SUMMARYHigh resolution polyacrylamide gel electrophoresis (PAGE) of chick embryo fibroblast cells infected with the avian influenza virus FPV-Rostock revealed two distinct polypeptides migrating in the region of the nucleoprotein (NP). Onedimensional fingerprinting of these polypeptides showed that they were both nucleoprotein, and [nP]orthophosphate labelling revealed that they differed with respect to their state of phosphorylation. Pulse-chase studies using [35S]methionine indicated that phosphorylation of a certain proportion of NP occurs rapidly after synthesis and is associated with transport to the nucleus. Nucleoprotein which remained in the cytoplasm was predominantly non-phosphorylated. Both the phosphorylated and the non-phosphorylated types of NP were found in ribonucleoprotein complexes (RNPs) of different densities isolated on renografin gradients, but RNPs isolated from the nucleus contained much more phosphorylated NP than those from the cytoplasm. The kinase responsible for nucleoprotein phosphorylation appears to be influenced by temperature of incubation of the infected cells.

SUMMARYStructural and virus-induced infected cell polypeptides of several strains of influenza B virus were examined by high resolution polyacrylamide gel electrophoresis and shown to be directly analogous to those of the influenza A viruses. Eight structural polypeptides, P1, P2, Ps, HAj, HA2, NA, NP and M were observed in purified virus and at least two additional polypeptides, HA and NS could be detected in infected MDCK cells. The three P proteins plus NP were shown to be associated with RNA-dependent RNA polymerase activity and HA, HA1, HA2 and NA were shown to be glycosylated. Like the influenza A viruses, migrational differences of some of the infected cell polypeptides could be observed between different B strains. Investigation of a time course of virus replication failed to show any temporal control of protein synthesis in the infected cell.

A cold-recombinant virus CR 22, was derived from an attenuated cold-adapted parent strain. A/Ann Arbor/6/60 (H2N2), and a wild-type parent strain, A/Victoria/3/75 (H3N2). Antigenic analysis showed that CR 22 possesses the hemagglutinin and neruaminidase surface antigens derived from the A/Victoria/3/75 (H3N2) parent. From studies of virus-induced polypeptides using polyacrylamide gel electrophoresis, it was deduced that a polymerase protein, P1, is coded and by an RNA segment derived from the wild-type parent; all other genetic elements are derived from the attenuated parent. The attenuated parent and the recombinant CR 22 both possess temperature-sensitive (ts) lesions, evident by restriction of multiplication in fertile chicken eggs or in Madin-Darby canine kidney cell cultures at greater than or equal to 38 C. Genetic analysis of CR 22 by complementation tests using Hong Kong and Wilson Smith neurotropic ts mutants gave evidence for a ts lesion in the genetic elements coding for complementary RNA.