The multiple lncRNAs encoding hsrω gene is essential for oogenesis in Drosophila

In the background of limited studies on noncoding RNAs in Drosophila oogenesis, we show developmentally active hsr{omega} lncRNA gene to be essential in oogenesis and ovulation. The near-null hsr{omega}66 females, and ovaries with down- or up-regulated hsr{omega} display varyingly perturbed oogenesis including fewer ovarioles, high apoptosis, poor actin nuclear-cage (stage 10), low Cut levels in late chambers and, finally ovulation block. Restoration of normal oogenesis following targeted expression of hsr{omega}-RH transcript in hsr{omega}66 confirmed hsr{omega} mis-function to underlie these defects. Genetic interaction studies showed varying modulation of ovarian defects following mis-expression of Cut, and TBPH/TDP-43 or Caz/dFUS hnRNPs by altered hsr{omega} transcript levels. Dietary supplement of ecdysone to hsr{omega}66 females, which have reduced ecdysone titer, substantially restored normal oogenesis. Our results show for the first time that the multiple lncRNA producing hsr{omega} gene, which interacts with diverse hnRNPs and other regulatory molecules, As expected of a gene with key roles in dynamics of various hnRNPs, interactions between down or upregulated hsr{omega} transcripts and various oogenesis regulators are not linear. Summary StatementThe multiple lncRNA producing hsr{omega} gene critically impacts Drosophila oogenesis at multiple steps through intra- and inter-organ signaling.