特定lincRNA在体细胞重编程中的功能与机制

The latest study found that large intergenic non-coding RNA (lincRNAs) play crucial roles in pluripotent maintenance of stem cells. However, the functions and mechanisms of lincRNAs in iPS cells generation are not yet clear. Our preliminary study found three lincRNAs in stem cells had significantly higher expression level than that of mouse embryonic fibroblast (MEF) cells, knock-down of specific lincRNA significantly repressed the efficiency of somatic cell reprogramming, and that these lincRNAs can simultaneously bind transcription factor Sox2 and the important component EZH2 of PRC2 complexes. On this basis, with luciferase reptorter gene, RIP and ChIP assays, the project will identify the exact functions and mechanisms of specific lincRNA in the specifically regulating roles of EZH2 for gene expression by binding to different transcription factors, investigate the regulatory roles and mechanisms invovled in regulating specific lincRNA by transcription factors critically in stem cell pluripotency, and finally elucidate the important functions and mechanisms of particular lincRNA in the specifically regulating roles of critical transcription factors and PRC2 complex compotents in somatic cell reprogramming. The completion of this project, will provide important evidences for further clarifying the specific functions and upstream/downstream regulatory mechanisms of lincRNAs in somatic cell reprogramming process.

最新研究发现，基因间长链非编码RNA(lincRNAs)在干细胞多能性维持中具有极其关键的作用。但是，lincRNAs在体细胞重编程中的功能和调控机制尚不明确。我们研究发现3个lincRNAs在干细胞中的表达显著高于MEF细胞，kncok-down特定lincRNA可以显著抑制体细胞重编程效率，同时发现这些lincRNA可与转录因子Sox2和PRC2复合物重要组分EZH2结合。在此基础上，本项目将通过荧光素酶报告基因、RIP和ChIP等技术，确定特定lincRNA在EZH2结合不同转录因子而特异性调控下游基因表达中的功能和机制，揭示干细胞多能性关键转录因子对特定lincRNA的调控作用和机制，最终阐明特定lincRNA在体细胞重编程关键转录因子与PRC2复合物特异性调控作用中的重要功能及机制。本项目的完成，将为进一步研究体细胞重编程中lincRNAs的具体功能和上下游调控机制提供重要依据。

体细胞重编程能有效解决干细胞治疗应用中的免疫排斥和伦理学问题等，研究发现长链非编码RNA(lncRNAs)在干细胞多能性维持中具有关键作用,但其在体细胞重编程中的功能和调控机制尚不明确。项目立项以来,在发现特定lncRNAs对干细胞多能性获得和维持具有重要作用的基础上，我们深入研究了关键lncRNAs等表观遗传调节分子在体细胞重编程和干细胞多能性维持及分化中的功能, 确定了特定lncRNAs可能调控的miRNAs、转录因子及其相互调控关系，同时解析了DNA甲基化与组蛋白修饰在体细胞重编程中的协同作用和调控机制。项目实施取得了突出的成果，圆满完成了研究任务和目标，在国外重要杂志发表标注本项目基金号的学术论文19篇，培养研究生6名。具体成果如下：1）揭示了linc1614联合转录因子精确调控体细胞重编程基因转录的重要机制；2）揭示了lncRNA-1604通过miR-200c/ZEB信号轴调控干细胞多能性和神经分化的ceRNA机制；3）发现Sirt6可提高年老供体来源细胞重编程的基因组稳定性；4）揭示了HDAC2-TET1转换在体细胞重编程成熟中的重要功能及特定基因区域组蛋白乙酰化和DNA甲基化间相互作用的新机制；5）揭示了DNA甲基化与组蛋白修饰在体细胞重编程中的协同作用；6) 发现linc1557对干细胞多能性维持和早期分化具有重要的调控作用。