Synthesis, Secretion, Degradation, and Fate of Ameloblastin During the Matrix Formation Stage of the Rat Incisor as Shown by Immunocytochemistry and Immunochemistry Using Region-specific Antibodies

Uchida, Takashi; Murakami, Chikage; Dohi, Naofumi; Wakida, Kazuyoshi; Satoda, Takahiro; Takahashi, Osamu

doi:10.1177/002215549704501002

Cited by 90 publications

(95 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9,14 In the present study, we partially sequenced the amino acids of the major amyloid protein of canine APOT and compared the amino-terminal sequence with that of the enamel proteins rat ameloblastin and porcine sheathlin, which are transcribed in cells of the epithelial root sheath in normal incisor tooth germ. 16,47,48,50 We examined the immunohistochemical profile of the amyloid using antibodies to ameloblastin, sheathlin, amelogenin, and amyloid protein isolated from a canine APOT. …”

mentioning

confidence: 99%

Biochemical and Immunohistochemical Characterization of the Amyloid in Canine Amyloid-Producing Odontogenic Tumor

Hirayama

Miyasho

Ohmachi³

et al. 2010

Vet Pathol

View full text Add to dashboard Cite

The amyloid of canine amyloid-producing odontogenic tumor (APOT) was evaluated biochemically and immunohistochemically. The N-terminal amino-acid sequence of purified amyloid protein from a canine APOT was strikingly similar to the sequence in both rat ameloblastin and porcine sheathlin. Immunohistochemically, the amyloid in APOT from 9 dogs was strongly reactive with anti-rat ameloblastin, anti-porcine sheathlin, and anti-canine APOT amyloid and weakly reactive with anti-porcine amelogenin but negative for antibodies to cytokeratins, vimentin, desmin, a-smooth muscle actin, amyloid A, glial fibrillary acidic protein, or S100 protein. The neoplastic epithelial cells of APOT were focally reactive with antibodies to ameloblastin, sheathlin, amelogenin, and canine APOT amyloid. The similarity in amino-acid sequence of the amyloid protein of canine APOT to that of enamel proteins, such as ameloblastin, sheathlin, and amelogenin, and the expression of these antigens in both APOT amyloid and in the neoplastic cells suggest that the amyloid of canine APOT is derived from enamel proteins secreted by ameloblasts. Keywords ameloblasts, amyloid, dogs, enamel proteins, odontogenic tumorAmyloidosis is a heterogeneous group of disorders characterized by the deposition of amyloid proteins derived from any of at least 25 different precursor molecules. Amyloid is considered a pathologic substance that appears histologically as an extracellular, amorphous, congophilic protein with applegreen birefringence under polarized light. Amyloidosis can be categorized as systemic or localized. Common human types of localized amyloidosis include amyloidosis of endocrine organs associated (or not) with neoplastic conditions and cerebral amyloidosis of Alzheimer's disease. 21,51 Localized amyloid deposits with or without association with neoplasia also have been described in the human mammary gland, 41,52 respiratory tract, 26,34 gastrointestinal tract, 5,38 genitourinary tract, 13,17 skin, 24,25 and bone. 23 In animals, localized amyloidosis has been associated with neoplastic conditions such as calcifying epithelial odontogenic tumor (CEOT), 2,29 pancreatic endocrine tumor, 28 medullary thyroid carcinoma, 15 ameloblastoma, 10 mammary carcinoma, 43 intestinal carcinoid, 40 extramedullary plasmacytoma, 31,36 and myeloma. 12 CEOT is a rare neoplasm of the tooth-forming apparatus that produces a mineralized substance and amyloid. 30 The origin of the amyloid in human and animal CEOT is often debated but is still unknown. 2,19,27,29,37,42,46 Recent studies indicate that the amyloid in human CEOT is secreted by the neoplastic epithelial cells, but its precise nature remains unclear. 27,39,42 CEOT in veterinary medicine is classified as amyloidproducing odontogenic tumor (APOT). 9,14 In the present study, we partially sequenced the amino acids of the major amyloid protein of canine APOT and compared the amino-terminal sequence with that of the enamel proteins rat ameloblastin and porcine sheathlin, which are transcribed in cells of the epi...

show abstract

mentioning

confidence: 99%

Biochemical and Immunohistochemical Characterization of the Amyloid in Canine Amyloid-Producing Odontogenic Tumor

Hirayama

Miyasho

Ohmachi³

et al. 2010

Vet Pathol

View full text Add to dashboard Cite

show abstract

“…Both newly secreted matrix proteins present at the forming surface of the enamel layer and partially degraded molecular forms located deeper into it can be concentrated at, or relatively missing from, specific sites within the layer (Smith et al 1989a,b;Kogaya 1994;Nanci et al 1996;Murakami et al 1997;Uchida et al 1991aUchida et al ,b,1997. The most dramatic differences in intraenamel protein concentrations have been observed for nonamelogenins such as ameloblastin and enamelin, for which newly secreted forms are present in high concentration at the enamel surface near ameloblasts (Hu et al 1997a,b;Murakami et al 1997;Uchida et al 1997).…”

mentioning

confidence: 99%

“…The purpose of this investigation was to obtain information about the intracellular and extracellular distribution of ameloblastin vs amelogenin using qualitative and quantitative high-resolution immunocytochemistry in combination with immunoblotting and polyclonal antibodies against the full-length and an internal portion of recombinant ameloblastin, in contrast to synthetic peptide antibodies as was employed in a recent study reported by Uchida et al (1997). Another objective was to clarify issues about sites of expression vs sites of secretion for ameloblastin.…”

mentioning

confidence: 99%

Comparative Immunochemical Analyses of the Developmental Expression and Distribution of Ameloblastin and Amelogenin in Rat Incisors

Nanci

Zalzal

Lavoie

et al. 1998

J Histochem Cytochem.

128

155

View full text Add to dashboard Cite

SUMMARYMineralized tissues are unique in using proteins to attract and organize calcium and phosphate ions into a structured mineral phase. A precise knowledge of the expression and extracellular distribution of matrix proteins is therefore very important in understanding their function. The purpose of this investigation was to obtain comparative information on the expression, intracellular and extracellular distribution, and dynamics of proteins representative of the two main classes of enamel matrix proteins. Amelogenins were visualized using an antibody and an mRNA probe prepared against the major alternatively spliced isoform in rodents, and nonamelogenins by antibodies and mRNA probes specific to one enamel protein referred to by three names: ameloblastin, amelin, and sheathlin. Qualitative and quantitative immunocytochemistry, in combination with immunoblotting and in situ hybridization, indicated a correlation between mRNA signal and sites of protein secretion for amelogenin, but not for ameloblastin, during the early presecretory and midto late maturation stages, during which mRNA signals were detected but no proteins appeared to be secreted. Extracellular amelogenin immunoreactivity was generally weak near secretory surfaces, increasing over a distance of about 1.25 m to reach a level slightly above an amount expected if the protein were being deposited evenly across the enamel layer. Immunolabeling for ameloblastin showed an inverse pattern, with relatively more gold particles near secretory surfaces and much fewer deeper into the enamel layer. Administration of brefeldin A and cycloheximide to stop protein secretion revealed that the immunoblotting pattern of amelogenin was relatively stable, whereas ameloblastin broke down rapidly into lower molecular weight fragments. The distance from the cell surface at which immunolabeling for amelogenin stabilized generally corresponded to the point at which that for ameloblastin started to show a net reduction. These data suggest a correlation between the distribution of amelogenin and ameloblastin and that intact ameloblastin has a transient role in promoting/stabilizing crystal elongation. A meloblasts , like all hard tissue-forming cells, release an intricate set of extracellular matrix proteins optimized for promoting the development of a closely associated mineral phase (reviewed in Deutsch et al.

show abstract

“…On the other hand, enamel matrix proteins are distinctively less glycosylated. Sugar residues are mainly present on non-amelogenins and are predominately N -linked in the case of enamelin (Fukae et al 1996;Hu et al 1998) and a 65-kD sulfated enamel protein , and O -linked in the case of ameloblastin (Cerny et al 1996;Krebsbach et al 1996;Hu et al 1997;Uchida et al 1997;Nanci and Smith 2000). However, a highly glycosylated BL forms at the interface between ameloblasts and enamel at the start of the maturation stage of amelogenesis (Nanci et al 1993).…”

Section: Discussionmentioning

confidence: 99%

Localized Infusion of Tunicamycin in Rat Hemimandibles: Alteration of the Basal Lamina Associated with Maturation Stage Ameloblasts

Orsini

Zalzal

Nanci

2001

J Histochem Cytochem.

View full text Add to dashboard Cite

S U M M A R YAt the beginning of the maturation stage of amelogenesis, ameloblasts deposit a basal lamina (BL) at the interface between their apical surface and maturing enamel. This structure is rich in glycoconjugates and is proposed to exhibit adhesive and/or filtering functions. To clarify its role, we have applied a recently developed surgical window model to locally administer tunicamycin (TM), an antibiotic that interferes with N -glycosylation, in the rat hemimandible using an osmotic minipump. Male Wistar rats were infused with either TM or saline as a control. Lectin-gold cytochemistry was performed to reveal glycoconjugates in the BL. Immunogold labeling of enamel proteins and albumin was carried out to verify whether depletion of N -linked sugars in the BL affects the content and distribution of endogenous and exogenous proteins in the enamel layer. Under the influence of the drug, the BL became irregular and exhibited alterations in structural organization and composition. The number of Helix pomatia agglutinin binding sites was not significantly affected but their distribution was altered. The labeling density of wheat germ agglutinin over the BL was slightly reduced. Immunoreactivity for enamel proteins showed only a small decrease, but that of albumin, both between ameloblasts and within the enamel layer, increased significantly. No structural alterations were observed in the contralateral incisor and in other sampled tissues and organs. These results demonstrate that it is possible to achieve a localized administration of TM without systemic side effects and lend support to the proposal that the BL represents a specialized structure with filtering functions.

show abstract

Synthesis, Secretion, Degradation, and Fate of Ameloblastin During the Matrix Formation Stage of the Rat Incisor as Shown by Immunocytochemistry and Immunochemistry Using Region-specific Antibodies

Cited by 90 publications

References 33 publications

Biochemical and Immunohistochemical Characterization of the Amyloid in Canine Amyloid-Producing Odontogenic Tumor

Biochemical and Immunohistochemical Characterization of the Amyloid in Canine Amyloid-Producing Odontogenic Tumor

Comparative Immunochemical Analyses of the Developmental Expression and Distribution of Ameloblastin and Amelogenin in Rat Incisors

Localized Infusion of Tunicamycin in Rat Hemimandibles: Alteration of the Basal Lamina Associated with Maturation Stage Ameloblasts

Contact Info

Product

Resources

About