Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation.
PLoS One. 2012;7(12):e52527. doi: 10.1371/journal.pone.0052527. Epub 2012 Dec 20.
YB-1 is a eukaryotic protein with numerous intra- and extracellular functions based on its ability to interact with RNA, DNA, and many proteins. In spite of achievements in studying its functions, regulation of YB-1 synthesis in the cell remains poorly understood. In the current study Western and Northern blotting were used to determine the amounts of YB-1 and YB-1 mRNA in rabbit organs and several cell lines. As found, in the majority of studied eukaryotic cells a considerable proportion of YB-1 mRNA was stored in free mRNPs, i.e., was poorly translated. Also, we demonstrated that YB-1 synthesis depended on conditions that determined the rate of cell division. Specific suppression of YB-1 synthesis resulted from inhibition of the mTOR signaling pathway with inhibitor PP242, but not rapamycin. Experiments on reporter constructs showed that dependence of YB-1 mRNA translation on activity of the mTOR signaling pathway was dictated by 5' untranslated regions of this mRNA, irrelatively of the TOP-like sequences at the beginning of 5' UTR.
YB-1 是一种真核蛋白，具有与 RNA、DNA 和许多蛋白质相互作用的多种细胞内和细胞外功能。尽管在研究其功能方面取得了成就，但细胞中 YB-1 合成的调节仍知之甚少。在本研究中，使用 Western 和 Northern 印迹法来确定兔器官和几种细胞系中 YB-1 和 YB-1 mRNA 的含量。结果发现，在大多数研究的真核细胞中，相当一部分 YB-1 mRNA 储存在游离的 mRNPs 中，即翻译效率较低。此外，我们还证明 YB-1 的合成取决于决定细胞分裂速度的条件。使用抑制剂 PP242 特异性抑制 mTOR 信号通路会导致 YB-1 合成的抑制，但雷帕霉素不会。报告基因构建体实验表明，YB-1 mRNA 翻译对 mTOR 信号通路活性的依赖性是由该 mRNA 的 5'UTR 决定的，而与 5'UTR 起始处的 TOP 样序列无关。
