Toyoda T, Asano Y, Ishihama A
Department of Molecular Genetics, National Institute of Genetics, Mishima, Shizuoka, Japan.
J Gen Virol. 1995 Jul;76 ( Pt 7):1867-9. doi: 10.1099/0022-1317-76-7-1867.
Murine Mx1 protein is an interferon-inducible GTPase which localizes in nuclei and inhibits influenza virus infection. Wild-type Mx1 and two mutant Mx1 proteins, each carrying a single mutation either in the GTP-binding motif (S50I) or in the self-assembly motif (C71S), were expressed in MDCK cells. Wild-type Mx1 localized in nuclei, forming small granules with minute dots, and inhibited influenza virus growth. Mutant S50I, which had no GTP-binding or GTPase activities, formed linear structures in nuclei and lacked anti-viral activity, while C71S appeared diffuse in nuclei as minute dots without granules, but retained the inhibitory activity against influenza virus growth. A correlation existed between GTPase activity, intranuclear distribution and antiviral activity. We concluded that GTPase activity is essential for expression of the biological activity of Mx1 protein.
小鼠Mx1蛋白是一种干扰素诱导型GTP酶，定位于细胞核并抑制流感病毒感染。野生型Mx1和两种突变型Mx1蛋白在MDCK细胞中表达，每种突变型Mx1蛋白在GTP结合基序（S50I）或自组装基序（C71S）中携带单个突变。野生型Mx1定位于细胞核，形成带有微小斑点的小颗粒，并抑制流感病毒生长。没有GTP结合或GTP酶活性的突变体S50I在细胞核中形成线性结构且缺乏抗病毒活性，而C71S在细胞核中呈微小斑点状弥漫分布，无颗粒，但保留了对流感病毒生长的抑制活性。GTP酶活性、核内分布和抗病毒活性之间存在相关性。我们得出结论，GTP酶活性对于Mx1蛋白生物活性的表达至关重要。
