RÉSUMÉ
We are using a genetic approach to explore the synthesis and function of glycosylphosphatidylinositol (GPI). We have developed a novel strategy to isolate Saccharomyces cerevisiae mutants blocked in GPI anchoring by screening colonies of mutagenized yeast cells for those that fail to incorporate [3H]inositol into protein. Among our isolates are strains blocked in mannosylation of the GPI-anchorprecursor, and strains defective in the synthesis of N-acetylglucosaminyl phosphatidylinositol (GlcNAc-PI). We have characterized one mutant, gpi1, further. This strain is defective in GlcNAc-PI synthesis and is temperature-sensitive for growth. Completion of the first step in GPI assembly is therefore required for the growth of the unicellular eukaryote S. cerevisiae. We have isolated plasmids that complement the gpi1 mutation from S. cerevisiae genomic DNA-and fission yeast cDNA libraries.
Sujet(s)
Protéines fongiques/biosynthèse , Glycosylphosphatidylinositols/biosynthèse , Mutation/génétique , Précurseurs de protéines/biosynthèse , Saccharomyces cerevisiae/isolement et purification , Température , ADN complémentaire/génétique , Protéines fongiques/physiologie , Banque génomique , Glycosylphosphatidylinositols/physiologie , Précurseurs de protéines/physiologie , Saccharomyces cerevisiae/génétique , Saccharomyces cerevisiae/croissance et développementRÉSUMÉ
We are using a genetic approach to explore the synthesis and function of glycosylphosphatidylinositol (GPI). We have developed a novel strategy to isolate Saccharomyces cerevisiae mutants blocked in GPI anchoring by screening colonies of mutagenized yeast cells for those that fail to incorporate [3H]inositol into protein. Among our isolates are strains blocked in mannosylation of the GPI-anchor precursor, and strains defective in the synthesis of N-acetylglucosaminylphosphatidylinositol (GlcNAc-PI). We have characterized one mutant, gpil, further. This strain is defective in GlcNAC-PI synthesis and is temperature-sensitive for growth. Completion of the first step in GPI assembly is therefore required for the growth of the unicellular eukaryote S. cerevisiae. We have isolated plasmids that complement the gpil mutation from S. cerevisiae genomic DNA- and fission yeast cDNA libraries