Figure 3.

In defolliculated oocytes (DEs) expressing epidermal growth factor receptor (EGFR)–Grb7, integrin inhibition rescues germinal vesicle breakdown (GVBD). Stage VI Xenopus oocytes deprotected from follicular cells (D), and expressing EGFR were stimulated or not by EGF (5 nM), 1 h after microinjection with Grb7 (20 ng), with or without SH2 domain of Grb7 60 ng, and before an incubation or not with 500 nM of integrin inhibitor echistatin (Echist) for 12 h. A, the GVBD attesting for meiosis progression (maturation) was scored. B, the GVBD₅₀ representing the time of half-responsive DE oocytes to undergo GVBD was determined. C and D, immunoprecipitations were performed with anti-EGFR or anti-GST-Grb7 antibodies. Western blots were performed with antibodies against EGFR, phospho-tyrosine (P-Tyr), O-GlcNAcylation (O-GlcNAc), GST (Grb7-GST), O-linked N-acetylglucosamine (GlcNAc) transferase (OGT), and integrin β1. Experiments were performed on three different females. Statistical significance against DE was accepted for ∗p < 0.05 and ∗∗p < 0.01. GST, glutathione-S-transferase.