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euchromatin
Euchromatin is a lightly packed form of chromatin (DNA, RNA and protein) that is enriched in genes, and is often (but not always) under active transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus. 92% of the human genome is euchromatic. The remainder is called heterochromatin. ==Structure==
The structure of euchromatin is reminiscent of an unfolded set of beads along a string, wherein those beads represent nucleosomes. Nucleosomes consist of eight proteins known as histones, with approximately 147 base pairs of DNA wound around them; in euchromatin, this wrapping is loose so that the raw DNA may be accessed. Each core histone possesses a `tail' structure, which can vary in several ways; it is thought that these variations act as "master control switches," which determine the overall arrangement of the chromatin. In particular, it is believed that the presence of methylated lysine 4 on the histone tails acts as a general marker for euchromatin.
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「euchromatin」の詳細全文を読む
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