title: DNA replication-dependent nuclear dynamics of the Mre11 complex.
abstract: The Mre11 complex undergoes dramatic relocalization in the nuclei of gamma-irradiated and replicating human cells. In this study, we examined Mre11 complex localization and chromatin association in synchronous cultures to examine the molecular determinants of relocalization. The data indicate that the complex is deposited on chromatin in an S phase-specific manner. Mre11 complex chromatin association in S phase was resistant to detergent extraction, in contrast to that in gamma-irradiated cells. The complex exhibits extensive colocalization with proliferating cell nuclear antigen throughout S phase, and chromatin loading is enhanced by replication fork stalling, suggesting that the replication fork is a site of Mre11 complex chromatin loading. This is supported by the observation that the complex localized to single-stranded DNA arising in hydroxyurea-treated cells. Although the Mre11 complex appears to function as a DNA damage sensor, limited colocalization with Brca1 or gamma-H2AX was observed, arguing that neither DNA damage nor gamma-H2AX is required for Mre11 complex chromatin loading. These data provide a potential molecular basis for promotion of sister chromatid association and recombination by the Mre11 complex as well as for ATM-Mre11 complex-dependent activation of cell cycle checkpoints.
authors.affiliation: Laboratory of Genetics, University of Wisconsin Medical School, Madison, WI, USA.
authors.forename: Olga K
authors.initials: OK
authors.lastname: Mirzoeva
authors.forename: John H J
authors.initials: JH
authors.lastname: Petrini
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D019313:BRCA1 Protein / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism / Q000528:radiation effects; D002843:Chromatin / Q000378:metabolism; D004249:DNA Damage / Q000502:physiology; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology; D005720:Gamma Rays; D006367:HeLa Cells; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D016196:S Phase / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
chemical_list: D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae