Figure 5. Inhibition of ERK activity rescues the phenotypes induced by PEBP1 depletion.

(A) The increased level of ERK in ECs of EC-specific PEBP1 knockdown guts was reduced by EC-specific ERK knockdown. After induction for 7 days at 29° C, guts of Myo1A^ts>+, Myo1A^ts>PEBP1 RNAi, Myo1A^ts>PEBP1 RNAi;ERK RNAi or Myo1A^ts>ERK RNAi were stained with anti-GFP (green), anti-pERK (red) and DAPI (blue). Original magnification is 400×. Scale bar, 20 μm. (B) The increase in the number of cleaved caspase-3⁺ ECs in EC-specific PEBP1 knockdown guts was compensated by EC-specific ERK knockdown. After induction for 7 days at 29° C, guts were stained with anti-GFP (green), anti-cleaved caspase-3 (cCapase3, red) and DAPI (blue). Scale bar, 50 μm. (C) Increased mitotic index of EC-specific PEBP1 knockdown guts was reduced by EC-specific ERK knockdown. After induction for 7 days at 29° C, guts were stained with anti-GFP (green), anti-PH3 (red) and DAPI (blue). The number of PH3⁺ cells was counted in whole guts. Data (mean ± SEM) collated from 16–31 guts. N, number of counted guts. P values were calculated using a Student's t-test. ^***p < 0.001, ^**p < 0.01. (D) The increase in the mitotic ISCs with supernumerary centrosome (≥3) of EC-specific PEBP1 knockdown guts was reduced by EC-specific ERK knockdown. The number of γ-Tubulin signal was counted in mitotic ISC of whole guts. Data (mean ± SEM) were collated from 12–25 guts. N, number of counted guts. P values were calculated using a Student's t-test. ^***p < 0.001, ^**p < 0.01, ^*p < 0.05, n.s. not significant. (E) Midgut epithelium hyperplasia induced by EC-specific PEBP1 knockdown was compensated by EC specific ERK knockdown. After induction for 7 days at 29° C, guts were stained with anti-GFP (green), RP (red) and DAPI (blue). The yellow lines indicate RP of upper panels and white arrows indicate thickness. Original magnification is 400×. Scale bar, 20 μm.