A recent integrative study on human cells that included analysis of chromatin state maps, transcription factor-binding sites and modelling of enhancer-gene pairs combined with GWAS studies of autoimmunity-associated SNPs suggest a direct role for distal regulatory elements in disease aetiology.
Here, we give an overview of emerging principles of enhancer function, current models of enhancer architecture, genomic substrates from which enhancers emerge during evolution, and the influence of three-dimensional genome organization on long-range gene regulation.
The authors conclude with a 3-step model of enhancer activation during adipogenesis.
Collectively, our data suggest a stepwise model of enhancer activation during adipogenesis.
Combined with our earlier observations, these results suggest a step-wise model of enhancer activation during cell differentiation.
(E ) Molecular model of enhancer segment within the invertasome structure ('Discussion', 'Material and methods', and Figure 7C ).
These enhancers might help shed light on the factors driving the evolution of gene regulatory sequences and developing models of enhancer evolution.
1) The three-step model of enhancer activation is not directly supported by the experiments because there is no evaluation of the intermediates in the model.
The modeling of enhancer evolution at the macroevolutionary scale and their rate analyses revealed an evolutionary inclination toward diverse genomic landscapes.
For example, our model could be used to shed light on shadow enhancers (Perry et al. 2010; Barolo 2012), by using the GEMSTAT-GL model of locus-level modeling for regulatory function prediction instead of the GEMSTAT model of enhancer function.
In any case, our results clearly show that cHS4 affects gene expression in a way that is more complex than previously believed since the suppression of transgene-mediated insertional activation of this element is promoter specific and is not well described by simple directional models of enhancer-blocking activity.
