HBO1

HBO1 (histone acetyltransferase binding to ORC1), also known as KAT7/MYST2, is a member of the MYST family of histone acetyltransferases and functions as a major chromatin-modifying enzyme that regulates histone H3 and H4 acetylation, thereby influencing transcription, DNA replication, and genome maintenance^[1][2]. Mechanistically, HBO1 operates within multiprotein chromatin complexes containing JADE, ING, and MEAF6 family proteins, where scaffold subunits direct chromatin targeting and histone substrate specificity^[3][4]. Through these complexes, HBO1 contributes to chromatin-associated acetylation events that support DNA replication licensing, cell-cycle progression, and gene expression programs^[2][4][5]. Studies in epithelial regeneration and kidney injury models further demonstrate that HBO1-associated complexes participate in proliferative responses and correlate with histone H4 acetylation during tissue recovery^[6]. Disease-oriented investigations have linked aberrant HBO1 expression or activity to multiple cancer contexts, including osteosarcoma and other solid tumors, supporting its relevance as a regulator of tumor-associated chromatin states^[5][7]. Compared with related MYST acetyltransferases, HBO1 is distinguished by its assembly with alternative JADE or BRPF family cofactors, which can alter histone tail specificity and chromatin recruitment mechanisms^[3][4]. For experimental applications, the selective small-molecule inhibitor WM-3835 has been used to suppress HBO1-dependent acetylation and proliferation phenotypes, providing a useful tool for mechanistic studies of HBO1-regulated pathways^[5].