Xenbase Image ID: 48082

Fig. 1. Onset of Xsna expression in Xenopus mesoderm and ectoderm. Distribution of Xsna blastulae and gastrulae shown by in situ hybridisation under dark field illumination, with corresponding bright field views below. A-D, and F are sagittal sections with the most dorsal side on the left in D and on the right in F. Scale bar = 400 pm in A-D, F; 190 pm in E. A: Stage 9. First appearance of Xsna transcripts, in most- vegetal tier of marginal zone (z) on dorsal side (d), before external blastopore formation. B: Stage 10. Labelling is more intense and extensive on dorsal side (d) in involuted mesoderm (i) above forming blastopore lip (b). Arrows indicate movement of mesoderm. Xsna transcripts are also in most-vegetal tier of ventral (v) marginal zone (2). C: Stage 10.5. Xsna transcripts detected in involuting suprablastoporal endoderm (superficial layer of marginal zone; se, small arrowheads) and in all involuted mesoderm (i), but not in un-involuted mesoderm (u), with a sharp boundary to the labelling (large arrowheads) in blastopore lip (b). D: Stage 11. Involuting suprablastoporal endoderm (se, small arrowheads) and involuted mesoderm (i) are labelled. First appearance of Xsna transcripts in ectoderm (ec, arrows). E: Stage 11.5. Sharp boundary (large arrowheads) between expressing involuted mesoderm (i) and non-expressing un-involuted prospective mesoderm (u) still found in blastopore lip in mid-gastrulation. Ectoderm (ec) containing Xsna transcripts indicated (arrows). F: Stage 12. Mesoderm (m) lining nearly entire late-gastrula contains Xsna transcripts, including pre-chordal mesoderm (pm) anteriorly (a). Arrows indicate ectodermal (ec) Xsna expression. a = anterior; ac = animal cap; b = blastopore lip; bc = blastocoel: d = dorsal; e = endoderm; ec = ectoderm; i = involuted mesoderm; m = mesoderm; p = posterior; pm = pre-chordal mesoderm; se = suprablastoporal endoderm; u = un-involuted prospective mesoderm; v = ventral; z = marginal zone. Image published in: Essex LJ et al. (1993) Copyright © 1993. Image reproduced with permission of the Publisher, John Wiley & Sons. Gene Synonyms Species Stage(s) Tissue snai2.L slug, snai2-a, snai2-b, Snail2, xSlu, xslug, XSnail2 X. laevis Sometime during NF stage 9 to NF stage 10 vegetal dorsal marginal zone snai2.L slug, snai2-a, snai2-b, Snail2, xSlu, xslug, XSnail2 X. laevis Throughout NF stage 10 involuted dorsal mesoderm snai2.L slug, snai2-a, snai2-b, Snail2, xSlu, xslug, XSnail2 X. laevis Throughout NF stage 10.5 superficial marginal zone involuted dorsal mesoderm involuted ventral mesoderm blastopore lip snai2.L slug, snai2-a, snai2-b, Snail2, xSlu, xslug, XSnail2 X. laevis Throughout NF stage 11 superficial marginal zone involuted dorsal mesoderm involuted ventral mesoderm ectoderm snai2.L slug, snai2-a, snai2-b, Snail2, xSlu, xslug, XSnail2 X. laevis Throughout NF stage 11.5 mesoderm involuted dorsal mesoderm involuted ventral mesoderm blastopore lip ectoderm snai2.L slug, snai2-a, snai2-b, Snail2, xSlu, xslug, XSnail2 X. laevis Throughout NF stage 12 mesoderm anterior Image source: Published Larger Image Printer Friendly View

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