Jääskeläinen Kirsi M, Kaukinen Pasi, Minskaya Ekaterina S, Plyusnina Angelina, Vapalahti Olli, Elliott Richard M, Weber Friedemann, Vaheri Antti, Plyusnin Alexander
Department of Virology, Haartman Institute, FIN-00014 University of Helsinki, Finland.
J Med Virol. 2007 Oct;79(10):1527-36. doi: 10.1002/jmv.20948.
The S RNA genome segment of hantaviruses carried by Arvicolinae and Sigmodontinae rodents encodes the nucleocapsid (N) protein and has an overlapping (+1) open reading frame (ORF) for a putative nonstructural protein (NSs). The aim of this study was to determine whether the ORF is functional. A protein corresponding to the predicted size of Tula virus (TULV) NSs was detected using coupled in vitro transcription and translation from a cloned S segment cDNA, and a protein corresponding to the predicted size of Puumala virus (PUUV) NSs was detected in infected cells by Western blotting with an anti-peptide serum. The activities of the interferon beta (IFN-beta) promoter, and nuclear factor kappa B (NF-kappaB)- and interferon regulatory factor-3 (IRF-3) responsive promoters, were inhibited in COS-7 cells transiently expressing TULV or PUUV NSs. Also IFN-beta mRNA levels in IFN-competent MRC5 cells either infected with TULV or transiently expressing NSs were decreased. These data demonstrate that Tula and Puumala hantaviruses have a functional NSs ORF. The findings may explain why the NSs ORF has been preserved in the genome of most hantaviruses during their long evolution and why hantavirus-infected cells secrete relatively low levels of IFNs.
田鼠亚科和棉鼠亚科啮齿动物携带的汉坦病毒的S RNA基因组片段编码核衣壳（N）蛋白，并具有一个用于假定非结构蛋白（NSs）的重叠（+1）开放阅读框（ORF）。本研究的目的是确定该ORF是否具有功能。使用从克隆的S片段cDNA进行体外转录和翻译偶联，检测到一种与图拉病毒（TULV）NSs预测大小相对应的蛋白质，并且通过用抗肽血清进行蛋白质印迹法在感染细胞中检测到一种与普马拉病毒（PUUV）NSs预测大小相对应的蛋白质。在瞬时表达TULV或PUUV NSs的COS-7细胞中，干扰素β（IFN-β）启动子以及核因子κB（NF-κB）和干扰素调节因子3（IRF-3）响应启动子的活性受到抑制。同样，感染TULV或瞬时表达NSs的具有IFN活性的MRC-5细胞中的IFN-β mRNA水平也降低。这些数据表明图拉和普马拉汉坦病毒具有功能性的NSs ORF。这些发现可能解释了为什么NSs ORF在大多数汉坦病毒的基因组在其漫长的进化过程中得以保留，以及为什么汉坦病毒感染的细胞分泌相对较低水平的IFN。
