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Mutant alleles of tRNA Thr genes suppress the hisG46 missense mutation in Salmonella typhimurium
Author(s) -
Kupchella Eugene,
Koch Walter H.,
Cebula Thomas A.
Publication year - 1994
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850230202
Subject(s) - mutant , biology , genetics , allele , transfer rna , gene , missense mutation , suppressor mutation , microbiology and biotechnology , mutation , escherichia coli , mutagen , rna , dna
Extragenic suppressors of the hisG46 missense mutation were mapped to the 71 and 88 min regions of the Salmonella typhimurium chromosome, positions that in Escherichia coli contain the thrV (tRNA Thr1 ) and thrT (tRNA Thr3 ) genes, respectively. The suppressor loci were identified as mutant alleles of thrV and thrT , using allelespecific colony hybridization. An oligomer, based on the conserved 5′ sequence of the thrT and thrV genes in E. coli and designed to contain the putative mutant anticodon, discriminated between suppressor‐containing and wild‐type strains. Similarly, probes specific for the thrV ‐[SuGGG] and thrT [SuGGG] were used to differentiate the two suppressors. To date, all extragenic suppressors of hisG46 have been identified as either thrV [SuGGG] or thrT [SuGGG]. A near equal distribution of thrV [SuGGG] and thrT [SuGGG] suppressors was found among 29 spontaneous and 43 mutagen‐induced hisG46 extragenic suppressor revertants. It was concluded, therefore, that mutant alleles of thrV and thrT are predominantly, if not solely, responsible for intergenic suppression of the hisG46 mutation. © 1994 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.