Histone acetyltransferase complexes and H3K4me3-marked chromatin (HAT/H3K4me3)

Histone acetyltransferase (HAT) complexes and H3K4me3-marked chromatin represent a critical functional interface in the epigenetic regulation of eukaryotic gene expression. H3K4me3 (trimethylation of lysine 4 on histone H3) is a canonical marker of active promoters that serves as a docking site for reader proteins, including subunits of HAT complexes like SAGA and NuA4 (Taverna et al., 2007, Nature). These complexes utilize specialized domains, such as PHD fingers, to recognize H3K4me3, thereby localizing acetyltransferase activity to specific genomic regions to promote an open chromatin state and facilitate transcription (Lee and Workman, 2007, Nat Rev Mol Cell Biol). In many cancers, this interaction is dysregulated, leading to the aberrant expression of oncogenes or the silencing of tumor suppressors (Wang et al., 2021, Front Oncol). Therapeutic targeting of this system involves small-molecule inhibitors of HAT enzymes, such as p300/CBP or Tip60, or antagonists of the reader domains that mediate chromatin recruitment. While promising, targeting these broad epigenetic regulators poses challenges due to the potential for widespread transcriptional disruption and off-target effects in healthy tissues.

Other names

HAT-H3K4me3 interactionH3K4me3-recruited HAT complexesActive chromatin regulatory unitEpigenetic reader-writer complexes

Inhibition of the catalytic activity of histone acetyltransferase enzymes (e.g., KAT2A, EP300, KAT5) or the competitive antagonism of reader domains (e.g., PHD fingers, bromodomains) that recognize H3K4me3, thereby preventing the recruitment of HAT complexes to active chromatin sites and suppressing gene transcription.