[Cell-dependent and strain variations in the nucleocapsid protein P2(PA) of the influenza virus].

The electrophoretic pattern of influenza virus nucleocapsid proteins, P1 (PB1), P2 (PA), and P3 (PB2), was examined by high resolution electrophoresis in gradient polyacrylamide gel. The electrophoretic mobility of P polypeptides varied from strain to strain, and more marked variability was revealed in protein P2 (PA). In addition, P2 (PA) polypeptides exhibited diffuse distribution in gel, in contrast to those of P1 (PB1) and P3 (PB2) which had compact electrophoretic bands. This P2 electrophoretic heterogeneity was found to be host cell-dependent. From this observation, host-dependent modification of influenza virus nucleocapsid protein P2 (PA) was suggested.