RNA binding ability and cellular distribution are important for nonstructural protein 1 (NS1) of influenza A virus to act as a viral regulatory factor to control virus life cycle. In this study, we identified that the N-terminal residues 19−21 of NS1 are a highly conserved motif depending on all the available NS1 full length sequence of H5N1 influenza A virus from NCBI database. Site-directed mutation analysis demonstrated that the R¹⁹ residue of NS1 is critical for its RNA binding and nuclear localization. Furthermore, the residue R¹⁹ of NS1 was identified to be critical for regulating M1 mRNA splicing and NS1 nuclear export. Biological analysis of the rescued viruses indicated that the R¹⁹A mutation of NS1 did not interfere the replication of H5N1 virus during infection and attenuated the virulence of H5N1 virus in mice.

RNA结合能力和细胞分布对于甲型流感病毒的非结构蛋白1（NS1）起到控制病毒生命周期的病毒调节因子的作用很重要。在这项研究中，我们确定了NS1的N末端残基19-21是高度保守的基序，这取决于从NCBI数据库获得的H5N1甲型流感病毒的所有可用NS1全长序列。定点突变分析表明，NS1的R ¹⁹残基对于其RNA结合和核定位至关重要。此外，NS1的残基R ¹⁹被确定对于调节M1 mRNA剪接和NS1核输出至关重要。对获救病毒的生物学分析表明，R ¹⁹NS1的突变不会在感染过程中干扰H5N1病毒的复制，并减弱了小鼠中H5N1病毒的毒力。