## Description

This track displays maps of chromatin state of ENCODE cell types. Chemical modifications (methylation, acylation) to the histone proteins present in chromatin influence gene expression by changing how accessible the chromatin is to transcription.
The ChIP-seq method involves cross-linking histones and other DNA associated proteins to genomic DNA within cells using formaldehyde. The cross-linked chromatin is subsequently extracted, mechanically sheared, and immunoprecipitated using specific antibodies. After reversal of cross-links, the immunoprecipitated DNA is sequenced and mapped to the human reference genome. The relative enrichment of each antibody-target (epitope) across the genome is inferred from the density of mapped fragments.

## Display Conventions

These tracks are multi-view composite tracks that contains multiple data types (views). For each view, there are multiple subtracks that display individually on the browser. Each view within each track has separate display controls, as described here. Specific aspects of the views vary by track. The views include:
Peaks
Regions of significant ChIP-Seq affinity.
Signal
The density of tags mapping within a sliding window.
Raw Signal
Density graph (wiggle) of signal enrichment based on aligned read density.

## Credits

These data were generated and analyzed as part of the ENCODE project, a genome-wide consortium project with the aim of cataloging all functional elements in the human genome. This effort includes collecting a variety of data over a specific set of cell types. Consequently, data related to these tracks be available under ENCODE tracks.

## References

Segal E, Widom J. What controls nucleosome positions? Trends Genet. 2009 Aug;25(8):335-43.
Geiman TM, Robertson KD. Chromatin remodeling, histone modifications, and DNA methylation-how does it all fit together? J Cell Biochem. 2002;87(2):117-25.

## 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Data users may freely use ENCODE data, but may not, without prior consent, submit publications that use an unpublished ENCODE dataset until nine months following the release of the dataset.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 on the track configuration page and the download page. The full data release policy for ENCODE is available here.