Transcription is a fundamental process that mediates the interplay between genetic information and phenotype. Emerging evidence indicates that RNA polymerase II (Pol II) can catalyze transcription using both DNA and RNA templates. It is well established that Pol II initiates de novo transcription on DNA templates. However, it is unclear whether Pol II performs de novo transcription or relies on primers for initiation (primed transcription) on RNA templates. Using potato spindle tuber viroid (PSTVd) as a model, we presented evidence showing that circular PSTVd templates are critical for the synthesis of longer-than-unit-length (-)-strand products, which supports the de novo transcription based on the asymmetric rolling circle model of PSTVd replication. We further showed that the crucial factor for primed transcription, transcription factor IIS (TFIIS), is dispensable for PSTVd replication in cells. Together, our data support the de novo transcription on PSTVd RNA templates catalyzed by Pol II. This result has significant implications in understanding the mechanism and machinery underlying Pol II-catalyzed transcription using other RNA templates.

中文翻译：

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支持使用马铃薯纺锤块茎类病毒环状RNA模板催化RNA聚合酶II催化从头转录的证据。

转录是介导遗传信息和表型之间相互作用的基本过程。新兴证据表明，RNA聚合酶II（Pol II）可以同时使用DNA和RNA模板来催化转录。众所周知，Pol II可在DNA模板上启动从头转录。然而，尚不清楚Pol II是否进行从头转录或依赖于引物来启动RNA模板（引物转录）。使用马铃薯纺锤块茎类病毒（PSTVd）作为模型，我们提供的证据表明，圆形PSTVd模板对于合成长于单位长度（-）链的产物至关重要，该产物支持基于不对称序列的从头转录PSTVd复制的滚动圆模型。我们进一步表明引发转录的关键因素是 转录因子IIS（TFIIS）对于细胞中PSTVd复制是必不可少的。总之，我们的数据支持Pol II催化的PSTVd RNA模板的从头转录。该结果对于理解使用其他RNA模板的Pol II催化转录的机制和机制具有重要意义。