| 0812 Leucine-rich amelogenin peptide interactions and in vivo functions | ||
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N. HARUYAMA1, T. SREENATH1, A. CHO1, J. HATAKEYAMA2, and A.B. KULKARNI1, 1National Institute of Dental and Craniofacial Research, Bethesda, MD, USA, 2Tohoku University, Graduate School of Dentistry, Sendai, Japan Objective: We have recently reported that leucine-rich amelogenin peptide (LRAP), an alternate splice form of amelogenin, regulates RANKL expression and the proliferation and migration of cementoblast/periodontal ligament cells (Hatakeyama et al., J. Dental Res. 85:144, 2006). However, the precise molecular mechanism by which LRAP regulates these functions has not been characterized. The purpose of this study was to elucidate the molecular mechanism and define LRAP functions in vivo. Methods: We used a yeast two-hybrid assay to identify protein-binding partners for LRAP. Two cDNA libraries constructed from human bone marrow and mouse cementoblast/periodontal ligament cells were screened. We engineered transgenic mice using a murine 2.3-kb alpha1(I)-collagen promoter to drive a transgene consisting of LRAP, internal ribosome entry site (IRES), and enhanced green fluorescent protein (EGFP) to study in vivo functions. Results: In our initial screening, we identified a number of secreted proteins and integral membrane proteins that interact with LRAP in the yeast two-hybrid assay system. In addition, proteins whose functions range from immune reactions, enzymatic activity and cell-cell/cell-matrix adhesion events have also been identified. Our primary analysis of the transgenic mice revealed targeted expression of the transgene in odontoblasts and osteoblasts. Conclusion: We have identified and classified the proteins that bind to LRAP in our yeast two-hybrid system. Detailed analysis of these interactions will provide further insights into LRAP-mediated signal transduction mechanisms. The transgene expression analysis indicates tissue-specific expression patterns similar to the previous reports. The detailed phenotypic analysis of LRAP-EGFP transgenic mice will be presented. Taken together, these two approaches will be useful to understand the roles of amelogenins as signaling molecules. Supported by Division of Intramural Research, NIDCR, NIH | ||
| Seq #70 - Mechanisms of Odontogenesis 11:00 AM-12:00 PM, Thursday, 29 June 2006 Brisbane Convention & Exhibition Centre Exhibit Hall 1 | ||
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