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The Dentin Matrix Protein 1 (Dmp1) is Specifically Expressed in Mineralized, but not Soft, Tissues during Development
J.Q. Feng1,2,*,#,
H. Huang1,2,
Y. Lu1,*,
L. Ye1,
Y. Xie1,
T.W. Tsutsui3,
T. Kunieda3,4,
T. Castranio3,
G. Scott3,
L.B. Bonewald1 and
Y. Mishina3
1 Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, 650 E. 25th Street, Kansas City, MO 64108, USA;
2 Department of Orthopaedic Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China;
3 Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences/NIH Research Triangle Park, NC;
4 Graduate School of Natural Science and Technology, Okayama University;
Correspondence: #corresponding author, fengj{at}umkc.edu
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ABSTRACT
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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.
Key Words: Dmp1 expression • bone • tooth • development • knockout mice
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INTRODUCTION
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Dmp1 is an acidic phosphorylated extracellular matrix protein originally cloned from a rat incisor cDNA library (George et al.,1993). Fisher and co-workers have recently proposed that DMP1 belongs to a group of proteins called SIBLINGs, for Small, Integrin-Binding LIgand, N-linked Glycoprotein. These molecules share similar biochemical features, such as the presence of relatively large amounts of sialic acid and phosphate and the RGD cell-binding sequence. All of these family members can bind to hydroxyapatite and can be detected in blood (Fedarko et al., 2000; Fisher et al., 2001; Jain et al., 2002). The members of this family also include bone sialoprotein, osteopontin, dentin sialophosphoprotein, and osteoblast/osteocyte factor 45 (OF45, or MEPE).
Initial in situ hybridization and Northern analysis data suggested that the Dmp1 gene was odontoblast-specific (George et al.,1994, 1995). But later, expression of Dmp1 was reported in bone and brain (MacDougall et al.,1996; D’Souza et al.,1997; Hirst et al.,1997). Recently, Toyosawa and co-workers challenged the perception that Dmp1 was highly expressed in osteoblasts, since in situ hybridization and immunostaining in mice and chicks showed a much higher level of Dmp1 in osteocytes than in osteoblasts (Toyosawa et al.,2001). In contrast, we reported expression of Dmp1 in both osteoblasts and osteocytes in mice by in situ hybridization, which is in agreement with the rat immunostaining data reported by Butler and his co-workers (Butler et al.,2002). In addition, we documented expression of Dmp1 in hypertrophic chondrocytes of both primary and secondary ossification centers (Feng et al.,2002).
Because DMP1 is very acidic and secreted into the extracellular matrix during the formation and mineralization of bone and dentin, it is generally believed that DMP1 plays an important role in the initiation of mineralization (Butler and Ritchie, 1995). Narayanan and co-workers showed that overexpression of DMP1 in vitro induced differentiation of embryonic mesenchymal cells to odontoblast-like cells and enhanced mineralization (Narayanan et al.,2001). In contrast, Tartaix and his co-workers showed that DMP1 inhibited mineralization in a cell-free system in vitro (personal communication).
To study Dmp1 gene function and regulation in vivo, we had previously cloned the mouse Dmp1 gene (Feng et al.,1998) using a 129-strain mouse genomic library in the Lambda Fix II vector (Stratagene, La Jolla, CA, USA). The 10-Kb 5'-flanking region, 10-Kb transcription unit, and 10-Kb 3'-flanking region have been completely sequenced and published in Genbank (AJ242625). This information was essential for the generation of Dmp1 knockout mice.
The purpose of this study was to determine if DMP1 was critical for early mouse skeleton and tooth formation. In addition, we sought to clarify when and where the Dmp1 gene is actively expressed, and if expression of Dmp1 is linked to morphogenesis of mineralized tissues during early development. Here we describe the generation of Dmp1 null mice created by replacing exon 6 that contains 80% of the coding region for DMP1 with a lacZ reporter gene. We demonstrate that Dmp1 gene expression is associated with mineralized tissues and describe, for the first time, expression of Dmp1 in pulp cells, the precursors of odontoblasts. Dmp1 null embryos and newborns appear grossly normal, suggesting that DMP1 may not be critical for early mouse tooth and skeletal development.
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MATERIALS & METHODS
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Construction of the Targeting Vector and Generation of Dmp1 lacZ Knock-in Mice
To generate Dmp1 lacZ knock-in mice, we replaced a 1.9-Kb (+13478, Apa to +15392, EcoRV) of Dmp1 exon 6 with the lacZ and the neo (neomycin phosphotransferase gene) cassette. To aid in the expression of lacZ, an internal ribosome entry site (IRES) was inserted in front of the lacZ gene. In addition, loxP (recognition sequence for Cre recombinase) sites were added, flanking the neo cassette for future removal. To facilitate the homologous recombination at the exact locus of exon 6, we inserted a 3.8-Kb intron linked to the upstream of exon 6 (+9686, Sac1 to +13478, ApaI) upstream of the IRES-lacZ-polyA-neo cassette as a 5' arm, and inserted a 3.3-Kb 3' flanking region downstream of exon 6 (+15392 EcoRV to +18700 NheI) downstream of the IRES-lacZ-polyA-neo cassette as a 3' arm. The final Dmp1 knock-in construct (Fig. 1A ) was confirmed by restriction enzyme mapping and sequencing. A 25-µg quantity of linearized targeting vector was electroporated into 107 AB2.2 ES cells (Lexicon Genetics) that were subsequently cultured in the presence of G418 on mitotically inactivated STO fibroblasts (Lexicon Genetics). Twelve hundred G418-resistant ES clones were initially screened by BamHI digestion and hybridized with unique 5' and 3' probes external to the region of vector homology (Fig. 1B). Twenty-eight correctly targeted ES clones were identified. Three of the Dmp1-mutant ES clones were micro-injected into C57BL/6 blastocysts (Taconic), and the resulting chimeric embryos were transferred to the uterine horns of day 2.5 pseudopregnant foster mothers. Chimeras were identified among the resulting progeny by their agouti fur (ES-derived) and were subsequently bred with C57BL/6 mates. Tail DNA from the agouti pups that resulted from these matings was analyzed by Southern blot analysis with both of the probes used to identify Dmp1 heterozygotes. These were subsequently interbred to generate homozygotes with the C57BL/6 background. The animal use protocols were approved by Institutional Animal Care and Use Committees at both institutes.
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Figure 1. Generation of Dmp1 null mice by gene targeting. (A) Schematics of mouse Dmp1 wild-type locus with locations of key restriction enzyme sites, and the NLSLacZpA vector (NLS, nuclear localization signal peptide) with the neo cassette inserted into exon 6 at the ApaI and EcoRV sites. Southern blot screening strategy is also displayed. Note that the coding region for 384 out of 503 amino acids, including RGD, has been removed. (B) Representative Southern blot analysis of DNA from a wild-type and a heterozygous ES clone. DNA was digested with BamHI, and hybridized with 5' and 3' probes separately, resulting in a 15-Kb band that corresponds to the wild type. There are two additional BamHI cut sites on the lacZ neo cassette, which gives two bands for the heterozygous ES cell clone: 9.1 Kb for the 5' side and 6.8Kb for the 3' side, respectively. Analysis of the data demonstrates that one of the Dmp1 alleles is replaced by the inserted lacZ cDNA, whose expression will be used to reflect the endogenous Dmp1 expression pattern (see Fig. 2 ). (C) Northern blot and RT-PCR analyses. The mRNAs were extracted from wild-type (+/+), heterozygous (+/-), and homozygous knock-in (-/-) calvarial cells. PCR amplification was then performed with 2-µL aliquots of the target cDNA. A 5' primer (5'-CGGCTGGTGGACTCTCTAAG-3', corresponding to an oligonucleotide of 374 to 393 of Dmp1 cDNA) and a 3' primer (5'-CGGGGTCGTCGCTCTGCATC-3', corresponding to an oligonucleotide of 750 to 769 of Dmp1 cDNA) were used for Dmp1 RT-PCR. No wild-type Dmp1 mRNA was detected in the homozygous knock-in samples by both Northern and RT-PCR analysis, while a 5.8-Kb fusion transcript containing exons 1-5 of Dmp1 and the lacZ reporter gene was detected in both heterozygous and homozygous knock-in samples. (D) Dmp1 immunostaining. The femurs from neonatal Day 19 wild-type (left) and homozygous knock-in (right) mice were stained by an antibody to DMP1 peptide (105 to 125). There is no detectable signal (brown) in Dmp1 lacZ-knock-in homozygous mice, while a strong signal is obvious in osteocytes in control mice.
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Northern Blot and RT-PCR Analyses
Calvarial cells, enriched for cells with an osteoblast phenotype, were isolated from three-day-old wild-type, heterozygous, and homozygous for Dmp1 lacZ knock-in neonates according to procedures described previously (Feng et al.,2002). Cells were cultured in  -MEM supplemented with 7% FCS, 100 µg/mL ascorbic acid (Sigma), and 5 mM β-glycerophosphate (Sigma) for 21 days, followed by RNA extraction. One µg of total RNA was converted to cDNA by reverse transcriptase (Promega) with 0.1 µg oligo (dT) as a primer. PCR for Dmp1 detection were amplified for 30 cycles, with an annealing temperature at 56°C. A 0.6-Kb mouse Dmp1 which contains the exons 2-5 sequence was used for Northern analysis with methods previously described (Harris et al.,1994).
Tail PCR Genotyping
Genotyping of embryos was determined by PCR analysis of genomic DNA extracted from tail DNA with primers p01 (5'-CTTGACTTCA GGCAAATAGTGACC-3' ) and p02 (5'-GCGGAATTCGATAGC TTGGCTG-3') for detection of the targeted allele (280 bp), and primers p01 (5'-CTTGACTTCAGGCAAATAGTGACC-3' and p03 5'-CTGTTCCTCACTCTCACTGTCC-3') for detection of the wild-type allele (410 bp).
Radiography and Alizarin Red/Alcian Blue Staining of the Skeleton
Embryos at days 15 and 18 (E15 and E18) and newborns from wild-type and the Dmp1 null littermates were first examined on a Faxitron model MX-20 Specimen Radiography System with a digital camera attached (Buffalo Grove, IL, USA). After death, the animals were skinned, eviscerated, and fixed for more than 1 day in 95% ethanol. They were then stained with Alizarin red (0.09%) and Alcian blue (0.05%) for photography (Kaufman, 1992).
β-Galactosidase Expression Assay
β-galactosidase staining was assessed from embryos day-13- (E 13) to one-week-old pups according to the method described previously (Zhang et al.,2002). Briefly, embryos or pups were fixed with ice-cold 4% paraformaldehyde for 30 min, then stained overnight in freshly made X-Gal solution (1 mg/mL) at 37°C, followed by refixation, decalcification, wax-embedding, sectioning, and counterstaining.
In situ Hybridization
The digoxigenin (DIG)-labeled lacZ cRNA probe (0.5 Kb) was prepared with the use of an RNA Labeling Kit (Roche, Indianapolis, IN, USA). In situ hybridization on paraffin sections was carried out essentially as described previously (Feng et al.,2002). The hybridization temperature was set at 55°C, and washing temperature was at 70°C so that endogenous alkaline phosphatase (AP) would be inactivated. DIG-labeled nucleic acids were detected in an enzyme-linked immunoassay with a specific anti-DIG-AP antibody conjugate and the color substrates NBT and BCIP, according to the manufacturer’s instructions (Roche).
Immunocytochemistry of Dmp1 Protein
The deparaffinized long-bone sections were stained with a rabbit anti-rat Dmp1 peptide polyclonal antibody, which was made to the N-terminal peptide 90-111, a kind gift of Dr. Toyosawa (Toyosawa et al.,2001).
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RESULTS
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Generation of Dmp1 lacZ Knock-in Mice
Blastocyst micro-injection of a targeted heterozygous ES cell line resulted in chimeric animals that were subsequently bred to C57/Bl6 mice to yield mixed-background offspring heterozygous for the Dmp1 mutation. One of the mutant ES clones (1B4) was found to be capable of contributing to the germline of chimeric mice. Heterozygote intercrosses produced embryos with Mendelian ratios of wild-type (n = 69), heterozygous (n = 101), and homozygous knockout (n = 52) offspring. This deletion removed the DNA encoding Met119 through the end of the Dmp1 sequence, including the RGD region. Thus, homozygous embryos carrying two copies of this lacZ neo cassette are null for the Dmp1 gene. The resulting fusion transcript contains the first 5 exons of Dmp1 and a lacZ gene. Northern blot analysis of mRNA prepared from calvarial cells demonstrated expression of the expected 5.8-Kb fusion transcript and loss of the wild-type 2.8-Kb Dmp1 transcript in the Dmp1-deficient calvarial cells (Fig. 1C). RT-PCR (Fig. 1C) confirmed the absence of Dmp1 in the mutant, and immunohistochemistry of tibia sections confirmed the absence of DMP1 in osteocytes (Fig. 1D).
The LacZ Reporter Gene under Control of the Endogenous Dmp1 Gene is Found in Mineralized Tissues during Development.
The goal of generating Dmp1 lacZ-knock-in mice is not only to interrupt the function of the Dmp1 gene, but also to allow for the accurate determination of Dmp1 expression. This was accomplished by the use of a lacZ reporter gene replacing exon 6 of the Dmp1 gene. Expression of lacZ, as demonstrated by X-gal staining, reflects endogenous Dmp1 expression. Using embryos and mice that are heterozygous for the Dmp1 lacZ knock-in mutation, we determined expression of Dmp1. No β-gal activity was detected at embryonic stage E13.5 (data not shown). X-Gal staining in embryonic stage E15.5 to one-week-old heterozygous pups is shown in Fig. 2. The lacZ signal was detected as follows: in hypertrophic chondrocytes, the cells providing morphogenic signals that induce osteogenic differentiation of mesenchymal stem cells (Fig. 2A); in osteoblasts, the cells secreting matrix proteins for bone formation (Fig. 2A); and in osteocytes, the cells thought to translate mechanical strain into signals required for bone modeling and remodeling (Figs. 2A, 2B). LacZ is also expressed: in tooth pulp cells (Fig. 2B), some of which will differentiate into odontoblast cells; in odontoblast cells, the cells secreting matrix proteins for dentin formation (Fig. 2B); and in cementoblast cells, the cells secreting matrix proteins for cement formation (Fig. 2B). Because of low expression and poor penetrance of X-Gal into enamel, we used in situ hybridization with a lacZ probe to show that Dmp1-lacZ is expressed in ameloblasts, the cells that secrete matrix proteins for amelogenesis (Fig. 2B). However, lacZ expression was not detected in any soft tissues such as the brain, during both the embryonic and post-natal stages (data not shown), demonstrating that Dmp1 is indeed a gene associated with all mineralized tissues, including bone, cartilage, and tooth.
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Figure 2. Dmp1 lacZ expression pattern during early development. (A) Dmp1 expression in skeletogenesis. Dmp1 lacZ heterozygous embryos (E15.5), newborn, and day 7 pups were selected for the tracking of Dmp1 expression during early skeletal development. (B) Dmp1 expression pattern in tooth. Sections of incisor (left, newborn) and an adjacent area between the dentin and the cement (middle, newborn), and a 2nd molar subjected to in situ hybridization (right, lacZ probe) are shown. Note that lacZ staining, which reflects endogenous Dmp1 expression, is detected in all mineralized tissues mainly in the nucleus, due to the addition of a nuclear localization signal peptide. LacZ staining (green) is seen in hypertrophic chondrocytes (HC), osteoblasts (Ob), and osteocytes (Ocy), as well as in cementoblasts (Cb), pulp cells, and odontoblasts (Od). Dmp1 lacZ signals are also detected in ameloblasts (Am) by in situ hybridization. There is no X-Gal staining in brain tissue. AB, alveolar bone.
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Dmp1 Null Embryos Grossly Appear "Normal"
Embryos homozygous for Dmp1 null embryos could not be distinguished visibly from wild-type littermates by radiography at E15 (Fig. 3A), suggesting that Dmp1 may not be essential for the initiation of mesenchymal condensation during early skeletal formation. Alizarin red/Alcian blue staining of the whole skeleton at E18 and in newborns appeared "normal" (Figs. 3B, 3C). Closer comparison of the shape of each bone failed to demonstrate overt abnormalities. Histological analyses of tooth sections at E18 showed no apparent differences between the wild type and the Dmp1 null (Fig. 4A, left upper and lower panels, and right upper and lower panels for high magnification). Femurs obtained from E18 samples did not show obvious abnormalities, although the hypertrophic chondrocyte zone in the Dmp1 null embryos was slightly expanded, and the width was modestly increased in the Dmp1 null embryos compared with that in the control (Fig. 4B, left and right panels).
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Figure 3. Dmp1 null embryos and newborns appear grossly "normal". (A) Representative radiographs of the wild-type (+/+) and the knockout (-/-) embryos of day 15 are shown. (B,C) Alizarin red/Alcian blue staining of the wild-type (+/+) and the knockout (-/-) embryos of day 18 (B) and newborns (C) is shown.
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Figure 4. Histological analysis (H&E) of incisors and distal femurs from 18-day-old control and Dmp1 null embryos. (A) Representative tooth germs (upper incisors) of the wild-type (+/+, left) and the homozygous null (-/-, right) embryos of day 18 are shown. There are no apparent morphological changes in dentin (red) and odontoblast and ameloblast layers (purple). (B) Representative long bone (femur) of the wild-type (+/+, left) and the homozygous null (-/-, right) embryos of day 18 are shown. A slightly expanded hypertrophic zone and a widened bone shaft are shown. Am, ameloblast; HC, hypertrophic chondrocytes; Od, odontoblasts; d, dentin.
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DISCUSSION
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Recently, Toyosawa and co-workers (Toyosawa et al.,2001) have proposed that Dmp1 is osteocyte-specific, since they could not detect Dmp1 in osteoblasts of chicks and mice using both immunohistochemistry and in situ hybridization. In contrast, our in situ hybridization data showed that Dmp1 first appeared in hypertrophic cartilage cells, followed by osteoblasts, and later was strongly expressed in osteocytes (Feng et al.,2002). It appears that these controversial reports may be due to magnitude of gene or protein expression, or to background noise or variation between in situ hybridization assays used in different laboratories. To address further the issue of tissue specificity, we generated Dmp1 lacZ knock-in mice, where exon 6 of Dmp1 is replaced by a lacZ reporter gene. Because lacZ is under the control of the endogenous Dmp1 gene, the expression of lacZ, as demonstrated by X-Gal staining, precisely reflects endogenous Dmp1 expression. More importantly, a nuclear localization signal was added to the N-terminus of the β-gal; therefore, a strong signal detected mainly in the nucleus guarantees a high signal-to-noise ratio. Dmp1 is expressed in all mineralized tissues, and its expression is directly linked to amelogenesis, cementogenesis, odontogenesis, chondrogenesis, and osteogenesis during both embryonic and post-natal development. With this method, we have also found expression of Dmp1 in pulp cells, the precursors of odontoblasts. Because we could not detect expression of Dmp1 in soft tissues such as the brain, we therefore propose that Dmp1 is a specific marker for mineralized tissues.
DMP1 has long been speculated to enhance mineralization, since it is a highly phosphorylated extracellular matrix protein formed at the mineralization front, with relatively low expression compared with that of other non-collagenous proteins (Butler and Ritchie, 1995). However, in the present study, Dmp1 null embryos and newborns display no apparent differences when radiography and alizarin red/Alcian blue staining were used (Fig. 3). It is noteworthy that, to date, none of the mice lacking the non-collagenous extracellular matrix proteins such as BSP, OP, DSPP, MEPE, osteocalcin, osteonectin, and decorin shows any skeletal defects in newborns (Ducy et al.,1996; Danielson et al.,1997; Gilmour et al.,1998; Norose et al.,1998; Xu et al.,1998; Yoshitake et al.,1999). This could be due to compensatory mechanisms. However, we did observe a minor difference in the hypertrophic chondrocyte zone and long bone diameter between the wild-type and the Dmp1 null mice (Fig. 4), suggesting a specific, non-compensatory function for DMP1 in early skeleton formation.
In summary, we demonstrate that Dmp1 is a gene associated with mineralized tissues and that its expression is directly linked to amelogenesis, cementogenesis, dentinogenesis, chondrogenesis, and osteogenesis during development. In addition, we document, for the first time, the expression of Dmp1 in pulp cells, the precursors of odontoblasts. Based on our initial analyses, it appears that DMP1 is not essential for early mouse tooth and skeletal development.
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ACKNOWLEDGMENTS
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We thank Matt Erhinger, Paula King, and Mike Streiker for maintenance of the mouse colony. This work was supported by research grants from the NIH/NIDCR (DE00455, DE13480) (to J.Q.F.), DE13221 (to M.MacDougall, UT Health Science Center at San Antonio), and by the University of Missouri Research Board (to J.Q.F.).
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FOOTNOTES
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* contributed equally to this work; 
Received for publication April 21, 2003.
Revision received July 29, 2003.
Accepted for publication July 30, 2003.
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REFERENCES
|
|---|
- Butler WT, Ritchie H (1995). The nature and functional significance of dentin extracellular matrix proteins. Int J Dev Biol 39:169–179.[Medline]
[Order article via Infotrieve]
- Butler WT, Brunn JC, Qin C, McKee MD (2002). Extracellular matrix proteins and the dynamics of dentin formation. Connect Tissue Res 43:301–307.[Medline]
[Order article via Infotrieve]
- D’Souza RN, Cavender A, Sunavala G, Alvarez J, Ohshima T, Kulkarni AB, et al. (1997). Gene expression patterns of murine dentin matrix protein 1 (Dmp1) and dentin sialophosphoprotein (DSPP) suggest distinct developmental functions in vivo. J Bone Miner Res 12:2040–2049.[CrossRef][Medline]
[Order article via Infotrieve]
- Danielson KG, Baribault H, Holmes DF, Graham H, Kadler KE, Iozzo RV (1997). Targeted disruption of decorin leads to abnormal collagen fibril morphology and skin fragility. J Cell Biol 136:729–743.[Abstract/Free Full Text]
- Ducy P, Desbois C, Boyce B, Pinero G, Story B, Dunstan C, et al. (1996). Increased bone formation in osteocalcin-deficient mice. Nature 382:448–452.[CrossRef][Medline]
[Order article via Infotrieve]
- Fedarko NS, Fohr B, Robey PG, Young MF, Fisher LW (2000). Factor H binding to bone sialoprotein and osteopontin enables tumor cell evasion of complement-mediated attack. J Biol Chem 275:16666–16672.[Abstract/Free Full Text]
- Feng JQ, Li X, Harris SE, Dai J, MacDougall M (1998). Genomic organization, and promoter analysis of mouse dentin matrix protein-1(Dmp-1) gene in osteoblasts and odontoblast cell lines. Am Acad Orthop Surg Chem Biol Mineralized Tiss 155–159.
- Feng JQ, Zhang J, Dallas SL, Lu Y, Chen S, Tan X, et al. (2002). Dentin matrix protein 1, a target molecule for Cbfa1 in bone, is a unique bone marker gene. J Bone Miner Res 17:1822–1831.[CrossRef][Medline]
[Order article via Infotrieve]
- Fisher LW, Torchia DA, Fohr B, Young MF, Fedarko NS (2001). Flexible structures of SIBLING proteins, bone sialoprotein, and osteopontin. Biochem Biophys Res Commun 280:460–465.[CrossRef][Medline]
[Order article via Infotrieve]
- George A, Sabsay B, Simonian PA, Veis A (1993). Characterization of a novel dentin matrix acidic phosphoprotein. Implications for induction of biomineralization. J Biol Chem 268:12624–12630.[Abstract/Free Full Text]
- George A, Gui J, Jenkins NA, Gilbert DJ, Copeland NG, Veis A (1994). in situ localization and chromosomal mapping of the AG1 (Dmp1) gene. J Histochem Cytochem 42:1527–1531.[Abstract]
- George A, Silberstein R, Veis A (1995). in situ hybridization shows Dmp1 (AG1) to be a developmentally regulated dentin-specific protein produced by mature odontoblasts. Connect Tissue Res 33:67–72.[Medline]
[Order article via Infotrieve]
- Gilmour DT, Lyon GJ, Carlton MB, Sanes JR, Cunningham JM, Anderson JR, et al. (1998). Mice deficient for the secreted glycoprotein SPARC/osteonectin/BM40 develop normally but show severe age-onset cataract formation and disruption of the lens. EMBO J 17:1860–1870.[CrossRef][Medline]
[Order article via Infotrieve]
- Harris SE, Sabatini M, Harris MA, Feng JQ, Wozney J, Mundy GR (1994). Expression of bone morphogenetic protein messenger RNA in prolonged cultures of fetal rat calvarial cells. J Bone Miner Res 9:389–394.[Medline]
[Order article via Infotrieve]
- Hirst KL, Ibaraki-O’Connor K, Young MF, Dixon MJ (1997). Cloning and expression analysis of the bovine dentin matrix acidic phosphoprotein gene. J Dent Res 76:754–760.
- Jain A, Karadag A, Fohr B, Fisher LW, Fedarko NS (2002). Three SIBLINGs (small integrin-binding ligand, N-linked glycoproteins) enhance factor H’s cofactor activity enabling MCP-like cellular evasion of complement-mediated attack. J Biol Chem 277:13700–13708.[Abstract/Free Full Text]
- Kaufman MH (1992). The atlas of mouse development. London: Academic Press.
- MacDougall M, DuPont BR, Simmons D, Leach RJ (1996). Assignment of DMP1 to human chromosome 4 band q21 by in situ hybridization. Cytogenet Cell Genet 74:189.[Medline]
[Order article via Infotrieve]
- Narayanan K, Srinivas R, Ramachandran A, Hao J, Quinn B, George A (2001). Differentiation of embryonic mesenchymal cells to odontoblast-like cells by overexpression of dentin matrix protein 1. Proc Natl Acad Sci USA 98:4516–4521.[Abstract/Free Full Text]
- Norose K, Clark JI, Syed NA, Basu A, Heber-Katz E, Sage EH, et al. (1998). SPARC deficiency leads to early-onset cataractogenesis. Invest Ophthalmol Vis Sci 39:2674–2680.[Abstract/Free Full Text]
- Toyosawa S, Shintani S, Fujiwara T, Ooshima T, Sato A, Ijuhin N, et al. (2001). Dentin matrix protein 1 is predominantly expressed in chicken and rat osteocytes but not in osteoblasts. J Bone Miner Res 16:2017–2026.[CrossRef][Medline]
[Order article via Infotrieve]
- Xu T, Bianco P, Fisher LW, Longenecker G, Smith E, Goldstein S, et al. (1998). Targeted disruption of the biglycan gene leads to an osteoporosis-like phenotype in mice. Nat Genet 20:78–82.[CrossRef][Medline]
[Order article via Infotrieve]
- Yoshitake H, Rittling SR, Denhardt DT, Noda M (1999). Osteopontin-deficient mice are resistant to ovariectomy-induced bone resorption. Proc Natl Acad Sci USA 96:8156–8160.[Abstract/Free Full Text]
- Zhang J, Tan X, Contag CH, Lu Y, Guo D, Harris SE, et al. (2002). Dissection of promoter control modules that direct Bmp4 expression in the epithelium-derived components of hair follicles. Biochem Biophys Res Commun 293:1412–1419.[CrossRef][Medline]
[Order article via Infotrieve]
Journal of Dental Research, Vol. 82, No. 10,
776-780 (2003)
DOI: 10.1177/154405910308201003
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|
|
T. Fukuda, Y. Mishina, M. P. Walker, and R. P. DiAugustine
Conditional Transgenic System for Mouse Aurora A Kinase: Degradation by the Ubiquitin Proteasome Pathway Controls the Level of the Transgenic Protein
Mol. Cell. Biol.,
June 15, 2005;
25(12):
5270 - 5281.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
W. Yang, Y. Lu, I. Kalajzic, D. Guo, M. A. Harris, J. Gluhak-Heinrich, S. Kotha, L. F. Bonewald, J. Q. Feng, D. W. Rowe, et al.
Dentin Matrix Protein 1 Gene Cis-regulation: USE IN OSTEOCYTES TO CHARACTERIZE LOCAL RESPONSES TO MECHANICAL LOADING IN VITRO AND IN VIVO
J. Biol. Chem.,
May 27, 2005;
280(21):
20680 - 20690.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. Ye, Y. Mishina, D. Chen, H. Huang, S. L. Dallas, M. R. Dallas, P. Sivakumar, T. Kunieda, T. W. Tsutsui, A. Boskey, et al.
Dmp1-deficient Mice Display Severe Defects in Cartilage Formation Responsible for a Chondrodysplasia-like Phenotype
J. Biol. Chem.,
February 18, 2005;
280(7):
6197 - 6203.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. H. Tartaix, M. Doulaverakis, A. George, L. W. Fisher, W. T. Butler, C. Qin, E. Salih, M. Tan, Y. Fujimoto, L. Spevak, et al.
In Vitro Effects of Dentin Matrix Protein-1 on Hydroxyapatite Formation Provide Insights into in Vivo Functions
J. Biol. Chem.,
April 30, 2004;
279(18):
18115 - 18120.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. Ye, M. MacDougall, S. Zhang, Y. Xie, J. Zhang, Z. Li, Y. Lu, Y. Mishina, and J. Q. Feng
Deletion of Dentin Matrix Protein-1 Leads to a Partial Failure of Maturation of Predentin into Dentin, Hypomineralization, and Expanded Cavities of Pulp and Root Canal during Postnatal Tooth Development
J. Biol. Chem.,
April 30, 2004;
279(18):
19141 - 19148.
[Abstract]
[Full Text]
[PDF]
|
|
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TOP
ABSTRACT
INTRODUCTION