{"title":"The FHA domain of PNKP is essential for its recruitment to DNA damage sites and maintenance of genome stability","authors":"Kaima Tsukada , Mikio Shimada , Rikiya Imamura , Kotaro Saikawa , Masamichi Ishiai , Yoshihisa Matsumoto","doi":"10.1016/j.mrfmmm.2020.111727","DOIUrl":null,"url":null,"abstract":"<div><p><span>Polynucleotide<span> kinase phosphatase (PNKP) has dual </span></span>enzymatic activities<span><span><span><span><span> as kinase and phosphatase for DNA ends, which are the prerequisite for the ligation, and thus is involved in </span>base excision repair<span>, single-strand break repair and non-homologous end joining for double-strand break (DSB) repair. In this study, we examined mechanisms for the recruitment of PNKP to DNA damage sites by laser micro-irradiation and live-cell imaging analysis using confocal microscope. We show that the forkhead-associated (FHA) domain of PNKP is essential for the recruitment of PNKP to DNA damage sites. Arg35 and Arg48 within the FHA domain are required for interactions with </span></span>XRCC1 and XRCC4. PNKP R35A/R48A mutant failed to accumulate on the laser track and siRNA-mediated depletion of XRCC1 and/or XRCC4 reduced PNKP accumulation on the laser track, indicating that PNKP is recruited to DNA damage sites via the interactions between its FHA domain and XRCC1 or XRCC4. Furthermore, cells expressing PNKP R35A/R48A mutant exhibited increased sensitivity toward </span>ionizing radiation<span> in association with delayed SSB and DSB repair and genome instability, represented by micronuclei and chromosome bridges. Taken together, these findings revealed the importance of PNKP recruitment to DNA damage sites via its FHA domain for DNA </span></span>repair and maintenance of genome stability.</span></p></div>","PeriodicalId":49790,"journal":{"name":"Mutation Research-Fundamental and Molecular Mechanisms of Mutagenesis","volume":"822 ","pages":"Article 111727"},"PeriodicalIF":1.5000,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.mrfmmm.2020.111727","citationCount":"9","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mutation Research-Fundamental and Molecular Mechanisms of Mutagenesis","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0027510720300609","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOTECHNOLOGY & APPLIED MICROBIOLOGY","Score":null,"Total":0}
引用次数: 9
Abstract
Polynucleotide kinase phosphatase (PNKP) has dual enzymatic activities as kinase and phosphatase for DNA ends, which are the prerequisite for the ligation, and thus is involved in base excision repair, single-strand break repair and non-homologous end joining for double-strand break (DSB) repair. In this study, we examined mechanisms for the recruitment of PNKP to DNA damage sites by laser micro-irradiation and live-cell imaging analysis using confocal microscope. We show that the forkhead-associated (FHA) domain of PNKP is essential for the recruitment of PNKP to DNA damage sites. Arg35 and Arg48 within the FHA domain are required for interactions with XRCC1 and XRCC4. PNKP R35A/R48A mutant failed to accumulate on the laser track and siRNA-mediated depletion of XRCC1 and/or XRCC4 reduced PNKP accumulation on the laser track, indicating that PNKP is recruited to DNA damage sites via the interactions between its FHA domain and XRCC1 or XRCC4. Furthermore, cells expressing PNKP R35A/R48A mutant exhibited increased sensitivity toward ionizing radiation in association with delayed SSB and DSB repair and genome instability, represented by micronuclei and chromosome bridges. Taken together, these findings revealed the importance of PNKP recruitment to DNA damage sites via its FHA domain for DNA repair and maintenance of genome stability.
期刊介绍：
Mutation Research (MR) provides a platform for publishing all aspects of DNA mutations and epimutations, from basic evolutionary aspects to translational applications in genetic and epigenetic diagnostics and therapy. Mutations are defined as all possible alterations in DNA sequence and sequence organization, from point mutations to genome structural variation, chromosomal aberrations and aneuploidy. Epimutations are defined as alterations in the epigenome, i.e., changes in DNA methylation, histone modification and small regulatory RNAs.
MR publishes articles in the following areas:
Of special interest are basic mechanisms through which DNA damage and mutations impact development and differentiation, stem cell biology and cell fate in general, including various forms of cell death and cellular senescence.
The study of genome instability in human molecular epidemiology and in relation to complex phenotypes, such as human disease, is considered a growing area of importance.
Mechanisms of (epi)mutation induction, for example, during DNA repair, replication or recombination; novel methods of (epi)mutation detection, with a focus on ultra-high-throughput sequencing.
Landscape of somatic mutations and epimutations in cancer and aging.
Role of de novo mutations in human disease and aging; mutations in population genomics.
Interactions between mutations and epimutations.
The role of epimutations in chromatin structure and function.
Mitochondrial DNA mutations and their consequences in terms of human disease and aging.
Novel ways to generate mutations and epimutations in cell lines and animal models.
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