Abnormal Sperm Development in pcd (3J)-/- Mice: the Importance of Agtpbp1 in Spermatogenesis

Homozygous Purkinje cell degeneration (pcd) mutant males exhibit abnormal sperm development. Microscopic examination of the testes from pcd (3J)-/- mice at postnatal days 12, 15, 18 and 60 revealed histological differences, in comparison to wild-type mice, which were evident by day 18. Greatly reduced numbers of spermatocytes and spermatids were found in the adult testes, and apoptotic cells were identified among the differentiating germ cells after day 15. Our immunohistological analysis using an antihuman AGTPBP1 antibody showed that AGTPBP1 was expressed in spermatogenic cells between late stage primary spermatocytes and round spermatids. A global gene expression analysis from the testes of pcd (3J)-/- mice showed that expression of cyclin B3 and de-ubiquitinating enzymes USP2 and USP9y was altered by > 1.5-fold compared to the expression levels in the wild-type. Our results suggest that the pcd mutant mice have defects in spermatogenesis that begin with the pachytene spermatocyte stage and continue through subsequent stages. Thus, Agtpbp1, the gene responsible for the pcd phenotype, plays an important role in spermatogenesis and is important for survival of germ cells at spermatocytes stage onward.