Live-Cell Epigenome Manipulation by Synthetic Histone Acylation Catalyst System

Chemical modifications of histones play a pivotal role in the epigenome and regulation of gene expression, and their abnormality is tightly linked to numerous disease states in humans. Therefore, chemical tools to manipulate epigenome hold promise for both therapy and the elucidation of epigenetic mechanisms. We previously developed the chemical catalyst LANA-DSH, which binds to nucleosomes via a LANA peptide ligand, and selectively acylates proximal histone H2BK120 to the catalyst moiety by acti- vating acyl-CoAs. Thus far, however, histone acylation by a chem- ical catalyst system in living cells has not yet been demonstrated. Here, we report a chemical catalyst system, composed of a nucleo- some-binding catalyst (PEG-LANA-DSH) and a cell-permeable thioester acyl donor (NAC-acyl), that can promote regioselective lysine acylation of histones in living cells. Whereas LANA-DSH is rapidly decomposed in cells, attachment of polyethylene glycol (PEG) to the LANA moiety can prevent this undesired degradation. Increasing the size of PEG conferred LANA with greater in-cell stability, but reduced catalytic activity, indicating that there is an optimum PEG length balancing stability and catalytic activity. The optimized PEG-LANA-DSH catalyst 11 efficiently promoted H2BK120 acetylation in living cells, which subsequently sup- pressed ubiquitination of H2BK120, a mark regulating various chromatin functions, such as transcription and DNA damage re- sponse. Thus, our chemical catalyst system will be useful as a unique tool to manipulate the epigenome for therapeutic purposes or further understanding epigenetic mechanisms.