Attenuating Mutations in nsP1 Reveal Tissue-Specific Mechanisms for Control of Ross River Virus Infection
Attenuating Mutations in nsP1 Reveal Tissue-Specific Mechanisms for Control of Ross River Virus Infection
复制标题
DOI：
10.1128/jvi.02609-13
复制
发表时间：
2014-04-01
影响因子：
5.4
通讯作者：
Morrison, Thomas E.
中科院分区：
文献类型：
--
作者：
Burrack, Kristina A. Stoermer;Hawman, David W.;Morrison, Thomas E.
罗斯河病毒（RRV）是一组蚊子传播的甲病毒之一，可导致人类衰弱，通常是慢性肌肉骨骼疾病。以前，我们报道，替换的非结构蛋白1（nsP 1）基因的小鼠强毒RRV株T48与小鼠无毒力株DC 5692产生的病毒，在小鼠模型中的疾病是减毒的。在这里，我们发现，6 nsP 1株T48和DC 5692之间的非同义核苷酸的差异是RRV毒力的决定因素，我们确定两个非同义核苷酸的变化足以减毒表型。携带6个非同义DC 5692核苷酸差异的RRV T48（RRV-T48-nsP 1（6 M））在野生型和Rag 1（-/-）小鼠中均被减毒。尽管RRV T48和RRV-T48-nsP 1（6 M）在野生型和Rag 1（-/-）小鼠的组织中的减毒表型，但在接种后1至3天内无法区分。在野生型和Rag 1（-/-）小鼠中，接种后5天，骨骼肌组织中的RRV-T48-nsP 1（6 M）载量显著降低，但在其他组织中没有，这表明RRV-T48-nsP 1（6 M）突变体比RRV-T48以组织特异性方式对先天性抗病毒效应物更敏感。在体外实验中，我们发现nsP 1的减毒突变增强了对I型干扰素的敏感性。与这些发现一致，在I型干扰素受体缺陷的小鼠中，RRV T48和RRV-T48-nsP 1（6 M）载量相似。我们的研究结果表明，I型干扰素反应控制RRV感染的组织特异性的方式和特定的氨基酸变化nsP 1的RRV毒力的决定因素，通过调节RRV对干扰素的敏感性。
Ross River virus (RRV) is one of a group of mosquito-transmitted alphaviruses that cause debilitating, and often chronic, musculoskeletal disease in humans. Previously, we reported that replacement of the nonstructural protein 1 (nsP1) gene of the mouse-virulent RRV strain T48 with that from the mouse-avirulent strain DC5692 generated a virus that was attenuated in a mouse model of disease. Here we find that the six nsP1 nonsynonymous nucleotide differences between strains T48 and DC5692 are determinants of RRV virulence, and we identify two nonsynonymous nucleotide changes as sufficient for the attenuated phenotype. RRV T48 carrying the six nonsynonymous DC5692 nucleotide differences (RRV-T48-nsP1(6M)) was attenuated in both wild-type and Rag1(-/-) mice. Despite the attenuated phenotype, RRV T48 and RRV-T48-nsP1(6M) loads in tissues of wild-type and Rag1(-/-) mice were indistinguishable from 1 to 3 days postinoculation. RRV-T48-nsP1(6M) loads in skeletal muscle tissue, but not in other tissues, decreased dramatically by 5 days postinoculation in both wild-type and Rag1(-/-) mice, suggesting that the RRV-T48-nsP1(6M) mutant is more sensitive to innate antiviral effectors than RRV-T48 in a tissue-specific manner. In vitro, we found that the attenuating mutations in nsP1 conferred enhanced sensitivity to type I interferon. In agreement with these findings, RRV T48 and RRV-T48-nsP1(6M) loads were similar in mice deficient in the type I interferon receptor. Our findings suggest that the type I IFN response controls RRV infection in a tissue-specific manner and that specific amino acid changes in nsP1 are determinants of RRV virulence by regulating the sensitivity of RRV to interferon.