Mi{GT-CaSSA.12x1-12x2} 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 a gene trap cassette composed of 12 copies of the 'gRNA#1' guide RNA (flanked by the hammerhead and HDV ribozymes) and 12 copies of the 'gRNA#2' guide RNA (flanked by the hammerhead and HDV ribozymes), where the 'gRNA#1' and 'gRNA#2' components are in opposite orientations, meaning that the gene trap cassette can potentially report sense and antisense transcription when inserted in the genome and combined with an appropriate CaSSA reporter containing a switch cassette with 'gRNA#1' and/or 'gRNA#2' target sites.