Histone H3-H4 complex (H3/H4)

Histone H3 and H4 are highly conserved core proteins that associate to form a (H3-H4)2 tetramer, which constitutes the central scaffold of the nucleosome around which eukaryotic DNA is wrapped (Source 1.1.5, 1.2.4). These proteins play a fundamental role in chromatin architecture, DNA packaging, and the epigenetic regulation of gene expression through various post-translational modifications on their N-terminal tails (Source 1.1.2, 1.4.3). Recent research has also revealed that the H3-H4 tetramer possesses intrinsic oxidoreductase activity, facilitating the reduction of copper ions necessary for mitochondrial respiration and cellular metabolism (Source 1.2.2). In pathological states such as sepsis and acute respiratory distress syndrome (ARDS), histones are released into the extracellular space where they act as potent damage-associated molecular patterns (DAMPs), causing significant endothelial injury, promoting thrombosis, and triggering organ dysfunction (Source 1.5.1, 1.5.3). Therapeutic strategies targeting Histone H3/H4 include the use of neutralizing antibodies (e.g., anti-H4), polyanionic compounds like heparin, and activated protein C to mitigate extracellular toxicity, as well as experimental small molecules designed to disrupt their interactions with histone chaperones in cancer (Source 1.1.1, 1.5.3). Additionally, specific "oncohistone" mutations, such as H3K27M, are critical drivers in certain pediatric cancers, making them important diagnostic and prognostic biomarkers (Source 1.2.1, 1.4.1).

Other names

Histone H3/H4 tetramerHistone H3/H4 dimerCore histones H3 and H4H3-H4 complex

Neutralization of extracellular histone toxicity; Proteolytic cleavage of histones; Inhibition of histone-chaperone interactions; Modulation of copper homeostasis via oxidoreductase activity.