Role of Rad21 and Rec8 genes in ionising radiation response

The recently discovered multi-protein complex called cohesin serves as a chromosomal glue which plays important role in mediating chromosome segregation. Cohesin is also implicated in other cellular processes including homologous recombination, the upkeep of chromosome stability and DNA repair. Rad21 and its paralogous protein, Rec8 are key components of the cohesin complex. Rad21 has been implicated mainly in mitotic cell function, whereas Rec8 were thought to operate exclusively in meiosis. Recent studies in non-mammalian metazoa and in lower eukaryotes have shown that Rad21 is required for the effective repair of ionising radiation (IR) induced DNA double strand breaks (DSBs) and Rec8 is involved in meiotic homologous recombination (HR). To investigate the role of these genes in mammalian systems, we generated mutant lines of mice with heterozygous or homozygous deletions of Rad21 and Rec8 genes, respectively. The response of these mutant animals and cells to ionising radiation was analysed