title: Cellular Dynamics of Rad51 and Rad54 in Response to Postreplicative Stress and DNA Damage in HeLa Cells.
abstract: Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in response to postreplicative stress. Accordingly, HeLa cells were arrested at the G2-M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.
authors.affiliation: Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea.
authors.forename: Eui-Hwan
authors.initials: EH
authors.lastname: Choi
authors.affiliation: Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea.
authors.forename: Seobin
authors.initials: S
authors.lastname: Yoon
authors.affiliation: Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea.
authors.forename: Yoonsoo
authors.initials: Y
authors.lastname: Hahn
authors.affiliation: Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea.
authors.forename: Keun P
authors.initials: KP
authors.lastname: Kim
mesh_terms: D002453:Cell Cycle / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D004249:DNA Damage; D004265:DNA Helicases / Q000096:biosynthesis / Q000235:genetics*; D004268:DNA-Binding Proteins; D016195:G2 Phase / Q000235:genetics; D006367:HeLa Cells; D059765:Homologous Recombination; D006801:Humans; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D051135:Rad51 Recombinase / Q000096:biosynthesis / Q000235:genetics*; D013312:Stress, Physiological / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D004265:DNA Helicases; C103532:RAD54L protein, human
keywords: DNA damage; HeLa cell; Rad51; Rad54; homologous recombination