(A, D) Dorsal views of Tg(islet1:GFP) hindbrains processed for vangl2 in situs (purple) and anti-GFP immunostaining to label FBM neurons (brown). The level of the cross-sections is indicated by the broken lines. (B, E) vangl2 is expressed broadly in the endoderm, mesoderm and within the neural tube, including the floor plate (fp, black arrowhead). Some FBM neurons (white arrowhead) are immediately adjacent to the floor plate cells. (C, F) FBM neuron cell bodies and processes (white arrowhead) contact floor plate cells marked by shh expression (purple). n, notochord; oto, otocyst.