Transgenic construct used to study the 1A2 insulator. Consists of the y wing enhancer, the w eye enhancer, the y body enhancer, a loxP cassette containing the 454bp '1A2' insulator (su(Hw)BR-y-AS-C, an endogenous insulator containing su(Hw)-binding sites which is found between the y gene and the ac-sc complex), the y transcription unit (including the y bristle enhancer located downstream of the transcription start site) and the w gene.