The NSI gene contributes to the virulence of H5N1 avian influenza viruses
The NSI gene contributes to the virulence of H5N1 avian influenza viruses
复制标题
DOI：
10.1128/jvi.00993-06
复制
发表时间：
2006-11-01
影响因子：
5.4
通讯作者：
Chen, Hualan
中科院分区：
文献类型：
--
作者：
Li, Zejun;Jiang, Yongping;Chen, Hualan
本研究探讨了两株H5 N1亚型禽流感病毒对鸡的毒力和宿主范围的遗传基础。A/goose/Guangdong/1/96（GS/GD/1/96）是鸡的高致病性病毒，而A/goose/Guangdong/2/96（GS/GD/2/96）不能在鸡体内复制。这两种H5 N1病毒在PA、NP、M1和NS 1基因的序列上只有5个氨基酸不同。我们使用反向遗传学创建了四个单基因重组体，其中包含来自非致病性GS/GD/2/96的序列不同基因之一和来自高致病性GS/GD/1/96的其余七个基因片段。我们确定GS/GD/2/96的NS 1基因抑制GS/GD/1/96在鸡中的复制，而PA、NP或M基因的取代并不改变GS/GD/1/96的高致病性。相反，在GS/GD/2/96背景下产生的重组病毒中，只有含有GS/GD/1/96的NS 1基因的病毒能够在鸡中复制并引起疾病和死亡。这两个NS 1基因序列中的单个氨基酸差异位于位置149。我们证明，表达GS/GD/1/96 NS 1蛋白与Ala 149的重组病毒能够拮抗鸡胚成纤维细胞（CEF）中干扰素蛋白水平的诱导，但携带Val 149取代的重组病毒不能产生相同的效果。这些结果表明，NS 1基因是至关重要的禽流感病毒在鸡的致病性和氨基酸残基Ala 149与这些病毒拮抗干扰素诱导CEF的能力。
In the present study, we explored the genetic basis underlying the virulence and host range of two H5N1 influenza viruses in chickens. A/goose/Guangdong/1/96 (GS/GD/1/96) is a highly pathogenic virus for chickens, whereas A/goose/Guangdong/2/96 (GS/GD/2/96) is unable to replicate in chickens. These two H5N1 viruses differ in sequence by only five amino acids mapping to the PA, NP, M1, and NS1 genes. We used reverse genetics to create four single-gene recombinants that contained one of the sequence-differing genes from nonpathogenic GS/GD/2/96 and the remaining seven gene segments from highly pathogenic GS/GD/1/96. We determined that the NS1 gene of GS/GD/2/96 inhibited the replication of GS/GD/1/96 in chickens, while the substitution of the PA, NP, or M gene did not change the highly pathogenic properties of GS/GD/1/96. Conversely, of the recombinant viruses generated in the GS/GD/2/96 background, only the virus containing the NS1 gene of GS/GD/1/96 was able to replicate and cause disease and death in chickens. The single-amino-acid difference in the sequence of these two NS1 genes resides at position 149. We demonstrate that a recombinant virus expressing the GS/GD/1/96 NS1 protein with Ala149 is able to antagonize the induction of interferon protein levels in chicken embryo fibroblasts (CEFs), but a recombinant virus carrying a Val149 substitution is not capable of the same effect. These results indicate that the NS1 gene is critical for the pathogenicity of avian influenza virus in chickens and that the amino acid residue Ala149 correlates with the ability of these viruses to antagonize interferon induction in CEFs.