Figure 1. mTORC1 is essential for Wnt-driven proliferation in a MYC-dependent manner.

a+b) Representative IHC of phospho-rpS6 and phospho-4EBP1 showing increased staining 96hrs following Apc deletion. Raptor deletion caused a loss of positivity in both, whereas 10mg/kg rapamycin treatment (beginning at 24hrs) specifically disrupts rpS6 phosphorylation (representative of 6 biological replicates); c) Representative IHC of phospho-rpS6 96hrs after Cre induction showing that Wnt-driven rpS6 phosphorylation is MYC dependent (representative of 3 biological replicates); d) Animals were exposed to 14Gy γ-irradiation and intestinal regeneration was measured 72hrs later, by counting the number of viable crypts and multiplying that by the average size of the regenerating crypts. Boxplot shows that 10mg/kg rapamycin treatment and Raptor deletion significantly decrease intestinal regeneration. Whiskers are max and min, black line is median (n=5 biological replicates per group; **p-value<0.02, Mann-Whitney U test); e) Representative H+E staining of regenerating intestines 72hrs after exposure to 14Gy γ-irradiation. Arrowheads indicate regenerating crypt; (representative of 5 biological replicates).; f) Representative H+E staining 96hrs after Apc loss, showing that 10mg/kg rapamycin treatment or Raptor deletion prevent Wnt-driven proliferation (representative of 6 biological replicates). Treatment began 24hrs after Apc deletion. Red bar is graphical representation of crypt size. Scale bar = 100μm.