Characterization of two genes, Sig1 and Sig2, encoding distinct plastid sigma factors(1) in the moss Physcomitrella patens: phylogenetic relationships to plastid sigma factors in higher plants.
We isolated the cDNA for a sigma factor from the moss Physcomitrella patens, which possesses unusually large N-terminal extension and the conserved subdomains 1.2-4.2. Phylogenetic analyses indicated that this novel sigma factor and PpSIG1*(2), a plastid sigma factor previously identified from Physcomitrella, were classified into SigA and SigB groups, two major classes of higher plant plastid sigma factors, respectively. According to the nomenclature recently proposed, we renamed PpSIG1* into PpSIG2, and named the novel sigma factor PpSIG1. A transient expression assay using a green fluorescent protein showed that the N-terminal region of PpSIG1 acts as a chloroplast-targeting signal. Reverse transcription-PCR experiments showed that light induces the expression of the Sig1 and Sig2 genes encoding PpSIG1 and PpSIG2, respectively. Thus, PpSIG1 and PpSIG2 are likely plastid sigma factors regulating plastid gene expression in response to light signals.
Hara
K
K
Division of Biological Informatics, Graduate School of Human Informatics, Nagoya University, Furo-cho, Chikusa-ku, 464-8601, Nagoya, Japan
Morita
M
M
Takahashi
R
R
Sugita
M
M
Kato
S
S
Aoki
S
S
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins; D019068:Bryopsida / Q000166:cytology / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D017343:Genes, Plant / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D018087:Plastids / Q000235:genetics*; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D012808:Sigma Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D011993:Recombinant Fusion Proteins; C431272:Sig1 protein, Physcomitrella patens; C431273:Sig2 protein, Physcomitrella patens; C107904:SigA protein, Arabidopsis; D012808:Sigma Factor