Figure 1.

Ablation of Esr1 in the uterus epithelium leads to a defect in stromal cell decidualization. A, Uteri were collected from day 4 pregnant Esr1^fl/fl and Esr1^d/d mice. Uterine sections were subjected to IHC using an anti-ESR1 antibody targeting the C terminus of ESR1. Esr1^d/d mice displayed efficient deletion of ESR1 (b) when compared to Esr1^fl/fl control mice (a). B, Esr1^fl/fl and Esr1^d/d mice were subjected to experimentally induced decidualization. Uteri were collected 72 hours after administration of oil stimulus. Esr1^d/d uteri failed to give a decidual response. C, Ratio of wet weight gains of right and left horns. **, P < .01. D, ALP activity, indicated by purple color, was detected in the decidualized stroma of Esr1^fl/fl uteri (a) but not in the stroma of Esr1^d/d uteri (b).