State Key Laboratory of Virology and Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Department of Cellular and Molecular Medicine, Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093-0651, USA.
Nucleic Acids Res. 2017 Dec 1;45(21):12481-12495. doi: 10.1093/nar/gkx912.
The Ewing Sarcoma protein (EWS) is a multifaceted RNA binding protein (RBP) with established roles in transcription, pre-mRNA processing and DNA damage response. By generating high quality EWS-RNA interactome, we uncovered its specific and prevalent interaction with a large subset of primary microRNAs (pri-miRNAs) in mammalian cells. Knockdown of EWS reduced, whereas overexpression enhanced, the expression of its target miRNAs. Biochemical analysis revealed that multiple elements in target pri-miRNAs, including the sequences flanking the stem-loop region, contributed to high affinity EWS binding and sequence swap experiments between target and non-target demonstrated that the flanking sequences provided the specificity for enhanced pri-miRNA processing by the Microprocessor Drosha/DGCR8. Interestingly, while repressing Drosha expression, as reported earlier, we found that EWS was able to enhance the recruitment of Drosha to chromatin. Together, these findings suggest that EWS may positively and negatively regulate miRNA biogenesis via distinct mechanisms, thus providing a new foundation to understand the function of EWS in development and disease.
尤文肉瘤相关转录因子（EWS）是一种多功能 RNA 结合蛋白（RBP），在转录、前体 mRNA 加工和 DNA 损伤反应中具有明确的作用。通过生成高质量的 EWS-RNA 互作组，我们揭示了它在哺乳动物细胞中与一大类初级 microRNAs（pri-miRNAs）的特异性和普遍相互作用。EWS 的敲低降低了其靶 miRNA 的表达，而过表达则增强了其靶 miRNA 的表达。生化分析表明，靶 pri-miRNA 中的多个元件，包括茎环区域侧翼的序列，有助于 EWS 结合的高亲和力，并且靶和非靶之间的序列交换实验表明侧翼序列提供了由 Microprocessor Drosha/DGCR8 增强的 pri-miRNA 加工的特异性。有趣的是，虽然先前有报道称 EWS 可以抑制 Drosha 的表达，但我们发现 EWS 能够增强 Drosha 向染色质的募集。总之，这些发现表明 EWS 可能通过不同的机制正向和负向调节 miRNA 的生物发生，从而为理解 EWS 在发育和疾病中的功能提供了新的基础。
