Transgenic construct used in an enhancer-blocking assay to study whether a fragment from the lncRNA:yar promoter region can function as an insulator. Contains two markers; a y minigene with wing and body enhancers upstream of the y promoter and bristle and tarsal claw enhancers in an intron, and a w minigene. A 150bp fragment from the lncRNA:yar promoter region (containing two of the three transcription start sites) has been inserted in between the y wing and body enhancers and the y promoter. The lncRNA:yar fragment is flanked by loxP sites in direct orientation.

The wing and body enhancers of the y gene are separated from the y promoter and transcription unit by a 150bp fragment from the yar promoter region (containing two of the three transcription start sites).