Epidermal growth factor regulates gene expression of both epithelial and mesenchymal cells in mouse molar tooth organs in culture.

Epidermal growth factor and cis-hydroxyproline specifically inhibited synthesis of type 1 collagen, a major gene product of the differentiated dental mesenchymal cells (odontoblasts). In tandem, synthesis of enamel proteins, specific gene products of differentiated dental epithelial cells (ameloblasts), was also inhibited. Under these culture conditions, total protein synthesis in tooth organs was not inhibited but rather increased. Inhibition curves of the gene products specific for epithelial and mesenchymal phenotypes were quite similar, indicating coordinate and intimately associated regulation of gene expression under conditions that perturb cytodifferentiation.