ISOLATION AND DNA-SEQUENCE OF THE STE13 GENE ENCODING DIPEPTIDYL AMINOPEPTIDASE

We have isolated a mutant which exhibits partial constitutivity for a- specific gene expression in a cells. The wild-type gene was cloned and demonstrated to be allelic to the STE13 gene, which encodes the dipep tidyl aminopeptidase involved in processing of the alpha-factor prepro pheromone. Thus, the mating defect of the ste13 mutations in a cells m ay result both from the production of incompletely processed alpha-fac tor and from the increased expression of a-specific genes. The STE13 o pen reading frame of 931 amino acids contains a putative membrane-span ning segment near its amino terminus and is 31% identical to a second yeast dipeptidyl aminopeptidase (DAP2). A null mutant of STE13 has bee n constructed: it is viable and sporulation-proficient. The sequence h as been deposited in the GenBank data library under Accession Number L 21944.