Biochemistry: Complex assistance for DNA invasion.

Abstract

Repair of broken DNA is vital for genome stability and to prevent the development of cancer. Research shows how the tumour-suppressor protein BRCA1 promotes a DNA-repair pathway called homologous recombination. See Article p.360 Two of the hereditary breast cancer susceptibility genes (BRCAs) act during the initial stages of recombinational DNA repair. BRCA1, together with BARD1, helps to form the single-stranded DNA that is then bound by another complex, BRCA2–PALB2, which facilitates loading of the central DNA strand exchange factor, RAD51. Patrick Sung and colleagues now show that BRCA1–BARD1 can also directly interact with RAD51 and stimulate the formation of the synaptic complex—a crucial intermediate that aligns the damaged and repair template DNA molecules. Because cancer cells depend on functioning DNA repair to thrive, targeting these factors may provide therapeutic value.