B3RT sites have been inserted into the endogenous VGlut locus, such that they flank the coding exons. Sequence encoding a lexA::UnkAD driver has been inserted downstream of the 3' B3RT site. In the presence of B3R recombinase, the VGlut coding exons are excised, which 1. generates a null VGlut allele, and 2. results in the lexA::UnkAD driver being expressed under the control of endogenous VGlut regulatory sequences.