In male flies, hyper-transcription of the single X-chromosome takes place to equalize the gene dosage to that of females possessing two X chromosomes. This phenomenon of dosage compensation (DC) is mediated by the MSL complex in Drosophila. The MSL complex is composed of five proteins - MSL1/2/3, MLE, MOF, and two long non-coding RNAs- roX1 and roX2. The absence of any of the protein components leads to male specific lethality. Meanwhile, expression of only one of the two RNA species is sufficient to rescue male flies. The roX RNAs are implicated to play a role in targeting the complex to the X chromosome and for its spreading from the High Affinity Sites (HAS). However, the mechanisms of their action are not clear. During my PhD, I aim to biochemically characterize the interactions of these RNAs with the complex members and other proteins and further investigate the role of these interactions in facilitating DC in male flies.