Construct used to investigate the functional properties of a DNA fragment from a polytene chromosome interband region. A w+mC reporter is flanked on one side by a EcoRI-SalI fragment containing putative BEAF-32-binding sites (a subfragment of the 4.7kb fragment from the 61C7/C8 interband in P{61C-WS}) located between loxP recombination sites, and by the gypsy\su(Hw)BR430 insulator on the other side.