This application is guided by two questions: 1) how is OB-specific transcription achieved? What DNA elements and transcription factors combine to direct expression of a gene on osteoblasts (Obs), but not in other cell types?; and 2) how do osteogenic anabolic signals (PTH/cAMP, IGFs, FGFs, BMPs), acting through kinase cascades, regulate the OB-specific transcriptional machinery during development, bone growth and fracture repair? The two Specific Aims of this proposal are: 1) to understand how Msx2 regulates the osteoblast-specific transcriptional machinery, using the rat OC promoter as a model. Msx2 recognizes and regulates the rat OC promoter via the Hoxbox-1 element, presenting the unique opportunity to examine interactions between a homeodomain transcription factor and an osteoblast-specific promoter. By systematic mutation of Msx2 and co-transfection assays with rat promoter-luciferase reporter in cell lines, structure-function analyses will be performed. Included will be a homeodomain mutation described by others in the human MSX2 gene as responsible for craniosynostosis, Boston type. It is further proposed to purify and characterize positively acting factors, supporting OC promoter activity, using classical biochemical techniques. Nuclear factors that were recently defined as recognizing sequences in the adjacent, interacting FGF2/cAMP response elements will be emphasized. Protein-protein interactions necessary for Msx2 action will be characterized with epitope-tagged recombinant Msx2; 2) to define the role of Msx2 developmental osteobiology, mineralization, and skeletal morphogenesis. Expanded pan-osseous expression of Msx2 will be directed in transgenic mice with the full length 1.8kb rat OC promoter. This system will define the role of Msx2 as a regulator of osteoblast proliferation, differentiation, gene expression, and mineralization.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR043731-02
Application #
2442843
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1996-07-15
Project End
2000-06-30
Budget Start
1997-07-01
Budget End
1998-06-30
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Washington University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Sierra, Oscar L; Towler, Dwight A (2010) Runx2 trans-activation mediated by the MSX2-interacting nuclear target requires homeodomain interacting protein kinase-3. Mol Endocrinol 24:1478-97
Towler, Dwight A (2008) Oxidation, inflammation, and aortic valve calcification peroxide paves an osteogenic path. J Am Coll Cardiol 52:851-4
Cheng, Su-Li; Shao, Jian-Su; Cai, Jun et al. (2008) Msx2 exerts bone anabolism via canonical Wnt signaling. J Biol Chem 283:20505-22
Towler, Dwight A (2007) Calciotropic hormones and arterial physiology: ""D""-lightful insights. J Am Soc Nephrol 18:369-73
Towler, Dwight A (2007) Imaging aortic matrix metabolism: mirabile visu! Circulation 115:297-9
Towler, Dwight A; Shao, Jian-Su; Cheng, Su-Li et al. (2006) Osteogenic regulation of vascular calcification. Ann N Y Acad Sci 1068:327-33
Towler, Dwight A (2005) Inorganic pyrophosphate: a paracrine regulator of vascular calcification and smooth muscle phenotype. Arterioscler Thromb Vasc Biol 25:651-4
Shao, Jian-Su; Cheng, Su-Li; Pingsterhaus, Joyce M et al. (2005) Msx2 promotes cardiovascular calcification by activating paracrine Wnt signals. J Clin Invest 115:1210-20
Vattikuti, Radhika; Towler, Dwight A (2004) Osteogenic regulation of vascular calcification: an early perspective. Am J Physiol Endocrinol Metab 286:E686-96
Towler, Dwight A (2004) Vascular calcification in ESRD: Another cloud appears in the perfect storm--but highlights a silver lining? Kidney Int 66:2467-8

Showing the most recent 10 out of 21 publications