title: Cloning and molecular characterization of three genes, including two genes encoding serine hydroxymethyltransferases, whose inactivation is required to render yeast auxotrophic for glycine.
abstract: The genes encoding both the cytosolic and mitochondrial serine hydroxymethyltransferases (SHM2 and SHM1, respectively) and a third unidentified gene of the yeast Saccharomyces cerevisiae have been isolated and their nucleotide sequences determined. Analysis of the predicted amino acid sequence of the amino-terminal regions, sequence comparison with other genes encoding SHMT enzymes, and subcellular fractionation studies all suggested that the SHM1 gene encodes the mitochondrial SHMT, while the SHM2 gene encodes the cytosolic enzyme. The SHM2 gene but not the SHM1 gene has putative GCN4 sites upstream of the putative TATA box, suggesting regulation of its transcription by the general amino acid control system. Yeast mutants with disruptions at each SHM gene and in both genes were constructed and all mutants had the same growth requirements as the parental strains. Mutagenesis of the double-disrupted, shm1 shm2 yeast yielded strains of a single complementation group that are auxotrophic for glycine. Complementation of the glycine auxotrophy using a yeast genomic library retrieved the SHM1 and SHM2 genes and a third gene designated GLY1. Gene disruption studies demonstrated that inactivation of SHM1, SHM2, and GLY1 is required to yield yeast that are completely auxotrophic for glycine.
authors.affiliation: Department of Microbiology, University of Toronto, Ontario, Canada.
authors.forename: J B
authors.initials: JB
authors.lastname: McNeil
authors.forename: E M
authors.initials: EM
authors.lastname: McIntosh
authors.forename: B V
authors.initials: BV
authors.lastname: Taylor
authors.forename: F R
authors.initials: FR
authors.lastname: Zhang
authors.forename: S
authors.initials: S
authors.lastname: Tang
authors.forename: A L
authors.initials: AL
authors.lastname: Bognar
mesh_terms: D000446:Aldehyde-Lyases; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D005656:Fungal Proteins / Q000235:genetics*; D015870:Gene Expression; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D005998:Glycine / Q000378:metabolism*; D012696:Glycine Hydroxymethyltransferase / Q000235:genetics*; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D005656:Fungal Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D012696:Glycine Hydroxymethyltransferase; D000446:Aldehyde-Lyases; C086382:GLY1 protein, S cerevisiae; D005998:Glycine