Fig. 5. Wnt-β-catenin signaling synergizes with that of Ppar to confer blastocyst competency for implantation. (A,B) Overexpressing levels of Dkk1 (A) or PKF115-584 (B) blocked activation of dormant blastocysts for implantation in response to E₂ (3 ng/mouse). Numbers within the bar indicate the number of mice with implantation sites (IS)/total number of mice examined. (C,D) Representative photomicrographs of uteri without blue bands (C, right) and morphologically dormant blastocysts (D) recovered from mice treated with PKF115-584. (E,F) Recombinant Wnt3a protein (200 ng/ml) induced nuclear stabilization of active dephosphorylated β-catenin and Ppar expression in dormant blastocysts in culture. Co-treatment of Wnt3a with Dkk1 (1 µg/ml) or PKF115-584 (1 µM) antagonized Wnt3a-induced β-catenin stabilization. Cy3-labeled antigens in red, SYTO-13-labeled nuclei in green, and merge in yellow. (G,H) Wnt3a and/or GW501516 conferred blastocyst implantation competency. Dormant blastocysts were cultured in the presence of vehicle, Wnt3a (200 ng/ml) and/or GW501516 (a selective Ppar agonist, 1 µM) for 24 hours before transfer into pseudopregnant delayed recipients. Numbers within the bar in G indicate the number of recipients with IS/total number of mice examined, and those in H indicate the number of IS/total number of blastocysts transferred; ^*P<0.05, Student's t-test. Scale bars: 50 µm.