Figure 1. Amelogenin in human dental pulp tissue. (A) Trichrome stain section of a late bell stage of tooth organ. (B) Amelogenin immunolocalization on a frozen section of an early-bell-stage tooth organ shows amelogenin (red) in the forming dentin matrix (d). (C) Dental pulp cells grown in vitro show positive amelogenin immunostaining (green) in the cytoplasm. (D) In situ hybridization of amelogenin mRNA on a section of the same tooth as shown in panel A. Positive signal is correlated to the ameloblast cell layer, and the dentin matrix (d), separated by the negative (black) enamel matrix (e). (E) Type I collagen in situ hybridization shows positive signal in the odontoblast layer lining the forming dentin matrix.