MicroRNA与信使RNA多重相互作用的单分子表征

MicroRNA是能够与mRNA结合从而调控基因表达的一类生物分子，在癌症等疾病的诊断与治疗方面具有重要应用前景。目前其研究中遇到的一个瓶颈问题是如何表征MicroRNA与mRNA的多重相互作用。两者相互作用的动力学过程以及这些作用的胞内空间分布均不明确，极大阻碍了其基因调控功能的澄清与优化。本项目拟以miR-17和let-7两组家族作为模型体系，利用光谱解析和扩散速率解析的单分子成像技术，研究多个MicroRNA与mRNA互作的动力学特征并绘制纳米尺度上的胞内空间分布图；建立这些特征的序列结构基础，并进一步对MicroRNA序列和结构加以改进，以期优化其基因调控的高效性和特异性。本项目的成功实施将有助于在单分子层面上丰富人们对MicroRNA与mRNA多重互作的新认识，明确其动力学特征与胞内空间分布的结构基础，有望进一步推动MicroRNA在癌症的诊断与治疗的深入应用。

MicroRNAs are small non-coding RNA molecules, which can pair with some human messenger RNA (mRNA) to induce gene silencing. As a result, emerging miRNA species have been recognized as the biomarkers and targets for cancer therapy. Despite of its importance, the characterization of multiplex interactions between MicroRNAs and mRNAs still remains to be a challenged task. While it is known that multiple MicroRNAs can bind with one mRNA simultaneously, the cooperative effects between multiple MicroRNA species and their dependence on the heterogeneous intracellular environments still await further clarifications. Such a vacancy in our knowledge prohibits the design of MicroRNA for gene silencing with a high efficiency and specificity. Here we propose a single-molecule level characterization of the multiplex interactions and their spatial distribution in intracellular environments for miR-17 and let-7 MicroRNA families, by using our newly-developed spectrally-resolved and diffusivity-mapping single-molecule localization microscopy. We will first examine the dynamic characteristics and spatial distribution of MicroRNAs with different sequences, to establish the relationship between the structures and the functions of gene silencing of MicroRNAs. Next, we will engineer the sequences and structures of MicroRNAs, to improve the efficiency and specificity of gene silencing. Through these works, we aim to clarify the dynamic characteristics and intracellular spatial distribution of the multiplex MicroRNA-mRNA interactions, and their importance to their functions of gene silencing. We anticipate that our works will further shed light on various applications such as the cancer therapy based on MicroRNAs.