Histone acetylation is linked to
transcriptional activation and increases gene expression. DNA gets
wrapped around histones and transfers acetyl groups to histones and
hence genes can be turned on or off.
The modifications in histone helps
to modulate the packaging of chromatin. HAT's neutralizes charged
lysine residues which results in chromatin decondensation, and gene
gets transcribed.
HAT's play as transcriptional
co-activators, gene silencers, and can be seen as complexes with 20
subunits which are PCAF, ADA-Adaptor, Transcription factor II D
etc.. These complexes takes HAT's to target genes to acetylate
nucleosomal histones.
HAT's transfers an acetyl group to
lysine residues thereby neutralizing thier positive charge and also
lessens the interactions of histone and DNA.