A 12.6-kb fragment ("GH146" genomic enhancer") which flanks the insertion site of the P{GAL4} element in the P{GawB}GH146 insertion is fused upstream of mammalian optimised FLPo recombinase. The "GH146" genomic enhancer" includes all of the genomic DNA between the CG17390 annotation and the upstream annotation CG17389, as well as all CG17390 introns. FlyBase curator comment: CG17390 and CG17389 have subsequently been merged into a single annotation, corresponding to the Oaz gene (previously, CG17390 corresponded to the annotation for the Oaz gene).