A hydrophilic polymer grafted with a histone tail peptide as an artificial gene regulator

In chromatin, gene transcription is regulated through posttranslational modifications on the histone N-terminal tail sequences, typically an acetyl group modification on lysine residues. To realize a simple model of the gene regulation of chromatin, we designed a hydrophilic polymer grafted with histone H3 tail peptides. The polyplex formed from the polymer and DNA suppressed the gene expression effectively although the polyplex was weaker than the polyplex of poly-l-lysine and DNA. This weaker polyplex afforded the acetylation of the lysine residue of the grafted peptides by histone acetyltransferase. Subsequently, the gene expression was activated due to the relaxation of the polyplex which was brought by a cationic charge decrease in the grafted peptides. This molecular system is the first functional model of the gene regulation of the chromatin.