PNAS：法国科学家在古代永冻土中发现并复活一种前所未知的巨病毒

法国艾克斯-马赛大学的研究人员在一个3万年前的永冻土样本中发现并复活一种前所未知的巨病毒。这一成果提示巨病毒更加多样而且并不像此前认为的那样稀少。相关文章发表于2014年3月3日的《PNAS》杂志上。

在过去的10年中已经发现了几种属于巨型病毒科的巨病毒。这些病毒的形态和生理的相似性曾经提示所有巨病毒基本都有同样的特征，但是近来发现的潘多拉病毒用它的不同的形状、尺寸和生理特征挑战了这一理论。

Jean-Michel Claverie及其同事通过用卡氏棘阿米巴(Acanthamoeba castellanii)孵化3万年前的西伯利亚永冻土芯样本，调查了其他的巨病毒类型，卡氏棘阿米巴是常见的巨病毒宿主。

这组作者报告说，这个宿主被此前未知的一种巨病毒感染，它拥有混合的特征：它与潘多拉病毒的形状相同，蛋白质表达和复制类似于巨型病毒，尺寸比潘多拉病毒和巨型病毒更大，而且它的基因组只有这两族病毒尺寸的几分之一。

这组作者说，随着永冻土随不断增加的北极温度而融化，这种被命名为Pithovirus sibericum的病毒从古代永冻土中的复活提示了其他古代病毒复活的潜力，其中一些可能成为动物或人类的病原体。

法国国家科学研究中心(CNRS)在一份新闻声明，这项工作表明病毒可在冻土里面长期存活。

原文摘要：

Thirty-thousand-year-old distant relative of giant icosahedral DNA viruses with a pandoravirus morphology

Matthieu Legendre, Julia Bartoli, Lyubov Shmakova, Sandra Jeudy, Karine Labadie, Annie Adrait,Magali Lescot, Olivier Poirot, Lionel Bertaux, Christophe Bruley, Yohann Couté, Elizaveta Rivkina,Chantal Abergel and Jean-Michel Claverie

The largest known DNA viruses infect Acanthamoeba and belong to two markedly different families. The Megaviridae exhibit pseudo-icosahedral virions up to 0.7 μm in diameter and adenine–thymine (AT)-rich genomes of up to 1.25 Mb encoding a thousand proteins. Like their Mimivirus prototype discovered 10 y ago, they entirely replicate within cytoplasmic virion factories. In contrast, the recently discovered Pandoraviruses exhibit larger amphora-shaped virions 1 μm in length and guanine–cytosine-rich genomes up to 2.8 Mb long encoding up to 2,500 proteins. Their replication involves the host nucleus. Whereas the Megaviridae share some general features with the previously described icosahedral large DNA viruses, the Pandoraviruses appear unrelated to them. Here we report the discovery of a third type of giant virus combining an even larger pandoravirus-like particle 1.5 μm in length with a surprisingly smaller 600 kb AT-rich genome, a gene content more similar to Iridoviruses and Marseillevirus, and a fully cytoplasmic replication reminiscent of the Megaviridae. This suggests that pandoravirus-like particles may be associated with a variety of virus families more diverse than previously envisioned. This giant virus, named Pithovirus sibericum, was isolated from a >30,000-y-old radiocarbon-dated sample when we initiated a survey of the virome of Siberian permafrost. The revival of such an ancestral amoeba-infecting virus used as a safe indicator of the possible presence of pathogenic DNA viruses, suggests that the thawing of permafrost either from global warming or industrial exploitation of circumpolar regions might not be exempt from future threats to human or animal health.

标签: 潘多拉病毒 巨病毒 卡氏棘阿米巴

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