Figure 8.

Irx3 is sufficient for intermediate tubule formation in the Xenopus pronephric kidney. Single V2 blastomeres of eight-cell-stage embryos were injected with irx3 mRNA (0.15 ng). Injected embryos were raised to the embryonic stage indicated, fixed, and processed for β-gal activity. Expression of the slc12a1 marker gene was subsequently visualized by in situ hybridization. Lateral views of control and injected sides of two representative embryos displaying the gain-of-function phenotype are shown with accompanying enlargements of the pronephric kidney region. The arrowheads indicate the ectopic intermediate tubule tissues expressing slc12a1.