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{{Short description|Proposed biochemical transcription of genetic information}}
The '''histone code''' is a [[hypothesis]] that the transcription of genetic information encoded in [[DNA]] is in part regulated by chemical modifications to [[histone]] proteins, primarily on their unstructured ends. Together with similar modifications such as [[DNA methylation]] it is part of the [[epigenetic code]].<ref name="Jenuwein">{{cite journal |vauthors=Jenuwein T, Allis C |title=Translating the histone code |journal=Science |volume=293 |issue=5532 |pages=1074–80 |year=2001 |pmid=11498575 |doi=10.1126/science.1063127|citeseerx=10.1.1.453.900 |s2cid=1883924 }}</ref> Histones associate with [[DNA]] to form [[nucleosome]]s, which themselves bundle to form [[chromatin]] fibers, which in turn make up the more familiar [[chromosome]]. Histones are globular proteins with a flexible [[N-terminus]] (taken to be the tail) that protrudes from the nucleosome. Many of the histone tail modifications correlate very well to chromatin structure and both histone modification state and chromatin structure correlate well to gene expression levels. The critical concept of the '''histone code hypothesis''' is that the histone modifications serve to recruit other proteins by specific recognition of the modified histone via [[protein ___domain]]s specialized for such purposes, rather than through simply stabilizing or destabilizing the interaction between histone and the underlying DNA. These recruited proteins then act to alter chromatin structure actively or to promote transcription.
For details of gene expression regulation by histone modifications see [[Histone code#Modifications|table below]].
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