The novel Myb transcription factor LCR1 regulates the CO2-responsive gene Cah1, encoding a periplasmic carbonic anhydrase in Chlamydomonas reinhardtii.
Chlamydomonas reinhardtii acclimates to CO2-limiting stress by inducing a set of genes for a carbon-concentrating mechanism (CCM). This set includes the gene Cah1, which encodes a periplasmic carbonic anhydrase. Although physiological aspects of CO2response have been extensively studied, regulatory components, such as transcription factors involved in the acclimation, have not been well described in eukaryotic microalgae. Using an arylsulfatase gene driven by the Cah1 promoter, a regulatory mutant of Cah1 was isolated and named lcr1 (for low-CO2 stress response). The photosynthetic affinity for inorganic carbon of lcr1 was reduced compared with that of wild-type cells. Expression of three low-CO2-inducible genes, Cah1, Lci1, and Lci6, were regulated by LCR1 as shown by cDNA array and RNA gel blot analyses. The Lcr1 gene encodes a protein of 602 amino acids containing a single Myb domain, which binds to the Cah1-promoter region. Expression of Lcr1 was induced by lowering CO2 levels and controlled by the regulatory factor CCM1. These results suggest that LCR1 transmits the low CO2 signal to at least three CO2-responsive genes and then fully induces CCM.
Yoshioka
Satoshi
S
Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
Taniguchi
Fumiya
F
Miura
Kenji
K
Inoue
Takeshi
T
Yamano
Takashi
T
Fukuzawa
Hideya
H
D048868:Adaptor Proteins, Signal Transducing; D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002245:Carbon Dioxide / Q000494:pharmacology*; D002256:Carbonic Anhydrases / Q000235:genetics* / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D019897:Periplasm / Q000201:enzymology*; D010940:Plant Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D017434:Protein Structure, Tertiary; D020598:Proto-Oncogene Proteins c-myb / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D020418:Algal Proteins; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; C425934:ccm1 protein, Chlamydomonas reinhardtii; D002245:Carbon Dioxide; D004247:DNA; D002256:Carbonic Anhydrases