Zovoilis Athanasios, Smorag Lukasz, Pantazi Angeliki, Engel Wolfgang
Institute of Human Genetics, University of Goettingen, Heinrich-Dueker-Weg 12, D-37073 Goettingen, Germany.
Differentiation. 2009 Sep-Oct;78(2-3):69-78. doi: 10.1016/j.diff.2009.06.003. Epub 2009 Jul 22.
We report the biological effects of miR-290 cluster via gain-of-function or loss-of-function experiments in mouse embryonic stem cells (ESCs) cultured under differentiation conditions. Under these conditions we found that overexpression of miR-290 cluster in ESCs cannot prevent downregulation of Oct-4, but inhibition results in earlier downregulation of Oct-4 compared with the negative control. In consistence with previous findings that report ectopic expression of Brachyury during gastrulation in Argonaute-2 KO mice due to impaired miRNA function, we show that miR-290 cluster regulates negatively differentiation of ESCs towards mesodermal and germ cell lineage. These results suggest that although incapable to maintain pluripotent state alone, miR-290 cluster inhibits ESC differentiation and it is involved in the pathways controlling mesoderm and primordial germ cell differentiation. Finally, we provide proofs that members of this cluster target Dkk-1 gene, a Wnt pathway inhibitor, and affect this pathway, which can partially explain why miR-290 cluster favours pluripotency against differentiation.
我们通过在分化条件下培养的小鼠胚胎干细胞（ESC）中进行功能获得或功能丧失实验，报告了miR - 290簇的生物学效应。在这些条件下，我们发现ESC中miR - 290簇的过表达不能阻止Oct - 4的下调，但与阴性对照相比，抑制会导致Oct - 4更早下调。与之前的研究结果一致，即由于miRNA功能受损，在原肠胚形成期间Argonaute - 2基因敲除小鼠中异位表达Brachyury，我们表明miR - 290簇负向调节ESC向中胚层和生殖细胞谱系的分化。这些结果表明，尽管miR - 290簇不能单独维持多能状态，但它抑制ESC分化，并参与控制中胚层和原始生殖细胞分化的途径。最后，我们提供证据表明该簇的成员靶向Dkk - 1基因（一种Wnt途径抑制剂）并影响该途径，这可以部分解释为什么miR - 290簇有利于多能性而不利于分化。
