||Fig 3. Dse is expressed in the pre-migratory neural crest, anterior surface ectoderm, brain, and prechordal mesendoderm.
Embryos are shown in anterior view (A-D, G-L) and midsagittally sectioned through the head (E,F). (A-D) Early neurulae. Note Dse expression in the anterior neural ridge and prechordal mesendoderm. Dse transcripts overlap with Twist1 and Snai2 expression in the cranial neural crest (indented arrowheads). The bold line indicates the level of section in E. (E) Embryo at stage 18. Dse is expressed in the superficial layer of the anterior neural ridge and the inner layer of the fore- and midbrain anlage (arrows). The stippled line demarcates the border between the anterior neural plate and the underlying prechordal mesendoderm. (F) Absence of signals in the matching section of a sibling embryo that was probed with Dse sense RNA as control. (G) Late neurula at stage 24. Dse is expressed in the anterior neural ridge and derived sense plate. (H) Tailbud embryo at stage 26. Dse is transcribed in the sense plate. (I) Xag expression demarcates the cement gland and hatching gland. (J-L) Tailbud embryos at stages 27 and 28. Note segregation of anterior Dse expression into the stomodeum-adenohypophysis anlage and posterior domain that partially overlaps with the Pax3+ hatching gland. anr, anterior neural ridge; cg, cement gland; epi, epidermis; ey, eye; fb, forebrain; hg, hatching gland; mb, midbrain; no, notochord; pm, prechordal mesendoderm; se, sense plate; st, stomodeum-adenohypophysis anlage. Scale bars are 500 μm (A-D,G-L) and 50 μm (E,F).