Figure 6.

 TATA is an important determinant of IAB5–eve interactions. Transgenic embryos carry the indicated P transposons and are oriented as described in the legend to Fig. 5. (A,B) Nuclear cleavage 14 embryos that carry a P transposon with the distal CAT gene driven by the core eve promoter and the rightward lacZ gene driven by mini-white. The IAB5 enhancer selectively interacts with the eve promoter, and directs intense expression of the CAT reporter in the presumptive abdomen (A). In contrast, the white/lacZ reporter gene is not expressed above background levels (B). (C,D) Cellularizing embryos carrying the same P transposon as A and B except that a synthetic TATA sequence was inserted into the mini-white promoter. IAB5 activates the lacZ reporter gene in the presumptive abdomen (D). The eve/CAT fusion gene is also activated by IAB5 (C). These results suggest that the white^TATA promoter is almost as active as eve.