Sequential action of six virus-encoded DNA-packaging RNAs during phage phi 29 genomic DNA translocation
Sequential action of six virus-encoded DNA-packaging RNAs during phage phi 29 genomic DNA translocation
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DOI：
10.1128/jvi.71.5.3864-3871.1997
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发表时间：
1997-05-01
影响因子：
5.4
通讯作者：
Guo, PX
中科院分区：
文献类型：
--
作者：
Chen, CP;Guo, PX
噬菌体phi29编码的120个碱基的pRNA在基因组DNA包装中具有重要的作用。在DNA转运过程中，有6个DNA包装RNA（pRNA）与原衣壳的六重对称门顶结合，并在DNA包装反应完成后离开原衣壳，表明pRNA参与了基因组DNA向原衣壳的转运。为了进一步研究DNA包装的机制，关键是确定这六个pRNA分子是作为一个整合的实体工作还是每个pRNA作为一个功能性个体工作，如果pRNA单独工作，那么它们是以有通信的顺序工作还是以没有相互作用的随机顺序工作？补偿和互补分析的结果不支持整合模型，野生型和突变型pRNA之间结合概率的计算和竞争性抑制的实验数据排除了随机模型，而支持六种pRNA顺序作用的建议，pRNA的顺序作用也解释了为什么pRNA对突变如此敏感，因为pRNA突变的效果在六个连续步骤后将被放大6个数量级，导致观察到的由小的改变引起的DNA包装活性的完全丧失。当六种pRNA中的任何一种被无活性的pRNA取代时，DNA包装的完全阻断导致，强烈支持推测，即各个pRNA，可能与其他组分如包装ATP酶gp16一起，轮流介导包装的连续步骤，尽管这里提供的数据不能完全排除整合模型，到目前为止，还没有证据可以反驳这种连续行动模式。
A 120-base pRNA encoded by bacteriophage phi 29 has a novel and essential role in genomic DNA packaging, Six DNA-packaging RNAs (pRNAs) were bound to the sixfold symmetrical portal vertex of procapsids during the DNA translocation process and left the procapsid after the DNA-packaging reaction was completed, suggesting that the pRNA participated in the translocation of genomic DNA into procapsids. To further investigate the mechanism of DNA packaging, it is crucial to determine whether these six pRNA molecules work as an integrated entity or each pRNA acts as a functional individual, If pRNAs work individually, then do they work in sequence with communication or in random order without interaction? Results from compensation and complementation analysis did not support the integrated model, Computation of the probability of combination between wild-type and mutant pRNAs and experimental data of competitive inhibition excluded the random model while favoring the proposal that the six pRNAs functioned sequentially, Sequential action of the pRNA also explains why the pRNA is so sensitive to mutation, since the effect of a pRNA mutation will be amplified by 6 orders of magnitude after six consecutive steps, resulting in the observed complete loss of DNA-packaging activity caused by small alterations. When any one of the six pRNAs was replaced with an inactive one, complete blockage of DNA packaging resulted, strongly supporting the speculation that individual pRNAs, presumably together with other components such as the packaging ATPase gp16, take turns mediating successive steps of packaging, Although the data provided here could not exclude the integrated model completely, there is no evidence so far to argue against the model of sequential action.