Abstract
Using two-dimensional electrophoresis on total and nuclear extracts of human fibroblasts, we compared polypeptide patterns of cells treated with interferon-β (IFN-β), IFN-γ, or with dsRNA in the presence of anti-IFN antibodies. The analysis of whole-cell extracts revealed that, after a 6-h treatment, the three agents induce the synthesis of a common set of proteins in addition to others that are specifically induced either by IFNs or by dsRNA. After a 15-h treatment, this common set of proteins was only induced by IFNs. Furthermore, at this time, IFNs also regulated proteins whose synthesis was specifically induced or repressed by poly(I) · poly(C) in the 6-h treated cells. These results indicate that poly(I) · poly(C) regulates protein expression more rapidly and more transiently than IFNs. The analysis of nuclear extracts showed similar differential kinetics of protein expression. However, a greater number of polypeptides was found to have their synthesis specifically induced by dsRNA. Moreover, poly(I) · poly(C) was found to be mitogenic in these cells and did not induce a significant resistance to vesicular stomatitis virus (VSV). This study provides evidence for an overlap in the expression of proteins by dsRNA and IFNs, although these compounds do not share the same biological activities.
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