A set of transgenic insertion stocks containing a gene trap cassette, derived from Mi{MIC} insertions in coding introns using Recombinase-Mediated Cassette Exchange (RMCE); see http://flypush.imgen.bcm.tmc.edu/pscreen/technique.html. The gene trap cassette contains a Trojan GAL4 exon composed of a splice acceptor, T2A peptide, GAL4 coding sequence and an Hsp70 transcription termination signal. When inserted in a coding intron in the correct orientation, the cassette should result in truncation of the trapped gene product and expression of GAL4 under the control of the regulatory sequences of the trapped gene. Each insertion line contains one of three versions of the cassette (Mi{Trojan-GAL4.0}, Mi{Trojan-GAL4.1} or Mi{Trojan-GAL4.2}), depending on the frame required to generate a gene trap.
A PCR assay was used to to identify RMCE events that inserted the cassette in the correct orientation. Potential lines were then crossed to UAS-2x-EGFP and their expression was evaluated with anti-GFP antibodies to identify gene trap lines.
