Abstract
The study of suppressors of tryptophan synthase A protein missense mutations in Escherichia coli has led to the establishment of two nonadjacent genetic loci (gly V and gly W) specifying identical nucleotide sequences for a single isoaccepting species of glycine transfer ribonucleic acid (tRNA GLY 3 GGU/C). In one case, suppression of the missense mutation trpA78 was due to a mutation in a structural gene (gly W) for tRNA Gly 3 GGU/C. This mutation resulted in a base change in the anticodon and modification of an A residue adjacent to the 3' side of the anticodon, leading to the production of a tRNA Gly 3 UGU/C species. The resulting glyW51 (SU UGU/C) allele was mapped by interrupted mating and was located at approximately 37 min on the Escherichia coli genetic map. Other suppressor mutations affecting the primary sequence of tRNA Gly GGU/C and giving rise to the Ins and SU+A58 phenotypes were positioned at 86 min (glyV). Several independently arising missense suppressor mutations resulting in the SU+A78 phenotypes were isolated and mapped at these two genetic loci (glyV and glyW). The ratio of appearance of suppressor mutations at glyV and glyW suggests that there are three of four tRNAGly3 GGU/C structural gene copies at the glyV locus to one copy at the glyW locus. Structural genes for tRNA ly isoacceptors are now known at four distinct locations on the Escherichia coli chromosome: glyT (77 MIN), TRNA Gly 2 GGA/G; gly U (55 min), tRNAGly-1 minus; and gly V (86 MIN) AND GLYW (37 min), tRNAGly 3 GGU/C.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference22 articles.
1. Carbon J. S. Chang and L. L. Kirk. 1974. Clustered tRNA genes in Escherichia coli: transcription and processing. Brookhaven Symp. Biol. RNA Processing in press.
2. Genetic alteration of structure and function in glycine transfer RNA of Escherichia coli: mechanism of suppression of the tryptophan synthetase A78 mutation;Carbon J.;J. Mol. Biol.,1974
3. Glycine transfer RNA of Escherichia coli. H. Impaired GGArecognition in strains containing a genetically altered transfer RNA; reversal by a secondary suppressor mutation;Carbon J.;J. Mol. Biol.,1970
4. Clowes R. C. and W. Hayes. 1968. Experiments in microbial genetics. John Wiley and Sons New York.
5. The dual genetic control of ornithine transcarbamylase synthesis in Escherichia coli K12;Glansdorff N.;Mutat. Res.,1967
Cited by
24 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献