In the cell, transcription is regulated in part by the histone modification of chromatin. Specifically, histone acetyltransferase proteins and their associated complexes function with co-activators to regulate transcription. One family of histone acetyltransferases is the MYST family of transcriptional silencers, which is linked to ORC (origin recognition complex) function. The ORC is an initiator protein for DNA replication and mediates the acetylation of chromatin to control both DNA replication and gene expression. HBO1 (histone acetyltransferase binding to ORC) is a MYST family protein that interacts with ORC1, the largest subunit of the human ORC complex. 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.
Function:
Component of the HBO1 complex which has a histone H4-specific acetyltransferase activity, a reduced activity toward histone H3 and is responsible for the bulk of histone H4 acetylation in vivo. Through chromatin acetylation it may regulate DNA replication and act as a coactivator of TP53-dependent transcription. Specifically represses AR-mediated transcription.
Subcellular Location:
Nucleus; nucleoplasm.
Tissue Specificity:
Ubiquitously expressed, with highest levels in testis.
Post-translational modifications:
Phosphorylated upon DNA damage, probably by ATM or ATR.
Similarity:
Belongs to the MYST (SAS/MOZ) family.
Contains 1 C2HSLCtype zinc finger.
SWISS:
O95251
Gene ID:
11143
Database links:
Entrez Gene: 11143 Human
Entrez Gene: 217127 Mouse
Entrez Gene: 303470 Rat
Omim: 609176 Human
SwissProt: O95251 Human
SwissProt: Q5SVQ0 Mouse
SwissProt: Q810T5 Rat
Unigene: 21907 Human
Unigene: 90213 Mouse
Unigene: 12618 Rat
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