Structural Maintenance Of Chromosomes Protein 5 (SMC5)

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.

The transcript contains an Alu repetitive element in the 3-prime untranslated region, and the deduced 882-amino acid protein shares weak homology with Saccharomyces pombe Rad18, a DNA repair protein. RT-PCR detected SMC5 expression in all tissues examined, with highest levels in heart, placenta, lung, liver, skeletal muscle, and kidney.