Histone H3

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H3 histone, family 3A
Identifiers
Symbol H3F3A
Alt. Symbols H3F3
Entrez 3020
HUGO 4764
OMIM 601128
RefSeq NM_002107
UniProt Q66I33
Other data
Locus Chr. 1 q41
H3 histone, family 3B (H3.3B)
Identifiers
Symbol H3F3B
Entrez 3021
HUGO 4765
OMIM 601058
RefSeq NM_005324
UniProt P84243
Other data
Locus Chr. 17 q25

Histone H3 is one of the five main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N-terminal tail, H3 is involved with the structure of the nucleosomes of the 'beads on a string' structure.

The N-terminal tail of histone H3 protrudes from the globular nucleosome core and can undergo several different types of epigenetic modifications that influence cellular processes. These modifications include the covalent attachment of methyl or acetyl groups to lysine and arginine amino acids and the phosphorylation of serine or threonine. Methylation of lysine9 has been associated with gene silencing and the formation of relatively inactive regions of DNA known as heterochromatin. Acetylation of histone H3 occurs at several different lysine positions in the histone tail and is performed by a family of enzymes known as Histone Acetyl Transferases (HATs). Acetylation of lysine14 is commonly seen in genes that are being actively transcribed into RNA.

Other histone proteins involved: H1 H2A H2B H4

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