Identification of a catabolite-responsive element necessary for regulation of the cry4A gene of Bacillus thuringiensis subsp, israelensis

Bacillus thuringiensis subsp, israelensis produces a potent mosquitocidal protein, Cry4A. We have identified a 15-bp catabolite responsive element (cre), overlapping the -35 element of the cry4A promoter. Changing a guanine to adenine at position -49 in the promoter abolished glucose catabolite repression of cry4A and enhanced promoter activity two- to threefold. This cis regulatory element is essential for controlled toxin synthesis, vital to evolutionary success of B. thuringiensis subsp, israelensis.