||Figure 1. Expression of pkd2 mRNA during Xenopus Embryogenesis.
(A–C) Maternally deposited mRNA localized to the animal hemisphere of the zygote (A, A′) and four-cell stage embryos (B). Note animal-vegetal shift of expression as indicated in the zygote. (C) Lack of a specific signal in specimen hybridized with a sense probe.
(D–F) pkd2 transcripts in deep mesodermal layers of the early gastrula (D, D′, D′; black arrowheads; plane of section indicated in D by dotted line), in dorsal notochordal mesoderm at mid gastrula (E), and in tail organizer (white arrow) and posterior notochord at late gastrula stages (F, F′). Please note the lack of transcripts in the dorsal lip and the SM (white arrowheads). Border of inner and outer layer of marginal zone indicated by dotted line. Yolk plug and archenteron roof indicated by dashed lines.
(G) Deep neuroectodermal, tail organizer, and posterior notochordal expression at neurula stages; no expression of GRP detected (G4).
a, anterior; an, animal; ar, archenteron; bf, blastocoel floor; cbc, circumblastoporal collar; dl, dorsal lip; e, endoderm; el, epithelial layer (of cbc); l, left; n, notochord; ne, neuroectoderm; psm, presomitic mesoderm; r, right; s, somites; v, ventral; veg, vegetal; yp, yolk plug.