Abstract

Divergent lncRNAs that are transcribed in the opposite direction to nearby protein-coding genes comprise a significant proportion (∼20%) of total lncRNAs in mammalian genomes. Through genome-wide analysis, we found that the distribution of this lncRNA class strongly correlates with essential developmental regulatory genes. In pluripotent cells, divergent lncRNAs regulate the transcription of nearby genes. As an example, the divergent lncRNA Evx1as promotes transcription of its neighbor gene, EVX1, and regulates mesendodermal differentiation. At a single-cell level, early broad expression of Evx1as is followed by a rapid, high-level transcription of EVX1, supporting the idea that Evx1as plays an upstream role to facilitate EVX1 transcription. Mechanistically, Evx1as RNA binds to regulatory sites on chromatin, promotes an active chromatin state, and interacts with Mediator. Based on our analyses, we propose that the biological function of thousands of uncharacterized lncRNAs of this class may be inferred from the role of their neighboring adjacent genes.