We have identified a novel putative protein kinase-encoding gene from Schizosaccharomyces pombe (Sp), designated psk1+, by using a highly conserved amino acid (aa) sequence motif to design amplification of DNA fragments using PCR. The putative translation product of psk1+ contains 436 aa, with a molecular mass of 49,317 Da. A single psk1+ was identified by genomic Southern blot analysis, and the genomic mapping indicated that psk1+ was localized in Sp chromosome III. Growth of wild-type Sp cells was inhibited by 0.5 microM phenylarsine oxide, a protein tyrosine phosphatase inhibitor, but psk1- cells were relatively resistant to this drug.