title: The Neurospora crassa cya-5 nuclear gene encodes a protein with a region of homology to the Saccharomyces cerevisiae PET309 protein and is required in a post-transcriptional step for the expression of the mitochondrially encoded COXI protein.
abstract: The cya-5 nuclear mutant of Neurosopora crassa was previously shown to be deficient in cytochrome aa3, cytochrome c oxidase activity, and the immunologically detectable COXI protein. We have now demonstrated that the mitochondria of this mutant contain mRNA for the COXI protein and that COXI cannot be detected during pulse-chase labeling experiments of mitochondrial translation products. Cloning and analysis of the cya-5 gene reveal a long open reading frame capable of encoding a 1136 amino-acid protein. Sequence analysis suggests that the potential CYA-5 protein contains a mitochondrial targeting sequence at its amino-terminus. The long open reading frame also contains a 200 amino-acid region with homology to the PET309 protein, which is required for the production or stability of intron-containing coxI mRNAs, as well as the translation of mature coxI mRNAs, in the yeast Saccharomyces cerevisiae. These data suggest that the CYA-5 protein of N. crassa is required in a post-transcriptional step for COXI expression, most probably for the efficient translation of coxI mRNA.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors.forename: J W
authors.initials: JW
authors.lastname: Coffin
authors.forename: R
authors.initials: R
authors.lastname: Dhillon
authors.forename: R G
authors.initials: RG
authors.lastname: Ritzel
authors.forename: F E
authors.initials: FE
authors.lastname: Nargang
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003576:Electron Transport Complex IV / Q000096:biosynthesis* / Q000235:genetics; D005656:Fungal Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008565:Membrane Proteins; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000235:genetics* / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D016366:Open Reading Frames; D010448:Peptide Initiation Factors; D010947:Plants, Toxic; D014176:Protein Biosynthesis; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana
chemical_list: C109360:CYA5 protein, Neurospora crassa; D005656:Fungal Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; C095480:PET309 protein, S cerevisiae; D010448:Peptide Initiation Factors; D029701:Saccharomyces cerevisiae Proteins; D003576:Electron Transport Complex IV