Molecular mechanism of recombination repair in the radioresistant bacterium

Sato, Katsuya; Kikuchi, Masahiro; Oba, Hirofumi; Narumi, Issei

To investigate the role of the RecFOR pathway in DNA double-strand break (DSB) repair in , we generated a disruptant strain and characterized the disruption effect. The disruptant strain exhibited hypersensitivity to rays than the wild-type strain. PFGE analysis showed that genome restitution ability following irradiation was severely impaired in the disruptant strain, suggesting that RecF has a crucial role in DSB repair. Furthermore, following irradiation, induction of RecA, which is essential protein for DNA recombination repair, was observed in the disruptant strain just as the wild-type strain. However a large amount of RecA protein in the disruptant strain remained inactive following irradiation. We suppose that the defect in RecA activation resulted in hypersensitivity to ionizing radiation and failure to repair radiation-induced DSB in the disruptant strain.