The analysis of functional domains of NS1 protein involved in the regulation of influenza C virus replication

为了研究C型流感病毒NS1蛋白上调剪接的机制，我们试图寻找NS1的核定位信号。在COS-1细胞中表达NS1 c端缺失突变体，利用免疫荧光分析表达突变体的胞内定位。由残基1-246组成的野生型NS1和残基1-154的c端缺失突变体主要定位于细胞质中。然而，残基1-108的c端缺失突变体定位于细胞核和细胞质中。这些结果表明NS1的核输出信号可能存在于残基109和残基154之间。

To investigate the mechanism by which influenza C virus NS1 protein can up-regulate splicing, we tried to find the nuclear localization signal of NS1. The C-terminal deletion mutants of NS1 were expressed in COS-1 cells and the intracellular localization of the expressed mutants was analyzed by immunofluorescence. The wild type NS1 composed of residues 1-246 and C-terminal deletion mutant of residues 1-154 were localized in the cytoplasm predominantly. However, C-terminal deletion mutant of residues 1-108 was localized in the nucleus and cytoplasm. These results suggest that nuclear export signal of NS1 may be present between residues 109 and 154.