POLYPEPTIDES SPECIFIED BY INFLUENZA-VIRUS GENOME .1. EVIDENCE FOR 8 DISTINCT GENE PRODUCTS SPECIFIED BY FOWL PLAGUE VIRUS

The structural polypeptides of fowl plague virus (influenza A) and those synthesized in fowl plague virus-infected chick embryo fibroblasts were analyzed for high resolution polyacrylamide gel electrophoresis. Eight distinct virus gene products were detected: 3 polymerase-associated polypeptides (P1, P2, P3), hemagglutinin (HA), nucleoprotein (NP), neuraminidase (NA), membrane polypeptide (M), and a nonstructural polypeptide (NS). The molecular weights of these polypeptides correlate closely with the molecular weights of the 8 genome RNA species found in fowl plague virus. The 3 high molecular weight polypeptides, P1, P2 and P3, were detected both in virions and infected cells, and their separate identity established by a 2-dimensional tryptic peptide mapping procedure. An active RNA polymerase enzyme complex isolated from virions and virus-infected cells contained all 3 P proteins together with the NP protein. The nonstructural polypeptide (NS), together with the P proteins and the NP, appeared early in the infectious cycle, while the M protein and HA protein appeared later in infection. The NS and M polypeptides, which have similar molecular weights, were separated on SDS[sodium dodecyl sulfate]-polyacrylamide gels and shown to be distinct by tryptic peptide mapping.