Open AccessMutations preventing expression of sup3 tRNASer nonsense suppressors of Schizosaccharomyces pombe.
Author(s) -
David Pearson,
Ian M. Willis,
Herbert Hottinger,
John B. Bell,
Ashok Kumar,
Urs Leupold,
Dieter Söll
Publication year - 1985
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.5.4.808
Subject(s) - biology , schizosaccharomyces pombe , genetics , gene , schizosaccharomyces , mutant , transcription (linguistics) , locus (genetics) , transfer rna , point mutation , allele , saccharomyces cerevisiae , rna splicing , microbiology and biotechnology , rna , linguistics , philosophy
Suppression of nonsense codons in Schizosaccharomyces pombe by sup3-e tRNASerUGA or sup3-i tRNASerUAA is reduced or abolished by mutations within the suppressor locus. Twenty-five suppressor-inactive sup3-e genes and thirteen mutant sup3-i genes were isolated from S. pombe genomic clone banks by colony hybridization. Sequence analysis of these revertant alleles corroborates genetic evidence for mutational hotspots within the sup3 tRNA gene. Fifteen types of point mutations or insertions were found. Many of these replace bases which are highly or completely conserved in eucaryotic tRNA genes. Transcription of the altered sup3 genes in a Saccharomyces cerevisiae extract enabled the identification of mutations which affect the rate of 5'-end maturation or splicing of the tRNA precursors or both. A total of seven mutations were found which alter transcriptional efficiencies. Of these, five are located outside the internal transcription control regions.