Premium
Characterization of three cDNA species encoding plastid RNA polymerase sigma factors in Arabidopsis thaliana : evidence for the sigma factor heterogeneity in higher plant plastids
Author(s) -
Tanaka Kan,
Tozawa Yuzuru,
Mochizuki Nobuyoshi,
Shinozaki Kazuo,
Nagatani Akira,
Wakasa Kyo,
Takahashi Hideo
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00906-x
Subject(s) - plastid , sigma factor , rna polymerase , biology , complementary dna , gene , genetics , arabidopsis thaliana , specificity factor , rna , arabidopsis , microbiology and biotechnology , polymerase , gene expression , nucleic acid sequence , chloroplast , mutant
By database search analysis, we identified three Arabidopsis EST (Expression Sequence Tag) entries having similarity to eubacterial RNA polymerase sigma factors. cDNA clones corresponding to these partial sequences were isolated, and the complete nucleotide sequences were determined. All three sequences encode proteins highly homologous to cyanobacterial and plastid sigma factors, and the gene products have N‐terminal extensions which are assumed to function as plastid‐targeting transit peptides. Thus we have concluded that the gene products are RNA polymerase sigma factors of plastids, and named sigA , sigB and sigC , respectively. Expression of these genes was analyzed by RNA gel‐blot analysis and shown to be induced by illumination after a short‐term dark adaptation. This strongly suggests that light regulation of the nuclear encoded sigma factor genes is involved in light‐dependent activation of plastid promoters.