Riechmann J L, Laín S, García J A
Centro de Biología Molecular, CSIC-UAM, Universidad Autónoma de Madrid, Spain.
Virology. 1990 Aug;177(2):710-6. doi: 10.1016/0042-6822(90)90537-2.
A full-length cDNA clone of the 9786 nt plum pox virus (PPV) RNA genome has been cloned downstream from a phage T7 RNA polymerase promoter. The RNAs synthesized by in vitro run-off transcription in the presence of the 5' cap analog m7GpppG were infectious in Nicotiana clevelandii plants. No infectivity was detected when the transcriptions were carried out in the absence of the cap analog. Inoculations of the local lesion host Chenopodium foetidum indicated that the infectivity of the synthetic transcripts was about 1% of that of the native viral RNA. An extra G present at the 5' terminus of the transcripts was lost during their replication in plants, and the typical length distribution of the poly(A) tails was recovered. The viral RNA recovered from transcript-infected plants had approximately the same specific infectivity as native viral RNA. A G/A sequence heterogeneity found between different cDNA subgenomic clones was used to demonstrate that the infections were caused by the in vitro transcripts and were not the result of contamination.
一个9786个核苷酸的李痘病毒（PPV）RNA基因组的全长cDNA克隆已被克隆到噬菌体T7 RNA聚合酶启动子的下游。在存在5'帽类似物m7GpppG的情况下通过体外径流转录合成的RNA在克利夫兰烟草植株中具有感染性。当在没有帽类似物的情况下进行转录时，未检测到感染性。对局部病斑寄主臭藜的接种表明，合成转录本的感染性约为天然病毒RNA的1%。转录本5'末端存在的一个额外的G在其在植物中的复制过程中丢失，并且恢复了聚（A）尾的典型长度分布。从转录本感染的植物中回收的病毒RNA具有与天然病毒RNA大致相同的比感染性。利用不同cDNA亚基因组克隆之间发现的G/A序列异质性来证明感染是由体外转录本引起的，而不是污染的结果。
