The embryogenesis and regeneration of the skeleton are complex developmental events dependent on the successful induction of endochondral osteogenesis. Little is known, however, about the genetic control of bone induction. Bone morphogenetic proteins (BMPs) are members of a highly conserved family of molecules involved in the regulation of embryonic pattern formation and osteogenesis. Recombinant human BMP-4 can induce the entire developmental program of endochondral osteogenesis in an ectopic site in a manner identical to that seen in the autosomal dominant genetic disorder, fibrodysplasia ossificans progressive (FOP). FOP is a progressively disabling condition characterized by congenital malformations of the toes and disordered temporal and spatial induction of endochondral osteogenesis at ectopic sites. BMP-4 messenger RNA and proteins uniquely over-expressed inlymphocytes from patients who have FOP. These data indicate that over expression of BMP-4, a potent bone-inducing morphogen, is associated with disabling ectopic osteogenesis in man. Tow related hypotheses provide the focus for our longterm goals; First, the molecular structure and function of the human BMP-4 gene provides fundamental insight into the genetic regulation of endochondral bone induction and pattern formation in humans; second, BMP-4 is the prime candidate gene for FOP; and the molecular structure and/or regulatory control of that gene is abnormal in patients who have FOP. To address these hypothesis, we intend to: 1. Define the regulatory regions of the human BMP-4 gene by reporter gene expression assays. 2. Identify DNA-binding proteins for the BMP-4 gene in normal and FOP cells by gel mobility shift and footprinting assays using nuclear protein extracts from FOP and non-FOP cells. 3. Examine the rate of BMP-4 transcript initiation and mRNA stability in FOP cells relative to control cells by nuclear run-on and transcription inhibition experiments. 4. Examine the expression of BMP type I and type II receptors in FOP cells by RT-PCR and immunohistochemistry. 5. Identify genetic markers that are closely linked to the BMP-4 gene locus and utilize these markers to establish or exclude genetic linkage of the BMP-4 gene with FOP. Analysis of the regulatory control of the human BPM-4 gene will foster that longterm goal of elucidating basic mechanisms of normal and disordered bone induction, and of designing rational molecular diagnostic and treatment strategies for a wide range of developmental disorders of the skeleton in humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
2R01AR041916-04
Application #
2006286
Study Section
Special Emphasis Panel (ZRG4-ORTH (05))
Project Start
1994-06-01
Project End
2001-05-31
Budget Start
1997-06-01
Budget End
1998-05-31
Support Year
4
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Orthopedics
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Pacifici, Maurizio; Shore, Eileen M (2016) Common mutations in ALK2/ACVR1, a multi-faceted receptor, have roles in distinct pediatric musculoskeletal and neural orphan disorders. Cytokine Growth Factor Rev 27:93-104
Wang, Haitao; Lindborg, Carter; Lounev, Vitali et al. (2016) Cellular Hypoxia Promotes Heterotopic Ossification by Amplifying BMP Signaling. J Bone Miner Res 31:1652-65
Chakkalakal, Salin A; Uchibe, Kenta; Convente, Michael R et al. (2016) Palovarotene Inhibits Heterotopic Ossification and Maintains Limb Mobility and Growth in Mice With the Human ACVR1(R206H) Fibrodysplasia Ossificans Progressiva (FOP) Mutation. J Bone Miner Res 31:1666-75

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