Analysis of the cytosolic proteins of chick embryo gonads by two-dimensional gel electrophoresis.

Gonads and mesonephros dissected from normal chick embryos, as well as a blood sample, were labelled in vitro with [35S]methionine and [14C]leucine. The patterns of cytosolic protein synthesis of the different tissues were analysed using two-dimensional (2-D) polyacrylamide gel electrophoresis. Three developmental stages, i.e. 8, 12 and 17 days of incubation, were investigated. Five sex-specific proteins were detected in the male and two in the female. In the testis, only one protein is already present at the 8-day stage. In the ovary, one protein exists since the 8-day stage, but it is also synthesized in the mesonephros. The second ovary-specific protein appeared only at the 12-day stage.