Analysis of nucleotide sequences and multimeric forms of a novel satellite RNA associated with Beet black scorch virus
Analysis of nucleotide sequences and multimeric forms of a novel satellite RNA associated with Beet black scorch virus
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DOI：
10.1128/jvi.79.6.3664-3674.2005
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发表时间：
2005-03-01
影响因子：
5.4
通讯作者：
Yu, JL
中科院分区：
文献类型：
--
作者：
Guo, LH;Cao, YH;Yu, JL
测定了甜菜黑焦病毒分离物X （BBSV-X）的卫星RNA （sat-RNA）的全长序列。该病毒全长615个核苷酸，与辅助病毒或其他已报道的病毒缺乏广泛的序列同源性。纯化后的病毒颗粒含有丰富的单链正链单体和少量的二聚体。从植物总RNA提取物中提取的单链RNA也主要包括单体和少量的二聚体，通过杂交可以发现，纯化的双链RNA也含有单体和二聚体。用BBSV rna和sat-RNA的体外转录本共接种苋菜，评估了各种形式的sat-RNA（包括单体、二聚体和四聚体）的复制和积累。二聚体sat- rna在连接区域中有5个或10个碱基缺失或15个碱基插入，它们优先积累。相比之下，单体sat-RNA的复制受到5‘或3’端5个核苷酸缺失的严重抑制。因此，单体5‘和3’端的序列或完整并置的多聚体的存在对于sat-RNA的复制和单体后代的优势是必不可少的。比较体外合成的单体或多聚体卫星rna启动复制的时间过程，提出了二聚体形式在复制中起中间作用的可能性。我们提出复制主要涉及多聚体，可能是二聚体形式。这些形式可以通过在5‘端序列的复制终止和/或在多聚体连接的3’端进行内部起始而恢复为单体。
The full-length sequence of a satellite RNA (sat-RNA) of Beet black scorch virus isolate X (BBSV-X) was determined. This agent is 615 nucleotides long and lacks extensive sequence homology with its helper virus or with other reported viruses. Purified virus particles contained abundant single-stranded plus-sense monomers and smaller amounts of dimers. Single-stranded RNAs from total plant RNA extracts also included primarily monomers and smaller amounts of dimers that could be revealed by hybridization, and preparations of purified double-stranded RNAs also contained monomers and dimers. Coinoculation of in vitro transcripts of sat-RNA to Chenopodium amaranticolor with BBSV RNAs was used to assess the replication and accumulation of various forms of sat-RNA, including monomers, dimers, and tetramers. Dimeric sat-RNAs with 5- or 10-base deletions or 15-base insertions within the junction regions accumulated preferentially. In contrast, the replication of monomeric sat-RNA was severely inhibited by five-nucleotide deletions in either the 5' or the 3' termini. Therefore, sequences at both the 5' and the 3' ends of the monomers or the presence of intact juxtaposed multimers is essential for the replication of sat-RNA and for the predomination of monomeric progeny. Comparisons of the time courses of replication initiated by in vitro-synthesized monomeric or multimeric sat-RNAs raised the possibility that the dimeric form has an intermediate role in replication. We propose that replication primarily involves multimers, possibly as dimeric forms. These forms may revert to monomers by a termination of replication at 5' end sequences and/or by internal initiation at the 3' ends of multimeric junctions.