Role of OD314 During Odontoblast Differentiation

Park, Joo Cheol; Kim, Ik Hwan; Kim, Heung Joong; Jeong, Moon Jin; Oh, Hyun Ju; Jeong, Je O; Son, Ho Hyun

Abstract

Odontoblasts are responsible for the formation and maintenance of dentin which is a mineralized part in dentin-pulp complex of tooth. OD314 was obtained by subtractive hybridization between odontoblasts and osteoblast/dental papilla cells, and differentiatially expressed in the odontoblasts but not in osteoblasts and dental papilla cells. In this study, to better understand the biological function of new odontoblast-enriched gene, OD314, we examined expression of OD314 in cultured MDPC-23 cells and intracellular localization of OD314 protein. We also evaluate the effect of OD314 over-expression and inactivation on the cells by northern analysis. When MDPC-23 cells are cultured in the differentiation and mineralization medium for 28 days, OD314 mRNA expression was gradually increased from the beginning to day 21 and remained relatively high on day 28. Immunofluorescent staining of cultured MDPC-23 revealed localization of OD314 on the cytoplasm, especially near the nuclear membrane. However, a small amount of fluorescence was also observed in the nucleus. Inactivation of OD314 by RNA interference up-regulated the expression of DSPP, whereas over-expression of OD314 by CMV-OD314 plasmid down-regulated the expression of ON. These results suggest that OD314, a odontoblat-enriched gene, may play important roles in the odontoblast differentiation and dentin mineralization.