Chromatin accessibility classification of TAD boundaries discloses new chromatin insulators (Hi-C 1)

Structural proteins such as CTCF and the cohesin complex have been identified enriched at domain boundaries. However, we still lack a complete understanding of the function of boundaries and what makes one boundary more effective at insulating genomic interactions than others.

To understand how domains are structured, we experimentally classified boundaries according to their accessibility degree as a proxy of protein occupancy in K562 human cells. To determine if accessibility indeed reflects more robust boundaries and domains, we experimentally explored whether domain boundaries exhibit different degrees of accessibility in K562 cell line. To do so, we performed Hi-C experiments varying the incubation time of digestion with the restriction enzyme.