The importance of location and orientation of male specific lethal complex binding sites of differing affinities on reporter gene dosage compensation in Drosophila

► Insertion of a strong binding site for the MSL complex either upstream or at the 3′ end of a reporter gene led to MSL complex binding and transcription upregulation in males. ► In contrast, gene transcription, binding site orientation and the local chromatin environment all appear to influence MSL complex binding to a weak site and transcription enhancement. ► Our results suggest that transcription enhancement in males requires a level of MSL complex binding above a certain threshold.