Are genes switched on when they kiss?

Chromatin loops are pervasive and permit the tight compaction of DNA within the confined space of the nucleus. Looping enables distal genes and DNA elements to engage in chromosomal contact, to form multigene complexes. Advances in biochemical and imaging techniques reveal that loop-mediated contact is strongly correlated with transcription of interacting DNA. However, these approaches only provide a snapshot of events and therefore are unable to reveal the dynamics of multigene complex assembly. This highlights the necessity to develop single cell-based assays that provide single molecule resolution, and are able to functionally interrogate the role of chromosomal contact on gene regulation. To this end, high-resolution single cell imaging regimes, combined with genome editing approaches, are proving to be pivotal to advancing our understanding of loop-mediated dynamics.