Fig. 5.

dmECR enhancer activity overlaps endogenous Hmx1 protein localization. (A,I,P) Diagrams of E10.5 (A), E11.5 (I) and E14.5 (P) mouse embryos highlighting the different transverse sections displayed in B-H (E10.5), J-O (E11.5) and Q-X (E14.5). (B-H,J-O,Q-X) Comparison of endogenous mouse Hmx1 expression (brown) with dmECR enhancer activity, visualized by staining with X-gal (blue), in transverse cryosections at E10.5, E11.5 and E14.5. (G-H) dmECR and Hmx1 expression domains overlap in the anterior (G,G′) and posterior (H) regions of the exterior portion of BA2 at E10.5 (red arrows). (J) At E11.5, sectioning showed overlap between dmECR staining in the craniofacial mesenchyme (CM) of the lateral face with the rostral CM expression of endogenous Hmx1 (black arrows). (K) E11.5 dmECR staining overlaps endogenous Hmx1 in dorsal BA1 (black arrows). (N) Few cells share dmECR and Hmx1 expression domains in the CM of the anterior region of BA2 (black arrow) at E11.5. (O) Posteriorly, dmECR and Hmx1 expression domains were regionally restricted to the dorsal domain of BA2 at E11.5 (black arrows). (Q,S-V) Adjacent to the ear, overlapping dmECR and Hmx1 staining is evident (asterisks). In the ear, the ventral dmECR activity was almost distinct from the small dorsal region of endogenous Hmx1 expression (arrows). (R) Overlap in dmECR activity and endogenous Hmx1 was evident in the caudal region of the trigeminal ganglion (tg). (V′-X) Overlap in dmECR and Hmx1 expression was also apparent in the eye (V′), the frontonasal region (W) and CM of the lateral face (X). BA1-3, branchial arches 1-3; Bc, branchial cleft; fac, facial acoustic complex; fn, facial nerve; fv, fourth ventricle; gg, geniculate ganglion; l, lens; lp, lens placode; nc, nasal capsule; ns, nasal septum; oc, optic cup; or, optic recess; os, optic stalk; ot, otic vesicle; ov, otic vesicle; p, pinna; sag, statoacoustic ganglion; tv, telencephalic vesicle. Scale bars: 100 µm.