The attP cassette in the Mi{MIC}CCAP-RMI05804 insertion 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 CCAP-R. The splice acceptor ensures that the T2A-Scer\GAL4 open reading frame is incorporated into the CCAP-R mRNA, while the T2A sequence is expected to truncate the native CCAP-R gene product and promotes the separate translation of the Scer\GAL4 open reading frame. Thus Scer\GAL4 expression is driven by the native CCAP-R regulatory sequences.
ScerGAL4CCAP-R-MI05804-TG4.1 drives expression in a subset of CNS neurons synaptically downstream of CCAP/burs neurons. The expression pattern is almost entirely non-overlapping with that of ScerGAL4rk.pan, which drives in the pattern of the bursicon receptor.