| |
Fig. 3. Whole-mount in situ hybridization analysis of Hoxb4 (purple stain) and XRap1 (light blue stain) expression. (A) A gastrula stage embryo (stage 10.5) with the blastopore on the right. XRap1 staining is predominately in the dorsal ectoderm (which gives rise to the neural plate). No Hoxb4 expression is observed at this stage. (B) A late gastrula/early neurula stage embryo (stage 12, lateral view with the dorsal side down). Hoxb4 expression is apparent on the ventral/posterior side of the embryo and extends into the neural plate. XRap1 expression is confined to the neural plate. (C) Lateral view of a neurula (stage 20) embryo, anterior to left and dorsal side uppermost. XRap1 expression persists in the whole of the neural tube with the exception of the Hoxb4 expressing cells, roughly midway along the axis. (D) Lateral view of the anterior most (head) end of an early tailbud (stage 24) embryo. XRap1 staining is in the anterior neural tube including the eye, and abuts the area of Hoxb4 expression. (E) Lateral view of a tailbud (stage 28) embryo, anterior to left. (F) Enlargement of the anterior end of the embryo shown in (E). XRap1 and Hoxb4 expression domains abut closely in the hindbrain just posterior to the otic vesicle and in the head mesenchyme, where a stripe of Hoxb4 expression (*) marks the fourth pharyngeal arch. bp, blastopore; dbl, dorsal blastopore lip; ey, eye; ov, otic vesicle. |
