Identification of protein tyrosine phosphatases expressed in murine male germ cells.

We cloned five cDNAs encoding putative protein tyrosine phosphatases (PTPs; protein-tyrosine-phosphatase phosphohydrolase, EC 3.1.3.48) from the murine testis by using degenerate primers and the polymerase chain reaction cloning technique. Two of them were identical to the mouse cytoplasmic PTP and PTP-1B. The remaining three were likely to represent the murine counterparts of human PTP delta, human PTP epsilon, and rat striatum-enriched PTP. The cells expressing these genes were determined either by in situ hybridization histochemistry or by Northern blot hybridization. Moreover, Northern blot hybridization revealed that the transcripts of PTP-1B, mouse cytoplasmic PTP and the murine homologue of human PTP delta were quantitatively and/or structurally regulated during germ cell development, suggesting their roles in spermatogenesis.