miR-34a is essential for p19Arf-driven cell cycle arrest
miR-34a is essential for p19Arf-driven cell cycle arrest
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DOI：
10.4161/cc.27725
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发表时间：
2014-03-01
期刊：
影响因子：
4.3
通讯作者：
Skapek, Stephen X.
中科院分区：
文献类型：
--
作者：
Iqbal, Nida;Mei, Jie;Skapek, Stephen X.
Arf肿瘤抑制基因产物p19（Arf）调节早期癌细胞和胚胎发育期间的细胞增殖。除了普遍接受的p53依赖性作用外，p19（Arf）在这两种情况下也独立于p53发挥作用。一种这样的具有体内相关性的p53非依赖性作用包括其对Pdgfr β的抑制，这是小鼠视觉所必需的过程。我们利用基于细胞培养的模型和小鼠模型来定义miR-34 a在这一过程中的新作用。Arf在培养细胞中的异位表达增强了预测靶向Pdgfr ss合成的几种microRNA的表达，包括miR-34家族。由于miR-34 a被认为是p53依赖性效应子，我们研究了它是否也有助于p19（Arf）的p53非依赖性效应。事实上，在缺乏p53的小鼠胚胎成纤维细胞（MEF）中，Arf驱动的Pdgfr β抑制及其对Pdgf-B刺激的DNA合成的阻断都被针对miR-34 a的抗microRNA完全中断。异位miR-34 a直接靶向Pdgfr β和含有野生型Pdgfr β 3 ' UTR序列的质粒报告基因，但不靶向突变miR-34 a靶序列的质粒报告基因。尽管miR-34 a表达与p53-p19（Arf）-Arf表达的众所周知的效应子相关，但其敲低与缺乏p53的MEFs中的miR-34 a水平相关。最后，对小鼠胚胎眼的分析表明，在正常小鼠发育过程中，Arf控制了体内miR-34 a以及相关miR-34 b和c的表达。我们的研究结果表明，miR-34 a提供了p19（Arf）和其p53非依赖性能力之间的重要联系，以阻断由Pdgfr β驱动的细胞增殖。这对Arf的发育和肿瘤抑制作用有影响。
The Arf tumor suppressor gene product, p19(Arf), regulates cell proliferation in incipient cancer cells and during embryo development. Beyond its commonly accepted p53-dependent actions, p19(Arf) also acts independently of p53 in both contexts. One such p53-independent effect with in vivo relevance includes its repression of Pdgfr beta, a process that is essential for vision in the mouse. We have utilized cell culture-based and mouse models to define a new role for miR-34a in this process. Ectopic expression of Arf in cultured cells enhanced the expression of several microRNAs predicted to target Pdgfr ss synthesis, including the miR-34 family. Because miR-34a has been implicated as a p53-dependent effector, we investigated whether it also contributed to p53-independent effects of p19(Arf). Indeed, in mouse embryo fibroblasts (MEFs) lacking p53, Arf-driven repression of Pdgfr beta and its blockade of Pdgf-B stimulated DNA synthesis were both completely interrupted by anti-microRNA against miR-34a. Ectopic miR-34a directly targeted Pdgfr beta and a plasmid reporter containing wild-type Pdgfr beta 3 ' UTR sequence, but not one in which the miR-34a target sequence was mutated. Although miR-34a expression has been linked to p53-a well-known effector of p19(Arf)-Arf expression and its knockdown correlated with miR-34a level in MEFs lacking p53. Finally, analysis of the mouse embryonic eye demonstrated that Arf controlled expression of miR-34a, and the related miR-34b and c, in vivo during normal mouse development. Our findings indicate that miR-34a provides an essential link between p19(Arf) and its p53-independent capacity to block cell proliferation driven by Pdgfr beta. This has ramifications for developmental and tumor suppressor roles of Arf.