H4K5ac is synthesized histone H4 peptide corresponding to residues within 1-102 of human histone H4 with acetylation K5 modification. H4K5 is acetylated by TIP60 and CBP/p300 proteins. CAP/p300 open transcriptional start site chromatin by acetylating histones. H4K5ac has also been implicated in epigenetic bookmarking which allows gene expression patterns to be faithfully passed to daughter cells through mitosis. Important cell-type specific genes are marked in some way that prevents them from being compacted during mitosis and ensures their rapid transcription. H4K5ac appears to prime activity-dependent genes expressed during learning.
