Interactions between dosage compensation complex components Msl-1, Msl-2 and NURF component NURF301 with long non-coding RNA gene hsrω

Hyperactivity of the single X-chromosome in male Drosophila is achieved by establishing a ribonucleoprotein complex, called Dosage Compensation Complex (DCC), on the male X chromosome. Msl-1 and Msl-2 proteins, involved in the initiation and establishing of DCC on male X chromosome, are very crucial component of this complex. In the present study, it has been found here that a long non-coding RNA gene hsr{omega} genetically interacts with Msl-1 as well as Msl-2 and suppresses the lethal phenotype of Msl-1 or Msl-2 down-regulation in its up-regulated background. Additionally, it is also found here that an ATP-dependent chromatin remodeler, NURF301, also interacts with hsr{omega} in same manner. General lethality caused by Act-GAL4 driven global expression of NURF301-RNAi and the male-specific lethality following Msl-1-RNAi or Msl-2-RNAi transgene expression were partially suppressed by over-expression of hsr{omega}, but not by down regulation through hsr{omega}-RNAi. Likewise, eye phenotypes following ey-GAL4 driven down-regulation of NURF301 or Msl-1 or Msl-2 were also partially suppressed by over-expression of hsr{omega}. Act-GAL4 driven global over-expression of hsr{omega} along with Msl-1-RNAi or Msl-2-RNAi transgene substantially restored levels of MSL-2 protein on the male X chromosome. Similarly, levels and distribution of Megator protein, which was reduced and distribution at nuclear rim and in nucleoplasm was affected in the MT and SG nuclei, is also restored when hsr{omega} transcripts are down-regulated in Act-GAL4 driven Msl-1-RNAi or Msl-2-RNAi genetic background. NURF301, a known chromatin remodeler, when down-regulated shows decondensed X chromosome in male larvae. Down-regulation of hsr{omega} results in restoration of chromosome architecture without affecting the level of ISWI protein-another chromatin remodeler protein, known to interacting with hsr{omega}.