Transcription of the influenza ribonucleic acid genome by a virion polymerase. I. Optimal conditions for in vitro activity of the ribonucleic acid-dependent ribonucleic acid polymerase.

In vitro reaction conditions have been determined for the maximal synthesis of product ribonucleic acid by the influenza (WSN) virion ribonucleic acid polymerase. The reaction requires the presence of all four triphosphates, Mg(2+) and Mn(2+) ions, monovalent cations, nonionic detergent, and ribonucleoside triphosphates at concentrations above certain threshold values. The optimum pH for the reaction is around 8.0 to 8.2 and the kinetics of product synthesis are linear through at least 6 hr when incubated at 31 to 33 C.