit specific sensitivity to γ-irradiation and hydroxyurea, mitotic nuclear arrest at S-phase accompanied by activation of the ATL-1 and CHK-1 DNA damage checkpoint kinases, as well as accumulation of both mitotic and meiotic recombination intermediates, indicating that ZTF-8 functions in DSBR. However, impaired meiotic DSBR progression partially fails to trigger the CEP-1/p53-dependent DNA damage checkpoint in late pachytene, also supporting a role for ZTF-8 in meiotic DDR. ZTF-8 partially co-localizes with the 9-1-1 DDR complex and interacts with MRT-2/Rad1, a component of this complex. The human RHINO protein rescues the phenotypes observed in ztf-8 mutants, suggesting functional conservation across species. We propose that ZTF-8 is involved in promoting repair at stalled replication forks and meiotic DSBs by transducing DNA damage checkpoint signaling via the 9-1-1 pathway. Our findings define a conserved function for ZTF-8/RHINO in promoting genomic stability in the germline.
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Affiliation(s)
- Hyun-Min Kim
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Monica P. Colaiácovo
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
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Barlow JH, Nussenzweig A. Replication initiation and genome instability: a crossroads for DNA and RNA synthesis. Cell Mol Life Sci 2014; 71:4545-59. [PMID: 25238783 DOI: 10.1007/s00018-014-1721-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/28/2014] [Indexed: 12/16/2022]
Abstract
Nuclear DNA replication requires the concerted action of hundreds of proteins to efficiently unwind and duplicate the entire genome while also retaining epigenetic regulatory information. Initiation of DNA replication is tightly regulated, rapidly firing thousands of origins once the conditions to promote rapid and faithful replication are in place, and defects in replication initiation lead to proliferation defects, genome instability, and a range of developmental abnormalities. Interestingly, DNA replication in metazoans initiates in actively transcribed DNA, meaning that replication initiation occurs in DNA that is co-occupied with tens of thousands of poised and active RNA polymerase complexes. Active transcription can induce genome instability, particularly during DNA replication, as RNA polymerases can induce torsional stress, formation of secondary structures, and act as a physical barrier to other enzymes involved in DNA metabolism. Here we discuss the challenges facing mammalian DNA replication, their impact on genome instability, and the development of cancer.
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