Individual stripe regulatory elements in the Drosophila hairy promoter respond to maternal, gap, and pair-rule genes.

Striped expression of the pair-rule gene hairy (h) plays a central role in regulating segmentation in Drosophila. We have used h-lacZ reporter gene fusions to delineate h sequences that drive individual stripe expression. We show that 14 kb of 5'-flanking DNA directs expression of seven lacZ stripes in the blastoderm embryo. Within this region, we identify discrete sequences required for expression of individual stripes 1, 5, 6, and 7, and dispersed elements active in the stripe 2 domain. Only the stripe 1 element directs lacZ expression in an accurate h stripe; stripes 5, 6, and 7 are displaced by one to two cells relative to their h counterparts. These results indicate that regulatory sequences are dispersed within the h promoter. We have determined the sensitivity of the lacZ stripes to maternal, gap, and pair-rule gene mutations. Our results suggest that different but overlapping subsets of gap genes regulate each stripe and that activation and repression are both important in generating the stripe pattern.