Noncomplementing mutations in a nuclear gene (CBP1) of Saccharomyces cerevisiae D273-10B specifically affect the synthesis of cytochrome b, a mitochondrially encoded carrier of the respiratory chain. The nuclear mutants have been shown to have lowered levels of cytochrome b-specific transcripts. This phenotype is attributed to the inability of the mutant strains to process the 5' end of the cytochrome b pre-mRNA. Impairment of the processing function encoded by the CBP1 gene introduces an instability in the transcripts and promotes nucleolytic degradation. Mutations in CBP1 can be suppressed by a ρ- genome in which the 5' untranslated leader of the oli1 gene (subunit 9 of the ATPase) is fused near the 5' side of the cytochrome b coding sequence. The rearranged genome allows the cytochrome b gene to be transcribed from the oli1 promoter and results in novel cytochrome b transcripts with the 5' leader sequence of the oli1 mRNA. The presence of the oli1 leader sequence confers stability to the RNA and circumvents the CBP1 processing function.
|Original language||English (US)|
|Number of pages||10|
|Journal||Journal of Biological Chemistry|
|State||Published - 1984|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology