Fig. 3

Klu overactivation results in a loss of Delta-Notch signaling and ISC differentiation. a–d Clonal expression of different Klu isoforms using the esg-Gal4-driven FlipOut (esg-F/O) system to generate ISC clones. a Control esg-FO clones grow to occupy most of the posterior midgut 2 weeks after clonal induction. b–d Clones expressing either full-length Klu (UAS-kluFL, b) or the Klu zinc-finger DNA-binding domain fused to the Engrailed Repressor Domain (UAS-ERD-kluZF, d) resulted in a block of differentiation. This was not observed when expressing the Klu zinc-finger DNA-binding domain fused to the VP16 transcriptional activator domain (UAS-VP16-kluZF, c). Representative areas of posterior midguts are shown. e Quantification of genotypes in a–d. n = 5 midguts for each genotype. f–i Su(H)-F/O control clones contain GFP-Pdm1 double-positive cells, representative of EB > EC differentiation (f, g closeup in h, i). j–m Su(H)-F/O>UAS-klu clones contained much less GFP-Pdm1 double-positive cells, indicative of impaired EB > EC differentiation upon Klu expression. n Quantification of the percentage of GFP-Pdm1 double-positive cells in images of posterior midguts from control (f–i) and UAS-klu Su(H)-F/O (j–m) clones. n = 7 midguts for each genotype. For quantifications in e and n: Error bars represent mean ± SD. Significance was calculated using Student’s t-test with Welch’s correction. Scale bar = 50 µm