Effect of Interferon Treatment on Cellular Messenger RNA

Cell monolayers wre treated with interferon, and then were labeled with RNA precursors. Messenger ribonucleoprotein and transfer RNA were liberated from isolated polysomes, and analyzed by electrophoresis on polyacrylamide gels. The messenger ribonucleoproteins and transfer RNA from interferon-treated cells migrated slightly slower than did the corresponding components from control cells. It was shown that the differences in migration speeds was attributable to the fact that the messenger RNAs and transfer RNA that were polysomebound (i.e., being translated) were slightly larger than control-cell RNAs. This phenomenon was seen in mouse L cells, primary mouse-embryo cells, and rabbit-kidney cells. Ribosomal 28S and 18S RNA was not altered, nor was nuclear RNA. Several types of evidence indicate that the biochemical changes are attributable to the interferon in the preparations, and not to impurities. These data may bear on the mechanism by which interferon-treated cells recognize and translate viral RNA poorly. It is tentatively suggested that interferon treatment of cells leads to a change in cellular messenger RNA such that the cell can distinguish it from the subsequently infecting viral RNA.