The studies proposed examine the regulation of the osteocalcin gene as a model for identifying DNA sequences and transcription factors that contribute to the osteoblast phenotype. Osteocalcin knock-out mice have increased bone formation, suggesting that silencers of osteocalcin gene transcription play an important role in the regulation of bone formation. Sequences in the rat osteocalcin gene have been identified that contribute to silencing of osteocalcin-CAT fusion genes. Sequences identical to the core motifs of these elements are found in several other osteoblast genes and these silencers are also induced in a prechondroblastic cell line (MLB13MYC clone 17 [C17]) that acquires an osteoblast-like phenotype in response to BMP-2. One of these silencers will be cloned and characterized along with other factors induced during BMP-directed cell differentiation. Using differential display PCR, four mRNAs that are induced post-BMP-2 treatment of C17 cells have been identified and the applicant has found that two of these products are expressed in a tissue-specific manner and represent novel sequences not currently found in currently available data bases. Full-length cDNAs encoding these products are to be isolated and their functions in developing bone determined. In addition, characterization of a sequence adjacent to the VDRE of the rat and human osteocalcin gene absolutely required for transcriptional activation by Vit D will be performed and isolation of proteins that interact with this DNA will be determined.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK036597-13
Application #
2900189
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Program Officer
Tondravi, Mehrdad M
Project Start
1986-07-01
Project End
2002-03-31
Budget Start
1999-04-01
Budget End
2000-03-31
Support Year
13
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02199
Gori, Francesca; Zhu, Eric D; Demay, Marie B (2009) Perichondrial expression of Wdr5 regulates chondrocyte proliferation and differentiation. Dev Biol 329:36-43
Zhu, Eric D; Demay, Marie B; Gori, Francesca (2008) Wdr5 is essential for osteoblast differentiation. J Biol Chem 283:7361-7
Gori, Francesca; Friedman, Lauren G; Demay, Marie B (2006) Wdr5, a WD-40 protein, regulates osteoblast differentiation during embryonic bone development. Dev Biol 295:498-506
Yu, Xijie; Sabbagh, Yves; Davis, Siobhan I et al. (2005) Genetic dissection of phosphate- and vitamin D-mediated regulation of circulating Fgf23 concentrations. Bone 36:971-7
Gori, Francesca; Demay, Marie B (2005) The effects of BIG-3 on osteoblast differentiation are not dependent upon endogenously produced BMPs. Exp Cell Res 304:287-92
Gori, Francesca; Demay, Marie B (2004) BIG-3, a novel WD-40 repeat protein, is expressed in the developing growth plate and accelerates chondrocyte differentiation in vitro. Endocrinology 145:1050-4
Sooy, Karen; Demay, Marie B (2002) Transcriptional repression of the rat osteocalcin gene by deltaEF1. Endocrinology 143:3370-5
Kearns, A E; Donohue, M M; Sanyal, B et al. (2001) Cloning and characterization of a novel protein kinase that impairs osteoblast differentiation in vitro. J Biol Chem 276:42213-8
Gori, F; Schipani, E; Demay, M B (2001) Fibromodulin is expressed by both chondrocytes and osteoblasts during fetal bone development. J Cell Biochem 82:46-57
Gori, F; Divieti, P; Demay, M B (2001) Cloning and characterization of a novel WD-40 repeat protein that dramatically accelerates osteoblastic differentiation. J Biol Chem 276:46515-22

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