title: Chromosomal localization and expression of CBS1, a translational activator of cytochrome b in yeast.
abstract: Translation of mitochondrial cytochrome b RNA in yeast requires the product of the nuclear gene CBS1, a 27.5 kDa soluble mitochondrial protein. In this paper we show that the CBS1 gene is located on chromosome IV immediately adjacent to COX9, the gene coding for cytochrome c oxidase subunit VIIa. CBS1 is transcribed as a very low abundant 900 b RNA. Transcription starts at a single position 101 bp upstream of the CBS1 initiation codon. At positions -39 to -27 of its leader sequence it contains a small open reading frame of 4 codons. By monitoring the beta-galactosidase activity of a CBS1/lacZ fusion construct we show that expression of CBS1 is subjected to regulation by oxygen and by glucose: the beta-galactosidase activity is elevated threefold in glycerol or galactose grown cells compared to that in glucose grown cells. A further threefold reduction of the activity is observed in anaerobically grown cells. In accordance with this result is the observation that the steady-state level of CBS1 mRNA of anaerobically grown cells is ninefold lower than that of aerobically cultured cells.
authors.affiliation: Institut für Genetik und Mikrobiologie, Universität München, Federal Republic of Germany.
authors.forename: V
authors.initials: V
authors.lastname: Forsbach
authors.forename: T
authors.initials: T
authors.lastname: Pillar
authors.forename: T
authors.initials: T
authors.lastname: Gottenöf
authors.forename: G
authors.initials: G
authors.lastname: Rödel
mesh_terms: D000595:Amino Acid Sequence; D000693:Anaerobiosis; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D003573:Cytochrome b Group / Q000096:biosynthesis / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics; D005786:Gene Expression Regulation; D005800:Genes, Fungal; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012331:RNA, Fungal / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D003573:Cytochrome b Group; D012331:RNA, Fungal; D003576:Electron Transport Complex IV