ABSTRACT

The pluripotency of embryonic stem cells (ESCs) is controlled by a multilayer regulatory network, of which the key factors include core pluripotency genes Oct4, Sox2 and Nanog, and multiple microRNAs (miRNAs). Recently, long noncoding RNAs (lncRNAs) have been discovered as a class of new regulators for ESCs, and some lncRNAs could function as competing endogenous RNAs (ceRNAs) to regulate mRNAs by competitively binding to miRNAs. Here, we identify mmu-miR-139-5p as a new regulator for Nanog by targeting Nanog 3′ untranslated region (UTR) to repress Nanog expression in mouse ESCs and embryos. Such regulation could be released by an ESC-specifically expressed ceRNA named lnc-NAP. The expression of lnc-NAP is activated by OCT4, SOX2, as well as NANOG through promoter binding. Downregulation of lnc-NAP reduces Nanog abundance, which leads to decreased pluripotency of mouse ESCs and embryonic lethality. These results reveal lnc-NAP as a new regulator for Nanog in mouse ESCs, and uncover a feed-forward regulatory loop of Nanog through the participation of lnc-NAP.

 抽象的

胚胎干细胞（ESC）的多能性由多层调控网络控制，其中关键因素包括核心多能性基因Oct4、Sox2和Nanog ，以及多种微小RNA（miRNA）。最近，长非编码RNA（lncRNA）被发现是一类新的ESC调控因子，并且一些lncRNA可以作为竞争性内源RNA（ceRNA）通过竞争性结合miRNA来调节mRNA。在这里，我们通过靶向Nanog 3'非翻译区（UTR）来抑制小鼠 ESC 和胚胎中Nanog 的表达，从而将 mmu-miR-139-5p 确定为Nanog的新调节因子。这种调节可以由 ESC 特异性表达的 ceRNA（名为lnc-NAP）来释放。 lnc-NAP的表达由 OCT4、SOX2 以及 NANOG 通过启动子结合激活。 lnc-NAP的下调会降低Nanog丰度，从而导致小鼠 ESC 的多能性和胚胎致死率降低。这些结果揭示了lnc-NAP作为小鼠ESC中Nanog的新调节剂，并通过lnc-NAP的参与揭示了Nanog的前馈调节环。