Analysis of the in vitro product of an RNA-dependent RNA polymerase isolated from influenza virus-infected cells.

The products synthesized in vitro by an RNA-dependent RNA polymerase isolated from influenza virus-infected BHK21-F cells were analyzed by velocity sedimentation, annealing techniques, and acrylamide-agarose gel electrophoresis. Approximately 50% of the RNA synthesized in vitro remains associated with the 50 to 70S ribonucleoprotein complex containing polymerase activity; the remainder of the RNA polymerase product sediments heterogeneously with a peak at 13S. At least 90% of the in vitro product hybridizes with virion RNA. If polypeptides are labeled early in the growth cycle, both the P and NP polypeptides are detected in the ribonucleoprotein complex by acrylamide gel electrophoresis. The results suggest that the polypeptide composition and the products of the cell-associated RNA polymerase are similar to those of the RNA transcriptase associated with influenza virus particles.