Fig. 4.

Somatic cells regulate Il7 mRNA translation and IL7 protein secretion. (A) Ratio of renilla luciferase (RL) to firefly luciferase (FL) activity in oocytes cultured as denuded oocytes (DOs) or cumulus oocyte complexes (COCs). Oocytes were injected with two reporters and cultured as detailed in Fig. 3 with or without amphiregulin (AREG, 100 nM) for 17 h. At the end of the incubation, luciferase activity was measured in oocyte extracts. Error bars correspond to the SEM, and data are from at least three experiments from biologically different samples. *P < 0.05 vs. DO GV; ^#P < 0.05 vs. COC GV; **P < 0.05 vs. COC MII, two way ANOVA. (B) IL7 protein levels in spent media during oocyte maturation. Denuded oocytes (DOs), COCs, and cumulus cells (CCs) were incubated in maturing media with or without amphiregulin (AREG, 100 nM) for 20 h; culture supernatant was collected, and IL7 levels were measured by ELISA. Error bars correspond to the SEM, and data are from at least three experiments from biologically different samples. ND, not detectable. *P < 0.05 vs. DO MII; **P < 0.05 vs. DO MII+AREG; ^#P < 0.05 vs. COC MII, ANOVA. (A, Inset) Bmp6 3′ UTR reporter translation during oocyte maturation. Ratio of RL to FL activity in oocytes cultured as COCs. Oocytes still in complex with cumulus cells were injected with two reporters, one coding for RL under the control of Bmp6 3′ UTR and one coding for FL with a polyadenylated 3′ UTR as the control. COCs were cultured as detailed in Fig. 3 with or without amphiregulin (AREG, 100 nM) for 17 h. At the end of the incubation, luciferase activity was measured in oocyte extracts. Error bars correspond to the SEM, and data are from at least three experiments from biologically different samples. NS, Not significant, two way ANOVA.