Ectoderm deletion of <i>Wntless</i> leads to loss of cranial bone and dermal lineage markers in the mesenchyme.

<p>Indirect immunofluorescence with DAPI-stained (blue) nuclei was performed on coronal mouse embryonic head sections at E12.5 or as indicated (A,B, F, G, H, I, M, N, P, R, T, V). Alkaline Phosphatase staining (C, J), in situ hybridization (D, E, K, L, O, S), or β-galactosidase staining with eosin counterstain (Q, U) was performed on coronal tissue sections. Diagram in (A) demonstrates plane of section and region of interest for E12.5-E13.5 (A–T). Box and dashed lines in (Q, U) demonstrate the region of high magnification, and β-galactosidase stained sections were included for perspective for (R, V). Diagram inset in high magnification photograph from (Q) shows plane of section and region of interest for E15.5. Red arrows indicate changes in marker expression and black arrows in (U) high magnification indicate ectopic cartilage. Scale bars represent 100 µm.