title: The Dentin matrix protein 1 (Dmp1) is specifically expressed in mineralized, but not soft, tissues during development.
abstract: Dentin Matrix Protein 1 (Dmp1) was originally identified from dentin. However, its expression and function in vivo are not clear. To clarify these two issues, we have generated mice carrying a truncated Dmp1 gene by using gene targeting to replace exon 6 with a lacZ gene. Northern blot analysis shows the expected 5.8-kb Dmp1-lacZ fusion transcript and loss of the wild-type 2.8-kb Dmp1 transcript, confirmed by a lack of immunostaining for the protein. Using heterozygous animals, we demonstrate that Dmp1 is specific for mineralized tissues. Not previously shown, Dmp1 is also expressed in pulp cells. Dmp1-deficient embryos and newborns display no apparent gross abnormal phenotype, although there are a modest expansion of the hypertrophic chondrocyte zone and a modest increase in the long bone diameter. This suggests that DMP1 is not essential for early mouse skeletal or dental development.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001842:Bone and Bones / Q000473:pathology; D002113:Calcification, Physiologic / Q000235:genetics*; D002678:Chimera; D019902:Chondrocytes / Q000473:pathology; D003782:Dental Pulp / Q000473:pathology; D004622:Embryo, Mammalian; D005091:Exons / Q000235:genetics; D016326:Extracellular Matrix Proteins; D018390:Gene Targeting; D006984:Hypertrophy; D007763:Lac Operon / Q000235:genetics; D051379:Mice; D008817:Mice, Mutant Strains; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics*; D014074:Tooth Calcification / Q000235:genetics*; D014083:Tooth Germ / Q000473:pathology; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: C513308:Dmp1 protein, mouse; D016326:Extracellular Matrix Proteins; D010750:Phosphoproteins