title: Spaciotemporal association and bone morphogenetic protein regulation of sclerostin and osterix expression during embryonic osteogenesis.
abstract: Sclerostin (SOST), a member of the cystine-knot superfamily, is essential for proper skeletogenesis because a loss-of-function mutation in the SOST gene results in sclerosteosis featured with massive bone growth in humans. To understand the function of SOST in developmental skeletal tissue formation, we examined SOST gene expression in embryonic osteogenesis in vitro and in vivo. During osteoblastic differentiation in primary calvarial cells, the levels of SOST expression were increased along with those of alkaline phosphatase activity and nodule formation. In situ hybridization study revealed that SOST mRNA expression was observed in the digits in embryonic 13-d limb buds, and SOST expression was observed in osteogenic front in embryonic 16.5-d postcoitus embryonic calvariae, and this expression persisted in the peripheral area of cranial bone in the later developmental stage (embryonic 18.5-d post coitum). These temporal and spacial expression patterns in vivo and in vitro were in parallel to those of osterix (Osx), which is a critical transcriptional factor for bone formation. Similar coexpression of SOST and Osx mRNA was observed when the primary osteoblastic calvarial cells were cultured in the presence of bone morphogenetic protein (BMP)2 in vitro. Moreover, endogenous expression of SOST and Osx mRNA was inhibited by infection of noggin-expression adenovirus into the primary osteoblastic calvarial cells, suggesting that endogenous BMPs are required for these cells to express SOST and Osx mRNA. Thus, expression and regulation of SOST under the control of BMP were closely associated with those of Osx in vivo and in vitro.
authors.affiliation: Department of Molecular Pharmacology, Tokyo Medical and Dental University, 3-10 Kanda-Surugadai 2-Chome, Chiyoda-ku, Tokyo, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ohyama
authors.forename: Akira
authors.initials: A
authors.lastname: Nifuji
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Maeda
authors.forename: Teruo
authors.initials: T
authors.lastname: Amagasa
authors.forename: Masaki
authors.initials: M
authors.lastname: Noda
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D021461:Animals, Outbred Strains; D001846:Bone Development; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology*; D001842:Bone and Bones / Q000196:embryology*; D002352:Carrier Proteins; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D005314:Embryonic and Fetal Development; D018507:Gene Expression Regulation, Developmental; D018014:Gene Transfer Techniques; D005819:Genetic Markers / Q000235:genetics; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D010006:Osteoblasts / Q000166:cytology; D011506:Proteins / Q000235:genetics / Q000494:pharmacology; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D012886:Skull / Q000196:embryology; D000076182:Sp7 Transcription Factor; D013997:Time Factors; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta; D000099176:Noggin Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D005819:Genetic Markers; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D000099176:Noggin Protein; C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; C486030:Sost protein, mouse; C479466:Sp7 protein, mouse