Whole mount in situ hybridization analysis with Fgf8 (A, D, G, J, M, P), Barx1 (B, E, H, K, N, Q) and Dlx5 (C, F, I, L, O, R) probes on E10.5 (A-I) and E11.5 (J-R) of control (A-C and J-L), Prx1+/-;Prx2-/- (D-F and M-O) and Prx1;Prx2 double mutant (G-I and P-R) heads.
A is a frontal view of E10.5 head showing expression of Fgf8 in the mandibular epithelium of the lateral region (A). The medial boundary of the expression of Fgf8 in the mandibular epithelium (indicated by arrows) in the Prx1/Prx2 double mutants (G) is extended into the medial region as compared to control (A). The medial boundary of the expression of Fgf8 in the mandibular epithelium of Prx1+/-;Prx2-/- (D) is intermediate between those in the control and Prx1/Prx2 double mutants.
Expression of Barx1 and Dlx5 in the mandibular processes is restricted to the lateral mesenchyme in the controls (B, C) and extended more into the mesenchyme of the medial region in the Prx1+/-;Prx2-/- (E, F) and Prx1/Prx2 double mutants (H, I).
J, M and P are top views of mandibular processes showing Fgf8 expression in E11.5 embryos. Note that in control embryos Fgf8 is expressed in presumptive incisors (circles) and molars (J). M and P are views of mandibular processes from Prx1+/-;Prx2-/- and Prx1;Prx2 double mutant showing that the expression of Fgf8 is detected in the molars but not in the incisors. Note that the expressions of Barx1 and Dlx5 in the Prx1;Prx2 double mutant (Q, R) are extended into the medial region as compared to controls (K, L). Scale bars =1 mm.