CBP1 function is required for stability of a hybrid cob-oli1 transcript in yeast mitochondria.
The nuclear gene product CBP1 stabilizes cytochrome b transcripts in yeast mitochondria. In cbp1 mutant strains, cytochrome b gene (cob) transcripts are not detectable by Northern blot analysis. The results of previous studies led to the hypothesis that CBP1 interacts with the 5'-untranslated sequence of the cob mRNA, or pre-mRNA, to stabilize the message. To determine what portion of the cob leader is sufficient for interaction with CBP1, we have investigated the stability of transcripts from a novel hybrid gene, cob-oli1, in which the 5'-terminal third of the cob leader sequence was fused to the coding sequence of the gene for ATP synthase subunit 9, oli1. The hybrid cob-oli1 transcript was stable in a strain wild-type at the CBP1 locus, but was undetectable in the cbp1 mutant background. That the cob-oli1 transcript was translated to produce ATP synthase subunit 9 in CBP1 strains containing the cob-oli1 gene was verified by 35S-methionine labeling of mitochondrial proteins. We conclude that the 5'-terminal portion of the cob message is sufficient for CBP1 function and discuss the hypothesis that CBP1 interacts directly with this region of the transcript to promote cob mRNA stability.
Mittelmeier
T M
TM
Department of Molecular and Cellular Biology, University of Arizona, Tucson 85721.
Dieckmann
C L
CL
D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D015139:Blotting, Southern; D003001:Cloning, Molecular; D003573:Cytochrome b Group / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D014176:Protein Biosynthesis; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014158:Transcription, Genetic; D015003:Yeasts / Q000235:genetics* / Q000378:metabolism
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C064042:CBF1 protein, S cerevisiae; D003573:Cytochrome b Group; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D006180:Proton-Translocating ATPases