title: Nuclear foci of mammalian Rad51 recombination protein in somatic cells after DNA damage and its localization in synaptonemal complexes.
abstract: Rad51 protein of Saccharomyces cerevisiae is a structural homolog of the Escherichia coli recombination enzyme RecA. In yeast, the Rad51 protein is required for mitotic and meiotic recombination and for repair of double-strand breaks in DNA. We have used antibodies raised against the homologous human protein, HsRad51, expressed in E. coli, to visualize the spatial distribution of the protein in mammalian somatic and meiotic cells. In cultured human cells, the HsRad51 protein is concentrated in multiple discrete foci in the nucleoplasm; it is largely absent from cytoplasm and nucleoli. After treatment of cells with methyl methanesulfonate, ultraviolet irradiation, or 137Cs irradiation, the percentage of cells with HsRad51 protein immunofluorescence increases; the same cells show unscheduled DNA synthesis. Induction of Rad51 foci is blocked by inhibitors of transcription. In mouse pachytene spermatocytes, the mouse homolog of Rad51 protein is highly enriched in synaptonemal complexes that are formed between the paired homologous chromosomes during meiotic prophase. We conclude that the mammalian proteins homologous to yeast Rad51 are involved in repair of DNA damage and recombinational repair during meiosis.
authors.affiliation: Department of Genetics, Yale University School of Medicine, New Haven, CT 06510.
authors.forename: T
authors.initials: T
authors.lastname: Haaf
authors.forename: E I
authors.initials: EI
authors.lastname: Golub
authors.forename: G
authors.initials: G
authors.lastname: Reddy
authors.forename: C M
authors.initials: CM
authors.lastname: Radding
authors.forename: D C
authors.initials: DC
authors.lastname: Ward
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D002588:Cesium Radioisotopes; D002875:Chromosomes / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D003001:Cloning, Molecular; D004249:DNA Damage; D017931:DNA Primers; D004260:DNA Repair; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D003609:Dactinomycin / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D015723:Gene Library; D006801:Humans; D007668:Kidney; D008297:Male; D008540:Meiosis; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D051135:Rad51 Recombinase; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011995:Recombination, Genetic / Q000187:drug effects / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013090:Spermatocytes / Q000166:cytology / Q000378:metabolism*; D013573:Synaptonemal Complex / Q000187:drug effects / Q000528:radiation effects; D013950:Thymus Gland / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D002588:Cesium Radioisotopes; D017931:DNA Primers; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D003609:Dactinomycin; C495151:RAD51 protein, S cerevisiae; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; C495154:Rad51 protein, mouse