High impact information on COB

• The function of ABC1 in the suppression of a defect in apocytochrome b mRNA translation and in the activity of the bc1 complex suggests that the ABC1 protein would be a novel chaperonin involved both in biogenesis and bioenergetics of mitochondria [1].
• Genetic and biochemical evidence has strongly suggested that several introns located in yeast mitochondrial genes specifying apocytochrome b or cytochrome oxidase encode trans-acting proteins (termed mRNA-maturases) responsible for splicing the cognate intron and maturation of the mRNA [2].
• The mitochondrial cob-box gene coding for apocytochrome b in yeast has five introns and six exons or two introns and three exons depending on the wild-type strain considered [3].
• We made specific mutations in the internal guide sequence and the flanking exons of the fifth intron in the yeast mitochondrial gene for apocytochrome b (COB) [4].
• We have studied the mitochondrial DNA and the phenotypes of strains of Saccharomyces cerevisiae with specific intervening sequences in two mosaic genes: cob (the gene for apocytochrome b) and oxi3 (the gene for subunit I of cytochrome oxidase) [5].

Biological context of COB

• Nucleotide sequence and intron structure of the apocytochrome b gene of Neurospora crassa mitochondria [6].
• The first two introns of the gene have a sequence homology of 50%, while the reading frame of the fourth intron is 70% homologous with an intron of the apocytochrome b gene [7].
• The two loci map in the box region, the split gene coding for apocytochrome b [8].
• Only the latter mutants are found to be leaky in that (a) RNA splicing occurs, and (b) in three of them, to a minor degree an apocytochrome b homologue is synthesized, which, however, does not lead to respiratory competence [9].
• The possibility is discussed that mutated apocytochrome b intronic reading frame products lead to these aberrant events in the processing of transcripts of the gene for subunit I of cytochrome c oxidase [10].

Associations of COB with chemical compounds

• Its NH2-terminal part is likely to be specified by sequence alpha and thus to be homologous to that of apocytochrome b [11].

Analytical, diagnostic and therapeutic context of COB

• The intron of the mitochondrial apocytochrome b gene, cobA, of Aspergillus nidulans has been subjected to sequence analysis [12].
• [J. Biol. Chem. 250 (1977) 8236-8242] and by immunoprecipitation with a specific antiserum against apocytochrome b [13].

References