MicroRNAs (miRNAs) are a class of endogenous small RNAs that regulate target gene expression at the post-transcriptional level. miRNAs play an important role in almost all physiological activities including the processes of embryonic stem cell (ESC) pluripotency maintenance and differentiation, as well as induced pluripotent stem cell (iPSC) reprogramming. In this study, we identified eight novel miRNAs by mining the deep sequencing dataset from mouse ESCs and three kinds of reprogrammed pluripotent cells. Most of them are conserved at least in Murinae animals. Seven of them are derived from gene introns. We further showed that miR-novel-41 is a mirtron that derives from the intron of Man2c1, a protein-coding gene. Mirtrons are a kind of special non-canonical miRNAs encoded in introns. Their precursors are not processed by Drosha but generated by intron splicing. Intron splicing is required for the maturation of mirtrons and allows pre-miRNA-like hairpins to form [1]. Both ends of the precursor of a canonical mirtron are precisely generated by the splicing reaction. Some spliced pre-miRNA-like hairpins have a single-stranded tail on either the 5′ or 3′ end, named as 5′- or 3′-tailed mirtrons, which will be digested by exonuclease to leave a pre-miRNA for Dicer processing [2,3]. The potential functions of these novel miRNAs were also preliminarily explored by target genes prediction.

中文翻译：

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在小鼠胚胎干细胞和重编程的多能细胞中鉴定新型miRNA。

MicroRNA（miRNA）是一类内源性小RNA，它们在转录后水平上调控靶基因的表达。miRNA在几乎所有生理活动中都起着重要作用，包括胚胎干细胞（ESC）多能性维持和分化过程以及诱导性多能干细胞（iPSC）重编程。在这项研究中，我们通过从小鼠ESC和三种重新编程的多潜能细胞中提取深度测序数据集，鉴定出八种新颖的miRNA。他们中的大多数至少在穆里纳（Muriinae）受保存动物。它们中的七个来自基因内含子。我们进一步显示，miR-novel-41是一个mirtron，它是来自蛋白质编码基因Man2c1的内含子。Mirtrons是内含子中编码的一种特殊的非规范性miRNA。它们的前体不是由Drosha处理的，而是由内含子剪接产生的。mirtron的成熟需要内含子剪接，并可以形成类似miRNA的前发夹[1]。规范反应的前驱体的两端是通过剪接反应精确生成的。一些剪接的pre-miRNA样发夹在5'或3'末端有一条单链尾巴，称为5'或3'尾mirtrons，它们将被核酸外切酶消化，从而留下Dicer的pre-miRNA。处理[2,3]。这些新的miRNA的潜在功能还通过靶基因预测进行了初步探索。