Enhancer-derived RNA: A Primer

Abstract

Enhancer-derived RNAs (eRNAs) are a group of RNAs transcribed by RNA polymerase II from the domain of transcription enhancers, a major type of cis-regulatory elements in the genome. The correlation between eRNA production and enhancer activity has stimulated studies on the potential role of eRNAs in transcriptional regulation. Additionally, eRNA has also served as a marker for global identification of enhancers. Here I review the brief history and fascinating properties of eRNAs.

Keywords: Enhancer; Gene regulation; Next-generation sequencing; Non-coding RNA; eRNA.

Figure 1

eRNA and transcriptional activation A typical gene is associated with two types of cis-regulatory elements: one proximal (the promoter) and the other distal (the enhancer) to the transcription start site of the gene. Except for house-keeping genes, a gene’s transcriptional activity is usually “off” when its enhancer(s) is inactive (A). However, when an enhancer is activated by transcription factors, it can loop toward the promoter and turn “on” the transcription of the gene (B). Previously, both enhancers and promoters were classified as non-coding elements, yet recent studies indicate that active enhancers are bi-directionally transcribed to eRNAs. eRNA, enhancer-derived RNA.