The initial information for patterning of early tooth development resides in the epithelium. Later, this is shifted to the mesenchyme. The process is governed by multiple epithelial-mesenchymal interactions. Integrins are cell surface receptors for extracellular matrix components. Expression of the beta 5 integrin subunit alternates between epithelium and mesenchyme during early tooth development (Yamada et al. [1994] Int. J. Dev. Biol. 38: 553-556). By immunofluorescence and in situ hybridization we show here a remarkably similar oscillating expression pattern of the alpha v integrin subunit. This subunit is known to associate with beta 5, and we therefore suggest that integrin alpha v beta 5 is involved in epithelial-mesenchymal interactions during tooth development. We also demonstrate that the developing tooth epithelium expresses the alpha 6, beta 1 and beta 4 subunits. The laminin receptors alpha 6 beta 1 and alpha 6 beta 4 may thus in part mediate the effect of basement membranes on tooth epithelial development. Interestingly, the enamel knot region expressed very little alpha 6 integrin subunit, whereas some expression was seen transiently in the condensing mesenchyme. During early tooth development, integrins possessing the alpha 6 subunit might also be involved in cell-cell interactions independently of laminins.
Integrin subunit expression associated with epithelial-mesenchymal interactions during murine tooth development.
HIRSCH, Emilio;ALTRUDA, Fiorella;
1996-01-01
Abstract
The initial information for patterning of early tooth development resides in the epithelium. Later, this is shifted to the mesenchyme. The process is governed by multiple epithelial-mesenchymal interactions. Integrins are cell surface receptors for extracellular matrix components. Expression of the beta 5 integrin subunit alternates between epithelium and mesenchyme during early tooth development (Yamada et al. [1994] Int. J. Dev. Biol. 38: 553-556). By immunofluorescence and in situ hybridization we show here a remarkably similar oscillating expression pattern of the alpha v integrin subunit. This subunit is known to associate with beta 5, and we therefore suggest that integrin alpha v beta 5 is involved in epithelial-mesenchymal interactions during tooth development. We also demonstrate that the developing tooth epithelium expresses the alpha 6, beta 1 and beta 4 subunits. The laminin receptors alpha 6 beta 1 and alpha 6 beta 4 may thus in part mediate the effect of basement membranes on tooth epithelial development. Interestingly, the enamel knot region expressed very little alpha 6 integrin subunit, whereas some expression was seen transiently in the condensing mesenchyme. During early tooth development, integrins possessing the alpha 6 subunit might also be involved in cell-cell interactions independently of laminins.
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