P{ST.lexA::HG} is an enhancer trap construct that contains the weak P\T promoter upstream of sequence encoding a lexA::GAD driver that consists of the Ecol\lexA DNA-binding domain and the hinge and transcriptional transactivation domains of Scer\GAL4. An excisable loxP cassette containing a w+mC marker is present downstream of the driver sequence. An attP site is present upstream of the P\T promoter sequence, allowing for subsequent recombinase-mediated cassette exchange.