Retroviral RNA packaging: a review.
Retroviral RNA packaging: a review.
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逆转录病毒 RNA 包装：综述。
DOI：
10.1007/978-3-7091-9326-6_49
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Rein,A
中科院分区：
文献类型：
--
作者：
Rein,A
在逆转录病毒中，“Gag”或核心多蛋白能够组装成病毒颗粒并包装病毒的基因组RNA。这种蛋白质如何识别病毒RNA尚不清楚。Gag多聚蛋白含有一个锌指结构域;该结构域发生变化的突变体组装成病毒粒子，但这些粒子的大部分缺乏病毒RNA。因此，RNA包装机制中的一个关键元件是锌指结构域。包装所需的RNA序列（“包装信号”）已经通过缺失分析和通过测量含有有限插入的病毒序列的非病毒mRNA的折叠来研究。这些实验表明，病毒RNA中的全部或部分包装信号位于基因组的5端附近。这些信号看起来相当大，即，数百个核苷酸。每个病毒颗粒实际上包含两个相同的+链基因组RNA分子的二聚体。二聚体连接的性质尚不清楚。在某些实验情况下（包括锌指突变体），病毒制备物中只有一小部分颗粒含有基因组RNA。令人惊讶的是，在这些情况下包装的基因组RNA是二聚体。由于这一重要的观察结果，推测只有二聚体被包装，并且二聚体结构是包装信号的元素。还表明二聚体在病毒从细胞释放后经历构象变化（“RNA成熟”），并且这种变化可能取决于Gag多蛋白的切割，这是由病毒编码的蛋白酶催化的组装后事件。
In retroviruses, the “Gag” or core polyprotein is capable of assembling into virus particles and packaging the genomic RNA of the virus. How this protein recognizes viral RNA is not understood. Gag polyproteins contain a zinc-finger domain; mutants with changes in this domain assemble into virions, but a large fraction of these particles lack viral RNA. Thus, one crucial element in the RNA packaging mechanism is the zinc-finger domain. RNA sequences required for packaging (“packing signals”) have been studied both by deletion analysis and by measuring encapsidation of nonviral mRNAs containing limited insertions of viral sequence. These experiments show that all or part of the packaging signal in viral RNA is located near the 5 end of the genome. These signals appear to be quite large, i.e., hundreds of nucleotides. Each virus particle actually contains a dimer of two identical, + strand genomic RNA molecules. The nature of the dimeric linkage is not understood. In some experimental situations (including zinc-finger mutants), only a small fraction of the particles in a virus preparation contain genomic RNA. It is striking that the genomic RNA packaged in these situations is dimeric. Because of this important observation, it is speculated that only dimers are packaged, and that the dimeric structure is an element of the packaging signal. It is also suggested that the dimers undergo a conformational change (“RNA maturation”) after the virus is released from the cell, and that this change may depend upon the cleavage of the Gag polyprotein, a post-assembly event catalyzed by the virus-coded protease.