Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Biochem Biophys Res Commun. 2013 Jan 4;430(1):161-6. doi: 10.1016/j.bbrc.2012.11.053. Epub 2012 Nov 29.
The Mx protein is known to inhibit the multiplication of several RNA viruses. In chickens, a polymorphism at amino acid position 631 (631 aa) of Mx protein has been suggested to be involved in the antiviral ability against vesicular stomatitis virus (VSV) and influenza virus, indicating that a Ser-to-Asn substitution at 631 aa is the source of this antiviral ability. However, how the substitution at 631 aa contributes to the antiviral activity remains to be clarified. In this study, we investigated differences in antiviral activity against VSV and intracellular localization between Ser and Asn types at 631 aa of the chicken Mx protein. The results showed that chicken Mx protein with an Asn at 631 aa inhibited VSV multiplication and Mx distribution in a granular-like pattern in the cytoplasm. However, Mx carrying the Ser type did not inhibit viral growth and homogenous spread throughout the cytoplasm. Furthermore, we found that replacing Ser with Asn at 631 aa provided Mx with antiviral activity against VSV, with Mx showing granular-like distribution in the cytoplasm. These results demonstrated that a single amino acid polymorphism at 631 aa of the chicken Mx protein altered both the antiviral activity and intracellular localization.
Mx 蛋白已知能抑制几种 RNA 病毒的增殖。在鸡中，Mx 蛋白的 631 位氨基酸的多态性（631 aa）被认为与抗水疱性口炎病毒（VSV）和流感病毒的抗病毒能力有关，表明 631 aa 的丝氨酸到天冬酰胺取代是这种抗病毒能力的来源。然而，631 aa 的取代如何有助于抗病毒活性仍有待阐明。在这项研究中，我们研究了鸡 Mx 蛋白 631 aa 处的 Ser 和 Asn 类型在抗病毒活性和细胞内定位方面的差异。结果表明，第 631 位 aa 为天冬酰胺的鸡 Mx 蛋白抑制了 VSV 的增殖，并以颗粒状模式分布在细胞质中。然而，携带 Ser 型的 Mx 蛋白不能抑制病毒的生长和在细胞质中的均匀扩散。此外，我们发现，将 631 位 aa 的 Ser 替换为 Asn 赋予了 Mx 对 VSV 的抗病毒活性，并且 Mx 在细胞质中呈颗粒状分布。这些结果表明，鸡 Mx 蛋白 631 位 aa 的单个氨基酸多态性改变了抗病毒活性和细胞内定位。
