Guo P X, Erickson S, Anderson D
Science. 1987 May 8;236(4802):690-4. doi: 10.1126/science.3107124.
A small RNA of Bacillus subtilis bacteriophage phi 29 is shown to have a novel and essential role in viral DNA packaging in vitro. This requirement for RNA in the encapsidation of viral DNA provides a new dimension of complexity to the attendant protein-DNA interactions. The RNA is a constituent of the viral precursor shell of the DNA-packaging machine but is not a component of the mature virion. Studies of the sequential interactions involving this RNA molecule are likely to provide new insight into the structural and possible catalytic roles of small RNA molecules. The phi 29 assembly in extracts and phi 29 DNA packaging in the defined in vitro system were strongly inhibited by treatment with the ribonucleases A or T1. However, phage assembly occurred normally in the presence of ribonuclease A that had been treated with a ribonuclease inhibitor. An RNA of approximately 120 nucleotides co-purified with the phi 29 precursor protein shell (prohead), and this particle was the target of ribonuclease action. Removal of RNA from the prohead by ribonuclease rendered it inactive for DNA packaging. By RNA-DNA hybridization analysis, the RNA was shown to originate from a viral DNA segment very near the left end of the genome, the end packaged first during in vitro assembly.
枯草芽孢杆菌噬菌体phi 29的一种小RNA在体外病毒DNA包装中具有新的重要作用。病毒DNA包装对RNA的这种需求为伴随的蛋白质-DNA相互作用增添了新的复杂层面。该RNA是DNA包装机器病毒前体外壳的组成部分，但不是成熟病毒粒子的组成部分。对涉及这种RNA分子的序列相互作用的研究可能会为小RNA分子结构和可能的催化作用提供新的见解。用核糖核酸酶A或T1处理可强烈抑制提取物中的phi 29组装和体外特定系统中的phi 29 DNA包装。然而，在存在经核糖核酸酶抑制剂处理的核糖核酸酶A的情况下，噬菌体组装正常发生。一种约120个核苷酸的RNA与phi 29前体蛋白外壳（原头部）共纯化，并且该颗粒是核糖核酸酶作用的靶标。用核糖核酸酶从原头部去除RNA使其失去DNA包装活性。通过RNA-DNA杂交分析表明，该RNA源自基因组左端非常近的病毒DNA片段，该末端在体外组装过程中首先被包装。
