Brough Rachel, Wei Debbie, Leulier Sophie, Lord Christopher J, Rong Yikang S, Ashworth Alan
CRUK Gene Function and Regulation Group, The Institute of Cancer Research, Fulham Road, London SW3 6JB, UK.
DNA Repair (Amst). 2008 Jan 1;7(1):10-9. doi: 10.1016/j.dnarep.2007.07.013. Epub 2007 Sep 5.
The human BRCA2 cancer susceptibility protein functions in double-strand DNA break repair by homologous recombination and this pathway is conserved in the fly Drosophila melanogaster. Although a potential Drosophila melanogaster BRCA2 orthologue (dmbrca2; CG30169) has been identified by sequence similarity, no functional data addressing the role of this protein in DNA repair is available. Here, we demonstrate that depletion of dmbrca2 from Drosophila cells induces sensitivity to DNA damage induced by irradiation or treatment with hydroxyurea. Dmbrca2 physically interacts with dmrad51 (spnA) and the two proteins become recruited to nuclear foci after DNA damage. A functional assay for DNA repair demonstrated that in flies dmbrca2 plays a role in double-strand break repair by gene conversion. Finally, we show that depletion of dmbrca2 in cells is synthetically lethal with deficiency in other DNA repair proteins including dmparp. The conservation of the function of BRCA2 in Drosophila will allow the analysis of this key DNA repair protein in a genetically tractable organism potentially illuminating mechanisms of carcinogenesis and aiding the development of therapeutic agents.
人类乳腺癌易感蛋白BRCA2通过同源重组参与双链DNA断裂修复，且该途径在果蝇中保守存在。尽管已通过序列相似性鉴定出一种潜在的果蝇BRCA2直系同源物（dmbrca2；CG30169），但尚无关于该蛋白在DNA修复中作用的功能数据。在此，我们证明从果蝇细胞中去除dmbrca2会导致其对辐射或羟基脲处理诱导的DNA损伤敏感。Dmbrca2与dmrad51（spnA）发生物理相互作用，并且在DNA损伤后这两种蛋白会被募集到核灶中。一项DNA修复功能测定表明，在果蝇中dmbrca2通过基因转换在双链断裂修复中发挥作用。最后，我们表明细胞中dmbrca2的缺失与包括dmparp在内的其他DNA修复蛋白的缺陷具有合成致死性。BRCA2在果蝇中的功能保守性将有助于在一种遗传上易于处理的生物体中分析这种关键的DNA修复蛋白，这可能会阐明致癌机制并有助于开发治疗药物。
