Non-coding RNA derived from the region adjacent to the human HO-1 E2 enhancer selectively regulates HO-1 gene induction by modulating Pol II binding

• Published in: Nucleic acids research 2014-12, Vol.42 (22), p.13599-13614
• Main Authors: Maruyama, Atsushi, Mimura, Junsei, Itoh, Ken
• Format: Article
• Language: English
• Subjects: Basic-Leucine Zipper Transcription Factors - metabolism; Cell Nucleus - drug effects; Cell Nucleus - genetics; Enhancer Elements, Genetic; Fanconi Anemia Complementation Group Proteins - metabolism; Gene regulation, Chromatin and Epigenetics; HeLa Cells; Heme Oxygenase-1 - biosynthesis; Heme Oxygenase-1 - genetics; Humans; Maleates - pharmacology; Molecular Sequence Data; NF-E2-Related Factor 2 - metabolism; Oxidative Stress; Promoter Regions, Genetic; RNA Polymerase II - metabolism; RNA, Untranslated - biosynthesis; RNA, Untranslated - genetics; RNA, Untranslated - metabolism; Transcriptional Activation
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gku1169

Recent studies have disclosed the function of enhancer RNAs (eRNAs), which are long non-coding RNAs transcribed from gene enhancer regions, in transcriptional regulation. However, it remains unclear whether eRNAs are involved in the regulation of human heme oxygenase-1 gene (HO-1) induction. Here, we report that multiple nuclear-enriched eRNAs are transcribed from the regions adjacent to two human HO-1 enhancers (i.e. the distal E2 and proximal E1 enhancers), and some of these eRNAs are induced by the oxidative stress-causing reagent diethyl maleate (DEM). We demonstrated that the expression of one forward direction (5' to 3') eRNA transcribed from the human HO-1 E2 enhancer region (named human HO-1enhancer RNA E2-3; hereafter called eRNA E2-3) was induced by DEM in an NRF2-dependent manner in HeLa cells. Conversely, knockdown of BACH1, a repressor of HO-1 transcription, further increased DEM-inducible eRNA E2-3 transcription as well as HO-1 expression. In addition, we showed that knockdown of eRNA E2-3 selectively down-regulated DEM-induced HO-1 expression. Furthermore, eRNA E2-3 knockdown attenuated DEM-induced Pol II binding to the promoter and E2 enhancer regions of HO-1 without affecting NRF2 recruitment to the E2 enhancer. These findings indicate that eRNAE2-3 is functional and is required for HO-1 induction.