Immunoelectron microscopic demonstration of S-100b protein-like in centriole, cilia, and basal body.

We report here the ultrastructural localization of S-100b protein-like immunoreactivity in the centriole, cilia, and basal body. Duodenum and trachea of guinea pigs and rats were fixed and immunostained by the protein A-gold method. All centrioles, cilia, and basal bodies observed showed clear S-100b protein-like immunoreactivity. Specific colloidal gold particles were located over the microtubules in these cell organelles. However, other microtubules scattered throughout the cytoplasm were devoid of immunoreactivity. Although the functional significance of S-100b protein-like immunoreactivity in the centriole, cilia, and basal bodies remains to be elucidated, the present results introduce new perspectives into the investigation of localization and function of S-100 proteins.