Initial aspects of mineralization at the dentino-enamel junction in embryonic mouse incisor in vivo and in vitro: A tem comparative study

Meyer, Jean‐Marie; Bodier-Houllé, P.; Cuisinier, Frédéric; Lesot, Hervé; Ruch, J V

doi:10.1007/s11626-999-0019-3

Cited by 12 publications

(10 citation statements)

References 45 publications

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“…Prior to the onset of biomineralization, enamel associated proteins such as amelogenin, ameloblastin (30,36–38), enamelin, and enamelysin (39) are being expressed, as are dentin‐associated proteins such as type I collagen, dentin sialophosphoprotein (DSPP), osteocalcin, and dentin matrix protein 1 (DMP1) (29,40). Enamel crystallites first appear associated with electron‐dense granules on the fringe of the stippled material (41). Therefore, all of the extracellular matrix proteins normally associated with dentin and enamel formation are expressed prior to the onset of biomineralization, and therefore could theoretically participate in crystal nucleation.…”

Section: Discussionmentioning

confidence: 99%

A comparison of enamelin and amelogenin expression in developing mouse molars

Sun

Zhang

et al. 2001

European J Oral Sciences

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Amelogenin and enamelin are structural proteins in the enamel matrix of developing teeth. The temporal and spatial patterns of enamelin expression in developing mouse molars have not been characterized, while controversy remains with respect to amelogenin expression by odontoblasts and cementoblasts. Here we report the results of in situ hybridization analyses of amelogenin and enamelin expression in mouse molars from postnatal days 1, 2, 3, 7, 9, 14, and 21. Amelogenin and enamelin mRNA in maxillary first molars was first observed in pre-ameloblasts on the cusp slopes at day 2. The onsets of amelogenin and enamelin expression were approximately synchronous with the initial accumulation of predentin matrix. Both proteins were expressed by ameloblasts throughout the secretory, transition, and early maturation stages. Enamelin expression terminated in maturation stage ameloblasts on day 9, while amelogenin expression is still detected in maturation stage ameloblasts on day 14. No amelogenin expression was observed in day 21 mouse molars. Amelogenin and enamelin RNA messages were restricted to ameloblasts. No expression was observed in pulp, bone, or along the developing root. We conclude that amelogenin and enamelin are enamel-specific and do not directly participate in the formation of dentin or cementum in developing mouse molars.

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Section: Discussionmentioning

confidence: 99%

A comparison of enamelin and amelogenin expression in developing mouse molars

Sun

Zhang

et al. 2001

European J Oral Sciences

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“…Amelogenin exists in the form of a liquid crystal mesophase, constituted in vitro and in vivo by nanospheres structurally stable at 37°C, and may be as a thixotropic gel implicated in the growth of enamel crystal (Moradian-Oldak et al 1998). On images of developing enamel, amelogenins clearly appear to be organized in rows neighboring the c-axis of the ribbon-like enamel crystallites (Meyer et al 1999). In dentin this function was devoted to type I collagen, which provides the physical support and the environment favoring mineral deposition (Weiner and Wagner et al 1998).…”

Section: Introductionmentioning

confidence: 99%

High-resolution electron-microscopic study of the relationship between human enamel and dentin crystals at the dentinoenamel junction

Bodier-Houllé

Steuer

Meyer

et al. 2000

Cell and Tissue Research

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The development of dentin and of enamel share a common starting locus: the dentinoenamel junction (DEJ). In this study the relationship between enamel and dentin crystals has been investigated in order to highlight the guiding or modulating role of the previously mineralized dentin layer during enamel formation. Observations were made with a high-resolution electron microscope and, after digitalization, image-analysis software was used to obtain digital diffractograms of individual crystals. In general no direct epitaxial growth of enamel crystals onto dentin crystals could be demonstrated. The absence of direct contact between the two kinds of crystals and the presence of amorphous areas within enamel particles at the junction with dentin crystals were always noted. Only in a few cases was the relationship between enamel and dentin crystals observed, which suggested a preorganization of the enamel matrix influenced by the dentin surface structure. This could be explained either by the existence of a proteinaceous continuum between enamel and dentin or by the orientation of enamel proteins by dentin crystals.

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“…These T-A cells, in turn, arise from stem cells located in the posterior part of the incisor, which is called the cervical loop (Smith and Warshawsky, '75; Harada et al, '99; Wang et al, 2007). The lingual and labial portions of the cervical loop differ in their origin, morphology, cell-matrix interaction and gene expression (Smith and Warshawsky, '75; Kieffer et al, '99; Meyer et al, '99; Harada et al, 2002; Wang et al, 2007). …”

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confidence: 99%

Temporal analysis of ectopic enamel production in incisors from sprouty mutant mice

et al. 2008

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The mouse incisor has two unusual features: it grows continuously and it is covered by enamel exclusively on the labial side. The continuous growth is driven in part by epithelial stem cells in the cervical loop region that can both self-renew and give rise to ameloblasts. We have previously reported that ectopic enamel is found on the lingual side of the incisor in mice with loss-of-function of sprouty (spry) genes. Spry2+/−; Spry4−/− mice, in which three sprouty alleles have been inactivated, have ectopic enamel as a result of upregulation of epithelial-mesenchymal FGF signaling in the lingual part of the cervical loop. Interestingly, lingual enamel is also present in the early postnatal period in Spry4−/− mice, in which only two sprouty alleles have been inactivated, but ectopic enamel is not found in adults of this genotype. To explore the mechanisms underlying the disappearance of lingual enamel in Spry4−/− adults, we studied the fate of the lingual enamel in Spry4−/− mice by comparing the morphology and growth of their lower incisors with wild type and Spry2+/−; Spry4−/− mice at several timepoints between the perinatal period and adulthood. Ameloblasts and enamel were detected on the lingual side in postnatal Spry2+/−; Spry4−/+ incisors. By contrast, new ectopic ameloblasts ceased to differentiate after postnatal day 3 in Spry4−/− incisors, which was followed by a progressive loss of lingual enamel. Both the posterior extent of lingual enamel and the time of its last deposition were variable early postnatally in Spry4−/− incisors, but in all Spry4−/− adult incisors the lingual enamel was ultimately lost through continuous growth and abrasion of the incisor.

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Initial aspects of mineralization at the dentino-enamel junction in embryonic mouse incisor in vivo and in vitro: A tem comparative study

Cited by 12 publications

References 45 publications

A comparison of enamelin and amelogenin expression in developing mouse molars

A comparison of enamelin and amelogenin expression in developing mouse molars

High-resolution electron-microscopic study of the relationship between human enamel and dentin crystals at the dentinoenamel junction

Temporal analysis of ectopic enamel production in incisors from sprouty mutant mice

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