Mutation of a highly conserved base in the yeast mitochondrial 21S rRNA restricts ribosomal frameshifting.
A mutation shown to cause resistance to chloramphenicol in Saccharomyces cerevisiae was mapped to the central loop in domain V of the yeast mitochondrial 21S rRNA. The mutant 21S rRNA has a base pair exchange from U2677 (corresponding to U2504 in Escherichia coli) to C2677, which significantly reduces rightward frameshifting at a UU UUU UCC A site in a +1 U mutant. There is evidence to suggest that this reduction also applies to leftward frameshifting at the same site in a -1 U mutant. The mutation did not increase the rate of misreading of a number of mitochondrial missense, nonsense or frameshift (of both signs) mutations, and did not adversely affect the synthesis of wild-type mitochondrial gene products. It is suggested here that ribosomes bearing either the C2677 mutation or its wild-type allele may behave identically during normal decoding and only differ at sites where a ribosomal stall, by permitting non-standard decoding, differentially affects the normal interaction of tRNAs with the chloramphenicol resistant domain V. Chloramphenicol-resistant mutations mapping at two other sites in domain V are described. These mutations had no effect on frameshifting.
Weiss-Brummer
B
B
Institut für Genetik und Mikrobiologie, Lehrstuhl für Genetik, Universität München, Germany.
Zollner
A
A
Haid
A
A
Thompson
S
S
D000595:Amino Acid Sequence; D001483:Base Sequence; D002702:Chloramphenicol Resistance / Q000235:genetics*; D018389:Codon, Nonsense / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000235:genetics; D016368:Frameshift Mutation / Q000235:genetics*; D017930:Genes, Reporter; D008928:Mitochondria / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010641:Phenotype; D017354:Point Mutation / Q000235:genetics; D014176:Protein Biosynthesis; D012313:RNA / Q000737:chemistry / Q000235:genetics; D012331:RNA, Fungal / Q000737:chemistry / Q000235:genetics*; D000077278:RNA, Mitochondrial; D012335:RNA, Ribosomal / Q000737:chemistry / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development
D018389:Codon, Nonsense; D012331:RNA, Fungal; D000077278:RNA, Mitochondrial; D012335:RNA, Ribosomal; D012313:RNA; D003576:Electron Transport Complex IV