title: Histone H4 Methyltransferase Suv420h2 Maintains Fidelity of Osteoblast Differentiation.
abstract: Osteogenic lineage commitment and progression is controlled by multiple signaling pathways (e.g., WNT, BMP, FGF) that converge on bone-related transcription factors. Access of osteogenic transcription factors to chromatin is controlled by epigenetic regulators that generate post-translational modifications of histones ("histone code"), as well as read, edit and/or erase these modifications. Our understanding of the biological role of epigenetic regulators in osteoblast differentiation remains limited. Therefore, we performed next-generation RNA sequencing (RNA-seq) and established which chromatin-related proteins are robustly expressed in mouse bone tissues (e.g., fracture callus, calvarial bone). These studies also revealed that cells with increased osteogenic potential have higher levels of the H4K20 methyl transferase Suv420h2 compared to other methyl transferases (e.g., Suv39h1, Suv39h2, Suv420h1, Ezh1, Ezh2). We find that all six epigenetic regulators are transiently expressed at different stages of osteoblast differentiation in culture, with maximal mRNAs levels of Suv39h1 and Suv39h2 (at day 3) preceding maximal expression of Suv420h1 and Suv420h2 (at day 7) and developmental stages that reflect, respectively, early and later collagen matrix deposition. Loss of function analysis of Suv420h2 by siRNA depletion shows loss of H4K20 methylation and decreased expression of bone biomarkers (e.g., alkaline phosphatase/Alpl) and osteogenic transcription factors (e.g., Sp7/Osterix). Furthermore, Suv420h2 is required for matrix mineralization during osteoblast differentiation. We conclude that Suv420h2 controls the H4K20 methylome of osteoblasts and is critical for normal progression of osteoblastogenesis. J. Cell. Biochem. 118: 1262-1272, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Khani
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Roman
authors.initials: R
authors.lastname: Thaler
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Paradise
authors.affiliation: Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota.
authors.forename: David R
authors.initials: DR
authors.lastname: Deyle
authors.affiliation: Department of Urology and Department of Clinical Research, University of Bern, Bern, Switzerland.
authors.forename: Marianne
authors.initials: M
authors.lastname: Kruijthof-de Julio
authors.affiliation: Faculty of Medicine, Millennium Institute on Immunology and Immunotherapy, University of Chile, Santiago, Chile.|Faculty of Medicine, Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile.
authors.forename: Mario
authors.initials: M
authors.lastname: Galindo
authors.affiliation: Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Gordon
authors.affiliation: Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont.
authors.forename: Gary S
authors.initials: GS
authors.lastname: Stein
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Amel
authors.initials: A
authors.lastname: Dudakovic
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota.|Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Andre J
authors.initials: AJ
authors.lastname: van Wijnen
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D044127:Epigenesis, Genetic; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics* / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D008745:Methylation; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D010012:Osteogenesis; D017423:Sequence Analysis, RNA
chemical_list: D015415:Biomarkers; D006657:Histones; D011495:Histone-Lysine N-Methyltransferase; C542918:KMT5C protein, human
keywords: BONE; DIFFERENTIATION; EPIGENETICS; EPIGENOME; HISTONE; METHYL TRANSFERASE; OSTEOBLAST; OSTEOCYTE