Figure 3. Runt is sufficient to antagonize Bcd-dependent activation.

(A–C). Expression patterns of reporter genes containing Type 0 (A), Type I (B), and Type II enhancers (C) in embryos also carrying a hs-run construct. The left embryo of each pair was raised at room temperature (wt); the right embryo was heat-shocked to induce ubiquitous expression of Run (hs-run). (D–H). Expression patterns of a reporter gene carrying the wild type hb P2 enhancer (D) or mutated forms of the enhancer with one (E), two (F), or three introduced Run-binding motifs (G). Patterns are shown in wild type (wt) and run³ mutants as indicated. (H). Expression of a mutated form of the hb P2 reporter in which each inserted Run motif in (G) (green box) was mutated to a different unrelated sequence (a, b, c). Posterior boundary positions (% EL; mean ± std) and sample sizes (n) are shown for each experiment.