Cyst contains essential RhoGEF and C-terminal regions. (A) Schematic of Cyst^R GFP-tagged structure–function constructs. Constructs were generated from the cyst genomic region, expressed under the endogenous promoter, and are immune to cyst shRNA (red cross; see Fig. 1 A). GFP replaces deleted regions (dashed lines). (B) Quantification of embryonic survival when Cyst isoforms were expressed in a cyst RNAi background. Cyst^RΔN partially rescues cyst RNAi embryos (68% embryonic viable). n = number of fertilized eggs analyzed. Survival was scored by subtracting the number of hatched larvae from total number of (fertilized) embryos counted. Whether eggs were fertilized or not was determined in cuticle preparations. (C) Embryo cuticles of the indicated genotypes showing that Cyst^RΔDH-PH and Cyst^RΔC fail to rescue the cyst RNAi phenotype. Scale bar, 100 µm.