RNA binding protein may inhibit a polymerase activity nonspecifically

 A protein that binds to RNA may inhibit an in vitro RNA synthesis activity via the direct interaction with template RNA. If we find an inhibitory reaction in a factor, and detect the inhibitory activity by an in vitro RNA synthesis assay, we should doubt whether it is actually true or not. If the inhibitory protein has a RNA binding activity, it may prevent the polymerase protein bind to the template. We should exhibit the specificity of inhibitory reaction when we demonstrate the true function of the inhibitory protein. If the protein can inhibit the polymerase activity of vesicular stomatitis virus L protein, we should doubt whether the protein cannot inhibit the polymerase activity of other kinds of polymerases.