Fine oral filaments in Paramecium: a biochemical and immunological analysis

In Paramecium, several kinds of the oral networks of fine filaments are def ined at the ultrastructural level. Using the sodium chloride-treated oral a pparatus of Paramecium as an antigen to produce monoclonal antibodies, we h ave begun to identify the proteins constituting these networks. Immunoblott ing showed that all positive antibodies were directed against three bands ( 70-, 75- and 83-kD), which corresponded to quantitatively minor components of the antigen; there was no antibody specific for the quantitatively major components (58- and 62-kD). Immunolocalization with four of these antibodi es directed against one or several of these three bands showed that these p roteins are components of the fine filaments supporting the oral area: a de coration of the basal bodies and the outer lattice was also observed on the cortex. Immunofluorescence on interphase cells suggested that the three pr oteins colocalized on the left side of the oral apparatus, whereas only the 70-kD band was detected on the right side. During division, the antigens o f the antibodies were detected at different stages after oral basal body as sembly. The antibodies cross-reacted with the tetrins, which are oral filam ent-forming proteins in Tetrahymena, demonstrating that tetrin-related prot eins are quantitatively minor components of the oral and the somatic cytosk eleton of Paramecium.