title: Insulin-like growth factor-II regulates bone sialoprotein gene transcription.
abstract: Insulin-like growth factor-I and -II (IGF-I and IGF-II) have been found in bone extracts of several different species, and IGF-II is the most abundant growth factor stored in bone. Bone sialoprotein (BSP) is a noncollagenous extracellular matrix glycoprotein associated with mineralized connective tissues. In this study, we have investigated the regulation of BSP transcription by IGF-II in rat osteoblast-like ROS17/2.8 cells. IGF-II (50 ng/ml) increased BSP mRNA and protein levels after 6-h stimulation, and enhanced luciferase activities of the constructs pLUC3 (-116 to +60), pLUC4 (-425 to +60), pLUC5 (-801 to +60) and pLUC6 (-938 to +60). Effects of IGF-II were inhibited by tyrosine kinase, extracellular signal-regulated kinase1/2 and phosphatidylinositol 3-kinase inhibitors, and abrogated by 2-bp mutations in cAMP response element (CRE), FGF2 response element (FRE) and homeodomain protein-binding site (HOX). The results of gel shift assays showed that nuclear proteins binding to CRE, FRE and HOX sites were increased by IGF-II (50 ng/ml) at 3 and 6 h. CREB1, phospho-CREB1, c-Fos and c-Jun antibodies disrupted the formation of the CRE-protein complexes. Dlx5 and Runx2 antibodies disrupted the FRE- and HOX-protein complex formations. These studies therefore demonstrated that IGF-II increased BSP transcription by targeting CRE, FRE and HOX elements in the proximal promoter of the rat BSP gene. Moreover, phospho-CREB1, c-Fos, c-Jun, Dlx5 and Runx2 transcription factors appear to be key regulators of IGF-II effects on BSP transcription.
authors.affiliation: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan.
authors.forename: Jin
authors.initials: J
authors.lastname: Choe
authors.affiliation: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan.|Anhui Medical University of Stomatology Hospital, Anhui, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Periodontology and Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Takai
authors.affiliation: Department of Periodontology and Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Nakayama
authors.affiliation: Department of Periodontology and Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan. ogata.yorimasa@nihon-u.ac.jp.
authors.forename: Yorimasa
authors.initials: Y
authors.lastname: Ogata
mesh_terms: D000818:Animals; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics; D016222:Fibroblast Growth Factor 2 / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics; D007335:Insulin-Like Growth Factor II / Q000502:physiology*; D058574:Integrin-Binding Sialoprotein / Q000235:genetics*; D009154:Mutation; D010006:Osteoblasts / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011505:Protein-Tyrosine Kinases / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D014157:Transcription Factors / Q000502:physiology; D014158:Transcription, Genetic
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D018398:Homeodomain Proteins; D058574:Integrin-Binding Sialoprotein; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012333:RNA, Messenger; D014157:Transcription Factors; D016222:Fibroblast Growth Factor 2; D007335:Insulin-Like Growth Factor II; D011505:Protein-Tyrosine Kinases
keywords: Bone formation; Bone sialoprotein; IGF-II; Osteoblasts; Transcription