Antagonistic dark/light‐induced SigB/SigD, group 2 sigma factors, expression through redox potential and their roles in cyanobacteria

FEBS Letters

Asayama, Munehiko¹  Takahashi, Hideo²  Takahashi, Hiroyuki²  Tanaka, Kan²  Shirai, Makoto¹  Imamura, Sousuke¹ 

[1] Laboratory of Molecular Genetics, College of Agriculture, Ibaraki University, Ami, Inashiki, Ibaraki 300-0393, Japan;Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan

关键词: Sigma factor;    RNA polymerase;    Light/dark response;    Redox;    DCMU;    3-(3′;    4′-dichlorophenyl)-1;    1′-dimethylurea;    DBMIB;    2;    5-dibromo-3-methyl-6-isopropyl-p-benzoquinone;   

DOI  :  10.1016/S0014-5793(03)01188-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The expression of group 2 sigma factors is characterized in a cyanobacterium Synechocystis sp. PCC 6803 grown in culture, changing light conditions (white, red and blue light, and darkness), or the presence of drugs (rifampicin, chloramphenicol, DCMU, and DBMIB), and the roles of these sigma factors are elucidated. The expression of dark/light-induced SigB/SigD was accelerated under opposite redox (oxidation/reduction) states in an electron transport chain of photosynthesis. Expression of the dark-induced lrtA and light-induced psbA2/3 transcript was significantly reduced in the sigB and sigD knockout strains, respectively. Abundant amounts of sigB transcript and protein were observed in the sigC knockout strain, implying that SigC represses SigB expression under light. These findings clearly showed that SigB/SigD with another group 2 sigma, SigC, contribute to transcription for a subset of dark/light-responsive genes in the cyanobacterium. A possible model for SigB/SigD is presented and the potential ability for promoter recognition is also discussed.

【 授权许可】

Unknown