A TI{T-GEM.0} Trojan-Gal4 expression module (T-GEM) has been inserted into an intron of Pburs. The insertion is in the correct orientation to gene trap Pburs with the Trojan GAL4 exon: the splice acceptor ensures that the T2A-GAL4 open reading frame is incorporated into the Pburs mRNA, while the T2A sequence is expected to truncate the native Pburs gene product and promotes the separate translation of the GAL4 open reading frame. Thus GAL4 driver expression is driven by the native Pburs regulatory sequences.