An inhibitor of p300 histone acetylase is isolated and identified from a hum an cDNA library. This inhibitor is a nuclear protein consisting of 855 amino ac id residues. This inhibitor binds to the cysteine/histidine rich domain of p300 and thus inhibits the transcriptional activation by p300. Moreover, it inhibits the transcriptional activity of p53, which is coactivated by p300, to thereby inhibit the cell cycle arrest depending on p53.
P300 HISTONE ACETYLASE INHIBITOR