Mechanism of interferon action. I. Characterization of a 54-kDa protein induced by gamma interferon with properties similar to a cytoskeletal component.

A polypeptide of 54-kDa molecular mass (p54) induced by molecularly cloned human interferon gamma (rIFN-gamma) in human amnion U cells was characterized biochemically and immunologically. Rabbit polyclonal antibody to p54 was prepared using p54 purified from human amnion U cells as the immunogen. As measured by immunoprecipitation of [35S]methionine pulse-labeled extracts or by immunoblot analysis of unlabeled extracts, the synthesis of p54 was greatly elevated in three human cell lines treated with IFN-gamma, amnion U, fibroblast GM2767, and fibroblast F153. Moreover, the rabbit anti-p54 polyclonal antibody preparation cross-reacted with cytoskeleton-associated polypeptides prepared from human cells and from sea urchin embryos. By use of a monoclonal antibody probe directed against the common domain of intermediate filaments (anti-intermediate filament antibody), it was established that intermediate filament components are also induced by rIFN-gamma. Anti-p54 polyclonal antibody cross-reacted with anti-intermediate filament antibody-recognized, rIFN-gamma-induced polypeptides. Thus, it appears that p54 may be an IFN-induced cytoskeleton-associated polypeptide.