Kaverin N V, Matrosovich M N, Gambaryan A S, Rudneva I A, Shilov A A, Varich N L, Makarova N V, Kropotkina E A, Sinitsin B V
D.I. Ivanovsky Institute of Virology, Russian Academy of Medical Sciences, Gamaleya Str. 16, 123098, Moscow, Russia.
Virus Res. 2000 Feb;66(2):123-9. doi: 10.1016/s0168-1702(99)00131-8.
In our previous studies influenza A virus reassortants having neuraminidase (NA) gene of A/USSR/90/77 (H1N1) strain and hemagglutinin (HA) genes of H3, H4 and H13 subtypes were shown to produce a low virus yield and to exhibit a strong tendency to virion aggregation. More detailed studies with the use of a H3N1 reassortant and its high-yield non-aggregating variants revealed that NA of A/USSR/90/77 strain is inefficient in the removal of the terminal sialic acid residues from the virion components, and that the inefficiency of NA may be compensated by mutations in HA gene leading to a decrease of the receptor-binding affinity (Kaverin, N.V. , Gambaryan, A.S., Bovin, N.V., Rudneva, I.A., Shilov, A.A., Khodova, O.M., Varich, N.L., Sinitsin, B.V., Makarova, N.L., Kaverin, N.V., 1998. Postreassortment changes in influenza virus hemagglutinin restoring HA-NA functional match, Virology 244, 315-321). The present report describes studies performed with the use of H2N1 and H4N1 reassortants having HA genes of A/Pintail/Primorie/695/76 (H2N3) and A/Duck/Czechoslovakia/56 (H4N6) strains respectively and NA gene of A/USSR/90/77 strain. The low-yield reassortants and their high-yield non-aggregating variants were studied in both direct and competitive binding assays with sialic acid-containing substrates. The non-aggregating variants were shown to have a decreased affinity as compared to the initial reassortants toward high-molecular-weight sialic acid-containing substrates. The sequencing of HA genes revealed that all non-aggregating variants of H2N1 and H4N1 reassortants had amino acid substitutions increasing the negative charge of the HA molecule in the vicinity of the receptor-binding pocket. The results suggest that the influenza virus reassortants containing low-functional NA undergo similar postreassortment changes irrespective of the HA subtype: their receptor-binding activity decreased due to negatively charged amino acid substitutions in the vicinity of the receptor-binding pocket.
在我们之前的研究中，具有A/USSR/90/77（H1N1）株神经氨酸酶（NA）基因以及H3、H4和H13亚型血凝素（HA）基因的甲型流感病毒重配体显示出病毒产量低，并呈现出强烈的病毒粒子聚集倾向。对一株H3N1重配体及其高产非聚集变体进行的更详细研究表明，A/USSR/90/77株的NA在从病毒粒子成分上去除末端唾液酸残基方面效率低下，并且NA的低效可能通过HA基因中的突变得到补偿，从而导致受体结合亲和力降低（卡韦林，N.V.，甘巴里扬，A.S.，博温，N.V.，鲁德涅娃，I.A.，希洛夫，A.A.，霍多娃，O.M.，瓦里奇，N.L.，西尼辛，B.V.，马卡罗娃，N.L.，卡韦林，N.V.，1998年。流感病毒血凝素重配后的变化恢复了HA-NA功能匹配，《病毒学》244，315 - 321）。本报告描述了分别使用具有A/长尾鸭/滨海边疆区/695/76（H2N3）株HA基因和A/鸭/捷克斯洛伐克/56（H4N6）株HA基因以及A/USSR/90/77株NA基因的H2N1和H4N1重配体所进行的研究。在与含唾液酸底物的直接和竞争性结合试验中研究了低产重配体及其高产非聚集变体。结果显示，与初始重配体相比，非聚集变体对高分子量含唾液酸底物的亲和力降低。对HA基因的测序表明，H2N1和H4N1重配体的所有非聚集变体在受体结合口袋附近都有增加HA分子负电荷的氨基酸取代。结果表明，含有低功能NA的流感病毒重配体无论HA亚型如何都会经历类似的重配后变化：由于受体结合口袋附近带负电荷的氨基酸取代，它们的受体结合活性降低。
