Comparison of cellular localization of NS1 from different subtypes of influenza A virus
(2.University of Chinese Academy of Sciences, Beijing China 100049)
(3.School of Life Sciences, Anhui University, Hefei, Anhui, China 230039)
【Abstract】NS1 is a multifunctional low-molecular protein encoded by influenza A virus genome, which can inhibit antiviral immunological responses of host cells. In order to assess the differences in subcellular localization of NS1 in different influenza A virus subtypes, we performed laser scanning confocal microscopy to observe the subcellular location of NS1 in different cell lines at different time points after infection with influenza A virus WSN (H1N1), PR8 (H1N1), CA04 (H1N1), SD (H9N2) and AH01 (H7N9) in A549 cells and MDCK cells as well as the 293T cells transfected with the pCMV-Myc-NS1 plasmid capable of expressing NS1 of different influenza A virus subtypes respectively. The NS1-WSN and NS1-PR8 accumulated mainly in the cytoplasm at 24 h post infection, while the NS1-CA04 and NS1-SD appeared mainly in the nuclei. Moreover, the subcellular localization of the NS1 was also examined in the transfected 293T cells with the plasmids harboring the full-length NS1 from WSN, SD and AH01 strains. As a result, the NS1-WSN was mainly located in the cytoplasm 24 h post transfection, while the NS1-SD and the NS1-AH01 were mainly detected in the nuclei. After amino acid sequence alignment, point mutation on key amino acids was carried out on the NS1-WSN. The results showed that the single point mutation did not lead to changes in the subcellular localization of the NS1 and the difference in the subcellular localization was not determined by the single amino acid. In general, the analysis on the difference in subcellular localization of NS1 from different subtypes may contribute to further understanding on the interactions between NS1 and the proteins from different localizations in host cells, the regulatory mechanisms of influenza A virus as well as the innate immunity in virus-infected cells.
【Keywords】 influenza A virus; NS1 protein; cellular location; amino acid mutation;
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