Dipeptidyl aminopeptidase yspI mutants of Schizosaccharomyces pombe: genetic mapping of dpa1+ on chromosome III

Abstract

A mutant strain of Schizosaccharomyces pombe lacking dipeptidyl aminopeptidase yspI was isolated from a strain already defective in aminopeptidase activity by means of a staining technique with the chromogenic substrate ala-pro-4-methoxy-beta-naphthylamide to screen colonies for the absence of the enzyme. The defect segregated 2(+):2(-) in meiotic tetrads, indicating a single chromosomal gene mutation, which was shown to be recessive. Gene dosage experiments indicated that the mutation resides in the structural gene of dipeptidyl aminopeptidase yspI, dpa1(+). The dpa1(+) gene was located on chromosome III by using m-fluorophenylalanine-induced haploidization and mitotic analysis, dpa1 mutants did not show any obvious phenotype under a variety of conditions tested