Extremely High Mutation Rate of a Hammerhead Viroid
Extremely High Mutation Rate of a Hammerhead Viroid
复制标题
DOI：
10.1126/science.1169202
复制
发表时间：
2009-03-06
期刊：
影响因子：
56.9
通讯作者：
Sanjuan, Rafael
中科院分区：
文献类型：
--
作者：
Gago, Selma;Elena, Santiago F.;Sanjuan, Rafael
类病毒是具有最少非蛋白质编码RNA基因组的植物病原体，其突变率尚不清楚。它们的复制由宿主RNA聚合酶介导，在某些情况下，由锤头状核酶介导，锤头状核酶是嵌入类病毒中的小的自切割基序。利用无活力基因型的群体频率等于突变率的原则，我们筛选了使菊花褪绿斑驳类病毒锤头状结构失活的变化。我们获得了每个位点1/400的突变率，这是任何生物实体的最高报告。这种容易出错的复制只能被极其简单的基因组所容忍，例如类病毒的基因组，据推测，RNA世界的原始复制子。我们的研究结果表明，复制保真度的出现对于生命早期复杂性的进化至关重要。
The mutation rates of viroids, plant pathogens with minimal non-protein-coding RNA genomes, are unknown. Their replication is mediated by host RNA polymerases and, in some cases, by hammerhead ribozymes, small self-cleaving motifs embedded in the viroid. By using the principle that the population frequency of nonviable genotypes equals the mutation rate, we screened for changes that inactivated the hammerheads ofChrysanthemum chlorotic mottle viroid. We obtained a mutation rate of 1/400 per site, the highest reported for any biological entity. Such error-prone replication can only be tolerated by extremely simple genomes such as those of viroids and, presumably, the primitive replicons of the RNA world. Our results suggest that the emergence of replication fidelity was critical for the evolution of complexity in the early history of life.