Fig. 7.

tfap2a and tfap2b function in a proposed genetic regulatory network to control distal nephron differentiation. (A) Schematic comparing DE progenitor maturation in wild-type embryos and trm mutants. Mutant cells display no perturbations in specification of the renal lineage. Mutant progenitors undergo segment specification and exhibit features of mature epithelium. In the final phase of differentiation, mutant cells fail to express DE-specific solute transporters. (B) Diagram depicts proposed tfap2a distal nephron gene regulatory network. irx3b promotes tfap2a expression (green), and tfap2a functions upstream of irx1a (orange). irx1a promotes expression of kcnj1a.1 and slc12a1 (teal). tfap2a acts upstream of tfap2b as the core regulator of solute transporter expression (orange). tfap2b functions redundantly (purple) to activate distal solute transporters.