Immunolocalization of myosin and tropomyosin in cells undergoing ciliogenesis during regeneration of rat tracheal epithelium.

During the regeneration of the mucociliary lining of the respiratory airways, many cells differentiate into ciliated cells. Early stages of ciliogenesis in these cells is characterized morphologically by appearance of MTOC, filosomes and centrioles throughout the apical cytoplasm. Tracheas removed during the period of ciliated cell differentiation which occurs 50-60 hr after minor mechanical injury were paraformaldehyde fixed and specific affinity sites for antitropomyosin and antimyosin antibodies were demonstrated by an indirect immunoperoxidase technique. The epithelium, after development of the osmiophilic reaction product, was embedded in epoxy and observed unstained with an electron microscope. Both antibodies had similar and specific binding sites in filosomes, MTOCs, microfilaments and on the microtubule triplets and foot processes of centrioles. Such localization suggests that these mechanochemical proteins may in addition to microfilament stabilization and contraction serve a specialized function in ciliogenesis.