TY - JOUR
T1 - ChlH, the H subunit of the Mg-chelatase, is an anti-sigma factor for SigE in Synechocystis sp. PCC 6803
AU - Osanai, Takashi
AU - Imashimizu, Masahiko
AU - Seki, Asako
AU - Sato, Shusei
AU - Tabata, Satoshi
AU - Imamura, Sousuke
AU - Asayama, Munehiko
AU - Ikeuchi, Masahiko
AU - Tanaka, Kan
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2009/4/21
Y1 - 2009/4/21
N2 - Although regulation of sigma factors has been intensively investigated, anti-sigma factors have not been identified in oxygenic photosynthetic organisms. A previous study suggested that the sigma factor, SigE, of the cyanobacterium Synechocystis sp. PCC 6803, a positive regulator of sugar catabolism, is posttranslation-ally activated by light-to-dark transition. In the present study, we found that the Hsubunit of Mg-chelataseChlH interacts with sigma factor SigE by yeast two-hybrid screening, and immunoprecipita-tion analysis revealed that ChlH associates with SigE in a light-dependent manner in vivo. We also found that Mg2+ promotes the interaction of SigE and ChlH and determines their localization in vitro. In vitro transcription analysis demonstrated that ChlH inhibits the transcription activity of SigE. Based on these results, we propose a model in which ChlH functions as an anti-sigma factor, transducing light signals to SigE in a process mediated by Mg 2+.
AB - Although regulation of sigma factors has been intensively investigated, anti-sigma factors have not been identified in oxygenic photosynthetic organisms. A previous study suggested that the sigma factor, SigE, of the cyanobacterium Synechocystis sp. PCC 6803, a positive regulator of sugar catabolism, is posttranslation-ally activated by light-to-dark transition. In the present study, we found that the Hsubunit of Mg-chelataseChlH interacts with sigma factor SigE by yeast two-hybrid screening, and immunoprecipita-tion analysis revealed that ChlH associates with SigE in a light-dependent manner in vivo. We also found that Mg2+ promotes the interaction of SigE and ChlH and determines their localization in vitro. In vitro transcription analysis demonstrated that ChlH inhibits the transcription activity of SigE. Based on these results, we propose a model in which ChlH functions as an anti-sigma factor, transducing light signals to SigE in a process mediated by Mg 2+.
KW - Cyanobacteria
KW - Transcription
UR - http://www.scopus.com/inward/record.url?scp=66149094287&partnerID=8YFLogxK
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U2 - 10.1073/pnas.0810040106
DO - 10.1073/pnas.0810040106
M3 - Article
C2 - 19342483
AN - SCOPUS:66149094287
VL - 106
SP - 6860
EP - 6865
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 16
ER -