Cloning of theILV2, ILV3 andILV5 genes of Saccharomyces cerevisiae

The molecular analysis of theILV genes which code for enzymes catalyzing steps in the biosynthesis of isoleucine and valine, is a prerequisite for the eincidation of the pathway-specific and general amito acid control mechanisms regulating isoleucine and valine biosynthesis in Saccharomyces. TheILV2, ILV3 andILV5 genes of Saccharomyces cerevisiae have been cloned by complementation of mutations in these genes. Southern hybridization analysis shows that the cloned genes represent unique sequences of the wild-type genome of S. cerevisiae. The identity of the cloned genes is demonstrated by their specificity in the complementation of a collection of mutant alleles of theILV genes and by site-directed integration of the cloned fragments at theILV loci.