2
|
Soriano I, Vazquez E, De Leon N, Bertrand S, Heitzer E, Toumazou S, Bo Z, Palles C, Pai CC, Humphrey TC, Tomlinson I, Cotterill S, Kearsey SE. Expression of the cancer-associated DNA polymerase ε P286R in fission yeast leads to translesion synthesis polymerase dependent hypermutation and defective DNA replication. PLoS Genet 2021; 17:e1009526. [PMID: 34228709 PMCID: PMC8284607 DOI: 10.1371/journal.pgen.1009526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/16/2021] [Accepted: 06/11/2021] [Indexed: 12/15/2022] Open
Abstract
Somatic and germline mutations in the proofreading domain of the replicative DNA polymerase ε (POLE-exonuclease domain mutations, POLE-EDMs) are frequently found in colorectal and endometrial cancers and, occasionally, in other tumours. POLE-associated cancers typically display hypermutation, and a unique mutational signature, with a predominance of C > A transversions in the context TCT and C > T transitions in the context TCG. To understand better the contribution of hypermutagenesis to tumour development, we have modelled the most recurrent POLE-EDM (POLE-P286R) in Schizosaccharomyces pombe. Whole-genome sequencing analysis revealed that the corresponding pol2-P287R allele also has a strong mutator effect in vivo, with a high frequency of base substitutions and relatively few indel mutations. The mutations are equally distributed across different genomic regions, but in the immediate vicinity there is an asymmetry in AT frequency. The most abundant base-pair changes are TCT > TAT transversions and, in contrast to human mutations, TCG > TTG transitions are not elevated, likely due to the absence of cytosine methylation in fission yeast. The pol2-P287R variant has an increased sensitivity to elevated dNTP levels and DNA damaging agents, and shows reduced viability on depletion of the Pfh1 helicase. In addition, S phase is aberrant and RPA foci are elevated, suggestive of ssDNA or DNA damage, and the pol2-P287R mutation is synthetically lethal with rad3 inactivation, indicative of checkpoint activation. Significantly, deletion of genes encoding some translesion synthesis polymerases, most notably Pol κ, partially suppresses pol2-P287R hypermutation, indicating that polymerase switching contributes to this phenotype.
Collapse
Affiliation(s)
- Ignacio Soriano
- ZRAB, University of Oxford, Oxford, United Kingdom
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Enrique Vazquez
- Genomics Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Nagore De Leon
- ZRAB, University of Oxford, Oxford, United Kingdom
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | | | - Ellen Heitzer
- Institute of Human Genetics, Diagnostic & Research Center for Molecular BioMedicine, Medical University of Graz, Graz, Austria
| | - Sophia Toumazou
- ZRAB, University of Oxford, Oxford, United Kingdom
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Zhihan Bo
- ZRAB, University of Oxford, Oxford, United Kingdom
| | - Claire Palles
- Gastrointestinal Cancer Genetics Laboratory, Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Chen-Chun Pai
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Timothy C. Humphrey
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
| | - Ian Tomlinson
- Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Sue Cotterill
- St. George’s, University of London, Cranmer Terrace, Tooting, London, United Kingdom
| | | |
Collapse
|
4
|
Gao M, Guo G, Huang J, Hou X, Ham H, Kim W, Zhao F, Tu X, Zhou Q, Zhang C, Zhu Q, Liu J, Yan Y, Xu Z, Yin P, Luo K, Weroha J, Deng M, Billadeau DD, Lou Z. DOCK7 protects against replication stress by promoting RPA stability on chromatin. Nucleic Acids Res 2021; 49:3322-3337. [PMID: 33704464 PMCID: PMC8034614 DOI: 10.1093/nar/gkab134] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 01/21/2021] [Accepted: 03/02/2021] [Indexed: 02/05/2023] Open
Abstract
RPA is a critical factor for DNA replication and replication stress response. Surprisingly, we found that chromatin RPA stability is tightly regulated. We report that the GDP/GTP exchange factor DOCK7 acts as a critical replication stress regulator to promote RPA stability on chromatin. DOCK7 is phosphorylated by ATR and then recruited by MDC1 to the chromatin and replication fork during replication stress. DOCK7-mediated Rac1/Cdc42 activation leads to the activation of PAK1, which subsequently phosphorylates RPA1 at S135 and T180 to stabilize chromatin-loaded RPA1 and ensure proper replication stress response. Moreover, DOCK7 is overexpressed in ovarian cancer and depleting DOCK7 sensitizes cancer cells to camptothecin. Taken together, our results highlight a novel role for DOCK7 in regulation of the replication stress response and highlight potential therapeutic targets to overcome chemoresistance in cancer.
Collapse
Affiliation(s)
- Ming Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Guijie Guo
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jinzhou Huang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiaonan Hou
- Department of Medical Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Hyoungjun Ham
- Department of Biochemistry and Molecular Biology, Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Wootae Kim
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Fei Zhao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Xinyi Tu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Qin Zhou
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Chao Zhang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Qian Zhu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jiaqi Liu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yuanliang Yan
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhijie Xu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Ping Yin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Kuntian Luo
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - John Weroha
- Department of Medical Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Min Deng
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Daniel D Billadeau
- Department of Biochemistry and Molecular Biology, Division of Oncology Research, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhenkun Lou
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| |
Collapse
|