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Fig. 2. Ectopic expression of XCyp26 or dnRAR inhibits pronephros formation and expression of pronephros marker genes. Four-cell stage embryos were injected with XCyp26 (D–F) or dnRAR (G–I) encoding mRNA together with LacZ mRNA into the four blastomeres (A–I) or the two blastomeres fated to give rise to the left side (J–L). In the later case, the right side of the embryo is used as an internal control. A–I: In situ hybridization (purple staining) for XPax-2 (A, D, G) XSMP-30 (B, E, H) and XWT-1 (C, F, I). X-gal staining is revealed in red (D–I). In control embryos, XPax-2 is expressed in the tubules and the duct while XSMP-30 is restricted to the tubules and XWT-1 expressed in the glomus. No signal for these genes in either of theses structures was detected. J–L: Transverse histological section of tadpole stage 38. Several pronephric tubules (red circle) are clearly visible on the control side (K, and high magnification in panel J) whereas none is observed on the injected side (K, and high magnification in panel L). |
