Repetitive prime-and-realign mechanism converts short capped RNA leaders into longer ones that may be more suitable for elongation during rice stripe virus transcription initiation
Repetitive prime-and-realign mechanism converts short capped RNA leaders into longer ones that may be more suitable for elongation during rice stripe virus transcription initiation
复制标题
重复引发和重新对齐机制将短帽 RNA 前导序列转换为较长的 RNA 前导序列，可能更适合水稻条纹病毒转录起始过程中的延伸
DOI：
10.1099/vir.0.033902-0
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发表时间：
2012-01-01
影响因子：
3.8
通讯作者：
Tao, Xiaorong
中科院分区：
文献类型：
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作者：
Yao, Min;Zhang, Tianqi;Tao, Xiaorong
研究发现，黄瓜花叶病毒（CMV） rna在水稻条纹病毒（RSV）共侵染本烟菌过程中充当转录起始的帽供体。CMV rna的5‘端优先在与RSV模板的3’端具有多碱基互补的残基上被切割。扩增CMV的引物长度在12 ~ 20nt之间，其中扩增长度在12 ~ 16nt之间的引物最适合扩增，并产生更多的CMV- rsv嵌合mRNA转录物。从CMV rna中切割出来的原帽供体主要是短的（10- 13nt）。然而，经过长距离延伸的CMV封顶RNA先导体被发现包含多达5个额外的AC二核苷酸重复。序列分析显示，这些AC二核苷酸在多次启动和重组循环中用于增加短帽供体的大小。每个引物-重组周期向被盖住的RNA先导体上添加一个AC二核苷酸；因此，最初的帽体供体逐渐转化为更长的帽体RNA先导体（12- 20nt）。有趣的是，从CMV RNA1/2中切割出来的原始10 nt（或11 nt）帽供体没有直接延伸；只使用增加到>= 12 nt的带帽RNA引线进行直接延伸。这些发现表明，这种重复的引物和重组可能有助于将短帽CMV RNA先导物转化为更长的、更合适的大小，从而在RSV转录起始过程中提供更稳定的转录复合体用于延伸。
Cucumber mosaic virus (CMV) RNAs were found to serve as cap donors for rice stripe virus (RSV) transcription initiation during their co-infection of Nicotiana benthamiana. The 5' end of CMV RNAs was cleaved preferentially at residues that had multiple-base complementarity to the 3' end of the RSV template. The length requirement for CMV capped primers to be suitable for elongation varied between 12 and 20 nt, and those of 12-16 nt were optimal for elongation and generated more CMV-RSV chimeric mRNA transcripts. The original cap donors that were cleaved from CMV RNAs were predominantly short (10-13 nt). However, the CMV capped RNA leaders that underwent long-distance elongation were found to contain up to five repetitions of additional AC dinucleotides. Sequence analysis revealed that these AC dinucleotides were used to increase the size of short cap donors in multiple prime-and-realign cycles. Each prime-and-realign cycle added an AC dinucleotide onto the capped RNA leaders; thus, the original cap donors were gradually converted to longer capped RNA leaders (of 12-20 nt). Interestingly, the original 10 nt (or 11 nt) cap donor cleaved from CMV RNA1/2 did not undergo direct extension; only capped RNA leaders that had been increased to >= 12 nt were used for direct elongation. These findings suggest that this repetitive priming and realignment may serve to convert short capped CMV RNA leaders into longer, more suitable sizes to render a more stabilized transcription complex for elongation during RSV transcription initiation.