The PBac{BlueEye.hsp70-PBac\T.PBac.Hsp27-EGFP.RedEye} construct contains two components, a source of piggyBac transposase (Tni\piggyBac\T^hs.PK) which is marked with Avic\GFP^ECFP.3xP3 and a Avic\GFP^EGFP.Hsp27 enhancer trapping construct which is marked with Disc\RFP^3xP3.cHa. The entire construct contains three pBac repeats. The two pBac repeats at the outside are in inverted orientation and are utilised if the entire construct is inserted into the genome. The third pBac repeat separates the Tni\piggyBac\T^hs.PK,Avic\GFP^ECFP.3xP3 component from the Avic\GFP^EGFP.Hsp27,Disc\RFP^3xP3.cHa component. It is oriented such that it is inverted relative to the right end repeat but is in the same orientation as the left end repeat. Thus, after recovery of animals carrying the entire construct, the Avic\GFP^EGFP.Hsp27,Disc\RFP^3xP3.cHa component can be excised using Tni\piggyBac\T, leaving behind the Tni\piggyBac\T^hs.PK,Avic\GFP^ECFP.3xP3 component (this portion is represented by PBac{5pBlueEye.hsp70-PBac\T} and since it has only one pBac end it will be stably integrated). It has been determined that the Avic\GFP^EGFP.Hsp27 part of the Avic\GFP^EGFP.Hsp27,Disc\RFP^3xP3.cHa component is not useful for enhancer trapping.