title: 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.
abstract: In Saccharomyces cerevisiae, chitin forms the primary division septum and the bud scar in the walls of vegetative cells. Three chitin synthetic activities have been detected. Two of them, chitin synthase I and chitin synthase II, are not required for synthesis of most of the chitin present in vivo. Using a novel screen, I have identified three mutations, designated csd2, csd3, and csd4, that reduce levels of chitin in vivo by as much as 10-fold without causing any obvious perturbation of cell division. The csd2 and csd4 mutants lack chitin synthase III activity in vitro, while csd3 mutants have wild-type levels of this enzyme. In certain genetic backgrounds, these mutations cause temperature-sensitive growth on rich medium; inclusion of salts or sorbitol bypasses this phenotype. Gene disruption experiments show that CSD2 is nonessential; a small amount of chitin, about 5% of the wild-type level, is detected in the disruptants. DNA sequencing indicates that the CSD2 protein has limited, but statistically significant, similarity to chitin synthase I and chitin synthase II. Other significant similarities are to two developmental proteins: the nodC protein from Rhizobium species and the DG42 protein of Xenopus laevis. The relationship between the nodC and CSD2 proteins suggests that nodC may encode an N-acetylglucosaminyltransferase that synthesizes the oligosaccharide backbone of the nodulation factor NodRm-1.
authors.affiliation: Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: C E
authors.initials: CE
authors.lastname: Bulawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002686:Chitin / Q000096:biosynthesis* / Q000235:genetics; D002687:Chitin Synthase / Q000235:genetics*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D005799:Genes, Dominant; D005800:Genes, Fungal / Q000235:genetics*; D005964:Glucosyltransferases / Q000235:genetics; D006358:Hot Temperature; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D017351:N-Acetylglucosaminyltransferases; D012231:Rhizobium / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013489:Suppression, Genetic; D014982:Xenopus laevis / Q000235:genetics
chemical_list: D002686:Chitin; D005964:Glucosyltransferases; D017351:N-Acetylglucosaminyltransferases; C037649:N-acetyllactosaminide beta-1,6-N-acetylglucosaminyltransferase; D002687:Chitin Synthase