Osteocalcin (OC), a vitamin K dependent calcium binding protein, is the only known bone-specific protein. It is a significant component of the extracellular matrix and circulating levels are widely used as a clinical marker of bone turnover. Osteocalcin synthesis and gene expression are modulated by numerous physiologic factors that are known to regulate osteoblast function, including steroid hormones. We have developed a normal diploid rat osteoblast culture system that produces a bone-like extracellular matrix to study regulation of OC within the complexity of changes that occur during extracellular matrix formation and mineralization. We have documented the differential expression and selective modification of osteocalcin by steroid hormones during the developmental sequence of osteoblast differentiation. We have cloned the rat OC gene, identified its vitamin D responsive element and a primary transcriptional regulatory element, both of which contain AP-1 sites that bind the oncogene encoded fos-jun proteins. It is known for other genes that transcription is regulated by interactions between independent elements as well as by multiple classes of transcription factors within a regulatory element. The synergistic and antagonistic effects of steroids on OC gene expression suggests that such regulatory mechanisms are operative. We propose to use normal diploid osteoblasts and a panel of chimeric gene constructs with deletions or targeted mutations in promoter regulatory elements to (1) define the levels and mechanisms at which regulation of osteocalcin gene transcription is mediated, both in vitro and in vivo (transgenic mice) in relation to tissue specificity bone development; (2) define physiologic mediators (vitamin D, glucocorticoid, estrogen) of OC gene transcription by characterizing the positive and negative promoter regulatory sequences, their cognate sequence-specific transcription factors, and the functional proximity of regulatory elements from chromatin structure studies; and (3) carry out functional studies by altering (by inhibition or premature upregulation) of OC expression. A systematic analysis of the OC promoter, focusing on positive and negative regulatory elements and steroid responsive elements that regulate OC gene transcription, we will make a contribution towards understanding its role in bone metabolism and, in a broad biological context, elucidate mechanisms associated with the regulation of genes by physiologic modulators.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE012528-17
Application #
6379834
Study Section
Oral Biology and Medicine Subcommittee 1 (OBM)
Program Officer
Zhang, Guo He
Project Start
1989-04-01
Project End
2002-05-31
Budget Start
2001-06-01
Budget End
2002-05-31
Support Year
17
Fiscal Year
2001
Total Cost
$324,649
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
660735098
City
Worcester
State
MA
Country
United States
Zip Code
01655
Tracy, Kirsten M; Tye, Coralee E; Page, Natalie A et al. (2018) Selective expression of long non-coding RNAs in a breast cancer cell progression model. J Cell Physiol 233:1291-1299
Tai, Phillip W L; Wu, Hai; van Wijnen, André J et al. (2017) Genome-wide DNase hypersensitivity, and occupancy of RUNX2 and CTCF reveal a highly dynamic gene regulome during MC3T3 pre-osteoblast differentiation. PLoS One 12:e0188056
Farina, Nicholas H; Ramsey, Jon E; Cuke, Melissa E et al. (2017) Development of a predictive miRNA signature for breast cancer risk among high-risk women. Oncotarget 8:112170-112183
Wu, Hai; Gordon, Jonathan A R; Whitfield, Troy W et al. (2017) Chromatin dynamics regulate mesenchymal stem cell lineage specification and differentiation to osteogenesis. Biochim Biophys Acta Gene Regul Mech 1860:438-449
Hong, Deli; Messier, Terri L; Tye, Coralee E et al. (2017) Runx1 stabilizes the mammary epithelial cell phenotype and prevents epithelial to mesenchymal transition. Oncotarget 8:17610-17627
Gordon, Jonathan A R; Stein, Janet L; Westendorf, Jennifer J et al. (2015) Chromatin modifiers and histone modifications in bone formation, regeneration, and therapeutic intervention for bone-related disease. Bone 81:739-745
Aguilar, Rodrigo; Grandy, Rodrigo; Meza, Daniel et al. (2014) A functional N-terminal domain in C/EBP?-LAP* is required for interacting with SWI/SNF and to repress Ric-8B gene transcription in osteoblasts. J Cell Physiol 229:1521-8
Duverger, Olivier; Isaac, Juliane; Zah, Angela et al. (2013) In vivo impact of Dlx3 conditional inactivation in neural crest-derived craniofacial bones. J Cell Physiol 228:654-64
Lian, Jane B; Stein, Gary S; van Wijnen, Andre J et al. (2012) MicroRNA control of bone formation and homeostasis. Nat Rev Endocrinol 8:212-27
Gordon, Jonathan A R; Hassan, Mohammad Q; Saini, Sharanjot et al. (2010) Pbx1 represses osteoblastogenesis by blocking Hoxa10-mediated recruitment of chromatin remodeling factors. Mol Cell Biol 30:3531-41

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