Kuhn R J, Griffin D E, Owen K E, Niesters H G, Strauss J H
Division of Biology, California Institute of Technology, Pasadena 91125, USA.
J Virol. 1996 Nov;70(11):7900-9. doi: 10.1128/JVI.70.11.7900-7909.1996.
Sindbis virus and Ross River virus are alphaviruses whose nonstructural proteins share 64% identity and whose structural proteins share 48% identity. Starting from full-length cDNA clones of both viruses, we have generated two reciprocal Sindbis-Ross River chimeric viruses in which the structural and nonstructural regions have been exchanged. These chimeric viruses replicate readily in several cell lines. Both chimeras grow more poorly than do the parental viruses, with the chimera containing Sindbis virus nonstructural proteins and Ross River virus structural proteins growing considerably better in both mosquito and Vero cell lines than the reciprocal chimera does. The reduction in replicative capacity in comparison with the parental viruses appears to result at least in part from a reduction in RNA synthesis, which suggests that the structural proteins or sequence elements within the structural region interact with the nonstructural proteins or sequence elements within the nonstructural region, that these interactions are required for efficient RNA replication, and that these interactions are suboptimal in the chimeras. The chimeras are able to infect mice, but their growth is attenuated. Western equine encephalitis virus, a virus widely distributed throughout the Americas, has been previously shown to have arisen by natural recombination between two distinct alphaviruses, but other naturally occurring recombinant alphaviruses have not been found. The present results suggest that most nonstructural/structural chimeras that might arise by natural recombination will be viable but that interactions between different regions of the genome, some of which were previously known but some of which remain unknown, limit the ability of such recombinants to become established.
辛德毕斯病毒和罗斯河病毒属于甲病毒属，其非结构蛋白的同源性为64%，结构蛋白的同源性为48%。我们从这两种病毒的全长cDNA克隆出发，构建了两种相互的辛德毕斯-罗斯河嵌合病毒，其中结构区和非结构区进行了交换。这些嵌合病毒能在多种细胞系中轻松复制。两种嵌合体的生长情况均不如亲本病毒，其中含有辛德毕斯病毒非结构蛋白和罗斯河病毒结构蛋白的嵌合体在蚊子和非洲绿猴肾细胞系中的生长情况都比反向嵌合体好得多。与亲本病毒相比，复制能力的降低似乎至少部分是由于RNA合成的减少，这表明结构蛋白或结构区内的序列元件与非结构蛋白或非结构区内的序列元件相互作用，这些相互作用是高效RNA复制所必需的，且在嵌合体中这些相互作用并不理想。嵌合体能够感染小鼠，但其生长受到抑制。西部马脑炎病毒广泛分布于美洲，此前已证明它是由两种不同的甲病毒自然重组产生的，但尚未发现其他自然发生的重组甲病毒。目前的结果表明，大多数可能通过自然重组产生的非结构/结构嵌合体是可行的，但基因组不同区域之间的相互作用，其中一些是已知的，一些仍然未知，限制了此类重组体得以确立的能力。
