Application of High-Resolution Immunocytochemistry to the Study of the Secretory, Resorptive, and Degradative Functions of Ameloblasts

¹ Departements de stomatologie et d'anatomie, Universite de Montreal C. P. 6128, succ. A, Montreal Quebec, Canada H3C 3J7
² Laboratory for Developmental Biology, University of Southern California, Andrus Gerontology Center, Los Angeles, California 90089-0191
³ Departments of Anatomy and Oral Biology, McGill University, 3640 University Street, Montreal, Quebec, Canada H3A 2B2

Dr. Antonio Nanci, Départment de stomatologie, Faculté de méderine dentaire, C. P. 6128, succursale A, Montréal, Qusistance of Marie Lesage.

The distribution of enamel proteins (EP) within extracellular and subcellular compartments of the enamel organ has been characterized by use of the protein A-gold immunocytochemical technique and an antibody against mouse amelogenins. EP were immunolocalized within the protein synthetic and secretory organelles, and within lysosomal elements of ameloblasts in both the secretion and maturation stages. The results provide direct evidence that ameloblasts maintain active secretory and degradative pathways for EP throughout the secretory and early maturation stages of amelogenesis. The origin of the immunoreactive material within lysosomes is unclear and could derive from the direct shunting of newly formed EP from the synthetic organelles to the lysosomes or from endocytosis of aged proteins. These findings ultimately provide new insights into the multifunctional role which ameloblasts play throughout amelogenesis.

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