title: Human SMC5/6 complex promotes sister chromatid homologous recombination by recruiting the SMC1/3 cohesin complex to double-strand breaks.
abstract: The structural maintenance of chromosomes (SMC) family of proteins has been implicated in the repair of DNA double-strand breaks (DSBs) by homologous recombination (HR). The SMC1/3 cohesin complex is thought to promote HR by maintaining the close proximity of sister chromatids at DSBs. The SMC5/6 complex is also required for DNA repair, but the mechanism by which it accomplishes this is unclear. Here, we show that RNAi-mediated knockdown of the SMC5/6 complex components in human cells increases the efficiency of gene targeting due to a specific requirement for hSMC5/6 in sister chromatid HR. Knockdown of the hSMC5/6 complex decreases sister chromatid HR, but does not reduce nonhomologous end-joining (NHEJ) or intra-chromatid, homologue, or extrachromosomal HR. The hSMC5/6 complex is itself recruited to nuclease-induced DSBs and is required for the recruitment of cohesin to DSBs. Our results establish a mechanism by which the hSMC5/6 complex promotes DNA repair and suggest a novel strategy to improve the efficiency of gene targeting in mammalian somatic cells.
authors.affiliation: Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA.
authors.forename: Patrick Ryan
authors.initials: PR
authors.lastname: Potts
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Porteus
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yu
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism* / Q000502:physiology*; D002460:Cell Line; D011508:Chondroitin Sulfate Proteoglycans / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D019457:Chromosome Breakage; D004247:DNA / Q000235:genetics; D004249:DNA Damage / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D011995:Recombination, Genetic; D012854:Sister Chromatid Exchange / Q000502:physiology*; D000097722:Cohesins; D000098550:Structural Maintenance of Chromosome Protein 1
chemical_list: D018797:Cell Cycle Proteins; D011508:Chondroitin Sulfate Proteoglycans; D002868:Chromosomal Proteins, Non-Histone; D004247:DNA; D009687:Nuclear Proteins; D000097722:Cohesins; D000098550:Structural Maintenance of Chromosome Protein 1; C492318:SMC3 protein, human; C432931:SMC5 protein, human; C432932:SMC6 protein, human