Fig. 3.

FOXB2-dependent Wnt signaling requires multiple protein domains. (A) FOXB2 mutation or truncation decreased its TOPflash activity in 293T cells, except for a G277A mutation. Numbers indicate amino acid positions. Major protein features are shown in the inset cartoon. FKH, forkhead domain; NLS, nuclear localization sequence; EH1, engrailed homology 1 motif. (B) qPCR analysis in 293T cells showed that FOXB2 N- or C-terminal truncation blocked WNT7B induction. (C) A FOXB2/B1 chimera with the central domain of FOXB1 was largely inert in TOPflash activation, similar to FOXB1. Protein expression levels in A–C were generally comparable for all constructs (SI Appendix, Fig. S3 B and C; *P < 0.05, **P < 0.01, and ***P < 0.001 versus control).