Figure 1.

Oocytes induced to mature with cdc2 exhibit reduced levels of XFGFR protein when depleted of c-mos. Intact or c-mos–depleted oocytes were induced to mature by injection of recombinant cdc2/cyclin B (cdc2/B1), and some oocytes were also injected with in vitro synthesized mos RNA. Immature and progesterone-matured oocytes are included for comparison. (Top panel) Extracts of oocytes were assessed for XFGFR translation by Western analysis with the Ab50 antibody. (Second panel) mos protein levels were determined in the same oocyte extracts as in the top panel by immunoprecipitation with a polyclonal anti-mos^Xe antibody (Santa Cruz Biotechnology), followed by Western analysis with a monoclonal anti-mos antibody (5S). The upper band in all lanes is the immunoglobulin G pulled down in the immunoprecipitation step. (Third panel) The stage of oocyte arrest was inferred from the level of cdc2 activity in oocyte extracts, as assayed in vitro with exogenously provided histone H1 as a substrate for cdc2. (Bottom panel) XFGFR mRNA levels were assessed by RNase protection analysis.