HBO1 (KAT7) Does Not Have an Essential Role in Cell Proliferation, DNA Replication, or Histone 4 Acetylation in Human Cells

ABSTRACT

HBO1 (MYST2/KAT7) is essential for histone 3 lysine 14 acetylation (H3K14ac) but is dispensable for H4 acetylation and DNA replication in mouse tissues. In contrast, previous studies using small interfering RNA (siRNA) knockdown in human cell lines have suggested that HBO1 is essential for DNA replication. To determine if HBO1 has distinctly different roles in immortalized human cell lines and normal mouse cells, we performed siRNA knockdown of HBO1. In addition, we used CRISPR/Cas9 to generate 293T, MCF7, and HeLa cell lines lacking HBO1. Using both techniques, we show that HBO1 is essential for all H3K14ac in human cells and is unlikely to have a direct effect on H4 acetylation and only has minor effects on cell proliferation. Surprisingly, the loss of HBO1 and H3K14ac in HeLa cells led to the secondary loss of almost all H4 acetylation after 4 weeks. Thus, HBO1 is dispensable for DNA replication and cell proliferation in immortalized human cells. However, while cell proliferation proceeded without HBO1 and H3K14ac, HBO1 gene deletion led to profound changes in cell adhesion, particularly in 293T cells. Consistent with this phenotype, the loss of HBO1 in both 293T and HeLa principally affected genes mediating cell adhesion, with comparatively minor effects on other cellular processes.

KEYWORDS:

• histone acetylation
• HBO1
• MYST2
• KAT7
• chromatin

SUPPLEMENTAL MATERIAL

Supplemental material is available online only.

ACKNOWLEDGMENTS

We thank Stephen Wilcox, Liz Milla, Liam O’Connor, and the WEHI Systems Biology and Personalized Medicine division for help with next-generation sequencing of CRISPR/Cas9-induced indels.

This work was supported by the Australian National Health and Medical Research Council under senior research fellowships 1003435 (T.T.) and 575512 (A.K.V.) and project grants 1029481, 103070, 1051078 (to T.T. and A.K.V.), and 1049720 (to M.J.H.) and by operational infrastructure grants from the Australian Federal Government (IRISS) and the Victorian State Government (OIS).

A.J.K., S.E., R.E.M., and L.T. carried out experiments. A.J.K., T.T., A.L.G., G.K.S., and A.K.V. analyzed data. T.T. conceived and initiated the project. A.K.V. and T.T. supervised the project. A.J.K., T.T., and A.K.V. wrote the manuscript. M.J.H. contributed ideas and reagents and interpreted results.

We declare no conflict of interest.