Expression of Wnt ligands, Wntless, and Wnt signaling response in cranial ectoderm and mesenchyme.

<p>(A, B) RT-PCR for individual Wnt ligands was performed on cDNA from purified mouse embryonic cranial mesenchyme and surface ectoderm. (C, D G, H) Indirect immunofluorescence with DAPI counterstained nuclei (blue), (E) <i>in situ</i> hybridization, or immunohistochemistry (F, I) was performed on coronal mouse embryonic head sections. (G, H, I) Boxes indicate region in insets at higher magnification. White arrowheads indicate co-expression of (G) Wls/Runx2 or (D,H) Lef1/Runx2, (I) red arrowheads indicate osteoblast progenitors, and blue arrowheads indicate dermal progenitors. (F–I) White hatched lines demarcate ectoderm from mesenchyme. (J) Summary scheme of E12.5 supraorbital cranial mesenchyme. (J) Embryonic axes, figure depicts lateral view of embryonic head, region of interest in sections used in figures are shown. Scale bars represent 100 µm.