Figure 3. Distal ureter maturation defects in Ptprs^–/–Ptprf^ΔP/ΔP embryos.

Top: Diagrams of WT E11.5–E15.5 urogenital systems. (A–H) H&E-stained sagittal sections of representative control (A–D) and Ptprs^–/–Ptprf^ΔP/ΔP urogenital systems (E–H) at different developmental stages. At E11.5, no difference in CND length was observed between control (A) and Ptprs^–/–Ptprf^ΔP/ΔP embryos (E). CND length is indicated by dotted lines, distal ureter is indicated by solid lines. At E13.5 (B and F) and E14.5 (C and G), the distal ureter was in close apposition with the bladder epithelium in control embryos (B and C). In contrast, Ptprs^–/–Ptprf^ΔP/ΔP embryos harbored a distal ureter located away from the bladder (F and G). (D and H) At E15.5, distal ureter elimination allowed the ureter to reconnect into bladder (dotted white circle) in a normal control (D), while the distal ureter remained at a distance from the bladder epithelium in Ptprs^–/–Ptprf^ΔP/ΔP embryos (H). (I) Length of CNDs was quantified at different developmental stages. Although there was no difference in CND lengths at E11.5, the CND was significantly longer in Ptprs^–/–Ptprf^ΔP/ΔP at E12.5 and E13.5. Error bars indicate SEM. (J–M) In situ hybridization on E12.5 transversal sections using antisense cRNA probes against Ptprf (J), Ptprs (K), Ptprd (L), and a sense probe against Ptprs (M). (J) Ptprf expression was mostly restricted to the CND, while Ptprs expression was detected ubiquitously in the mesenchyme and cloaca epithelium (K). (L) Ptprd was predominantly expressed in the mesenchyme. (M) A sense Ptprs probe was used as negative control. Scale bars: 10 μm. ND, nephric duct; dUr, distal ureter; CE, cloaca epithelium.