ABSTRACT
The 8.1 kb chromosomal fragment partially suppressing the ogd1 mutation in Saccharomyces cerevisiae has been cloned. The molecular analysis revealed that its suppressor gene codes for a natural glutamine tRNA(CAG) and maps on chromosome XIII in the upstream region of the URA10 gene. The multicopy plasmids containing this tRNA gene also suppressed the standard trp1-1 amber mutation and conferred the sensitivity of yeast cells to paromomycin and increased temperature.
Subject(s)
Genes, Fungal , Genes, Suppressor , Ketoglutarate Dehydrogenase Complex/genetics , RNA, Transfer, Gln , RNA, Transfer, Gln/genetics , Saccharomyces cerevisiae/genetics , Chromosome Mapping , Chromosomes, Fungal , Cloning, Molecular , Glycerol/metabolism , Ketoglutarate Dehydrogenase Complex/metabolism , Mutation , Paromomycin/pharmacology , Protein Biosynthesis , RNA, Transfer, Gln/metabolism , Restriction Mapping , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/metabolism , TemperatureABSTRACT
The activity of mitochondrial 2-oxoglutarate dehydrogenase in S. cerevisiae can be impaired either by the ogd1 or the kgd1 mutation. The OGD1 gene and two suppressor genes were isolated by complementation of the ogd1 mutant. The complementation of the kdg1 mutant by the OGD1 gene, an allelism test, and meiotic mapping, revealed that the ogd1 and kgd1 mutations are allelic. The two mutations were differentiated by the cloned suppressor gene which was able to partially complement ogd1, but not kgd1. The molecular analysis of the suppressor gene revealed its identity with the natural tRNA(GlnCAG) gene found in the upstream region of URA10.
