title: DNA sequence of the beta-isopropylmalate dehydrogenase gene and phylogenetic analysis of the yeast Saccharomyces exiguus Yp74L-3.
abstract: The beta-isopropylmalate dehydrogenase (LEU2) gene from a homothallic wild-type yeast, Saccharomyces exiguus Yp74L-3, was analyzed to estimate the phylogenetic position of this strain in yeasts. The beta-isopropylmalate dehydrogenase gene of Yp74L-3 was first isolated as a clone complementing the leu2 mutation of Saccharomyces cerevisiae, and then confirmed to complement the haploid leu2 mutant derived from strain Yp74L-3 through genetic transformation. The nucleotide sequence of the cloned DNA revealed an open reading frame (ORF) encoding the beta-isopropylmalate dehydrogenase composed of 365 amino acids. The beta-isopropylmalate dehydrogenase coding sequence from the Yp74L-3 strain displayed 76.7% similarity to that of S. cerevisiae. Candidates for a UAS and a TATA-box in the 5'-upstream region and for a poly-A attachment site in the 3'-downstream region were found. A phylogenetic tree constructed from the nucleotide sequences of the beta-isopropylmalate dehydrogenase coding regions revealed that Yp74L-3 is located between S. cerevisiae and the Kluyveromyces yeasts. The LEU2 gene cloned from Yp74L-3 will serve as an effective genetic marker for constructing the transformation system in S. exiguus Yp74L-3.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Fukuyama University, Gakuen-cho, Fukuyama, Hiroshima 729-0292, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hisatomi
authors.forename: K
authors.initials: K
authors.lastname: Horio
authors.forename: T
authors.initials: T
authors.lastname: Mimoto
authors.forename: M
authors.initials: M
authors.lastname: Tsuboi