title: Colocalization of dentin matrix protein 1 and dentin sialoprotein at late stages of rat molar development.
abstract: Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) are acidic proteins found in the extracellular matrices of bones and teeth. Recent data from gene knockouts, along with those of gene mutations, indicate that these two phosphoproteins are critical for bone and tooth development and/or maintenance. However, the precise functions of the two proteins have not been elucidated. In order to gain insights into their functions in tooth formation, we performed systematic, comparative investigations on the immunolocalization of DMP1 and dentin sialoprotein (DSP, a cleaved fragment of DSPP), using the rat first molar at different developmental stages as a model. Immunohistochemistry (IHC) was performed with specific, monoclonal antibodies against the COOH-terminal fragments of DMP1 and against DSP. In 1-day- and 1-week-old rats, weak immunoreactions for DMP1 were observed in dentinal tubules while stronger reactions for DSP were seen in the tubules and predentin. In rats older than 2 weeks, immunoreactions for DMP1 were found in dentinal tubules, predentin and odontoblasts. In 5-week- and 8-week-old rats, strong immunoreactions for DMP1 were widely distributed in odontoblasts and predentin. The distribution pattern of DSP was strikingly similar to that of DMP1 after 2 weeks and the localization of each was distinctly different from that of bone sialoprotein (BSP). The unique colocalization of DMP1 and DSPP in tooth development suggests that the two proteins play complementary and/or synergistic roles in formation and maintenance of healthy teeth.
authors.affiliation: Department of Endodontics and Periodontics, The University of Texas-Houston Health Science Center Dental Branch, 6516 M.D. Anderson Boulevard, DBB Rm 375, Houston, TX 77030, USA.
authors.forename: Otto
authors.initials: O
authors.lastname: Baba
authors.forename: Chunlin
authors.initials: C
authors.lastname: Qin
authors.forename: Jan C
authors.initials: JC
authors.lastname: Brunn
authors.forename: James N
authors.initials: JN
authors.lastname: Wygant
authors.forename: Bradley W
authors.initials: BW
authors.lastname: McIntyre
authors.forename: William T
authors.initials: WT
authors.lastname: Butler
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001842:Bone and Bones / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D058574:Integrin-Binding Sialoprotein; D008963:Molar / Q000254:growth & development*; D009804:Odontoblasts / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry; D011498:Protein Precursors; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000096:biosynthesis* / Q000378:metabolism; D013997:Time Factors; D000099311:Dentin Sialophosphoprotein
chemical_list: D000911:Antibodies, Monoclonal; D016326:Extracellular Matrix Proteins; D058574:Integrin-Binding Sialoprotein; D010750:Phosphoproteins; D011498:Protein Precursors; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C081635:Dmp1 protein, rat; C546873:Ibsp protein, rat