Radiation response mechanism of the radioresistant bacterium ; A Novel key protein "PprM"

Oba, Hirofumi; Sghaier, H.; Sato, Katsuya; Yanagisawa, Tadashi*; Narumi, Issei

PprI, which is unique to , is invoked by present data as the most important protein for radiation response mechanism. However, despite the interest in mechanism underlying the radiation response in , little is known about the exact function of PprI protein. In this study, functional analysis of PprI protein was performed. Western blot analysis and gel shift assay suggested that PprI itself does not control directly the expression of and . We identified a novel regulatory protein PprM by 2D-PAGE. -disruptant strain showed significant sensitivity to -rays. Western blot analysis revealed that PprM involves in RecA and PprA induction. By reporter assay it was found that PprM protein regulates the expression at the promoter level. These results suggest that PprM is involved in the unique radiation response mechanism controlled by PprI in .