中文摘要：

小檗碱（BBR）是一种天然小分子药物，具有多种药理活性，作用于多个靶点。我们在之前的研究中发现，小檗碱具有稳定mRNA、避免其降解的活性，并初步证实这与它和mRNA 3’端polyA尾部的结合有关，然而其具体机制尚不清楚。本文首次报道了相关的机制研究。研究结果表明，小檗碱结合于poly A、避免mRNA降解的这一过程需要PABP（poly A结合蛋白）参与。利用RNA—EMSA（RNA凝胶电泳迁移）、RIP（RNA免疫共沉淀）和荧光光谱等多项技术证明了小檗碱能够促进PABP与poly A的结合，从而增强mRNA的稳定性。此外利用二维核磁共振技术揭示BBR与AMP结合的特异性。本文结论是小檗碱促进蛋白表达的机制与其作用于poly A、稳定mRNA，从而促进蛋白翻译、上调蛋白表达相关。

英文摘要：

Berberine （BBR） is a natural small molecule with various pharmacological activities and biological targets. BBR has been shown to inhibit mRNA decay in our previous studies, which is associated with its high binding affinity to the poly-adenine （poly A） tail at the 3＇ end of mRNA. However, the exact mechanism remains unknown. In this research, we discovered that deficiency of cytoplasmic poly A binding protein （PABP）, which protects mRNA from nucleolytic attack as a poly A-PABP complex, led to the loss of BBR＇s effect on mRNA decay inhibition. We also demonstrated using fluorescence spectroscopy, RNA-EMSA （RNA-electrophoretic mobility shift assay） in vitro, and RIP （RNA immunoprecipitation） that BBR could significantly promote PABP binding to poly A. We might conclude that BBR could stabilize mRNA by enhancing the interaction between poly A and PABP. In addition, the HMBC （~H detected heteronuclear multiple bond correlation） studies demonstrated that BBR could bind to AMP, a monomer of poly A, directly and specifically. Further evidence of molecular docking suggested that BBR might act as a linker to stabilize the poly A-PABP, and elongate the half-life of mRNAs. This demonstrates that BBR might affect protein translation initiation and up-regulate protein expression.