Lin N S, Lee Y S, Lin B Y, Lee C W, Hsu Y H
Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China.
Proc Natl Acad Sci U S A. 1996 Apr 2;93(7):3138-42. doi: 10.1073/pnas.93.7.3138.
A satellite RNA of 836 nt depends on the bamboo mosaic potexvirus (BaMV) for its replication and encapsulation. The BaMV satellite RNA (satBaMV) contains a single open reading frame encoding a 20-kDa nonstructural protein. A full-length infectious cDNA clone has been generated downstream of the T7 RNA polymerase promoter. To investigate the role of the 20-kDa protein encoded by satBaMV, satBaMV transcripts containing mutations in the open reading frame were tested for their ability to replicate in barley protoplasts and in Chenopodium quinoa using BaMV RNA as a helper genome. Unlike other large satellite RNAs, mutants in the open reading frame did not block their replication, suggesting that the 20-kDa protein is not essential for satBaMV replication. Precise replacement of the open reading frame with sequences encoding chloramphenicol acetyltransferase resulted in high level expression of chloramphenicol acetyltransferase in infected C. quinoa, indicating that satBaMV is potentially useful as a satellite-based expression vector.
一个836个核苷酸的卫星RNA依赖竹花叶马铃薯X病毒（BaMV）进行复制和包装。BaMV卫星RNA（satBaMV）包含一个单一的开放阅读框，编码一个20 kDa的非结构蛋白。在T7 RNA聚合酶启动子下游已构建出一个全长感染性cDNA克隆。为了研究satBaMV编码的20 kDa蛋白的作用，以BaMV RNA作为辅助基因组，对开放阅读框中含有突变的satBaMV转录本在大麦原生质体和藜麦中的复制能力进行了测试。与其他大型卫星RNA不同，开放阅读框中的突变体并未阻断其复制，这表明20 kDa蛋白对satBaMV复制并非必不可少。用编码氯霉素乙酰转移酶的序列精确替换开放阅读框，导致氯霉素乙酰转移酶在受感染的藜麦中高水平表达，这表明satBaMV有潜力作为一种基于卫星的表达载体。
