FIG. 3.

The Mod(mdg4)-67.2 protein interacts with a region of Su(Hw) that is required for insulation. The Su(Hw) protein contains 12 zinc fingers (gray boxes) and an enhancer-blocking region within residues 737 to 880 (black box). The Su(Hw)-CTD and the indicated mutant forms fused to GST were expressed in E. coli and bound to glutathione beads. The autoradiograms of SDS-PAGE gels show the amount of ³⁵S-Mod(mdg4)-67.2 and ³⁵S-luciferase control protein (luc) prepared by translation in vitro that bound to the various GST-Su(Hw)-CTD beads and to GST-only control beads. The left-hand lane (load, lane 1) shows the amount of input labeled proteins. Mod(mdg4)-67.2 binds to the GST-Su(Hw)-CTD beads (lane 3), but deletions that affect the enhancer-blocking region of Su(Hw) prevent binding of Mod(mdg4)-67.2 (lanes 4, 5 and 6). All the results were reproduced in multiple independent experiments.