The attP cassette in the Mi{MIC}crcMI02300 insertion has been replaced with a Trojan GAL4 cassette that contains a splice acceptor site followed by the T2A peptide and the Scer\GAL4 coding sequence. The insertion is in the correct orientation to gene trap crc. The splice acceptor ensures that the T2A-Scer\GAL4 open reading frame is incorporated into the crc mRNA, while the T2A sequence is expected to truncate the native crc gene product and promotes the separate translation of the Scer\GAL4 open reading frame. Thus Scer\GAL4 expression is driven by the native crc regulatory sequences.