O95251

HBO1 is a nuclear protein that is highly expressed in human testis. In addition to binding ORC, HBO1 represses AR (androgen receptor)-mediated transcription by binding AR through its N-terminal transcriptional repression domain. HBO1 may play a role in regulating AR-dependent gene transcription in normal and prostate cancer cells. The protein encoded by this gene is part of the multimeric HBO1 complex, which possesses histone H4-specific acetyltransferase activity. This activity is required for functional replication origins and is involved in transcriptional activation of some genes. In both cases, the acetylation of histone H4 helps unfold chromatin so that the DNA can be accessed and replicated or transcribed.