The attP cassette in the Mi{MIC}ChAT^MI04508 insertion (which is in a coding intron common to all splice forms of ChAT) has been replaced with a Trojan GAL4 cassette that contains a splice acceptor site followed by the T2A peptide, the Scer\GAL4 coding sequence and an Hsp70 transcription termination signal. The insertion is in the correct orientation to gene trap ChAT. The splice acceptor ensures that the T2A-Scer\GAL4 open reading frame is incorporated into the ChAT mRNA, while the T2A sequence is expected to truncate the native ChAT gene product and promotes the separate translation of the Scer\GAL4 open reading frame. Thus Scer\GAL4 expression is driven by the native ChAT regulatory sequences.