Wagner Cassia, Reddy Vijay, Asturias Francisco, Khoshouei Maryam, Johnson John E, Manrique Pilar, Munson-McGee Jacob, Baumeister Wolfgang, Lawrence C Martin, Young Mark J
Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA.
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.
J Virol. 2017 Sep 27;91(20). doi: 10.1128/JVI.00925-17. Print 2017 Oct 15.
Our understanding of archaeal virus diversity and structure is just beginning to emerge. Here we describe a new archaeal virus, tentatively named Metallosphaera turreted icosahedral virus (MTIV), that was isolated from an acidic hot spring in Yellowstone National Park, USA. Two strains of the virus were identified and were found to replicate in an archaeal host species closely related to Each strain encodes a 9.8- to 9.9-kb linear double-stranded DNA (dsDNA) genome with large inverted terminal repeats. Each genome encodes 21 open reading frames (ORFs). The ORFs display high homology between the strains, but they are quite distinct from other known viral genes. The 70-nm-diameter virion is built on a T=28 icosahedral lattice. Both single particle cryo-electron microscopy and cryotomography reconstructions reveal an unusual structure that has 42 turret-like projections: 12 pentameric turrets positioned on the icosahedral 5-fold axes and 30 turrets with apparent hexameric symmetry positioned on the icosahedral 2-fold axes. Both the virion structural properties and the genome content support MTIV as the founding member of a new family of archaeal viruses. Many archaeal viruses are quite different from viruses infecting bacteria and eukaryotes. Initial characterization of MTIV reveals a virus distinct from other known bacterial, eukaryotic, and archaeal viruses; this finding suggests that viruses infecting are still an understudied group. As the first known virus infecting a sp., MTIV provides a new system for exploring archaeal virology by examining host-virus interactions and the unique features of MTIV structure-function relationships. These studies will likely expand our understanding of virus ecology and evolution.
我们对古菌病毒多样性和结构的认识才刚刚开始浮现。在此，我们描述一种新的古菌病毒，暂命名为嗜热栖热菌带炮塔二十面体病毒（MTIV），它是从美国黄石国家公园的酸性温泉中分离出来的。鉴定出了该病毒的两个菌株，并发现它们能在与[具体宿主物种名称缺失]密切相关的古菌宿主物种中复制。每个菌株都编码一个9.8至9.9千碱基对的线性双链DNA（dsDNA）基因组，带有大的反向末端重复序列。每个基因组编码21个开放阅读框（ORF）。这些ORF在菌株之间显示出高度同源性，但与其他已知的病毒基因有很大不同。直径70纳米的病毒粒子构建在T = 28的二十面体晶格上。单颗粒冷冻电子显微镜和冷冻断层扫描重建都揭示了一种不寻常的结构，有42个类似炮塔的突起：12个五聚体炮塔位于二十面体的5重轴上，30个具有明显六聚体对称性的炮塔位于二十面体的2重轴上。病毒粒子的结构特性和基因组内容都支持MTIV作为一个新的古菌病毒家族的创始成员。许多古菌病毒与感染细菌和真核生物的病毒有很大不同。MTIV的初步特征表明它是一种与其他已知的细菌、真核生物和古菌病毒不同的病毒；这一发现表明感染[具体宿主物种名称缺失]的病毒仍然是一个研究不足的群体。作为第一个已知感染[具体宿主物种名称缺失]物种的病毒，MTIV通过研究宿主 - 病毒相互作用以及MTIV结构 - 功能关系的独特特征，为探索古菌病毒学提供了一个新系统。这些研究可能会扩展我们对病毒生态学和进化的理解。
