Proteins of the Drosophila melanogaster male reproductive system: two-dimensional gel patterns of proteins synthesized in the XO, XY, and XYY testis and paragonial gland and evidence that the Y chromosome does not code for structural sperm proteins.

Abstract

Testes and paragonial glands of Drosophila melanogaster wild-type males were labeled in vitro using (35S)methionine, and the proteins synthesized were analyzed by 2-dimensional gel electrophoresis. Testes and paragonial glands were also labeled in vivo by feeding male larvae 35S-labeled yeast and then dissecting the adult males. Approximately 1200 proteins were resolved by autoradiography of the gels. The in vitro method was shown to be more sensitive and to allow faithful synthesis of all proteins produced in vivo. [3H]Proline was also used to label testes, and no significant differences from the 35Spattern were noted. Testes and paragonial glands from XO and XYY males were labeled in vitro with [35S]methionine, and the proteins synthesized were compared to those produced by wild-type males of identical autosomal background. No differences attributable to the Y chromosome could be detected in the testes or paragonial gland samples. Pure sperm were dissected manually from in vivo labeled males and the proteins analyzed. Ninety-two proteins were detected, which were all synthesized in comparable amounts by XO, XY, and XYY males, showing that the Y chromosome does not code for any of these structural sperm proteins. It is postulated that no Y chromosome products were detected because they are organizational or regulatory proteins present only in very small amounts in the adult testes. 35S-labeled males were also mated to unlabeled females and the transferred proteins analyzed on two-dimensional PAGE. The contributions of the testis and paragonial gland to the ejaculate were determined.