RNA promoters located on (-)-strands of a subviral RNA associated with turnip crinkle virus.
RNA promoters located on (-)-strands of a subviral RNA associated with turnip crinkle virus.
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RNA 启动子位于与芜菁皱纹病毒相关的亚病毒 RNA 的 (-) 链上。
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
A. Simon
中科院分区：
文献类型：
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作者：
H. Guan;C. Song;A. Simon
卫星(Sat)RNA C是萝卜皱缩病毒(TCV)的非必需亚病毒RNA之一，其复制依赖于TCV编码的RNA依赖的RNA聚合酶(RdRp)。早期的工作表明，使用部分纯化的、模板特异的TCV RdRp在体外合成(-)链需要(+)链sat-RNAC的3‘端的茎环结构(Song C，Simon AE，1995，J Mol Biol 254：6-14)。Sat-RNAC(-)链上的顺式序列在体外可以作为单独的启动子，现在已经被定义。两个启动子序列位于(-)链Sat-RNAC上，一个位于3‘端附近的11个碱基，另一个由14个碱基组成，位于5’端41个碱基。两个启动子序列都含有多个连续的C残基和多个连续的嘌呤，没有明显的二级结构，表明特定的一级序列除了发夹结构外，还可以被TCV RdRp识别。3‘-近端启动子序列使用带有天然sat-RNA3’端的(-)链模板从3‘端直接合成(AUCCC-3’)。当模板的3‘端存在质粒衍生的碱基时，两个启动子序列都可以引导RdRp在启动子内的多个连续C残基启动内部转录。这一结果表明，多个连续的C残基对于转录启动是重要的，当天然的3‘端序列位于3’端时，有助于RdRp在分子的3‘端启动。
Satellite (sat-) RNA C, one of the nonessential subviral RNAs of turnip crinkle virus (TCV), is dependent on the TCV-encoded RNA-dependent RNA polymerase (RdRp) for its replication. Earlier work showed that a stem-loop structure at the 3' end of (+)-strand sat-RNA C is required for synthesis of (-)-strands in vitro using a partially purified, template-specific TCV RdRp (Song C, Simon AE, 1995, J Mol Biol 254:6-14). Cis-sequences on (-)-strands of sat-RNA C that can serve as separate promoters in vitro have now been defined. Two promoter sequences are located on (-)-strand sat-RNA C, one comprising 11 bases located near the 3' end, and the other consisting of 14 bases located 41 bases from the 5' end. Both promoter sequences contain multiple consecutive C residues followed by multiple consecutive purines and have no obvious secondary structure, suggesting that, along with hairpin structures, specific primary sequences can be recognized by the TCV RdRp. The 3'-proximal promoter sequence directed synthesis from the 3' terminus using (-)-strand templates with the natural sat-RNA 3' end (AUCCC-3'). When plasmid-derived bases were present at the 3' ends of the templates, both promoter sequences could direct the RdRp to initiate transcription internally at the multiple consecutive C residues within the promoters. This result suggests that multiple consecutive C residues are important for transcription initiation and that natural 3'-end sequences, when located at 3' termini, help the RdRp to initiate at the 3' end of the molecule.