Enhancer RNA
Enhancers are gene regulatory sequences present at both upstream and downstream of the transcription unit. They are cis-acting elements (50-1000bp) regulating both spatial and temporal control of gene expression e.g. activating in specific cells. Enhancers as non-coding sequences can also be a transcription unit i.e. generating non-coding enhancer RNA (eRNA) regulating the transcription of the gene. eRNA is divided into Class 1, Class 2 and Class 3 (involved in binding with TFs, and controlling gene expression). Due to chromatin folding, these enhancers are spatially close to the promoter while being far linearly. The enhancer is bound by activator proteins which shows specific binding with transcription mediator complex and chromatin regulators thus recruiting RNA Polymerase2. Enhancer units in the genome could be discovered by DNase sensitivity assay, H3K4 methylation pattern (monomethylation - activation, trimethylation - repression), H3K27 acetylation, ChIP analysis of coactivator ...