Odontogenic ameloblast-associated and amelotin are novel basal lamina components.
Odontogenic ameloblast-associated (ODAM) and amelotin (AMTN) are secreted by maturation stage ameloblasts and accumulate at the interface with enamel where an atypical basal lamina (BL) is present. This study aimed at determining and quantifying the ultrastructural distribution of ODAM and AMTN at the cell-tooth interface. Ultrathin sections of enamel organs from the early to mid- and late maturation stage of amelogenesis were processed for immunogold labeling with antibodies against ODAM, AMTN or with the lectins wheat germ agglutinin, Helix                         pomatia agglutinin (HPA) and Ricinus communis I agglutinin. Immunolabeling showed that both ODAM and AMTN localized to the BL. Quantitative analyses indicated that at the beginning of maturation there is a concentration of ODAM on the cell side of the BL while AMTN appears more concentrated on the enamel side. In the late maturation stage, such differential distribution is no longer apparent. All three lectins are bound to the BL. Competitive incubation with native lectins did not affect the binding efficiency of ODAM; however, AMTN binding was significantly reduced after incubation with HPA. In conclusion, ODAM and AMTN are bona fide components of the BL associated with maturation stage ameloblasts and they organize into different subdomains during the early maturation stage. The data also suggest that the BL is a dynamic structure that rearranges its organization as enamel maturation advances. Finally, the abrogation of AMTN antibody labeling by HPA supports the presence of O-linked sugars in the molecule and/or its close association with other O-glycosylated molecules.
Laboratory for the Study of Calcified Tissues and Biomaterials, Université de Montréal, Station Centre-Ville, Montreal, QC, H3C 3J7, Canada.
Juliana
J
Dos Santos Neves
Rima M
RM
Wazen
Shingo
S
Kuroda
Sylvia
S
Francis Zalzal
Pierre
P
Moffatt
Antonio
A
Nanci
D000818:Animals; D001485:Basement Membrane / Q000378:metabolism* / Q000648:ultrastructure; D001667:Binding, Competitive / Q000502:physiology; D003746:Dental Enamel Proteins / Q000378:metabolism*; D017979:Gold Colloid; D007124:Immunoenzyme Techniques; D007180:Incisor / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D037102:Lectins / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D016253:Microscopy, Immunoelectron; D009805:Odontogenesis / Q000502:physiology*; D011506:Proteins / Q000378:metabolism*
C507066:Amtn protein, mouse; D003746:Dental Enamel Proteins; D017979:Gold Colloid; D047908:Intracellular Signaling Peptides and Proteins; D037102:Lectins; C555400:ODAM protein, mouse; D011506:Proteins