Analysis of Venezuelan equine encephalitis virus capsid protein function in the inhibition of cellular transcription
Analysis of Venezuelan equine encephalitis virus capsid protein function in the inhibition of cellular transcription
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DOI：
10.1128/jvi.01576-07
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发表时间：
2007-12-01
影响因子：
5.4
通讯作者：
Frolov, Ilya
中科院分区：
文献类型：
--
作者：
Garmashova, Natalia;Atasheva, Svetlana;Frolov, Ilya
致脑炎的新世界甲病毒，包括委内瑞拉（VEEV）、东部（EEEV）和西部马脑炎病毒，构成了美国持续的公共卫生威胁。它们在中美洲、南美洲和北美洲传播，能够在人类、马和其他家畜中引起致命疾病。我们最近证明，这些病毒已经发展出干扰细胞转录的能力，并将其用作下调细胞抗病毒反应的手段。本研究的结果表明，N-末端，类似于35个氨基酸长的肽的VEEV和EEEV衣壳蛋白在下调细胞转录和发展的细胞病变效应中起着最关键的作用。鉴定的VEEV特异性肽C（VEE）33-68包括具有不同功能的两个结构域：α-螺旋结构域，螺旋I，其关键地参与支持蛋白质在细胞质和细胞核中的存在之间的平衡，以及下游肽，其可能含有功能性核定位信号。这两个结构域的完整性不仅决定了VEEV衣壳的细胞内分布，而且对于抑制转录的直接衣壳蛋白功能也是必需的。我们的研究结果表明，VEEV衣壳蛋白与核孔复合物相互作用，这种相互作用与蛋白质的能力，导致转录关闭，并最终导致细胞死亡。VEEV衣壳的N-末端片段被VEEV TC-83基因组中其辛德毕斯病毒特异性对应物取代不影响病毒体外复制，但降低细胞致病性并导致体内减毒。这些发现可用于设计针对新世界甲病毒的新一代活的减毒重组疫苗。
The encephalitogenic New World alphaviruses, including Venezuelan (VEEV), eastern (EEEV), and western equine encephalitis viruses, constitute a continuing public health threat in the United States. They circulate in Central, South, and North America and have the ability to cause fatal disease in humans and in horses and other domestic animals. We recently demonstrated that these viruses have developed the ability to interfere with cellular transcription and use it as a means of downregulating a cellular antiviral response. The results of the present study suggest that the N-terminal, similar to 35-amino-acid-long peptide of VEEV and EEEV capsid proteins plays the most critical role in the downregulation of cellular transcription and development of a cytopathic effect. The identified VEEV-specific peptide C(VEE)33-68 includes two domains with distinct functions: the alpha-helix domain, helix I, which is critically involved in supporting the balance between the presence of the protein in the cytoplasm and nucleus, and the downstream peptide, which might contain a functional nuclear localization signal(s). The integrity of both domains not only determines the intracellular distribution of the VEEV capsid but is also essential for direct capsid protein functioning in the inhibition of transcription. Our results suggest that the VEEV capsid protein interacts with the nuclear pore complex, and this interaction correlates with the protein's ability to cause transcriptional shutoff and, ultimately, cell death. The replacement of the N-terminal fragment of the VEEV capsid by its Sindbis virus-specific counterpart in the VEEV TC-83 genome does not affect virus replication in vitro but reduces cytopathogenicity and results in attenuation in vivo. These findings can be used in designing a new generation of live, attenuated, recombinant vaccines against the New World alphaviruses.