The effect of a previously isolated antisuppressor mutation from bakers' yeast, that reduced the efficiency of the tyrosine-inserting ochre suppressor, SUP7-o, on other tyrosine-inserting ochre suppressors has been determined. As expected, the antisuppressor mutation, mod5-1, restricted the capacity of all eight tyrosine-inserting ochre suppressors to suppress nonsense mutations. Based on the suppression of five ochre alleles in the presence of mod5, the eight class I suppressors can be grouped into three subclasses. The most efficient subclass had only one member, SUP4-o. Members of the second group included SUP2-o, SUP3-o, SUP7-o, and SUP8-o. The third and least efficient subclass included SUP5-o, SUP6-o, and SUP1 1-o. These differences in efficiencies are a function of the relative expression of the eight genes encoding tRNA(TYR).
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1007/BF00405428 | DOI Listing |
Genes Environ
December 2017
Department of Biological Sciences, Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8570 Japan.
The high-fidelity transmission of genetic information is crucial for the survival of organisms, the cells of which have the ability to protect DNA against endogenous and environmental agents, including reactive oxygen species (ROS), ionizing radiation, and various chemical compounds. The basis of protection mechanisms has been evolutionarily conserved from yeast to humans; however, each organism often has a specialized mode of regulation that uses different sets of machineries, particularly in lower eukaryotes. The divergence of molecular mechanisms among related organisms has provided insights into the evolution of cellular machineries to a higher architecture.
View Article and Find Full Text PDFEMBO J
October 1994
CNRS, Laboratoire d'Enzymologie, Gif-sur-Yvette, France.
We have isolated and sequenced the minor species of tRNA(Ile) from Saccharomyces cerevisiae. This tRNA contains two unusual pseudouridines (psi s) in the first and third positions of the anticodon. As shown earlier by others, this tRNA derives from two genes having an identical 60 nt intron.
View Article and Find Full Text PDFNucleic Acids Res
February 1992
Institut de Biologie Moléculaire, CNRS, Strasbourg, France.
The expression of mutant tyrosine-inserting ochre suppressor SUP4-o tRNA genes in vivo in S. cerevisiae was examined as a basis for further studies of tRNA transcription and processing. In vivo yeast precursor tRNAs have been identified by filter hybridization and primer extension analysis.
View Article and Find Full Text PDFCurr Genet
January 1984
Biology Department, Loyola University of Chicago, 6525 N. Sheridan Road, 60626, Chicago, Illinois, USA.
The effect of a previously isolated antisuppressor mutation from bakers' yeast, that reduced the efficiency of the tyrosine-inserting ochre suppressor, SUP7-o, on other tyrosine-inserting ochre suppressors has been determined. As expected, the antisuppressor mutation, mod5-1, restricted the capacity of all eight tyrosine-inserting ochre suppressors to suppress nonsense mutations. Based on the suppression of five ochre alleles in the presence of mod5, the eight class I suppressors can be grouped into three subclasses.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 1981
Yeast mutants with decreased expression of a tRNATyr gene were obtained by selection for functional inactivation of the tyrosine-inserting ochre suppressor SUP4 and subsequent screening for production of the tRNA gene product in vivo. One mutant with reduced suppressor activity was characterized by a decreased quantity of the suppressor-specific tRNA; a precursor to this tRNA, matured at both 5' and 3' termini but still containing a 14-nucleotide intervening sequence, was present in an amount greater than 7-fold that in the parent. By RNA sequence analysis of the accumulated precursor, we have identified the mutation as an A leads to G transition at the 5' splice junction.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!