title: Analysis of ionizing radiation-induced foci of DNA damage repair proteins.
abstract: Repair of DNA double-strand breaks by homologous recombination requires an extensive set of proteins. Among these proteins are Rad51 and Mre11, which are known to re-localize to sites of DNA damage into nuclear foci. Ionizing radiation-induced foci can be visualized by immuno-staining. Published data show a large variation in the number of foci-positive cells and number of foci per nucleus for specific DNA repair proteins. The experiments described here demonstrate that the time after induction of DNA damage influenced not only the number of foci-positive cells, but also the size of the individual foci. The dose of ionizing radiation influenced both the number of foci-positive cells and the number of foci per nucleus. Furthermore, ionizing radiation-induced foci formation depended on the cell cycle stage of the cells and the protein of interest that was investigated. Rad51 and Mre11 foci seemed to be mutually exclusive, though a small subset of cells did show co-localization of these proteins, which suggests a possible cooperation between the proteins at a specific moment during DNA repair.
authors.affiliation: Department of Cell Biology and Genetics, Erasmus MC, University Medical Center, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
authors.forename: Lieneke R
authors.initials: LR
authors.lastname: van Veelen
authors.forename: Tiziana
authors.initials: T
authors.lastname: Cervelli
authors.forename: Mandy W M M
authors.initials: MW
authors.lastname: van de Rakt
authors.forename: Arjan F
authors.initials: AF
authors.lastname: Theil
authors.forename: Jeroen
authors.initials: J
authors.lastname: Essers
authors.forename: Roland
authors.initials: R
authors.lastname: Kanaar
mesh_terms: D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts; D005720:Gamma Rays; D006367:HeLa Cells; D006801:Humans; D000076228:MRE11 Homologue Protein; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis*; D051135:Rad51 Recombinase; D011839:Radiation, Ionizing; D013997:Time Factors
chemical_list: D004268:DNA-Binding Proteins; C121766:MRE11 protein, human; D018809:Proliferating Cell Nuclear Antigen; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D000076228:MRE11 Homologue Protein