Dynamic expression of E-cadherin in ameloblasts and cementoblasts in mice.

During embryonic development, E-cadherin mediates intercellular adhesion in a variety of epithelia in a spatio-temporal pattern. We have analyzed the distribution of this cell adhesion molecule in the mouse during odontogenesis, at both mRNA and protein levels, in the mandibular first molars and incisors. E-cadherin was strongly expressed at the bell stage by the cells of the dental organ, and by the pre-secretory ameloblasts and the cells of stratum intermedium at the early mineralization stage. At the onset of enamel secretion, E-cadherin disappeared from the apical pool of the ameloblasts and was later absent from the post-secretory ameloblasts. E-cadherin was also found in Hertwig's root sheath and later in the cells producing acellular cementum. These findings indicate that E-cadherin may be involved in the polarization of the ameloblasts and in the early stages of cementogenesis.