XB-IMG-1758
Xenbase Image ID: 1758
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Fig. 9. Placodal gene expression patterns in early tail bud Xenopus embryos (stages 21–22) in lateral views (anterior is to the left) and right frontal views (inserts). Color-coded arrows and arrowheads are used for the identification of comparable regions of gene expression. Expression in the prospective lens placode (which is not yet thickened at this stage) is indicated by L. Colors are explained in the schematic drawing, which shows the distribution of placodes in a stage 21 embryo (modified after Schlosser and Northcutt, 2000; see Fig. 14 for detailed explanation). The unpaired adenohypophysial placode is located medial to the ventral part of the olfactory placode and is, thus, hidden behind the olfactory placode in this lateral perspective (indicated by light green arrow and Ad in brackets). Various shades of green identify placodes (including the prospective lens placode) expressing Pax6, yellow identifies the profundal placode expressing Pax3, and brown and pink jointly identify the posterior placodal area expressing Pax2 and Pax8, with pink being reserved for the subregion, which will form the otic vesicle. Blue–green asterisks indicate downregulation of the respective genes in the region of the prospective lens placode, whereas brown asterisks indicate downregulation of the respective genes in a region intervening between the anterior and posterior subregions of the posterior placodal area. The pink and brown asterisks in I indicate downregulation of FoxI1c expression in the dorsal part of the posterior placodal area. For detailed description, see text. For additional abbreviations, see Fig. 1. Image published in: Schlosser G and Ahrens K (2004) Copyright © 2004. Image reproduced with permission of the Publisher, Elsevier B. V.
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