Figure 1.

A model for enhancer-promoter interactions within the nucleus of a cell. Enhancers may be located far away in linear distance to their target genes, but are brought into close proximity to these genes via chromatin loops and higher order chromatin structure. Enhancers are bound by sequence-specific transcription factors, which in turn facilitate the cooperative binding of chromatin remodeling enzymes, histone modifying enzymes, other co-factors, and ultimately the RNA polymerase II complex (RNA pol II). Both the target genes and the enhancers are transcribed by RNA pol II. Transcription of the enhancers give rise to non-coding RNA molecules called enhancer RNAs (eRNAs).