Transgenic construct that contains a Ecol\lacZarm.PV reporter flanked on each side by an insulator (scs' and scs respectively) to mitigate any chromosome position effects. A 170bp fragment of the run 3' UTR has been inserted into the SV40 3'UTR sequence of the lacZ reporter, in the Sxl non-binding orientation, to test whether the fragment has a role in dosage compensation.