Recent studies have revealed that active enhancers are transcribed, producing a 
class of noncoding RNAs called enhancer RNAs (eRNAs). eRNAs are distinct from 
long noncoding RNAs (lncRNAs), but these two species of noncoding RNAs may share 
a similar role in the activation of mRNA transcription. Emerging studies, 
showing that eRNAs function in controlling mRNA transcription, challenge the 
idea that enhancers are merely sites of transcription factor assembly. Instead, 
communication between promoters and enhancers can be bidirectional with 
promoters required to activate enhancer transcription. Reciprocally, eRNAs may 
then facilitate enhancer-promoter interaction or activate promoter-driven 
transcription.