Ionising radiation response of mouse embryonic fibroblast cell lines lacking cohesin REC8

Full text: The cohesin complex is required for the cohesion of sister chromatids. Cohesin is loaded onto chromosomes during DNA replication and maintains sister chromatid association until anaphase. The cohesin complex is also implicated in homologous recombination, the upkeep of chromosome stability, the repair of double stranded DNA breaks (dsbs) and most recently, chromatin remodelling. REC8 is a key component of the meiotic cohesin complex that we showed was conserved from yeast to humans (Parisi, et. al., 1999). We identified a mouse ortholog of the Rec8 gene and generated Rec8 mutant mice by targeted deletion. To determine the role of REC8 in DNA repair, we derived embryonic fibroblast cell lines from Rec8 mutant mice. By clonogenic assay we are evaluating the resistance of Rec8 -/- cells to ionising (IR) radiation, an indirect measure of repair of dsbs. The study may provide insights into the involvement of cohesins in recombination and IR response. Reference: Parisi, S., McKay, M.J., Molnar, M., Thompson, M.A., van der Spek, P.J., van Drunken-Schoenmaker, E., Kanaar, R., Lehmann, E., Hoeijmakers, J.H.J. and Kohli, J., 1999. Rec8p, a meiotic recombination and sister chromatid cohesion phosphoprotein of the Rad21 family conserved from fission yeast to humans. Mol Cell Biol. 19(5):3515-3528