RpoH(II) activates oxidative-stress defense systems and is controlled by RpoE in the singlet oxygen-dependent response in Rhodobacter sphaeroides.

ABSTRACT: Photosynthetic organisms need defense systems against photooxidative stress caused by the generation of highly reactive singlet oxygen ((1)O(2)). Here we show that the alternative sigma factor RpoH(II) is required for the expression of important defense factors and that deletion of rpoH(II) leads to increased sensitivity against exposure to (1)O(2) and methylglyoxal in Rhodobacter sphaeroides. The gene encoding RpoH(II) is controlled by RpoE, and thereby a sigma factor cascade is constituted. We provide the first in vivo study that identifies genes controlled by an RpoH(II)-type sigma factor, which is widely distributed in the Alphaproteobacteria. RpoH(II)-dependent genes encode oxidative-stress defense systems, including proteins for the degradation of methylglyoxal, detoxification of per

SUBMITTER: Nuss AM 

PROVIDER: S-EPMC2612413 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature