Cloning of the orotidine 5'-phosphate decarboxylase (ODC) gene of Schwanniomyces occidentalis by complementation of the ura3 mutation in S. cerevisiae.

A DNA fragment containing the gene encoding orotidine 5'-phosphate decarboxylase (ODC) from the yeast, Schwanniomyces occidentalis (formerly castellii) has been isolated from a genomic library constructed in the S. cerevisiae expression vector, pYcDE8. A recombinant plasmid, p2-1A, containing a 2.47 kb insert was shown to complement the ura3-52 mutation of several strains of S. cerevisiae. This DNA insert was shown to be from Schwanniomyces occidentalis by Southern hybridization analysis. A restriction enzyme cleavage map of the insert has been derived and the ODC gene localized to a 1.1 kb region by deletion analysis. In addition, we have demonstrated that expression of ODC is not dependent on the ADH1 promoter carried on pYcDE8. This is the first report of the cloning of a gene from a member of the genus Schwanniomyces.