Immunoblot detection and expression of enamel proteins at the apical portion of the forming root in porcine permanent incisor tooth germs

Abstract

There have been many immunohistochemical studies of enamel proteins during root formation. In the present article, the detection and expression of enamel proteins in tissue samples prepared from the apical portion of the forming root (APFR) in porcine permanent incisor tooth germs were studied. Amelogenin, enamelin, and sheathlin were detected by immunoblot analysis, but only in small amounts. The detection of their derivatives indicated their degradation. It is, at present, unclear as to which proteinases are involved in these degradations, because activity of enamel matrix serine proteinase 1 and enamelysin was not detected on gelatin and casein zymograms. The expression of enamel proteins was also proved in the APFR sample by the detection of polymerase chain reaction products of their cDNAs, and this may be related to cells of fragmentized Hertwig's epithelial root sheath. Amelogenin expression was not greater than that of enamelin and sheathlin. It was different from the expression pattern of secretory ameloblasts involved in enamel matrix formation. These results suggest that the amelogenins found in the APFR do not form a three-dimensional structure of amelogenin micelles, which has been proposed for the secretory enamel matrix structure. In this case, the enamel proteins could spread out easily following degradation into the matrix of future cementum. Some of their derivatives may play a role in the formation of the cementum.

The Receptor Activator of Nuclear Factor-κB Ligand-mediated Osteoclastogenic Pathway Is Elevated in Amelogenin-null Mice

“…During tooth development, at least nine different mRNA splice forms are generated from the amelogenin gene as a result of alternate splicing (26). Interestingly, the presence of amelogenins in the tooth root region has been detected only by immunohistochemical and in situ hybridization studies (9,10,27). However, these studies could not identify the presence of individual alternate splice forms of mRNA or their translational products.…”

Treatment of Intrabony Periodontal Defects With Enamel Matrix Derivative: A Literature Review

“…12,13 In fact, EMPs have been recently detected at the apical portion of the forming root by immunoblot analysis. 14 The introduction of EMD in periodontal regeneration was based on the apparent involvement of EMPs in the formation of acellular cementum and associated tooth-supporting tissues during root morphogenesis. [9][10][11][12][13][14] It was hypothesized that surgical application of EMD on previously diseased roots may form a natural extracellular matrix that controls regenerative processes, mimicking developmental interactions in a clinical setting.…”

“…14 The introduction of EMD in periodontal regeneration was based on the apparent involvement of EMPs in the formation of acellular cementum and associated tooth-supporting tissues during root morphogenesis. [9][10][11][12][13][14] It was hypothesized that surgical application of EMD on previously diseased roots may form a natural extracellular matrix that controls regenerative processes, mimicking developmental interactions in a clinical setting. 7,15 In support of this hypothesis, it has been demonstrated that EMD precipitated on root surfaces forms aggregated microspheres 7,16 that resemble the in vivo supramolecular globular assemblies of the EM.…”

Hertwig's epithelial root sheath, enamel matrix proteins, and initiation of cementogenesis in porcine teeth

“…In particular, amelogenins are believed to initiate specifically the genesis of acellular extrinsic fiber cementum (Hammarström 1997, Hammarström et al 1997). While experimental data confirming this assumption are lacking, several studies used biochemical (Slavkin et al 1989a, b, Fukae et al 2001) and histological (Slavkin et al 1989b, Luo et al 1991, Bosshardt & Schroeder 1996, Fong et al 1996, Thomas et al 1997, Bosshardt & Nanci 1998, 2000, Fong & Hammarström 2000, Hu et al 2001) techniques to demonstrate protein and gene expression of EMPs during root development. Slavkin et al (1989b) demonstrated both amelogenin and enamelin protein expression along the cervical‐most portion of growing molars from young mice, a region where acellular extrinsic fiber cementum prevails.…”