EBRs are required in vivo for regulation of tissue growth. (A) Schematic representation of the Ft ICD highlighting functional and conserved domains. EBR1, EBR2, and conserved E location and amino acid sequence are depicted, in addition to the conservation of the conserved E region (in red) between flies, mice, and humans. EBR1 and EBR1/2 flies have the indicated sequences removed and have a C-terminal 3× FLAG. Conserved E has the indicated sequence (highlighted in red) replaced with a 3× FLAG. (B) Quantification of adult wing size with haploinsufficiency for ft or ft, yki. Data are normalized against the mean of the cntrl/ft^fd (ft::FLAG/ft^fd). All EBR flies are overgrown, with ft^EBR1/2 causing additive overgrowth. Haploinsufficiency of ft, yki rescues overgrowth (****significance for ft^EBR1, ft^ΔE and ft^EBR1/2 compared to the respective genotypes haploinsufficient for ft alone). Data points indicate an individual wing with mean and SD represented (n ≥ 27 per genotype). ****P < 0.0001 using one-way ANOVA with a Tukey’s post-hoc test compared to cntrl/ft^fd or between indicated genotypes. (C–I) EBR deletion causes overgrowth and is rescued by haploinsufficiency of yki. Compared to control wings—ft::FLAG (C), loss of ft^EBR1 (D), ft^ΔE (E), and ft^EBR1/2 (F) cause overgrowth when over the null ft^fd allele. Additional loss of one copy of yki rescues overgrowth of all indicated genotypes ft^EBR1 (G), ft^ΔE (H), and ft^EBR1/2 (I). Scale bars are 500 µm.