Fig. 3. Competing promoters can influence the suHw-mediated blockage of the ftz-AE1 interaction. Reporter gene expression are monitored in transgenic embryos containing the AE1 enhancer placed between two competing promoter-reporter fusion genes. Transgenes are diagrammed beneath each image pair (see Fig. 2 legend for general descriptions). (A-D) Transgenic embryos containing ftz-white promoter/reporters. (A,B) AE1 specifically activates ftz/lacZ expression (B, anti-lacZ probe) but not the white gene expression (A, white expression) in transgenic embryos. (C,D) AE1-ftz/lacZ interaction is partially attenuated by the intervening suHw insulator (D, lacZ expression) without concomitant restoration of AE1-white interaction (C, white expression). (E-H) Transgenic embryos containing ftz-eve promoter/reporters. (E,F) AE1 simultaneously activates ftz/lacZ (F, lacZ expression) and the eve/CAT expression (E, CAT expression) in transgenic embryos. (G,H) AE1-ftz/lacZ interaction can be completely blocked by the intervening suHw insulator (H, lacZ expression) with a concomitant increase in the level of AE1-eve/CAT interaction (G, CAT expression). The inset in each panel shows the internal control Scr expression (see Fig. 2 legend, and Materials and Methods for details).
