The TRβ-VDR does not rescue impaired canonical Wnt signaling in vdr−/− primary keratinocytes. A, primary vdr−/− keratinocytes were cotransfected with Renilla luciferase, TOPflash luciferase, β-catenin, and LEF1 along with pcDNA, the wild-type VDR, or the TRβ-VDR. After 24 h, Wnt reporter activity (TOPflash) was quantitated. Firefly luciferase was normalized for cotransfected Renilla luciferase. B, COS-7 cells were cotransfected with Renilla luciferase, VDRE-luciferase, and the wild-type VDR or TRβ-VDR. After 18 h of treatment with 10−8 or 10−9 m vitamin D, VDRE-luciferase reporter activity was quantitated. Firefly luciferase was normalized for cotransfected Renilla luciferase. Results are an average of at least three independent transfections. *, p ≤ 0.05; **, p ≤ 0.005. Panels to the right are Western analyses demonstrating expression of the VDR and TRβ-VDR proteins.