The NH2-terminal and COOH-terminal Fragments of Dentin Matrix Protein 1 (DMP1) Localize Differently in the Compartments of Dentin and Growth Plate of Bone

Multiple studies have shown that dentin matrix protein 1 (DMP1) is essential for bone and dentin mineralization. After post-translational proteolytic cleavage, DMP1 exists within the extracellular matrix of bone and dentin as an NH2-terminal fragment, a COOH-terminal fragment, and the proteoglycan f...

Full description

Saved in:
Bibliographic Details
Published in:The journal of histochemistry and cytochemistry 2009-02, Vol.57 (2), p.155-166
Main Authors: Maciejewska, Izabela, Cowan, Cameron, Svoboda, Kathy, Butler, William T, D'Souza, Rena, Qin, Chunlin
Format: Article
Language:English
Subjects:
Animals
Animals, Newborn
Cattle
Dentin - growth & development
Dentin - metabolism
Extracellular Matrix Proteins - metabolism
Fluorescence Resonance Energy Transfer
Growth Plate - growth & development
Growth Plate - metabolism
Immunohistochemistry
Microscopy, Confocal
Molar - growth & development
Molar - metabolism
Organ Specificity
Phosphoproteins - metabolism
Rats
Rats, Sprague-Dawley
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Multiple studies have shown that dentin matrix protein 1 (DMP1) is essential for bone and dentin mineralization. After post-translational proteolytic cleavage, DMP1 exists within the extracellular matrix of bone and dentin as an NH2-terminal fragment, a COOH-terminal fragment, and the proteoglycan form of the NH2-terminal fragment (DMP1-PG). To begin to assess the biological function of each fragment, we evaluated the distribution of both fragments in the rat tooth and bone using antibodies specific to the NH2-terminal and COOH-terminal regions of DMP1 and confocal microscopy. In rat first molar organs, the NH2-terminal fragment localized to predentin, whereas the COOH-terminal fragment was mainly restricted to mineralized dentin. In the growth plate of bone, the NH2-terminal fragment appeared in the proliferation and hypertrophic zones, whereas the COOH-terminal fragment occupied the ossification zone. Forster resonance energy transfer analysis showed colocalization of both fragments of DMP1 in odontoblasts and predentin, as well as hypertrophic chondrocytes within the growth plates of bone. The biochemical analysis of bovine teeth showed that predentin is rich in DMP1-PG, whereas mineralized dentin primarily contains the COOH-terminal fragment. We conclude that the differential patterns of expression of NH2-terminal and COOH-terminal fragments of DMP1 reflect their potentially distinct roles in the biomineralization of dentin and bone matrices.
ISSN:0022-1554
1551-5044
DOI:10.1369/jhc.2008.952630