SPERMATOCYTES AND ROUND SPERMATIDS OF RAT TESTIS - PROTEIN-PATTERNS

Spermatogenesis is a process in the testis that involves meiotic cell division and spermiogenesis. The mechanisms of regulation and its asso ciated proteins are mostly unknown. This publication shows the two-dim ensional (2-D) gel electrophoresis protein map obtained from rat testi s using nonlinear 3.5-10 immobilized pH gradients for the first-dimens ional separation. Eighteen proteins were successfully identified in th e SWISS-PROT protein database using amino acid analysis of proteins re covered from polyvinylidene difluoride (PVDF) membranes and verified f or one of them by comparison with Anderson's rat liver reference map. Fourteen new polypeptides were identified and four were previously kno wn. Two of these new proteins were closely related to the spermatogene tic process. T-complex protein 1 is expressed in large amounts in germ cells. Androgen-dependent sperm-coating glycoprotein is secreted by e pididymal cells. In order to detect changes in protein expression duri ng meiosis and spermiogenesis, spermatocytes and round spermatid cell populations were purified by centrifugal elutriation and compared. In this way several proteins not found in the spermatocyte 2-D images cou ld be highlighted. The sperm-coating glycoprotein was thus shown to be present in large amounts in round spermatids.