Genomic and functional conservation of lncRNAs: lessons from flies

Over the last decade, the increasing interest in long non-coding RNAs (lncRNAs) has led to the discovery of these transcripts in multiple organisms. LncRNAs tend to be specifically, and often lowly, expressed in certain tissues, cell types and biological contexts. Although lncRNAs participate in the regulation of a wide variety of biological processes, including development and disease, most of their functions and mechanisms of action remain unknown. Poor conservation of the DNA sequences encoding for these transcripts makes the identification of lncRNAs orthologues among different species very challenging, especially between evolutionarily distant species such as flies and humans or mice. However, the functions of lncRNAs are unexpectedly preserved among different species supporting the idea that conservation occurs beyond DNA sequences and reinforcing the potential of characterising lncRNAs in animal models. In this review, we describe the features and roles of lncRNAs in the fruit fly Drosophila melanogaster, focusing on genomic and functional comparisons with human and mouse lncRNAs. We also discuss the current state of advances and limitations in the study of lncRNA conservation and future perspectives. This project was funded by Grants: BFU2015-67623-P and PGC2018-099763-B100, 2017SGR1455 from AGAUR (Generalitat de Catalunya) and a Grant from the Institució Catalana de Recerca i Estudis Avançats (via an ICREA Academia award) to M.C.; as well as support from the European Community under the FP7 programme (ERC-2011-AdG-294653-RNA-MAPS), 2U41 HG007234-05G from NIH/NHGRI (USA) and the Grant PGC2018-094017-B-I00 from the Spanish Ministerio de Ciencia, Innovación y Universidades to R.G.. C.C.-R. holds a predoctoral FPI contract from the Spanish Government (Ministerio de Ciencia e Innovación). R.A. is a predoctoral fellow of CONACYT, the “Becas al Extranjero” Program of Mexico.