Abstract
A proteomic analysis of proteins bound to the osteocalcin OSE2 sequence of the mouse osteocalcin promoter identified TRPS1 as a regulator of osteocalcin transcription. Mutations in the TRPS1 gene are responsible for human tricho-rhino-phalangeal syndrome, which is characterized by skeletal and craniofacial abnormalities. TRPS1 has been shown to bind regulatory promoter sequences containing GATA consensus binding sites and to repress transcription of genes involved in chondrocyte differentiation. Here we show that TRPS1 can directly bind the osteocalcin promoter in the presence or absence of Runx2. TRPS1 binds through a GATA binding sequence in the proximal promoter of the osteocalcin gene. The GATA binding site is conserved in mice, humans, and rats, although its location and orientation are not. Mutation of the mouse or human GATA binding sequence abrogates binding of TRPS1 to the osteocalcin promoter. We show that TRPS1 is expressed in osteosarcoma cells and upon induction of osteoblast differentiation in primary mouse bone marrow stromal cells and that TRPS1 regulates the expression of osteocalcin in both cell types. The expression of TRPS1 modulates mineralized bone matrix formation in differentiating osteoblast cells. These data suggest a role for TRPS1 in osteoblast differentiation, in addition to its previously described role in chondrogenesis.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Androgens / pharmacology
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Animals
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Binding Sites
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Blotting, Western
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Bone Density Conservation Agents / pharmacology
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Bone Marrow / drug effects
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Bone Marrow / metabolism
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Bone Neoplasms / genetics
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Bone Neoplasms / metabolism
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Bone Neoplasms / pathology
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Calcification, Physiologic / drug effects
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Cell Differentiation
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Cells, Cultured
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Cholecalciferol / pharmacology
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Chromatin Immunoprecipitation
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Chromatography, Liquid
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Core Binding Factor Alpha 1 Subunit / genetics
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Core Binding Factor Alpha 1 Subunit / metabolism
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DNA Primers
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DNA, Neoplasm / genetics
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DNA, Neoplasm / metabolism
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DNA-Binding Proteins / antagonists & inhibitors
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Enzyme-Linked Immunosorbent Assay
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GATA Transcription Factors / antagonists & inhibitors
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GATA Transcription Factors / genetics
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GATA Transcription Factors / metabolism*
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Gene Expression Regulation*
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Humans
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Immunoprecipitation
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Luciferases / metabolism
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Mice
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Osteoblasts / metabolism
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Osteocalcin / genetics*
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Osteosarcoma / genetics
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Osteosarcoma / metabolism
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Osteosarcoma / pathology
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Promoter Regions, Genetic / genetics*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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RNA, Small Interfering / pharmacology
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Rats
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Regulatory Sequences, Nucleic Acid
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Repressor Proteins / antagonists & inhibitors
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Repressor Proteins / genetics
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Repressor Proteins / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Stromal Cells / drug effects
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Stromal Cells / metabolism
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Transcription Factors / antagonists & inhibitors
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transfection
Substances
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Androgens
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Bone Density Conservation Agents
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Core Binding Factor Alpha 1 Subunit
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DNA Primers
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DNA, Neoplasm
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DNA-Binding Proteins
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GATA Transcription Factors
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RNA, Messenger
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RNA, Small Interfering
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Repressor Proteins
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TRPS1 protein, human
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Transcription Factors
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Trps1 protein, mouse
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Osteocalcin
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Cholecalciferol
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Luciferases