Linc-CEBPG与KSRP的相互作用对单核细胞分化的调控作用及机理研究

Long non-coding RNA (lncRNA) is the essential component of non-coding RNA family, which has been implicated in various cellular processes. However, the underlining mechanisms, especially their involvement in hematopoiesis and leukemogenesis are largely unknown. In this work, we select potential lncRNAs to study based on their genomic location and identify a candidate flanking the master monocytic transcription factor CEBPA, named linc-CEBPG. We have found that linc-CEBPG down-regulates the expression of CEBPA through binding with RNA binding protein KSRP and inhibits monocytic differentiation. We will further assess their regulatory roles in monocytic differentiation and confirm the interaction between linc-CEBPG and KSRP, and evaluate their cooperativity in regulating monocytic differentiation. Given the cis-acting of lncRNA on its adjacent genomic locus, we aim to illustrate the effect of linc-CEBPG/KSRP interaction on CEBPA expression, and clarify the molecular mechanism of the regulation. In addition, we will further study the involvement of linc-CEBPG and KSRP in leukemogenesis. These results will provide new insights into lncRNA study and strengthen our understanding of ncRNA:protein interacting model.

长链非编码RNA(lncRNA)是ncRNA家族的重要成员，当前研究所发现的lncRNA复杂而重要的生物学功能为研究者展现了一个新的调控领域。相对于lncRNA的大量发现和鉴定，其功能和机制仍有待进一步阐明，尤其是造血系统中lncRNA的研究仍处于起步阶段。本课题从定位于造血单核系分化重要转录因子CEBPA基因座旁侧的lncRNA：linc-CEBPG入手，在发现其与RNA结合蛋白KSRP结合并负调控CEBPA表达，进而抑制单核系分化的基础上，进一步明确linc-CEBPG和KSRP的生物学功能；确定两者相互作用参与调控单核系分化的机制；研究两者与CEBPA的内在联系及调控CEBPA表达的详细分子机制；并在单核系白血病病例中研究linc-CEBPG和KSRP的作用机理和诊疗价值。以上结果将进一步完善lncRNA的调控模式和作用机理，并为ncRNA:蛋白双色调控理论提供新的证据。

RNA结合蛋白是真核生物重要的转录后调节因子，其通过与多种RNA结合发挥调控作用。我们发现在造血粒系和单核系发育过程中也存在RNA结合蛋白介导的miRNA转录后加工调节现象，并以miR-129-1最为典型。RNA结合的蛋白KSRP，通过与pri-miR-129-1上三个功能性RNA元件的识别和结合，增强了Drosha/DGCR8复合物的募集，介导了该调控作用，影响了成熟miR-129的产生。而有趣的是，KSRP、pri-miR-129-1和miR-129-1在粒系和单核系分化过程中的表达趋势完全相反，KSRP和miR-129-1的功能表现为促进粒系发育，抑制单核系发育。进一步研究发现，成熟的miR-129可通过靶向抑制髓系发育重要转录因子RUNX1的表达，在粒系和单核系分化过程中发挥不同调控作用。因此，我们发现了一个KSRP-miR-129-RUNX1的调控轴，在不同的造血谱系发育中产生不同的生理效应。