Visualization of antigens attached to cytoskeletal framework in animal cells: Colocalization of simian virus 40 Vp1 polypeptide and actin in TC7 Cells
Actin and the simian virus 40 viral structural polypeptide Vp1 are observed to be present on cytoskeletal fibers of virus-infected TC7 cells, when these antigens in detergent-extracted whole cell mounts were labeled by specific antibodies and colloidal gold particles coated with a second antibody. In both cases, actin and Vp1 were found associated with fibers and fiber-associated electron-dense materials. Patches or clusters of colloidal gold particles denoting the presence of either Vp1 or actin were found on fibers uniformly distributed throughout the cytoplasm. By using simultaneous decoration of the two antigens with colloidal gold particles of different diameters, it was shown that the majority of Vp1 appears attached to cytoskeletal fibers in association with cellular actin. When Vp1 and actin were decorated with Imposil and ferritin simultaneously in infected cells that were fixed first and then permeabilized with saponin, both labels were found in the same spatial domain of the cell cytoplasm. Thus, the colocalization of Vp1 and actin on the cytoskeletal framework seems to reflect their actual state in the living cells. The electron-dense material to which colloidal gold particles localize in our cytoskeletal preparations may be the remnants of subcellular structures with which actin and Vp1 are both associated in intact cells.
Additional Information© 1983 by the National Academy of Sciences. Communicated by Norman Davidson, March 28, 1983. We thank Mr. P. Koen for his technical help. This work was supported by grants (to H. K.) from the National Cancer Institute (CA 21768) and the National Science Foundation (PCM 8209041), by Biomedical Research Support Grant RR07009 (to H.K.), and by Grant GM 06965 from the National Institutes of Health (to J.-P.R.). W. L. was supported by Grant 3T32CA9030 from the National Cancer Institute. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.
Published - KASpnas83.pdf