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Fig. 1. Conserved boundaries of expression of GATA factors in the nonneural ectoderm of frog and fish gastrulae. Double whole-mount in situ hybridizations of Xenopus early neurula embryos stained for GATA-2 (a,c,e,g) or GATA-3 (b,d,f,h) with the anterior neural marker, Otx2 (a and bJ, the hindbrain marker Krox20 (c and d), the spinal cord marker HoxB9 (e and f) and neural crest marker, slug (g and h). Anterior is to the left and posterior to the right except for a and b which are anterior views, (a) Embryo stained for Otx2 (turquoise) and GATA-2 (purple). At the most anterior end GATA-2 is expressed in the cement gland and abuts Otx2 whereas more posteriorly a gap can be seen between GATA-2 and Otx2 (asterisk). (b) Double staining for GATA-3 (purple) and Otx2 (turquoise). At the most anterior end GATA-3 expressed in the cement gland overlaps the expression of Otx2. More posteriorly, a gap exists between GATA-3 and Otx2 expression (asterisk). (e) Dorsal view of an embryo stained for GATA-2 (purple) and Krox 20 (turquoise) marking rhombomeres 3 and 5 of the hindbrain (r3 and (5). A gap can be seen between GATA-2 and Krox20 expression in r5 (arrow). (d) Dorsal view of an embryo stained for GATA-3 (purple) and Krox20 (turquoise). A gap is seen between GATA-3 and Krox20 staining In r5 (arrow). (e and f) Lateral view of embryos stained for GATA-2 and 3 (purple) and HoxB9 (B9, turquoise). Note that GATA-2 is expressed more posteriorly than GATA-3. (g and h) Dorsal views of embryos stained for GATA-2 (purple, g) or GATA-3 (purple, h) and the neural crest marker slug (turquoise, g and h). Note the gap between GATA and slug expression (asterisk, g and h). (i and j) Double whole-mount in Situ hybridization of Xbra (turquoise, i and j) with GATA-2 (dark blue, i) and GATA-3 (dark blue, J) In Xenopus mid-gastrula embryos (the notocordal Xbra signal is not yet visible, stage 11). Note that GATA-2 abuts Xbra expression, (i), but a gap is seen between GATA-3 and Xbra expression, (arrow, j). yp, yolk plug; d, dorsal; v, ventral; anterior is to the left. (k) A 70% epiboly (gastrula) zebrafish embryo, stained for gta2 (blue) and ntl (red). gta2 expression abuts ntl at all gastrula stages. (I) An intact 70-80% (gastrula) zebra fish embryo stained for gta3 (blue) and ntl (red). Note the gap between gta3 and ntl (arrow), This gap is also seen at eartier gastrula stages (data not shown). At late gastrula, ntl is expressed in the notochord (noto). (m) 17 mm saggital section through the region marked by the arrow in l showing the gap (arrow) between gta3 (blue) and ntl (red) expression. a, anterior; p, postenor; v, ventral. (n) A flat mount of a zebrafish embryo stained for gta3 (blue) and dlx3 (expressed strongly in pIa codal tissue at this stage) and pax2 (a marker of the midbrain/hindbrain border) both stained in red. Note the gap between dlx3 and pax2 staining representing neural crest. a, anterior; p, posterior; v, ventral. (0) Diagrammatic representation ofaXenopus/zebrafish gastrula embryo showing the boundaries of expression of GATA-2 and 3 between neural and nonneural ectoderm and between nonneural ectoderm and mesoderm which are conserved between the two species. |
