Different organisms use a variety of mechanisms to compensate for X chromosome dosage imbalance between the sexes. In Drosophila, the MSL complex increases transcription on the single X chromosome of males and is thought to regulate transcription elongation, although mechanistic details have been unclear. Here, a global run-on sequencing technique is used to reveal that the MSL complex seems to enhance transcription by facilitating the progression of RNA polymerase II across the bodies of active X linked genes. In this way, MSL can impose dosage compensation on diverse genes with a wide range of transcription levels along the X chromosome.
- Erica Larschan
- Eric P. Bishop
- Mitzi I. Kuroda