Sequence including the GAL4 coding sequence has been reintegrated into the Rx locus using the TI{mCherry}RxKO insertion. The loxP cassette containing w+* that was inserted as part of the reintegration event has been excised. This results in a Rx locus in which the ATG codon and sequence encoding the first 123 amino acids has been deleted and is replaced by a recombined attP/B site, the GAL4 coding sequence and a single loxP site. The GAL4 driver is expressed under the control of endogenous Rx regulatory sequences.