Myosin at the apical pole of ciliated epithelial cells as revealed by a monoclonal antibody

A monoclonal antibody (CC-212), obtained in a fusion experiment in which basal bodies from quail oviduct were used as immunogen, has been shown to label the apical pole of ciliated cells and to react with a 200-kD protein. This monoclonal antibody was demonstrated to be an anti- myosin from smooth muscle or from nonmuscular cells using the following criteria: On Western blots it reacted with the myosin heavy chains from gizzard and platelet extracts and from cultured cell line extracts, but did not react with striated muscle myosin heavy chains. By immunofluorescence it decorated the stress fibers of well-spread cells with a characteristic striated pattern, while it did not react with myotubes containing organized myofibrils. On native ciliated cells as well as on Triton-extracted ciliated cortices from quail oviduct, this monoclonal antibody decorated the apical pole with a stronger labeling of the periphery of the apical area. Ultrastructural localization was attempted using the immunogold technique on the same preparation. Myosin was associated with a filamentous material present between striated rootlets and the proximal extremities of the basal bodies. No labeling of the basal body itself or of axoneme was observed.