Lateral views (A–C, F, K), posterior views (D, G), ventro-distal view (H), transverse section (E), and sagittal sections of panel F (I, J) of representative embryos expressing Npe at indicated stages. From early bud to the somite stages, Npe was expressed in the posterior notochord (boundary marked by arrowheads in E, J) and node region in the distal tip of the embryo (A–K). At 7 somites, Npe was expressed in the posterior of the embryo (K). Early bud (EB), early head fold (EHF), late head fold (LHF), somite (so.). 0 somites (E8.0), 7 somites (E8.5).