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Hu Y, Smith CE, Cai Z, Donnelly LAJ, Yang J, Hu JCC, Simmer JP. Enamel ribbons, surface nodules, and octacalcium phosphate in C57BL/6 Amelx-/- mice and Amelx+/- lyonization. Mol Genet Genomic Med 2016; 4:641-661. [PMID: 27896287 PMCID: PMC5118209 DOI: 10.1002/mgg3.252] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Amelogenin is required for normal enamel formation and is the most abundant protein in developing enamel. METHODS Amelx+/+, Amelx+/- , and Amelx-/- molars and incisors from C57BL/6 mice were characterized using RT-PCR, Western blotting, dissecting and light microscopy, immunohistochemistry (IHC), transmission electron microscopy (TEM), scanning electron microscopy (SEM), backscattered SEM (bSEM), nanohardness testing, and X-ray diffraction. RESULTS No amelogenin protein was detected by Western blot analyses of enamel extracts from Amelx-/- mice. Amelx-/- incisor enamel averaged 20.3 ± 3.3 μm in thickness, or only 1/6th that of the wild type (122.3 ± 7.9 μm). Amelx-/- incisor enamel nanohardness was 1.6 Gpa, less than half that of wild-type enamel (3.6 Gpa). Amelx+/- incisors and molars showed vertical banding patterns unique to each tooth. IHC detected no amelogenin in Amelx-/- enamel and varied levels of amelogenin in Amelx+/- incisors, which correlated positively with enamel thickness, strongly supporting lyonization as the cause of the variations in enamel thickness. TEM analyses showed characteristic mineral ribbons in Amelx+/+ and Amelx-/- enamel extending from mineralized dentin collagen to the ameloblast. The Amelx-/- enamel ribbons were not well separated by matrix and appeared to fuse together, forming plates. X-ray diffraction determined that the predominant mineral in Amelx-/- enamel is octacalcium phosphate (not calcium hydroxyapatite). Amelx-/- ameloblasts were similar to wild-type ameloblasts except no Tomes' processes extended into the thin enamel. Amelx-/- and Amelx+/- molars both showed calcified nodules on their occlusal surfaces. Histology of D5 and D11 developing molars showed nodules forming during the maturation stage. CONCLUSION Amelogenin forms a resorbable matrix that separates and supports, but does not shape early secretory-stage enamel ribbons. Amelogenin may facilitate the conversion of enamel ribbons into hydroxyapatite by inhibiting the formation of octacalcium phosphate. Amelogenin is necessary for thickening the enamel layer, which helps maintain ribbon organization and development and maintenance of the Tomes' process.
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Affiliation(s)
- Yuanyuan Hu
- Department of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
| | - Charles E Smith
- Department of Biologic and Materials SciencesUniversity of Michigan School of Dentistry1210Eisenhower PlaceAnn ArborMichigan48108; Facility for Electron Microscopy ResearchDepartment of Anatomy and Cell BiologyFaculty of DentistryMcGill UniversityMontrealQuebecH3A 2B2Canada
| | - Zhonghou Cai
- Advanced Photon Source Argonne National Laboratory 9700 S. Cass Ave Building 431-B005 Argonne Illinois 60439
| | - Lorenza A-J Donnelly
- Department of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
| | - Jie Yang
- Department of Biologic and Materials SciencesUniversity of Michigan School of Dentistry1210Eisenhower PlaceAnn ArborMichigan48108; Department of Pediatric DentistrySchool and Hospital of StomatologyPeking University22 South AvenueZhongguancun Haidian DistrictBeijing100081China
| | - Jan C-C Hu
- Department of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
| | - James P Simmer
- Department of Biologic and Materials Sciences University of Michigan School of Dentistry 1210 Eisenhower Place Ann Arbor Michigan 48108
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2
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Gibson CW, Yuan ZA, Hall B, Longenecker G, Chen E, Thyagarajan T, Sreenath T, Wright JT, Decker S, Piddington R, Harrison G, Kulkarni AB. Amelogenin-deficient mice display an amelogenesis imperfecta phenotype. J Biol Chem 2001; 276:31871-5. [PMID: 11406633 DOI: 10.1074/jbc.m104624200] [Citation(s) in RCA: 380] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dental enamel is the hardest tissue in the body and cannot be replaced or repaired, because the enamel secreting cells are lost at tooth eruption. X-linked amelogenesis imperfecta (MIM 301200), a phenotypically diverse hereditary disorder affecting enamel development, is caused by deletions or point mutations in the human X-chromosomal amelogenin gene. Although the precise functions of the amelogenin proteins in enamel formation are not well defined, these proteins constitute 90% of the enamel organic matrix. We have disrupted the amelogenin locus to generate amelogenin null mice, which display distinctly abnormal teeth as early as 2 weeks of age with chalky-white discoloration. Microradiography revealed broken tips of incisors and molars and scanning electron microscopy analysis indicated disorganized hypoplastic enamel. The amelogenin null phenotype reveals that the amelogenins are apparently not required for initiation of mineral crystal formation but rather for the organization of crystal pattern and regulation of enamel thickness. These null mice will be useful for understanding the functions of amelogenin proteins during enamel formation and for developing therapeutic approaches for treating this developmental defect that affects the enamel.
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Affiliation(s)
- C W Gibson
- Department of Anatomy and Histology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania 19104, USA.
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3
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Ishiyama M, Inage T, Shimokawa H. An immunocytochemical study of amelogenin proteins in the developing tooth enamel of the gar-pike, Lepisosteus oculatus (Holostei, Actinopterygii). ARCHIVES OF HISTOLOGY AND CYTOLOGY 1999; 62:191-7. [PMID: 10399543 DOI: 10.1679/aohc.62.191] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previous studies have demonstrated the morphological similarity of the enamel-like layer found in the teeth of the coelacanth, lungfish and gar-pike to the enamel of tetrapods. In order to clarify the phylogenetic continuity between both structures, tooth germs of the gar-pike were immunocytochemically studied using an anti-bovine amelogenin polyclonal antibody. Intense immunoreaction was shown over the enamel-like matrix layer. Certain cell organelles associated with the secretory pathway of the ameloblasts were recognized as immunoreactive. These results indicate that the enamel-like layer of the gar-pike is a tissue homologous with the mammalian enamel because both possess a common, amelogenin-like substance.
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Affiliation(s)
- M Ishiyama
- Department of Histology, Nippon Dental University School of Dentistry, Niigata, Japan.
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4
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Inage T, Shimokawa H, Wakao K, Sasaki S. Gene expression and localization of amelogenin in the rat incisor. Adv Dent Res 1996; 10:201-7. [PMID: 9206338 DOI: 10.1177/08959374960100021401] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Gene expression and localization of amelogenin were studied in the developing rat incisor by the methods of in situ hybridization and immunohistochemistry. ISH revealed the first expression of amelogenin mRNA in the inner enamel epithelium of the cervical loop. The signals were clearly observed in pre-ameloblasts in the region bordering on predentin formation and became more intense toward the cells on the initial enamel matrix secretion. The maximal signals were found in the cytoplasm of secretory ameloblasts. From the terminal secretion zone, the signals then became gradually weaker toward the incisal edge but were still evident in the cytoplasm of shortening, transitional ameloblasts and those at the early maturation stage. No signals were found in the cells of the stratum intermedium and stellate reticulum throughout amelogenesis. Immunohistochemistry by means of an antibody against amelogenin C-telopeptide consisting of 12 amino acids revealed immunoreaction in the secretory ameloblasts reacting to the ISH. When a polyclonal antibody against amelogenin was used, immunoreaction was found in the distal ends of ruffle-ended ameloblasts (RA) in the maturation zone. Those results indicated that amelogenin is synthesized by ameloblastic cells from the inner enamel epithelium to the early maturation stage and is then resorbed by the RA.
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Affiliation(s)
- T Inage
- Department of Anatomy, Nihon University School of Dentistry, Tokyo, Japan
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5
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Yuan ZA, Golub EE, Collier PM, Gibson CW. Bovine enamel organ cells express tissue non-specific alkaline phosphatase mRNA. J Dent Res 1995; 74:1886-90. [PMID: 8600185 DOI: 10.1177/00220345950740121201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Alkaline phosphatase (AP) is expressed at high levels in all mineralizing tissues, and the isoform identified in developing enamel has biochemical properties similar to that found in bone. While the bone AP is referred to as the liver/bone/kidney or tissue non-specific (TNS) form, other APs are highly specific for tissue of expression. To determine unequivocally the AP isoform made by enamel organ cells, we constructed a fetal bovine enamel organ cDNA library, which yielded eight AP cDNA clones. In each case, the DNA sequence was homologous to the partial cDNA reported for bovine kidney AP (Garattini et al., 1987). It is concluded that enamel organ cells express the TNS-AP isoform. The extended 3' untranslated region of the cDNA has considerable homology to human TNS-AP, and the conservation of sequence suggests that the 3' end may have a role in post-transcriptional regulation of expression.
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Affiliation(s)
- Z A Yuan
- Department of Anatomy and Histology, University of Pennsylvania School of Dental Medicine, Philadelphia, 19104 USA
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6
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Abstract
The paper reviews the changes in ameloblast ultrastructure, concomitant with the changes in its functions across the major stages of amelogenesis. It describes the mechanisms associated with the major events in biosynthesis and degradation of the major enamel proteins (amelogenins and tuftelin/enamelins) and with the presecretory and postsecretory mechanisms leading to the heterogeneity of these extracellular matrix proteins. The gene structure, chromosomal localization, protein, primary structure and possible function, and the involvement of the different proteins in X-linked (amelogenin) and possibly in autosomally linked (tuftelin) amelogenesis imperfecta, the most common hereditary disease of enamel, are also discussed.
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Affiliation(s)
- D Deutsch
- Department of Oral Biology, Hebrew University Hadassah, Faculty of Dental Medicine, Jerusalem, Israel
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7
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Bonucci E. Ultrastructural organic-inorganic relationships in calcified tissues: cartilage and bone vs. enamel. Connect Tissue Res 1995; 33:157-62. [PMID: 7554948 DOI: 10.3109/03008209509016996] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Close organic-inorganic relationships exist in all calcified tissues, the inorganic substance being linked to crystal ghosts (CGs). These are organic, crystal-like structures present in areas of initial calcification. In cartilage and bone, they form aggregates with the same morphology and distribution as the calcification nodules; in enamel, they consist of long filament- and ribbon-like structures, having the same arrangement as untreated crystals. CGs of cartilage and bone are acidic structures with histochemical properties of proteoglycans; CGs of enamel probably correspond to enamelins. The close morphologic similarity between CGs and crystals suggests that the former have a role in the formation of the latter.
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Affiliation(s)
- E Bonucci
- Department of Experimental Medicine, University La Sapienza, Rome, Italy
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8
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Cleveland DB, Miller AS. DIAGNOSTIC LABORATORY AIDS IN ORAL AND MAXILLOFACIAL SURGICAL PATHOLOGY. Oral Maxillofac Surg Clin North Am 1994. [DOI: 10.1016/s1042-3699(20)30760-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Chen E, Piddington R, Decker S, Park J, Yuan ZA, Abrams WR, Rosenbloom J, Feldman G, Gibson CW. Regulation of amelogenin gene expression during tooth development. Dev Dyn 1994; 199:189-98. [PMID: 8018986 DOI: 10.1002/aja.1001990304] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The amelogenins are the predominant matrix proteins in developing enamel and are crucial for proper enamel mineralization. Transgenic mice were constructed in order to identify the segment of the amelogenin gene required for specific expression in enamel organ cells. A 3.5 kb fragment of the bovine X-chromosomal amelogenin gene that includes a TATA box, the transcription initiation site, and 32 bp of exon 1 was linked to the beta galactosidase gene and injected into fertilized mouse eggs. Newborn transgene positive mice expressed beta galactosidase activity in developing teeth treated with the chromogenic substrate Xgal. Foci of ameloblasts were positive in newborn mice; stain intensity and number of positive ameloblasts increased in 1-day and 2-day postnatal mice. Some of the adjacent stratum intermedium cells also were positive in the later stages. Targeting of the transgene to the enamel organ was specific; the only other cells observed to be positive were macrophages, which have endogenous beta galactosidase activity.
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Affiliation(s)
- E Chen
- Department of Anatomy and Histology, School of Dental Medicine, University of Pennsylvania, Philadelphia 19104
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10
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Shore RC, Robinson C, Kirkham J, Herold RC. An immunohistochemical study of the effects of fluoride on enamel development in the rat incisor. Arch Oral Biol 1993; 38:607-10. [PMID: 8368958 DOI: 10.1016/0003-9969(93)90127-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A monoclonal antiamelogenin antibody was used to investigate the effects of fluoride on enamel development in the rat incisor. The results suggested that during secretion the enamel matrix molecules are arranged in such a way as to mask the epitope recognized by the monoclonal antibody. However, during the transition stage of development as the matrix begins to be degraded the epitope becomes exposed and labelling intensity increases to reach a maximum at the end of transition/start of maturation. The effect of fluoride is to delay the appearance of labelling within the enamel matrix until the end of transition. This suggests that the fluoride may inhibit enzymatic degradation or disaggregation of the matrix, the resulting residual matrix then inhibiting crystal growth.
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Affiliation(s)
- R C Shore
- Department of Oral Biology, Dental School, University of Leeds, U.K
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11
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Inai T, Inai Y, Kurisu K. Immunohistochemical detection of an enamel protein-related epitope in rat bone at an early stage of osteogenesis. HISTOCHEMISTRY 1993; 99:355-62. [PMID: 7687593 DOI: 10.1007/bf00717047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Monoclonal antibody MI315 was produced against hamster tooth germ homogenate by in vitro immunization. It was found that MI315 reacted with enamel matrix, ameloblasts, and bone matrix at an early stage of osteogenesis. Decalcified tissues of rat femurs and mandibles were examined with MI315 using indirect immunofluorescence. In endochondral ossification of femurs, immunoreactivity was found in bone extracellular matrix (ECM) deposited on the surface of the cartilage core of primary spongiosa, but not in the cartilage core itself. In intramembranous ossification of 0-day-old rat mandibles, intense immunofluorescence was detected in bone ECM and a few young osteocytes, but not in osteoblasts. Immunoreactivity in bone ECM of 2-day-old rats decreased and almost disappeared from bone ECM of 4-day-old rats. Although in nondecalcified sections of 0-day-old rats, negligible immunofluorescence was detected in bone ECM which showed positive staining in decalcified tissues, the immunostaining appeared after decalcification using ethylenediaminetetraacetic acid (EDTA). These results indicate that a substance(s), which had a common epitope with an enamel-derived protein(s), existed in immature bone ECM of both endochondral and intramembranous ossification, and that it might be masked by bone mineral. Monoclonal antibody MI315 is a useful tool to investigate the time- and position-specific changes in osteogenesis and amelogenesis.
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Affiliation(s)
- T Inai
- Second Department of Conservative Dentistry, Faculty of Dentistry, Kyushu University, Fukuoka, Japan
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12
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Casasco A, Calligaro A, Casasco M. Proliferative and functional stages of rat ameloblast differentiation as revealed by combined immunocytochemistry against enamel matrix proteins and bromodeoxyuridine. Cell Tissue Res 1992; 270:415-23. [PMID: 1486596 DOI: 10.1007/bf00645042] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A double-staining immunocytochemical technique was used for the simultaneous detection, at the light- and electron-microscopical level, of proliferating bromodeoxyuridine (BrdU)-labelled cells and enamel protein (EP)-producing cells in the inner enamel epithelium (IEE) of rat tooth germ. BrdU-positive cells were found in the region of the IEE close to the cervical loop and never displayed EP-like immunoreactivity. BrdU-immunoreactivity was confined to the nucleus of replicating cells. In contrast, epithelial cells displaying EP-like immunoreactivity were found in the region of the forming dental cusp and were consistently BrdU-negative. EP-like immunoreactivity was detectable in the cytoplasmic compartments involved in the exocrine secretion pathway and in the extra-cellular matrix close to EP-immunoreactive cells. These data support the view that withdrawal from the cell cycle in the IEE is a temporal prerequisite for acquiring the functional competence of secreting EP. Moreover, cycling cells and secretory cells in the IEE constitute two separate compartments that are spatially defined, and that exhibit clear-cut staining patterns with respect to BrdU- and EP-immunoreactivity, respectively. We thus propose that BrdU-incorporation and EP-production may be used as specific markers of the differentiation of the IIE cells in studies of the possible role of growth factors, their receptors and oncoproteins in this tissue.
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Affiliation(s)
- A Casasco
- Institute of Histology and Embryology, University of Pavia, Italy
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13
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Kukita A, Harada H, Kukita T, Inai T, Matsuhashi S, Kurisu K. Primary and secondary culture of rat ameloblasts in serum-free medium. Calcif Tissue Int 1992; 51:393-8. [PMID: 1458344 DOI: 10.1007/bf00316886] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Enamel is the hardest tissue in vertebrates. Ameloblasts are derived from epithelial cells and are responsible for enamel formation. They secrete enamel matrix components in which amelogenins are the major proteins, the biochemical properties of which are well known. However, little is known about the characteristics of ameloblasts themselves or about the functions of amelogenins. In this study, we developed a novel primary and secondary culture system for ameloblasts using a monoclonal antibody which recognized amelogenin (En3). The cell layer on dentine removed from rat mandibular incisors was isolated and cultured in low calcium, serum-free medium. Primary culture was performed on collagen-coated culture plates and typically, two types of cells appeared. One major type changed morphology after the addition of a high concentration of calcium to the medium. Expression of amelogenin was shown as cytoplasmic particles in these cells using En3. In the secondary culture, expression of amelogenins was also observed. In this system, the cells grew and maintained the expression of amelogenin for about 3 weeks.
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Affiliation(s)
- A Kukita
- Second Department of Anatomy, Faculty of Dentistry, Kyushu University, Fukuoka, Japan
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14
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Gibson CW, Lally E, Herold RC, Decker S, Brinster RL, Sandgren EP. Odontogenic tumors in mice carrying albumin-myc and albumin-rats transgenes. Calcif Tissue Int 1992; 51:162-7. [PMID: 1422956 DOI: 10.1007/bf00298506] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Odontogenic tumors that produce abnormal tooth-like structures are repeatedly observed in mandibles of mice that carry both albumin-myc and albumin-ras transgenes. The earliest lesions appear among the periodontal ligament mesenchymal cells, but later lesions include an epithelial component. Subsequent tumor development recapitulates the process of normal tooth formation, which requires multiple sequential cell signals, and results in cell differentiation, matrix secretion, and mineralization. Tumor cells with epithelial morphology produce ras oncoprotein, consistent with an epithelial origin of these tumors. As albumin regulatory sequences direct oncogene expression in these mice, our findings also suggest that some of the albumin present in normal teeth may be locally produced and have a role in tooth mineral formation. The reproducibility of this phenotype makes these mice an excellent model for studies of both normal and neoplastic odontogenesis.
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Affiliation(s)
- C W Gibson
- Department of Anatomy and Histology, University of Pennsylvania School of Dental Medicine, Philadelphia
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15
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Aoba T, Shimoda S, Akita H, Holmberg C, Taubman MA. Anti-peptide antibodies reactive with epitopic domains of porcine amelogenins at the C-terminus. Arch Oral Biol 1992; 37:249-55. [PMID: 1381576 DOI: 10.1016/0003-9969(92)90046-b] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This was an immunological investigation of the processing of porcine amelogenins in situ. Rabbit and rat anti-peptide sera reacted specifically with the hydrophilic segment of the intact amelogenins at the C-terminus. The immunogens used were the synthetic peptides: (a) C13 composed of PATDKTKREEVDC and (b) C25 composed of MQSLLPDLPLEAWPATDKTKREEVD. These peptides correspond to the C-terminal 12- and 25-residue segments of porcine amelogenin, respectively. Cystine was introduced at the C-terminus of C12 for KLH-binding (C13). Western blot analysis disclosed that: (i) both rabbit and rat anti-C13 sera reacted selectively with the 25-kDa porcine amelogenin and three other minor components (27, 22 and 18 kDa); (ii) anti-C25 peptide sera, additionally, reacted with the 23-kDa amelogenins (a degradation derivative of the 25-kDa protein, lacking the 12-residue segment at the C-terminus) and as trace components, 20-, 16- and 14-kDa moieties. Importantly, all the proteins reactive with the anti-C13 serum were concentrated in the outer secretory enamel adjacent to the ameloblasts, decreasing significantly in the underlying inner secretory enamel. Immunohistochemical studies applying the anti-peptide sera to the developing tooth germs of a minipig also confirmed the localization of reactivity in the outer secretory region. Neither anti-peptide serum reacted with porcine non-amelogenins, serum proteins nor dentine matrix proteins at the dilutions tested. however, it was found that both the anti-C13 and C25 sera reacted with human keratin.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T Aoba
- Forsyth Dental Center, Boston, MA 02115
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16
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Jowett AK, Kimber SJ, Ferguson MW. Immunofluorescent lectin binding patterns and glycoprotein co-localization in the developing murine molar tooth. Arch Oral Biol 1992; 37:303-14. [PMID: 1381578 DOI: 10.1016/0003-9969(92)90053-b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Fluorescein-conjugated lectins were used in conjunction with antibodies to laminin, tenascin and amelogenin to investigate saccharide expression in the developing tooth germ. At the bud stage, peanut agglutinin (PNA) binding demonstrated residues that may be D-galactose-(beta 1----3)DGalNAc, and this staining occurred after the expression of tenascin. Only the cap-stage enamel organ suprabasal cells and the enamel knot stained intensely with Ulex europeus agglutinin-I, but not Lotus tetragonolobus agglutinin, implying the transient presence of blood group H type I oligosaccharides. At the late stages of amelogenesis, enamel synthesis is preceded by en bloc loss of inner enamel basement membrane components. Before this, Bandeiraea (Griffonia) simplicifolia--I (BSL-I) staining was lost from postmitotic ameloblasts, suggesting that a glycosylated species is initially removed. Additionally, PNA was co-localized with amelogenin protein, suggesting that it may express beta-D-galactosyl sequences. These results indicate that the glycosylation patterns of matrix components during odontogenesis may be important as they vary in a manner similar to that of the well-known glycoproteins.
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Affiliation(s)
- A K Jowett
- Department of Cell and Structural Biology, University of Manchester, U.K
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17
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Saku T, Okabe H, Shimokawa H. Immunohistochemical demonstration of enamel proteins in odontogenic tumors. J Oral Pathol Med 1992; 21:113-9. [PMID: 1374797 DOI: 10.1111/j.1600-0714.1992.tb00993.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Immunohistochemical localization of two enamel proteins, amelogenin and enamelin, in comparison with that of keratin, was determined in odontogenic tumors and the allied lesions in order to verify functional differentiation of the tumor cells as ameloblasts. Amelogenin and enamelin were demonstrated in small mineralized foci and in the tumor cells surrounding them in adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), and calcifying odontogenic cyst (COC). Hyaline droplets in AOT showed positive staining for both enamel proteins. These mineralized and hyaline materials were not positive for keratin, although tumor cells were positive. On the other hand, no immunoreaction for enamel proteins was obtained in ameloblastoima and odontogenic epithelial cell nests within myxoma and epulis. The results suggest that tumor cells of AOT and CEOT and lining epithelial cells of COC show ameloblastic differentiation in part, but that ameloblastoma cells do not attain functional matauration as secretory phase ameloblasts.
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Affiliation(s)
- T Saku
- Department of Pathology, Niigata University School of Dentistry, Japan
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18
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Mori M, Yamada K, Kasai T, Yamada T, Shimokawa H, Sasaki S. Immunohistochemical expression of amelogenins in odontogenic epithelial tumours and cysts. VIRCHOWS ARCHIV. A, PATHOLOGICAL ANATOMY AND HISTOPATHOLOGY 1991; 418:319-25. [PMID: 2024453 DOI: 10.1007/bf01600161] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Amelogenins, enamel proteins in odontogenic tumours, were detected immunohistochemically using a monoclonal antibody. They were strongly expressed in amyloid-like material, ghost cells, and the cells surrounding ghost cells of calcifying epithelial odontogenic tumours and cysts, whereas calcified bodies within the tumours and cysts showed negative staining. The expression of amelogenins was also positive in tumour cells of ameloblastoma, adenomatoid odontogenic tumour, squamous odontogenic tumour and ameloblastic fibroma. Peripheral tumour cells of the follicular ameloblastoma were positive with relatively intense staining. Undifferentiated or flattened tumour cells of adenomatoid odontogenic tumour and non-keratinized tumour cells of the squamous odontogenic tumour showed marked staining. Reduced ameloblasts in the odontoma displayed the strongest staining for amelogenins. The study suggests that biosynthesis of amelogenins may occur in the homogeneous materials of calcifying epithelial odontogenic tumours and cysts.
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Affiliation(s)
- M Mori
- Department of Oral and Maxillofacial Surgery, Asahi University School of Dentistry, Gifu, Japan
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19
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Uchida T, Tanabe T, Fukae M, Shimizu M, Yamada M, Miake K, Kobayashi S. Immunochemical and immunohistochemical studies, using antisera against porcine 25 kDa amelogenin, 89 kDa enamelin and the 13-17 kDa nonamelogenins, on immature enamel of the pig and rat. HISTOCHEMISTRY 1991; 96:129-38. [PMID: 1917569 DOI: 10.1007/bf00315983] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Enamel proteins were extracted from the newly formed layer of immature porcine enamel, and the 25 kDa amelogenin, 89 kDa enamelin and 13-17 kDa nonamelogenins were purified. Specific antisera were raised against these proteins. Antibodies specific to the C-terminal region (residues 149-173) of the 25 kDa amelogenin were generated by absorption of the anti-25 kDa amelogenin serum with 20 kDa amelogenin, which contains residues 1-148 of the antigen. Immunoelectro-transfer blotting of the extracted porcine enamel proteins showed that the anti-25 kDa amelogenin serum recognized the 25 kDa and other low and high molecular weight amelogenins. The C-terminal specific anti-25 kDa amelogenin serum reacted only with amelogenins having molecular weights over 23 kDa. The anti-89 kDa enamelin serum recognized the 89 kDa enamelin and lower molecular weight proteins, but neither the amelogenins nor the 13-17 kDa nonamelogenins. The antiserum against the 13-17 kDa nonamelogenins showed no cross reactivity to the 89 kDa enamelin, but recognized higher molecular weight nonamelogenins. In immunohistochemical preparations of the porcine tooth germs, the 25 kDa amelogenin-like immunoreactivity over immature enamel decreased in a gradient from the enamel surface to the middle layer. In the inner layer immunoreactivity was concentrated over the prism sheaths. The C-terminal specific 25 kDa amelogenin-like immunoreactivity was intense at the outer layer of immature enamel and decreased sharply toward the middle layer. Prism sheaths were intensely stained by the antiserum to the 13-17 kDa nonamelogenins.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T Uchida
- Department of Anatomy, Yamanashi Medical College, Japan
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Inai T, Kukita T, Ohsaki Y, Nagata K, Kukita A, Kurisu K. Immunohistochemical demonstration of amelogenin penetration toward the dental pulp in the early stages of ameloblast development in rat molar tooth germs. Anat Rec (Hoboken) 1991; 229:259-70. [PMID: 2012313 DOI: 10.1002/ar.1092290213] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In order to examine the synthesis and secretion of enamel protein by ameloblasts in their early stages of development, immunohistochemical localization was carried out at light and electron microscopic levels using a monoclonal antibody produced in a preliminary experiment. Materials used were tooth germs of mandibular first molars of rats at 0-5 days after birth. Immunoblot analysis after two-dimensional electrophoresis revealed that antigen molecules recognized by the monoclonal antibody were amelogenins of 26-28 kDa (pI, 6.6-7.0). An immunohistochemical examination using this monoclonal antibody demonstrated that the presecretory ameloblasts in their early stages of differentiation both synthesized amelogenin and secreted through a classical merocrine secretory pathway. In some presecretory ameloblasts as well as ameloblasts we observed the distended cisternae of rough endoplasmic reticulum (rER) which demonstrated heterogenous immunolabelling. The immunolabellings were also detected in the predentin as well as the intercellular spaces of odontoblasts and dental pulp cells which indicated penetration of amelogenin from the presecretory ameloblast layer to the dental pulp. The presence of coated pits at the plasma membrane of odontoblasts in close proximity to enamel protein along with the immunolabelling of lysosomes of the odontoblasts suggests the phagocytosis of the enamel protein into the odontoblasts. These observations suggest the possibility that the penetration of enamel protein toward the dental pulp and odontoblasts plays a role in the interaction between ameloblasts and odontoblasts.
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Affiliation(s)
- T Inai
- Second Department of Conservative Dentistry, Faculty of Dentistry, Kyushu University, Fukuoka, Japan
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Farge P, Ricard-Blum S, Joffre A, Ville G, Magloire H. Immunoblotting and cytochemical characterization of human enamel proteins. Arch Oral Biol 1991; 36:89-94. [PMID: 2059165 DOI: 10.1016/0003-9969(91)90070-b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mature enamel proteins (tuft proteins) and fetal enamel proteins were extracted by an homogenizing buffer method, subjected to SDS-PAGE and immunoblotted with a polyclonal antibody raised against the mature enamel proteins. Both fetal and tuft proteins were recognized by this immunoblotting. With the same antibody, immunolocalization of the developing enamel proteins was done on semi-thin-sections of human fetal tissue at the secretory stage, using an immunoperoxidase technique. Specific labelling of the enamel protein matrix was observed. It is concluded that a polyclonal antibody against mature enamel proteins (anti-tuft) can recognize the developing protein matrix at the secretory stage. This suggests that a common antigenic determinant is maintained throughout the course of amelogenesis in human enamel.
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Affiliation(s)
- P Farge
- Faculté d'Odontologie, URA CNRS 244, Université Claude Bernard, Lyon, France
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Herold RC, Rosenbloom J. Immunocytochemical localization of enamelin proteins in developing bovine teeth. Arch Oral Biol 1990; 35:373-9. [PMID: 2372242 DOI: 10.1016/0003-9969(90)90184-c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Enamelins were localized at both the light and electron microscopic level using an antienamelin monoclonal antibody and indirect immunogold methods. Bovine fetal incisors (crown-rump length 17-30 cm) were preserved in Karnovsky's fixative and embedded in Epon. For light microscopy, 2 microM thick sections were immunostained by the indirect method using the monoclonal antibody and goat anti-mouse IgG linked to 5 nM gold particles, followed by silver enhancement to increase the sensitivity of the method. For electron microscopy, thin sections were immunostained (indirect) with the antienamelin monoclonal antibody and goat anti-mouse IgG linked to 5 or 15 nM gold. Control samples were treated with an unrelated monoclonal antibody. The localization of enamelins was confined in the light microscopic sections to the extracellular enamel matrix. No gold staining was observed in the ameloblasts or other enamel organ cells even though the gold-silver technique is extremely sensitive. Ultrastructurally, enamelin was localized in the enamel extracellular matrix and associated ameloblasts. Both the crystal-containing and granular matrix were positively stained, with most gold particles being closely associated with the crystals. Counting of gold particles indicated more than 4 times as many amelogeninas enamelin-reactive antigenic sites in similar regions. Decalcification did not increase immunostaining with the anti-enamelin antibody in the extracellular matrix. Within ameloblasts, the gold particles were associated with secretory granules and Golgi complexes. Thus it appears that enamelins are synthesized in ameloblasts and secreted into the extracellular matrix in a similar manner to amelogenins and are preferentially associated with matrix hydroxyapatite crystals. Transient levels of enamelins within the ameloblasts are apparently too low to be detected by light microscopy.
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Affiliation(s)
- R C Herold
- Research Center in Oral Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia 19104
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Abstract
The present paper reviews the main features of amelogenin and enamelin biochemistry, molecular biology, structural and ultrastructural localization, and immunology. It also examines recent studies concerning the origin, chemical characterization, suggested role, and participation of these two major classes of extracellular developing enamel matrix proteins in the complex process of "matrix-mediated" mineralization.
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Affiliation(s)
- D Deutsch
- Dental Research Unit, Hebrew University--Hadassah Faculty of Dental Medicine, Jerusalem, Israel
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Nanci A, Slavkin HC, Smith CE. Application of high-resolution immunocytochemistry to the study of the secretory, resorptive, and degradative functions of ameloblasts. Adv Dent Res 1987; 1:148-61. [PMID: 3504166 DOI: 10.1177/08959374870010020301] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The distribution of enamel proteins (EP) within extracellular and subcellular compartments of the enamel organ has been characterized by use of the protein A-gold immunocytochemical technique and an antibody against mouse amelogenins. EP were immunolocalized within the protein synthetic and secretory organelles, and within lysosomal elements of ameloblasts in both the secretion and maturation stages. The results provide direct evidence that ameloblasts maintain active secretory and degradative pathways for EP throughout the secretory and early maturation stages of amelogenesis. The origin of the immunoreactive material within lysosomes is unclear and could derive from the direct shunting of newly formed EP from the synthetic organelles to the lysosomes or from endocytosis of aged proteins. These findings ultimately provide new insights into the multifunctional role which ameloblasts play throughout amelogenesis.
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