Protein phosphatase 1 gamma 2 is associated with nuclei of meiotic cells in rat testis.

We have shown that there are at least 4 isotypes of the catalytic subunit of type 1 protein phosphatase (PP1), PP1 alpha, PP1 gamma 1, PP1 gamma 2 and PP1 delta by rat cDNA cloning. Among these, PP1 gamma 2 mRNA was found to be abundant in rat testis. To study the roles of PP1 gamma 2 in rat spermatogenesis, we raised an antibody against a synthetic 21 mer peptide corresponding to the predicted amino acid sequence of the C-terminal region of the PP1 gamma 2. The antibody interacted with a testicular protein of 39-kDa prepared from rats after puberty (25 days after birth). However, the antibody did not interact with proteins extracted from the immature testes or from other tissues examined. Indirect immunofluorescent staining of PP1 gamma 2 of the seminiferous tubules from rats of various ages and costaining with DNA showed that the protein is located in the nuclei of late spermatocytes and of early spermatids. We suggest that PP1 gamma 2 plays some role in meiotic division during spermatogenesis.