Notch regulates Fgf20 expression. A, B E12.5 + 1 DIV explants in the absence and presence of DAPT were probed for Fgf20 mRNA. DAPT treatment decreased Fgf20 mRNA. C, Quantitative PCR analysis on E12.5 + 3 DIV explants confirms that DAPT treatment decreased Fgf20 expression. One-way ANOVA for correlated samples show statistical significance; *p < 0.05, n = 3 experiments. Fgf20 mRNA was probed by in situ hybridization in Jag1 conditional knockouts. D, E, Wild-type embryos showed Fgf20 expression (D) and no Fgf20 expression in Jag1 knockout littermates (E).