Hahn C S, Lustig S, Strauss E G, Strauss J H
Division of Biology, California Institute of Technology, Pasadena 91125.
Proc Natl Acad Sci U S A. 1988 Aug;85(16):5997-6001. doi: 10.1073/pnas.85.16.5997.
The alphaviruses are a group of 26 mosquito-borne viruses that cause a variety of human diseases. Many of the New World alphaviruses cause encephalitis, whereas the Old World viruses more typically cause fever, rash, and arthralgia. The genome is a single-stranded nonsegmented RNA molecule of + polarity; it is about 11,700 nucleotides in length. Several alphavirus genomes have been sequenced in whole or in part, and these sequences demonstrate that alpha-viruses have descended from a common ancestor by divergent evolution. We have now obtained the sequence of the 3'-terminal 4288 nucleotides of the RNA of the New World Alphavirus western equine encephalitis virus (WEEV). Comparisons of the nucleotide and amino acid sequences of WEEV with those of other alphaviruses clearly show that WEEV is recombinant. The sequences of the capsid protein and of the (untranslated) 3'-terminal 80 nucleotides of WEEV are closely related to the corresponding sequences of the New World Alphavirus eastern equine encephalitis virus (EEEV), whereas the sequences of glycoproteins E2 and E1 of WEEV are more closely related to those of an Old World virus, Sindbis virus. Thus, WEEV appears to have arisen by recombination between an EEEV-like virus and a Sindbis-like virus to give rise to a new virus with the encephalogenic properties of EEEV but the antigenic specificity of Sindbis virus. There has been speculation that recombination might play an important role in the evolution of RNA viruses. The current finding that a widespread and successful RNA virus is recombinant provides support for such an hypothesis.
甲病毒是一组由26种蚊媒病毒组成的病毒，可导致多种人类疾病。许多新大陆甲病毒会引起脑炎，而旧大陆病毒通常会引起发热、皮疹和关节痛。其基因组是一个具有正链极性的单链非节段RNA分子；长度约为11,700个核苷酸。几种甲病毒的基因组已全部或部分测序，这些序列表明甲病毒是通过趋异进化从一个共同祖先进化而来的。我们现已获得新大陆甲病毒西部马脑炎病毒（WEEV）RNA 3'末端4288个核苷酸的序列。将WEEV的核苷酸和氨基酸序列与其他甲病毒的序列进行比较，清楚地表明WEEV是重组病毒。WEEV的衣壳蛋白序列和3'末端80个（未翻译）核苷酸与新大陆甲病毒东部马脑炎病毒（EEEV）的相应序列密切相关，而WEEV的糖蛋白E2和E1序列与一种旧大陆病毒辛德毕斯病毒的序列更密切相关。因此，WEEV似乎是由一种类似EEEV的病毒和一种类似辛德毕斯病毒的病毒重组产生的，从而产生了一种具有EEEV致脑炎特性但具有辛德毕斯病毒抗原特异性的新病毒。有人推测重组可能在RNA病毒的进化中起重要作用。目前发现一种广泛传播且成功的RNA病毒是重组病毒，这为这一假说提供了支持。
