Dentin matrix protein-1, a candidate gene for dentinogenesis imperfecta

Dentinogenesis imperfecta (DGI) is an autosomal dominant inherited dental disease which affects dentin production and mineralization. Genetic linkage studies have determined linkage between DGI type II and group-specific component (Gc, vitamin D binding protein), interferon (gamma)-induced cytokine protein 10 (INP10) and secreted phosphoprotein 1 (SSP1, osteopontin, bone sialoprotein 1, early T-lymphocyte activation 1). Therefore, the gene locus has been localized to the long arm of human chromosome 4 in the region 4q13-q21. Dentin matrix protein-1 (DMP-1, AG-1) is a new acidic, phosphorylated dentin extracellular matrix protein which has recently been identified by cDNA cloning. The purpose of this study was to establish the possible association of DMP-1 with DGI type II by determining the human chromosomal localization of this protein. A DMP-1 DNA probe was generated using PCR amplification of the mouse full-length DMP-1 and labeled with [P-32] d-CTP. A panel of rodent somatic cell hybrid clones, previously cytogenetically characterized, was used for the assignment. High stringenly DNA hybridization studies and analysis of the chromosomal cell panel indicated that the DMP-1 gene locus is located on human chromosome 4. This data supports the hypothesis that DMP-1 is a candidate gene for the genetic disease DGI type II. This is based on chromosomal localization to human chromosome 4, the expression of DMP-1 mostly by odontoblasts, and its purported physical-chemical properties.