lincNORS: A Noncoding Regulator of the Cellular Sterol Homeostasis I

We hereby provide the initial portrait of lincNORS, a spliced lincRNA generated by the MIR193BHG locus, entirely distinct from the previously described miR-193b-365a tandem. While inducible by low O2 in a variety of cells and associated with hypoxia in vivo, our studies show that lincNORS is subject to multiple regulatory inputs, including estrogen signals. Biochemically, this lincRNA fine-tunes cellular sterol/steroid biosynthesis by repressing the expression of multiple pathway components. Mechanistically, the function of lincNORS requires the presence of RALY, an RNA-binding protein recently implicated in cholesterol homeostasis. We also noticed the proximity between this locus and naturally-occurring genetic variations highly significant for sterol/steroid -related phenotypes, in particular the age of sexual maturation. An integrative analysis of these variants provided a more formal link between these phenotypes and lincNORS, further strengthening the case for its biological relevance. Overall design: Hypoxia regulated genes (coding and long noncoding) was identified by transcriptomic profiling of MCF-7 cells under hypoxia (1% O2, 24 hrs) versus normoxia (21% O2, 24 hrs).