molecular basis for the virion formation of influenza virus

我们分析了神经氨酸酶（NA）在乙型流感病毒血凝素（HA）蛋白的血液吸附中的作用。乙型流感病毒突变体ts-7在NA蛋白上发生温度敏感突变。在高温下，感染细胞不表现出血液吸附活性，但添加细菌神经氨酸酶恢复了血液吸附活性。对B病毒点突变的HA cdna进行的实验表明，在160和217氨基酸残基上的两个n -乙酰糖基化位点是HA蛋白无法吸附到红细胞的原因。这些结果表明，乙型流感病毒HA蛋白在血液中的吸附需要神经氨酸酶的参与。由于神经氨酸酶抑制剂扎那米韦被报道不穿透细胞，我们研究了这种抑制剂的作用，发现扎那米韦抑制血液在感染B病毒的MDCK细胞上的吸附。这些结果表明，在两个蛋白移动到细胞表面后，NA对HA进行了脱盐。通过A/爱知/92病毒与A/WSN/33 （WSN）病毒的重配实验，获得了两种不同表型的病毒，分别含有A/爱知/92病毒的HA基因和WSN病毒的NA基因。PW15病毒能凝集鸡红细胞（CRBC），而PW10病毒不能。然而，这些病毒表达的HA蛋白不吸附CRBC。PW15病毒与PW10病毒基因群的差异在于膜蛋白(M)基因。前者含有A/爱知/4/92病毒的M基因，后者含有WSN病毒的M基因。在pw15感染的细胞中，CRBC的血液吸附时间比鹅红细胞晚30 min， M1蛋白从细胞核迁移到细胞质的时间比CRBC的吸附时间早30 min。另一方面，在pw10感染的细胞中，通过病毒复制未观察到血液对CRBC的吸附，在HA和NA活性达到最高水平后，M1蛋白仍留在细胞核中。因此M1蛋白可能参与了NA蛋白对HA蛋白的脱盐作用。少

We analyzed the role of neuraminidase (NA) on the haemadsorption of haemagglutinin (HA) protein of influenza B virus. The influenza B virus mutant ts-7 had temperature-sensitive mutation in the NA protein. At high temperature, infected cells did not exhibit haemadsorption activity, but addition of bacterial neuraminidase restored haemadsorption activity. Experiments with point-mutated HA cDNAs of B virus showed that two N-acetyl glycosylation sites at amino acid residues 160 and 217 were responsible for the inability of the HA protein to adsorb to erythrocytes. These results indicated that haemadsorption by the HA protein of influenza B virus required involvement of neuraminidase. Because the neuraminidase inhibitor Zanamivir was reported not to penetrate cells, we investigated the action of this inhibitor and found that Zanamivir inhibited haemadsorption on MDCK cells infected with B virus. These results indicated that desialidation of HA was done by NA after two proteins moved to cel … More l surface. From the reassortment experiments between A/Aichi/92 and A/WSN/33 (WSN) viruses, two different phenotype viruses which contained HA gene from A/Aichi/ 92 virus and the NA gene from WSN virus were obtained. PW15 viruse agglutinated chicken red blood cells (CRBC), while PW10 virus did not. However, the expressed HA proteins of these viruses did not adsorb CRBC.The difference in gene constellation between PW15 and PW10 viruses was the membrane protein (M) gene. The former had the M gene from A/Aichi/4/92 virus and the latter had that from WSN virus. In PW15-infected cells, haemadsorption of CRBC was observed 30 min later than that of goose red blood cells and the M1 protein migrated from the nucleus to the cytoplasm 30 min earlier than adsorption of CRBC was observed. On the other hand, in PW1O-infected cells, haemadsorption of CRBC was not observed through the virus replication and the M1 protein stayed in the nucleus after HA and NA activities reached maximum levels. Therefore M1 protein may contribute the desialidation of HA protein by NA protein. Less