Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea.
Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea.
Mol Cell. 2021 Aug 19;81(16):3422-3439.e11. doi: 10.1016/j.molcel.2021.07.002. Epub 2021 Jul 27.
Maturation of canonical microRNA (miRNA) is initiated by DROSHA that cleaves the primary transcript (pri-miRNA). More than 1,800 miRNA loci are annotated in humans, but it remains largely unknown whether and at which sites pri-miRNAs are cleaved by DROSHA. Here, we performed in vitro processing on a full set of human pri-miRNAs (miRBase version 21) followed by sequencing. This comprehensive profiling enabled us to classify miRNAs on the basis of DROSHA dependence and map their cleavage sites with respective processing efficiency measures. Only 758 pri-miRNAs are confidently processed by DROSHA, while the majority may be non-canonical or false entries. Analyses of the DROSHA-dependent pri-miRNAs show key cis-elements for processing. We observe widespread alternative processing and unproductive cleavage events such as "nick" or "inverse" processing. SRSF3 is a broad-acting auxiliary factor modulating alternative processing and suppressing unproductive processing. The profiling data and methods developed in this study will allow systematic analyses of miRNA regulation.
经典 microRNA (miRNA) 的成熟是由 DROSHA 起始的，它可以切割初级转录物 (pri-miRNA)。人类中注释了超过 1800 个 miRNA 基因座，但 DROSHA 是否以及在哪些位点切割 pri-miRNA 仍然很大程度上未知。在这里，我们对一整套人类 pri-miRNAs（miRBase 版本 21）进行了体外处理，然后进行测序。这种全面的分析使我们能够根据 DROSHA 的依赖性对 miRNA 进行分类，并绘制它们的切割位点及其相应的加工效率测量值。只有 758 个 pri-miRNA 可以被 DROSHA 可靠地加工，而大多数可能是非经典或错误的条目。对依赖 DROSHA 的 pri-miRNAs 的分析表明了加工的关键顺式元件。我们观察到广泛的替代加工和非生产性切割事件，如“切口”或“反向”加工。SRSF3 是一种广泛作用的辅助因子，可调节替代加工并抑制非生产性加工。本研究中开发的分析数据和方法将允许对 miRNA 调控进行系统分析。
