title: Discrimination of cytoskeletal elements of Paramecium by heterologous antisera: A preliminary investigation on the presence of intermediate filament-related protein.
abstract: The present study of the cytoskeleton of Paramecium employed a number of heterologous monoclonal antisera raised against intermediate filament proteins of higher organisms, and also an antiserum against a 49 K protein from Tetrahymena. Anti-49 K, and also monoclonal anti-bovine cytokeratin K 8.13 which has a broad cross-reaction spectrum for epithelial intermediate filaments, differentiated the microtubular systems of Paramecium into two categories. Those closely associated with surface membranes, such as basal bodies, contractile vacuole pores and the cytospindle, and the gullet also, were labeled by these antibodies. Others internal to the epiplasm are not labeled, such as transverse and postciliary microtubular bands associating with basal bodies, contractile vacuole canals, cytopharyngeal ribbons and postoral fibers. None of the heterologous anti-tubulins tested in this and previous studies generated such a pattern of discrimination of the microtubular systems of Paramecium, indicating that the discrimination by anti-49 K and by anti-cytokeratin K 8.13 was not based on the molecular composition (α- or β-tubulin) of the microtubular systems, their state of tyrosination, or acetylation. These two antibodies thus reveal a determinant that is associated exclusively with certain membrane-bound microtubular systems of Paramecium. This determinant appears to participate in the development of nascent structures like the cytospindle and the oral apparatus, since it co-distributed with these structures in their different stages of development. In addition, two monoclonal antibodies were superimposable specifically on certain cytoskeletal elements also residing close to surface membranes: anti-pig vimentin V 9 labeled the epiplasm underlying the inner alveolar membrane, while anti-human cytokeratin K 4.62 labeled the outer lattice lining the cortical ridges. On the other hand, anti-49 K labeled the micronucleus and its derivatives in all stages of sexual nuclear reorganization in Paramecium, unlike the specific labeling of postmeiotic and zygotic nuclei in Tetrahymena. The presence of intermediate filament-related protein in Paramecium is discussed.
authors.affiliation: Zoology Department, University of Hong Kong, Hong Kong.
authors.forename: V C
authors.initials: VC
authors.lastname: Lai
authors.forename: S F
authors.initials: SF
authors.lastname: Ng