Search academic texts

Information × Registration Number 0206U000666, 0102U000613 , R & D reports Title Molecular mechanisms that control peroxisome homeostasis, flavins and heterologous proteins biosynthesis as well as stress response in the nonconventional yeasts popup.stage_title Head Sibirny Andrey Andrejovych, Registration Date 02-02-2006 Organization Institute of cell biology, National Academy of Sciences of Ukraine popup.description2 Objects of study: non-conventional yeasts (methylotrophic, alkane-utilizing, riboflavin overproducing). The scientific goals of the study were: investigate mechanisms of yeast response to metabolic stresses; elaborate yeast systems for overexpression of native and foreign proteins; study of the yeast genes of riboflavin biosynthesis; elucidate mechanisms of peroxisome homeostasis in yeasts. Mutants of the methylotrophic yeast Hansenula polymorpha deficient in glutathione biosynthesis have been isolated and characterized. The genes GSH1 and GSH2 were cloned and sequenced. It was demonstrated that H. polymorpha GSH2 gene is homologous to the GSH1 gene, and GSH1 gene - to МЕТ1 of S. сerevisiae. We isolated H. polymorpha transformants carrying additional copies of the МЕT1/GSH1 and GSH2 genes that exhibited significantly elevated resistance and absorbance capacity to have metal ions. H. рolymorpha mutants deficient in glucose catabolite repression have been isolated and characterized. The gene responsiblefor the repression mechanism, GCR1, has been isolated. It encodes a protein homologous to yeast glucose transporters/sensors. gcr1 mutant strain was utilized for expression of heterologous proteins from repressible promoter of peroxisomal alcohol oxidase in glucose medium. Isolated strains efficiently expressed foreign proteins with various intracellular localization. It was demonstrated that protein products encoded by the genes of riboflavin biosynthesis in the yeast Candida famata exhibit the highest degree of primary amino acid sequence similarity to their couterparts from Debaryomyces hansenii. In D. hansenii genomic DNA, the gene encoding for DRAP-deiminase has been identified . We studied molecular mechanisms of autophagic peroxisome degradation in the methylotrophic (Pichia pastoris) and alkane-utilizing (Yarrowia lipolytica). In P. pastoris, three genes involved in this process have been identified. It was demonstrated that corresponding protein products are specifically involved in selectivepexophagy triggered by alternative carbon sources, but not in other related autophagic pathways, as general autophagy triggered by nitrogen starvation. Collection of pexophagy and general autophagy-deficient mutants of the yeast Y. lipolytica was isolated and characterized. It was established that macropexophagy in this yeast is dependent on early secretory pathway and, contrary to P. pastoris, is independent of the ergosterol glucosidase gene, UGT51, and, consequently, ergosterol glycosylation. Product Description popup.authors popup.nrat_date 2020-04-02 Close