Cloning and expression analysis of the bovine dentin matrix acidic phosphoprotein gene.

The dentin matrix acidic phosphoprotein gene has been mapped to human chromosome 4q21 and mouse chromosome 5q21. Expression studies have implicated a role for this gene in the mineralization of dentin. In the current investigation, a cDNA encoding bovine dentin matrix acidic phosphoprotein has been cloned and sequenced. A comparison of the bovine gene with its rat counterpart has indicated that the genes are conserved (67.4% identity; 79.5% similarity), particularly in the region of presumed functional elements such as the hydrophobic signal peptide sequence, the cell attachment Arg-Gly-Asp tripeptide, and numerous serine residues which are likely candidates for phosphorylation. Zoo blot analysis further indicated that a similar gene is found in all mammalian species tested, but not in chicks. However, Northern analysis has indicated that in the cow the message is detectable at high levels in fetal bovine brain and cultured long bone as well as in odontoblasts. These results support a potential role for dentin matrix acidic phosphoprotein in dentinogenesis.