Fig. 4. XFast-3 is expressed in a narrow window at early and mid-gastrulation. (A) Total RNA was extracted from embryos at the times indicated and analysed by RNase protection using probes against XFast-1, XFast-3 or FGFR (loading control). The protected fragments are indicated, as are the undigested probes. The lane marked tRNA is a control for probe digestion. (B) XFast-1 and XFast-3 are expressed strongly in the animal cap and in the prospective mesoderm of stage 10.25 embryos. The embryos were bisected through the dorsal lip before in situ hybridisation using probes against XFast-1 or XFast-3. Specific staining is blue, and is strongest in the prospective mesoderm and ectoderm. The dark brown colour is the pigmented animal cap.
