RT Journal Article
SR Electronic
T1 Bidirectional transcription marks accessible chromatin and is not specific to enhancers
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 048629
DO 10.1101/048629
A1 Robert S. Young
A1 Yatendra Kumar
A1 Wendy A. Bickmore
A1 Martin S. Taylor
YR 2016
UL http://biorxiv.org/content/early/2016/04/13/048629.abstract
AB Bidirectional transcription initiating at enhancers has been proposed to represent the signature of enhancer activity. Here we show that bidirectional transcription is a pervasive feature of all forms of accessible chromatin, including enhancers, promoters, CTCF-bound sites and other DNase hypersensitive regions. Transcription is less predictive for enhancer activity than epigenetic modifications such as H3K4me1 or the accessibility of DNA when measured in both enhancer assays and at endogenous loci. Bidirectional transcription initiation from accessible chromatin is therefore not sufficient for, nor specific to, enhancer activity. The stability of enhancer initiated transcripts does not influence measures of enhancer activity and we cannot detect any evidence of purifying selection on the resulting enhancer RNAs within the human population. Our results suggest that transcription initiating at enhancers is frequently a by-product of promiscuous RNA polymerase activity at accessible chromatin, and may not generally play a functional role in enhancer activity.