Enhancing our understanding of enhancers in T-helper cells.

A long-standing question in immunology has been to understand how transcription factors (TF) determine cell-type-specific transcription programs. Traditionally, investigating TFs in immune cells has been limited to measuring the effect of a single TF on a limited number of gene targets. The advent of next generation sequencing methods makes it possible to measure the effects of multiple transcription factors on a genome-wide scale. This holistic approach gives us a better understanding of the influence that multiple TFs have on cell-specific programs. In this issue of European Journal of Immunology, Fang et al. [Eur. J. Immunol. 2015. 45: 3150-3157] show that genomic regions cooccupied with two or more TFs show increased epigenetic histone marks of active enhancers, which correspond to increased transcriptional activity.