Mutants of Chlamydomonas reinhardtii deficient in mitochondrial complex I: characterization of two mutations affecting the nd1 coding sequence.
The mitochondrial rotenone-sensitive NADH:ubiquinone oxidoreductase (complex I) comprises more than 30 subunits, the majority of which are encoded by the nucleus. In Chlamydomonas reinhardtii, only five components of complex I are coded for by mitochondrial genes. Three mutants deprived of complex I activity and displaying slow growth in the dark were isolated after mutagenic treatment with acriflavine. A genetical analysis demonstrated that two mutations (dum20 and dum25) affect the mitochondrial genome whereas the third mutation (dn26) is of nuclear origin. Recombinational analyses showed that dum20 and dum25 are closely linked on the genetic map of the mitochondrial genome and could affect the nd1 gene. A sequencing analysis confirmed this conclusion: dum20 is a deletion of one T at codon 243 of nd1; dum25 corresponds to a 6-bp deletion that eliminates two amino acids located in a very conserved hydrophilic segment of the protein.
Remacle
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Laboratory of Genetics of Microorganisms, Department of Plant Biology, University of Liège, B-4000 Liège Sart-Tilman, Belgium.
Baurain
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Cardol
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Matagne
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics*; D016825:Chlamydomonas reinhardtii / Q000235:genetics*; D042967:Electron Transport Complex I; D017343:Genes, Plant; D006801:Humans; D008928:Mitochondria / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics*; D010641:Phenotype; D011995:Recombination, Genetic; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; C438148:nd1 protein, Rhodobacter capsulatus; D009247:NADH, NADPH Oxidoreductases; D042967:Electron Transport Complex I