The Red clover necrotic mosaic virus RNA2 trans-activator is also a cis-acting RNA2 replication element
The Red clover necrotic mosaic virus RNA2 trans-activator is also a cis-acting RNA2 replication element
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DOI：
10.1128/jvi.79.2.978-986.2005
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发表时间：
2005-01-01
影响因子：
5.4
通讯作者：
Okuno, T
中科院分区：
文献类型：
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作者：
Tatsuta, M;Mizumoto, H;Okuno, T
外壳蛋白基因的表达需要RNA介导的红三叶草坏死花叶病毒（WNW）中亚基因组RNA合成的反式激活，其基因组由两个正链RNA（RNA1和RNA2）组成。从RNAi合成亚基因组RNA所需的反式作用RNA元件先前已被定位到RNA2的蛋白质编码区，而RNA1的复制不需要RNA2。在这项研究中，我们研究了蛋白质编码区在RNA2复制的作用，通过分析的复制能力的RNA2突变体含有缺失或核苷酸取代。我们的研究结果表明，同样的茎环结构（SL2），作为一个RNA介导的外壳蛋白表达的反式激活剂的功能是至关重要的复制RNA2本身。然而，有趣的是，通过在对应于RNA2的SL2环的RNAi区域中的核苷酸取代破坏RNA-RNA相互作用不影响RNA2复制，表明RNA-RNA相互作用不是RNA2复制所必需的。进一步的突变分析表明，除了茎环结构本身，SL2茎和环中的核苷酸序列对RNA2的复制也很重要。这些发现表明，RNA 2中SL 2的结构和核苷酸序列在病毒的生活史中起着多重作用。
The expression of the coat protein gene requires RNA-mediated trans-activation of subgenomic RNA synthesis in Red clover necrotic mosaic virus WNW), the genome of which consists of two positive-strand RNAs, RNAI and RNA2. The trans-acting RNA element required for subgenomic RNA synthesis from RNAI has been mapped previously to the protein-coding region of RNA2, whereas RNA2 is not required for the replication of RNA1. In this study, we investigated the roles of the protein-coding region in RNA2 replication by analyzing the replication competence of RNA2 mutants containing deletions or nucleotide substitutions. Our results indicate that the same stem-loop structure (SL2) that functions as a trans-activator for RNA-mediated coat protein expression is critically required for the replication of RNA2 itself. Interestingly, however, disruption of the RNA-RNA interaction by nucleotide substitutions in the region of RNAI corresponding to the SL2 loop of RNA2 does not affect RNA2 replication, indicating that the RNA-RNA interaction is not required for RNA2 replication. Further mutational analysis showed that, in addition to the stem-loop structure itself, nucleotide sequences in the stem and in the loop of SL2 are important for the replication of RNA2. These findings suggest that the structure and nucleotide sequence of SL2 in RNA2 play multiple roles in the virus life cycle.