Fig. 5.

Ask1-p38 signaling in ECs promotes ISC proliferation upon damage. a–c Ask1 is required for p38 activation in ECs upon P.e. infection. p38 activation is increased in ECs in P.e.-infected control midguts (b right, red) compared with uninfected control midguts (a; right, red). p38 activation is blocked in infected Ask1^MB06487 midguts (c right, red) compared with infected control midguts. d–f Ask1 is required for p38 activation in ECs upon P.e. infection. p38 activation is increased in ECs in P.e.-infected control (EC-specific, Myo1A^ts) midguts (e right, red) compared with uninfected control midguts (d right, red). p38 activation is blocked, however, in P.e.-infected midguts expressing Ask1^RNAi in ECs for 7 days with Myo1A^ts (f right, red) compared with P.e.-infected control midguts. g Ask1 is required in ECs to promote ISC proliferation upon P.e. infection. The mean number of phosphorylated histone H3 Ser 10-positive cells per midgut with s.e.m. in control midguts (Myo1A^ts) (n = 37 midguts), P.e.-infected control midguts (n = 27 midguts), midguts expressing Ask1^RNAi in ECs for 7 days with Myo1A^ts (n = 27 midguts) and in P.e.infected midguts expressing Ask1^RNAi in ECs for 7 days (n = 27 midguts) (Mann–Whitney; p = 0.0003). Midguts pooled from three independent experiments. h–k Ask1 is required for p38 activation in ECs upon wounding. p38 is activated in ECs of wounded control midguts (i red) compared with unwounded control midguts (h red) or unwounded midguts expressing Ask1^RNAi in ECs for 7 days with Myo1A^ts (j red). p38 activation is blocked in ECs of wounded midguts expressing Ask1^RNAi in ECs for 7 days with Myo1A^ts (k red) relative to ECs in wounded control midguts. DNA is in blue. Scale bars in a–f, h–k are 50 μm. Representative images in a–c from two experiments; d–f, three experiments; h–k, two experiments. Source data are provided as a Source Data File