Isolation and characterization of the Saccharomyces cerevisiae MIS1 gene encoding mitochondrial C1-tetrahydrofolate synthase.
C1-Tetrahydrofolate synthase is a trifunctional polypeptide found in eukaryotic organisms that catalyzes 10-formyltetrahydrofolate synthetase (EC 6.3.4.3), 5,10-methenyltetrahydrofolate cyclohydrolase (EC 3.5.4.9), and 5,10-methylenetetrahydrofolate dehydrogenase (EC 1.5.1.5) activities. In Saccharomyces cerevisiae, C1-tetrahydrofolate synthase is found in both the cytoplasm and the mitochondria. The gene encoding yeast mitochondrial C1-tetrahydrofolate synthase was isolated using synthetic oligonucleotide probes based on the amino-terminal sequence of the purified protein. Hybridization analysis shows that the gene (designated MIS1) has a single copy in the yeast genome. The predicted amino acid sequence of mitochondrial C1-tetrahydrofolate synthase shares 71% identity with yeast C1-tetrahydrofolate synthase and shares 39% identity with clostridial 10-formyltetrahydrofolate synthetase. Chromosomal deletions of the mitochondrial C1-tetrahydrofolate synthase gene were generated using the cloned MIS1 gene. Mutant strains which lack a functional MIS1 gene are viable and can grow in medium containing a nonfermentable carbon source. In fact, deletion of the MIS1 locus has no detectable effect on cell growth.
Shannon
K W
KW
Department of Biochemistry, University of California, Berkeley 94720.
Rabinowitz
J C
JC
D000595:Amino Acid Sequence; D001483:Base Sequence; D004262:DNA Restriction Enzymes / Q000378:metabolism; D005574:Formate-Tetrahydrofolate Ligase / Q000235:genetics*; D005800:Genes, Fungal; D008025:Ligases / Q000235:genetics*; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics
D004262:DNA Restriction Enzymes; D008025:Ligases; D005574:Formate-Tetrahydrofolate Ligase