FIG 1.

The bithorax complex (BX-C) and Fab-7. (A) Genomic map showing the cis-regulatory regions within the bithorax complex (BX-C) located on the 3R chromosome. The two BX-C genes, abd-A and Abd-B, along with their nine regulatory domains (iab-2 to iab-9) are illustrated. BX-C insulators (20, 40, 52, 92) that are interspersed between the chromosomal domains are depicted as rectangular boxes of different colors. (B) A schematic drawing of the Fab-7 insulator (∼1.2 kb) and the probes used for electrophoretic mobility shift assays (EMSAs). DNase I-hypersensitive regions *, HS1, and HS2 are shown as orange boxes. Within HS1, the binding sites for GAGA factor (GAF) are shown as purple lines (GAGAG). The distal part of dHS1 corresponding to probes G3+4 and G5+6 is enlarged. The names, sizes, and locations of the various probes derived from dHS1 are illustrated.