## Description

Chemical modifications (e.g. methylation and acylation) to the histone proteins present in chromatin influence gene expression by changing how accessible the chromatin is to transcription. A specific modification of a specific histone protein is called a histone mark. This track shows the levels of enrichment of the H3K27Ac histone mark across the genome as determined by a ChIP-seq assay. The H3K27Ac histone mark is the acetylation of lysine 27 of the H3 histone protein, and it is thought to enhance transcription possibly by blocking the spread of the repressive histone mark H3K27Me3. Additional histone marks and other chromatin associated ChIP-seq data is available at the Broad Histone page.

## Display conventions

By default this track uses a transparent overlay method of displaying data from a number of cell lines in the same vertical space. Each of the cell lines in this track is associated with a particular color, and these cell line colors are consistent across all tracks that are part of the ENCODE Regulation supertrack. These colors are relatively light and saturated so as to work best with the transparent overlay. Unfortunately, outside the ENCODE Regulation tracks, older cell line color conventions are used that don't match the cell line colors used in the ENCODE Regulation tracks. The older colors were not used in the ENCODE Regulation tracks because they were too dark for the transparent overlay.

## Credits

This track shows data from the Bernstein Lab at the Broad Institute. The Bernstein lab is part of the ENCODE consortium.

## Data Release Policy

Data users may freely use ENCODE data, but may not, without prior consent, submit publications that use an unpublished ENCODE dataset until nine months following the release of the dataset. This date is listed in the Restricted Until column, above. The full data release policy for ENCODE is available here.