The cytochrome c gene from the green alga Chlamydomonas reinhardtii: Structure and expression in wild-type cells and in obligate photoautotrophic (dk) mutants

• Published in: Plant and cell physiology Vol. 41; no. 10; pp. 1149 - 1156
• Main Authors: Felitti, S.A. (Universidad Nacional del Litoral (Argentina)), Chan, R.L, Sierra, M.G, Gonzalez, D.H
• Format: Journal Article
• Language: English
• Published: Japan Oxford University Press 01.10.2000; Oxford Publishing Limited (England)
• Subjects: Amino Acid Sequence; Animals; Base Sequence; carbonyl cyanide m-chlorophenylhydrazone; CCCP; CELL STRUCTURE; CHLAMYDOMONAS REINHARDTII; Chlamydomonas reinhardtii - enzymology; Chlamydomonas reinhardtii - genetics; CYTOCHROME C; Cytochrome c Group - genetics; GenBank and DDBJ under accession number Z99829; GENE EXPRESSION; Gene Expression Regulation, Enzymologic; GENES; Key words: Chlamydomonas reinhardtii — Cytochrome c — Exon/intron structure — Gene expression — Mitochondrion; LIGHT; MITOCHONDRIA; Molecular Sequence Data; MUTANTS; Mutation; NMR; nuclear magnetic resonance; TCA; The nucleotide sequence reported in this paper has been submitted to the EMBL; tricarboxylic acids
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcd044

The expression of the Chlamydomonas reinhardtii cytochrome c gene was studied at the steady-state mRNA level. The inclusion of acetate under illumination produced a marked increase in cytochrome c transcripts. This effect was not affected by two inhibitors of mitochondrial energy metabolism. Three different obligate photoautotrophic mutants with defective mitochondria showed normal levels of induction, suggesting that utilization of acetate for respiration is not required for this process. Light, in the presence or absence of acetate, also promoted an increase in cytochrome c transcript levels. This effect could be abolished by treatment of the cells with an inhibitor of the photosynthetic electron transport chain, suggesting that light acts through photosynthesis to promote the induction. In addition, a genomic clone encompassing the Chlamydomonas cytochrome c gene has been isolated and analyzed. The gene contains three introns, two of which are located at positions similar to those in the rice and Arabidopsis cytochrome c genes, indicating the existence of an evolutionary link. It is concluded that the cytochrome c gene from C. reinhardtii is subject to metabolic regulation through a mechanism that responds to the intracellular level of either acetate or a compound derived from its metabolization through a pathway different from mitochondrial respiration.