Mi{Trojan-KDR.1} represents a transgenic construct generated in vivo by using phiC31:int-mediated recombination to replace the attP cassette of a Mi{MIC} element insertion with an intron phase 1 gene trap cassette composed of a splice acceptor site followed by the T2A peptide, the KDR coding sequence and an Hsp70 transcription termination signal. Integration of the cassette into a Mi{MIC} insertion in a coding intron (with the same phase) of a native Drosophila gene of interest will result in the cassette behaving as a 'Trojan' exon: the splice acceptor site ensures that the T2A-KDR open reading frame is incorporated into the mRNA of the native Drosophila gene, while the T2A sequence truncates the native gene product and promotes the separate translation of the KDR open reading frame. Thus KDR should be expressed under the control of the regulatory sequences of the native Drosophila gene of interest in the resulting Mi{Trojan-KDR.1} insertion line.