Using DNase I footprinting, we found no sites in the minimal upstream region of
mec-7 (bp -437 to -82) that bound bacterially produced MEC-3. In contrast, four sites bound bacterially produced, epitope-tagged UNC-86. Each site closely matched an UNC-86 consensus-binding sequence derived from UNC-86- binding sites found in the
mec-3 promoter (AAATTCAT; Xue et al., 1992) either on the sense (site 2) or the antisense (sites 1, 3 and 4) strand, and each site is contained within, or overlaps, one of the long stretches of conserved sequence between C. elegans and C. briggsae. UNC-86 binds to M7 sites 1-3 as a single species, UNC-86 binds to M7 site 4 and forms two complexes in EMSA.