Figure 5
From: Mechanism of cystogenesis by Cd79a-driven, conditional mTOR activation in developing mouse nephrons
Autonomous and non-autonomous mTORC1 activation in pre-cystic tubules of Cd79a-Tsc1 knockout (KO) kidneys. (a) Two adjacent sections (3–5 µm) of Cd79a-Cre;Tsc1ff.;RFPf/+ mice at postnatal day (P) 9 are stained with antibodies against red fluorescent protein (RFP, a marker of Cd79a-Cre activity), phosphorylated (p)-S6 (an indicator of mTORC1 activation, magenta), and E-cadherin (E-cad, a marker of distal and collecting ducts, green). RFP signals are red in the cytoplasm, but are occasionally yellow when they merge with E-cadherin on the basal-lateral plasma membrane. Some epithelial cells coexpress p-S6 with RFP, while others are stained with the p-S6 only, suggesting that pre-cystic tubules are composed of two heterogeneous subpopulations of p-S6–positive cells: one undergoes Cre recombination (autonomous component, arrowheads) and the other does not (non-Cre recombination, non-autonomous component, arrows). (b) Immunoblot analysis of p-S6 (p-S6S240/244) and p-Akt (p-AktS473). Analysis of whole kidney lysates indicates that p-S6 expression is enriched in Cd79a-Tsc1 KO kidneys compared to controls (upper panel). However, p-Akt abundance did not differ between the two groups (lower panel). The original gels was shown in Supplementary Fig. S12. (c) Quantification analysis. In Cd79a-Tsc1 KO kidneys, p-S6 and p-Akt expression levels at 1 week of age did not differ from those at 4 weeks. Data represent mean ± SEM and were statistically analyzed by one-way ANOVA. ****P < 0.0001.
