CSD2, CSD3, and CSD4, genes required for chitin synthesis in Saccharomyces cerevisiae: the CSD2 gene product is related to chitin synthases and to developmentally regulated proteins in Rhizobium species and Xenopus laevis.

摘要: Abstract In Saccharomyces cerevisiae, chitin forms the primary division septum and bud scar in walls of vegetative cells. Three synthetic activities have been detected. Two them, synthase I II, are not required for synthesis most present vivo. Using a novel screen, identified three mutations, designated csd2, csd3, csd4, that reduce levels vivo by as much 10-fold without causing any obvious perturbation cell division. The csd2 csd4 mutants lack III activity vitro, while csd3 wild-type this enzyme. In certain genetic backgrounds, these mutations cause temperature-sensitive growth on rich medium; inclusion salts or sorbitol bypasses phenotype. Gene disruption experiments show CSD2 is nonessential; small amount chitin, about 5% level, detected disruptants. DNA sequencing indicates protein has limited, but statistically significant, similarity to II. Other significant similarities two developmental proteins: nodC from Rhizobium species DG42 Xenopus laevis. relationship between proteins suggests may encode an N-acetylglucosaminyltransferase synthesizes oligosaccharide backbone nodulation factor NodRm-1.