Abstract
A specialized basal lamina (sBL) mediates adhesion of certain epithelial cells to the tooth. It is distinct because it does not contain collagens type IV and VII, is enriched in laminin-332, and includes three novel constituents called amelotin (AMTN), odontogenic ameloblast-associated (ODAM), and secretory calcium-binding phosphoprotein proline-glutamine rich 1 (SCPPPQ1). The objective of this study was to clarify the structural organization of the sBL. Fluorescence and immunogold labeling showed that the three proteins co-localize. Quantitative analysis of the relative position of gold particles on the sBL demonstrates that the distribution of ODAM is skewed towards the cell while that of AMTN and SCPPPQ1 tends towards the tooth surface. Bacterial two-hybrid analysis and co-immunoprecipitation, gel filtration of purified proteins and transmission electron and atomic force microscopies highlight the propensity of AMTN, ODAM, and SCPPPQ1 to interact with and among themselves and form supramolecular aggregates. These data suggest that AMTN, ODAM and SCPPPQ1 participate in structuring an extracellular matrix with the distinctive capacity of attaching epithelial cells to mineralized surfaces. This unique feature is particularly relevant for the adhesion of gingival epithelial cells to the tooth surface, which forms a protective seal that is the first line of defense against bacterial invasion.
Highlights
Basal laminae (BLs) act as an interface between epithelial cells and the underlying connective tissue, and comprise collagen types IV and VII, proteoglycans, and glycoproteins such as laminins[1,2,3]
Once enamel has fully completed its mineralization, the tooth erupts and part of the enamel organ (EO) covering the tooth crown fuses with the oral epithelium. This fusion results in the formation of a structure called junctional epithelium (JE), which adheres to the tooth surface through a specialized basal lamina (sBL) similar in composition to that found in the maturation stage EO
Since AMTN, odontogenic ameloblast-associated (ODAM) and SCPPPQ1 are unique to the sBL, they appear crucial to structuring this special extracellular matrix and to mediating the adhesion of epithelial cells to tooth surfaces
Summary
Basal laminae (BLs) act as an interface between epithelial cells and the underlying connective tissue, and comprise collagen types IV and VII, proteoglycans, and glycoproteins such as laminins[1,2,3]. Proteins from this cluster stabilize calcium and phosphate ions in tissue fluids and regulate their deposition in the extracellular matrix, this has not been formally determined for AMTN, ODAM and SCPPPQ1 They are produced by maturation stage ameloblasts and JE cells, and high-resolution immunogold analysis revealed that the three proteins localize to the sBL16,20,21. Since AMTN, ODAM and SCPPPQ1 are unique to the sBL, they appear crucial to structuring this special extracellular matrix and to mediating the adhesion of epithelial cells to tooth surfaces. In support of this notion, recent reports have shown JE detachment in ODAM-KO mice and loss of integrity of the maturation stage sBL in a transgenic mouse model expressing human laminin-γ222–24. Such information is a prelude for understanding the mechanisms that are implicated in structuring the sBL and its adhesion to mineralized surfaces
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
