Fig. 5. Conserved co-expression of ß-catenin/TCF/Lef targets in the renal epithelial lineage in vivo. (A) Ccnd1, Pax8 and Emx2 are expressed in epithelia deriving from the metanephric mesenchyme in vivo as determined by in situ hybridization on rat and mouse E15.5 kidneys. Ccnd1 and Pax8 are first activated in pretubular aggregates and maintained in nascent early epithelia. Emx2 is activated slightly later and appears first in early epithelia. Expression patterns are strictly conserved in the two species. (B) TCF/Lef-lacZ activity as determined by X-Gal staining is strong in emerging epithelia overlapping with the expression domain of target genes. Note that Pax8, Emx2 and the TCF/Lef reporter are also detected in the ureteric bud. SB, S-shaped body; PA, pretubular aggregate; UB, ureteric bud.