Fig. 5. E(spl)-C locus regulates Twist modulation into low and high domains. (A-D) Lateral views of stage 10 embryos stained with anti-Twist: (A,C) whole-mount embryo, (B,D) corresponding close-ups of embryos in (A,C). (A,B) Df E(spl)-C mutant maintains high Twist expression uniformly throughout its mesoderm, similar to N^null embryos. (C,D) Df E(spl)-C, P[gro⁺] mutant has expanded high Twist domains compared with wild type. Black arrowhead indicates cells, located in a presumptive low Twist domain, expressing higher levels of Twist than wild type.