miR-503 represses CUG-binding protein 1 translation by recruiting CUGBP1 mRNA to processing bodies.
miR-503 represses CUG-binding protein 1 translation by recruiting CUGBP1 mRNA to processing bodies.
复制标题
DOI：
10.1091/mbc.e11-05-0456
复制
发表时间：
2012-01
影响因子：
3.3
通讯作者：
Wang JY
中科院分区：
文献类型：
--
作者：
Cui YH;Xiao L;Rao JN;Zou T;Liu L;Chen Y;Turner DJ;Gorospe M;Wang JY
本研究表明，microRNA-503与CUG结合蛋白1(CUGBP1)mRNA相互作用，并通过将CUGBP1 mRNA招募到加工体来抑制其翻译。MicroRNAs(MiRNAs)和RNA结合蛋白(RBPs)在转录后水平共同调节基因表达，参与细胞功能的许多方面。RBP CUG结合蛋白1(CUGBP1)破坏并抑制了几个靶mRNAs的翻译，但调节CUGBP1丰度的确切机制仍不清楚。在这篇文章中，我们证明了miR-503，计算预测与CUGBP1基因的三个位点相关，抑制了CUGBP1的表达。MiR-503前体(Pre-miR-503)过表达降低了CUGBP1蛋白的从头合成，而使用反义RNA(Antagomir)抑制miR-503则促进了CUGBP1的生物合成并增加了其丰度；这两种干预都没有改变CUGBP1的总mRNA水平。使用异源报告构建物的研究表明，miR-503通过CUGBP1编码区位点的抑制作用强于通过单个CUGBP1 3‘-非翻译区靶点的抑制作用。而沉默P小体驻留蛋白Ago2、RCK或LSm4则降低miR-503介导的对CUGBP1表达的抑制。降低细胞内多胺水平可降低内源性miR-503水平，促进CUGBP1的表达，这种作用可被异位miR-503过表达所阻止。MiR-503抑制CUGBP1基因的表达，进而改变CUGBP1靶基因的表达，从而增加肠上皮细胞对细胞凋亡的敏感性。这些发现确认miR-503既是CUGBP1表达的新调节因子，也是肠上皮稳态的调节器。
This study shows that microRNA-503 interacts with the CUG-binding protein 1 (CUGBP1) mRNA and represses its translation by recruiting the CUGBP1 mRNA to processing bodies. microRNAs (miRNAs) and RNA-binding proteins (RBPs) jointly regulate gene expression at the posttranscriptional level and are involved in many aspects of cellular functions. The RBP CUG-binding protein 1 (CUGBP1) destabilizes and represses the translation of several target mRNAs, but the exact mechanism that regulates CUGBP1 abundance remains elusive. In this paper, we show that miR-503, computationally predicted to associate with three sites of the CUGBP1 mRNA, represses CUGBP1 expression. Overexpression of an miR-503 precursor (pre-miR-503) reduced the de novo synthesis of CUGBP1 protein, whereas inhibiting miR-503 by using an antisense RNA (antagomir) enhanced CUGBP1 biosynthesis and elevated its abundance; neither intervention changed total CUGBP1 mRNA levels. Studies using heterologous reporter constructs revealed a greater repressive effect of miR-503 through the CUGBP1 coding region sites than through the single CUGBP1 3′-untranslated region target site. CUGBP1 mRNA levels in processing bodies (P-bodies) increased in cells transfected with pre-miR-503, while silencing P-body resident proteins Ago2, RCK, or LSm4 decreased miR-503–mediated repression of CUGBP1 expression. Decreasing the levels of cellular polyamines reduced endogenous miR-503 levels and promoted CUGBP1 expression, an effect that was prevented by ectopic miR-503 overexpression. Repression of CUGBP1 by miR-503 in turn altered the expression of CUGBP1 target mRNAs and thus increased the sensitivity of intestinal epithelial cells to apoptosis. These findings identify miR-503 as both a novel regulator of CUGBP1 expression and a modulator of intestinal epithelial homoeostasis.