the relationship of ATAC-seq and H3K27ac

Question

[biohubx]

Hello, ATAC-seq/DNase-seq are mainly used to identify open chromatin regions/accessible chromatin. H3K27ac is a active enhancer marker. Does anyone know what the relationship of open chromatin regions and H3K27ac? Do all H3K27ac binding sites overlap/intersect with open chromatin regions?

Answer 1

[ATpoint]

One would expect a notable overlap between H3K27ac and open chromatin, but open chromatin is a very focal signal, usually < 1kb per peak while H3K27ac can well stretch several kilobases.

[i.sudbery]

Also, there are reasons for chromatin to be open other than for enhancer activity.

[biohubx]

maybe a little intersection of open chromatin regions and H3K27ac peaks

Answer 2

[dsull]

"elements with strong DNase-seq signal but no H3K27ac ChIP–seq signal might be CTCF-bound topological elements, and elements with strong H3K27ac signal but no DNase-seq signal might be sequences that are close to strong enhancers, but do not per se have enhancer activity due to the spreading H3K27ac signal over hundreds to thousands of base pairs"

• From https://www.nature.com/articles/s41588-019-0538-0