MHV NUCLEOCAPSID SYNTHESIS IN THE PRESENCE OF CYCLOHEXIMIDE AND ACCUMULATION OF NEGATIVE STRAND MHV RNA
MHV NUCLEOCAPSID SYNTHESIS IN THE PRESENCE OF CYCLOHEXIMIDE AND ACCUMULATION OF NEGATIVE STRAND MHV RNA
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DOI：
10.1016/0168-1702(86)90074-2
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发表时间：
1986-12-01
期刊：
影响因子：
5
通讯作者：
STOLTZFUS, CM
中科院分区：
文献类型：
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作者：
PERLMAN, S;RIES, D;STOLTZFUS, CM
我们发现，在感染小鼠肝炎病毒A59株（MHV-A59）的细胞中，基因组RNA合成被环己亚胺抑制，这与先前发表的结果一致（Sawicki， S.G.和Sawicki， D.L. (1986) J. Virol. 57, 328-334）。在本研究中，确定了在环己亚胺存在下合成的残留基因组RNA的命运。在药物存在下合成的基因组RNA几乎全部被纳入核衣壳结构，这表明即使在没有蛋白质合成的情况下，基因组RNA合成和衣壳化在mhv感染细胞中也是偶联的。由于测定可溶性N蛋白池的半衰期约为1小时，因此有足够的游离核衣壳N蛋白可用于此目的。负链RNA是基因组和亚基因组正链RNA合成的模板，预计主要在裂解周期的早期阶段积累。与这一预测一致，负链RNA在感染的前5-6小时内积累，在接下来的2.5小时内几乎没有额外的积累。与此形成鲜明对比的是，正链RNA在同样的2.5小时内增加了5-6倍。这些结果，结合已发表的数据，表明负链RNA是在感染周期的早期合成的，并且在感染细胞中是稳定的，还表明在晚期用环己亚胺治疗不会通过阻断负链模板的形成间接抑制正链RNA的合成。
We have found that genomic RNA synthesis is inhibited by cycloheximide in cells infected with mouse hepatitis virus, strain A59 (MHV-A59), in agreement with previously published results (Sawicki, S.G. and Sawicki, D.L. (1986) J. Virol. 57, 328-334). In the present study, the fate of the residual genomic RNA synthesized in the presence of cycloheximide was determined. Nearly all of the genomic RNA synthesized in the presence of drug was incorporated into nucleocapsid structures, suggesting that even in the absence of protein synthesis, genomic RNA synthesis and encapsidation are coupled in MHV-infected cells. Sufficient free nucleocapsid N protein was available for this purpose, since the pool of soluble N protein was determined to decay with a half-life of approximately one hour. Negative strand RNA is the template for the synthesis of both genomic and subgenomic positive strand RNA, and would be predicted to accumulate primarily during the early phases of the lytic cycle. In agreement with this prediction, negative strand RNA accumulated during the first 5-6 h of infection, with little additional accumulation occurring over the next 2.5 h. In marked contrast, positive strand RNA increased 5-6-fold over the same 2.5 h period. These results, taken in conjunction with published data, suggest that negative strand RNA is synthesized during the early period of the infectious cycle and is stable in infected cells and also suggest that treatment with cycloheximide at late times does not inhibit positive strand RNA synthesis indirectly by blocking the formation of negative strand templates.