Localication
of cis-acting regulatory elements in promoter region of SUP35 gene of Saccharomyces
cerevisiae
and phenotypic analysis of mutants with their disruptions.
Natalia A. Ryabinkova, Andrey S. Borchsenius, Sergey G. Inge-Vechtomov
Genetic and Breeding, St. Petersburg State Universit, Universytetskaya 7/9, St.
Petersburg, 199034, Russian Federation (nriabinkova@yahoo.com)
SUP35 gene of the yeast S. cerevisiae codes for translation termination factor eRF3 and it is essential for viability and plays an important role in cell cycle control. The mutation in the structural part of this gene has different pleiotropic effects (decreased cell viability, temperature and cold sensitivity, respiratory deficiency, sensitivity to paromomycin and benomyl, nonsense suppression). We analyzed the promoter of SUP35 gene by the method of in vivo genomic footprinting and have found four cis-acting regulatory elements. There are sites for recognition of proteins Mbp1, Reb1 (two sites) and Abf1. Each site was deleted using site-directed mutagenesis. We obtained strains bearing SUP35 disruption on chromosome and the mutant alleles on a centromeric plasmid. The phenotype of each mutant was tested. Only one mutant bearing Abf1-binding site deletion had visible phenotype. It demonstrated nonsense suppression. We also study the expression of the SUP35 mutants. The same mutant (deletion of Abf1 binding site) showed decreased level of SUP35 expression. We suggest that the study of the regulation of transcription may lead us to comprehension of different SUP35 functions. The work was supported by CRDF grant ST-012.