Structural Maintenance Of Chromosomes Protein 6 (SMC6)

Torres-Rosell et al. (2005) found that Smc5 (SMC5L1) and Smc6 in S. cerevisiae are enriched at nucleolar ribosomal DNA (rDNA) and at some telomeres. Mutant Smc5/Smc6 cells underwent an aberrant mitosis in which chromosome segregation of repetitive regions was impaired, leading to DNA damage and Rad9 -dependent activation of the Rad53 (CHEK2) protein kinase.Following Smc5/Smc6 inactivation, metaphase-arrested cells showed increased levels of X-shaped DNA (Holliday junctions) at the rDNA locus. Torres-Rosell et al. (2005) concluded that the SMC5/SMC6 complex prevents the formation of sister chromatid junctions, thereby ensuring the correct partitioning of chromosomes during anaphase.