Transgenic construct that contains an SV40 transcription terminator at the 5' end, 5xUAS regulatory sequences, the y transcription unit, a mini-w marker (with the w gene transcription terminator) and a SV40 transcription terminator at the 3' end. The y promoter is flanked by a pair of FRT sites. A loxP cassette containing the w eye enhancer has been inserted into the intron of the y gene. The presence of the SV40 sequences at both ends of the transgene is to prevent possible transcription passing through the transgene when it is integrated into the genome.