TI{CRIMIC.mTG4.1} represents a DNA segment that has been inserted into the genome by homology directed repair using CRISPR/Cas9 in combination with a donor plasmid. The inserted TI{CRIMIC.mTG4.1} DNA is not flanked by transposable element ends and consists of a recombination-mediated cassette exchange (RMCE) cassette flanked by a pair of inverted attP sites. The cassette consists of an intron phase 1 'Trojan miniGAL4' gene trap element (composed of a splice acceptor site followed by the T2A peptide, the miniGAL4(2) coding sequence and a polyadenylation signal). Integration of TI{CRIMIC.mTG4.1} 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-miniGAL4(2) 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 miniGAL4(2) open reading frame. Thus miniGAL4(2) should be expressed under the control of the regulatory sequences of the native Drosophila gene of interest in the resulting Trojan-CRIMIC miniGAL4(2) driver line. In addition, the presence of the inverted attP sites allows for the entire RMCE cassette sequence to be replaced with DNA from a compatible donor plasmid (where the sequence to be inserted is flanked by inverted attB sites) through recombination-mediated cassette exchange (RMCE) driven by the phiC31:int integrase.