Fig. 2. Normal expression patterns of Ras-dva and its transcriptional regulators, the homeobox genes Otx2 and Xanf1, in the gastrula and neurula stage Xenopus embryos as revealed by whole-mount in situ hybridization. All embryos are shown from the anterior, dorsal side upwards. Broken line indicates the neural plate border. (A) At midgastrula (stage 11) the Ras-dva is diffusely expressed within a broad territory that includes the presumptive anterior neural and non-neural ectoderm. (B) At late gastrula (stage 12.5) the Ras-dva expression weakens in the area corresponding to the anterior neural plate but it increases in the surrounding area. (C) At the midneurula (stage 14) Ras-dva is expressed in cells of the non-neural anterior ectoderm and in the lateral neural folds. (D-F) Normal expression patterns of the homeobox genes Otx2 and Xanf1. Although Ras-dva and Xanf1 are expressed in mutually excluding domains, the expression domains of Ras-dva and Otx2 are largely overlapping. (G,H) The results of in situ hybridization in halves of Xenopus embryos on the 12.5 and 14 stages. Left halves show the expression of Otx2 gene, right halves show Ras-dva expression. (I) The Xenopus embryo (stage 13) in which the left half is stained for Xanf1 expression and the right half is stained for Ras-dva expression. (J) The scheme of expression patterns of Ras-dva, Otx2 and Xanf1 at the midneurula stage (stage 14).