Histone H2A (H2A)

Histone H2A is one of the four core histones that form the nucleosome—the fundamental unit of chromatin structure in eukaryotic cells. Each nucleosome consists of an octamer containing two copies each of histones H2A, H2B, H3, and H4 around which approximately 147 base pairs of DNA are wrapped. The primary function of Histone H2A is to package DNA into higher-order structures within the nucleus; this compaction regulates access to genetic information for processes such as transcription, replication, recombination, and repair. Multiple variants exist—such as macroH2A (involved in X-chromosome inactivation), γ-H2AX (DNA damage response), and others—that confer specialized functions including epigenetic regulation and participation in cellular responses to stress or damage. Post-translational modifications on its N-terminal tail modulate interactions with other proteins involved in gene silencing/activation or recruitment during the DNA damage response pathway.

Other names

Core histone H2AHistone cluster 1, H2a family memberMacroH2A (for specific variants)H2A.X (variant)H2A.Z (variant)

Not applicable for direct targeting. Indirect mechanisms include modulation of post-translational modifications affecting gene expression and DNA repair through upstream enzyme inhibition