In vivo analysis of sequences necessary for CBP1-dependent accumulation of cytochrome b transcripts in yeast mitochondria

Telsa M. Mittelmeier, Carol L. Dieckmann

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

In Saccharomyces cerevisiae, cytochrome b, an essential component of the respiratory chain, is encoded by the mitochondrial gene cob. The cob transcription unit includes the tRNAGlu gene from positions -1170 to -1099 relative to the cob ATG at +1. The initial tRNAGlu-cob transcript undergoes several processing events, including removal of tRNAGlu and production of the mature 5′ end of cob mRNA at nucleotide -954. The nuclear gene product CBP1 is specifically required for the accumulation of cob mRNA. In cbp1 mutant strains, cob transcripts are not detectable by Northern (RNA) blot analysis, but the steady-state level of tRNAGlu is similar to that of wild type. The results of a previous study led to the conclusion that a 400-nucleotide region just downstream of tRNAGlu is sufficient for CBP1 function. In the present study, the microprojectile bombardment method of mitochondrial transformation was used to introduce deletions within this region of cob. The analysis of cob transcripts in strains carrying the mitochondrial deletion genomes indicates that a 63-nucleotide sequence that encompasses the cleavage site at -954 is sufficient both for CBP1 function and for correct positioning of the cleavage. Furthermore, the data indicate that CBP1 prevents the degradation of unprocessed cob transcripts produced by endonucleolytic cleavage at the 3′ end of tRNAGlu.

Original languageEnglish (US)
Pages (from-to)4203-4213
Number of pages11
JournalMolecular and cellular biology
Volume13
Issue number7
DOIs
StatePublished - Jul 1993

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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