Mitochondrial suppression of a yeast nuclear mutation which affects the translation of the mitochondrial apocytochrome b transcript

Abstract

Summary We describe a mitochondrial suppressor mutation, which restores respiratory competence to the nuclear pet⁻-mutant MK2. This mutant lacks the message of the mitochondrialcob-gene and instead accumulates a partially spliced pre-mRNA which is not translated. Complete processing and translation of thecob-RNA is restored by a rearrangement of the mitochondrial DNA, leading to a fusion of thecob-coding sequences with the leader ofoli1, the mitochondrial gene coding for subunit IX of the ATPase. We conclude that the nuclear gene affected in MK2 is essential to allow translation of transcripts which contain thecob-leader sequence.