P{DPE-GFP.TATA-GFP} is an enhancer trap construct that encodes two separate enhancer trap cassettes; one contains a downstream promoter element (DPE)-dependent minimal core promoter upstream of GFP, the other contains a TATA-dependent minimal core promoter upstream of GFP. loxP and FRT sites are also present, such that either P1cre or FLP recombinase can be used to excise the DPE-GFP cassette or TATA-GFP cassette respectively (in each case, a w^+* marker located between the two enhancer trap cassettes is removed by the recombination event).