Brown David M, Kauder Steven E, Cornell Christopher T, Jang Gwendolyn M, Racaniello Vincent R, Semler Bert L
Department of Microbiology and Molecular Genetics, College of Medicine, University of California, Irvine, California 92697, USA.
J Virol. 2004 Feb;78(3):1344-51. doi: 10.1128/jvi.78.3.1344-1351.2004.
We previously reported the isolation of a mutant poliovirus lacking the entire genomic RNA 3' noncoding region. Infection of HeLa cell monolayers with this deletion mutant revealed only a minor defect in the levels of viral RNA replication. To further analyze the consequences of the genomic 3' noncoding region deletion, we examined viral RNA replication in a neuroblastoma cell line, SK-N-SH cells. The minor genomic RNA replication defect in HeLa cells was significantly exacerbated in the SK-N-SH cells, resulting in a decreased capacity for mutant virus growth. Analysis of the nature of the RNA replication deficiency revealed that deleting the poliovirus genomic 3' noncoding region resulted in a positive-strand RNA synthesis defect. The RNA replication deficiency in SK-N-SH cells was not due to a major defect in viral translation or viral protein processing. Neurovirulence of the mutant virus was determined in a transgenic mouse line expressing the human poliovirus receptor. Greater than 1,000 times more mutant virus was required to paralyze 50% of inoculated mice, compared to that with wild-type virus. These data suggest that, together with a cellular factor(s) that is limiting in neuronal cells, the poliovirus 3' noncoding region is involved in positive-strand synthesis during genome replication.
我们之前报道过分离出一种缺失整个基因组RNA 3'非编码区的脊髓灰质炎病毒突变体。用这种缺失突变体感染HeLa细胞单层，结果显示病毒RNA复制水平仅有轻微缺陷。为了进一步分析基因组3'非编码区缺失的后果，我们检测了神经母细胞瘤细胞系SK-N-SH细胞中的病毒RNA复制情况。HeLa细胞中轻微的基因组RNA复制缺陷在SK-N-SH细胞中显著加剧，导致突变病毒生长能力下降。对RNA复制缺陷性质的分析表明，删除脊髓灰质炎病毒基因组3'非编码区会导致正链RNA合成缺陷。SK-N-SH细胞中的RNA复制缺陷并非由于病毒翻译或病毒蛋白加工存在重大缺陷。在表达人脊髓灰质炎病毒受体的转基因小鼠品系中测定了突变病毒的神经毒性。与野生型病毒相比，使50%的接种小鼠瘫痪所需的突变病毒量要多出1000倍以上。这些数据表明，脊髓灰质炎病毒3'非编码区与神经元细胞中有限的一种或多种细胞因子共同参与基因组复制过程中的正链合成。
