title: Sequence and expression of four mutant aspartic acid tRNA genes from the mitochondria of Saccharomyces cerevisiae.
abstract: Expression of the mitochondrial tRNAAsp gene of Saccharomyces cerevisiae has been examined in five syn- mutants known to affect tRNAAsp function, and in a rho- mutant which accumulates precursor tRNAs. By comparison of wild-type versus mutant DNA sequence, the lesion in each syn- mutant has been identified as a single base change within the mitochondrial tRNAAsp structural gene. The mutant tRNAAsp genes are transcribed, and the transcripts can be processed to mature 4S-size tRNAAsp. The steady-state level of each mutant tRNAAsp is lower than that of wild-type tRNAAsp. The RNA from two of the syn- mutants contained a second, slow-migrating form of mitochondrial tRNAAsp which is correctly processed at the 5' end. We conclude that the lesions in the syn- mitochondrial tRNAAsp genes block neither transcription of these genes, nor 5'-end processing of the transcripts. The effect of each point mutation must be manifested at the level of 3'-end processing, or at a functional level.
mesh_terms: D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D004722:Endoribonucleases / Q000378:metabolism; D005796:Genes; D005800:Genes, Fungal; D005838:Genotype; D009154:Mutation; D010957:Plasmids; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics*; D043262:Ribonuclease P; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D004272:DNA, Mitochondrial; D012346:RNA, Transfer, Amino Acyl; D004722:Endoribonucleases; D043262:Ribonuclease P