Mechanisms of LncRNA action. In numerous tissues, lncRNAs (indicated in green) have been shown to regulate gene expression at multiple levels: chromatin, transcription, mRNA, translation, and protein. Hematopoietic lncRNAs may act at any of these levels. “MicroRNA sponge” refers to the ability of lncRNAs to sequester cellular microRNAs and prevent them from binding mRNA targets.¹⁴  Professional illustration by Debra T. Dartez.