title: The mutant of sll1961, which encodes a putative transcriptional regulator, has a defect in regulation of photosystem stoichiometry in the cyanobacterium Synechocystis sp. PCC 6803.
abstract: In acclimation to changing light environments, photosynthetic organisms modulate the ratio of two photosynthetic reaction centers (photosystem I [PSI] and photosystem II). One mutant, which could not modulate photosystem stoichiometry upon the shift to high light, was isolated from mutants created by random transposon mutagenesis. Measurements of chlorophyll fluorescence and analysis of the reaction center subunits of PSI through western blotting in this mutant revealed that the content of PSI could not be suppressed under high-light condition. In the mutant, transposon was inserted to the sll1961 gene encoding a putative transcriptional regulator. DNA microarray analysis revealed that the expression of sll1773 was drastically induced in the sll1961 mutant upon exposure to high light for 3 h. Our results demonstrate that a transcriptional regulator, Sll1961, and its possible target proteins, including Sll1773, may be responsible for the regulation of photosystem stoichiometry in response to high light.
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa-shi, Chiba, Japan.
authors.forename: Tamaki
authors.initials: T
authors.lastname: Fujimori
authors.forename: Mieko
authors.initials: M
authors.lastname: Higuchi
authors.forename: Hanayo
authors.initials: H
authors.lastname: Sato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Aiba
authors.forename: Masayuki
authors.initials: M
authors.lastname: Muramatsu
authors.forename: Yukako
authors.initials: Y
authors.lastname: Hihara
authors.forename: Kintake
authors.initials: K
authors.lastname: Sonoike
mesh_terms: D000064:Acclimatization; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D002734:Chlorophyll / Q000378:metabolism; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D008027:Light; D009154:Mutation / Q000235:genetics; D045331:Photosystem I Protein Complex / Q000096:biosynthesis*; D046939:Synechocystis / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D045331:Photosystem I Protein Complex; D014157:Transcription Factors; D002734:Chlorophyll