无义介导的mRNA降解途径（NMD）是真核细胞中mRNA质量和数量监控机制之一。与mRNA成熟加工和蛋白质翻译过程相偶联，机制复杂。申请者前期研究发现importin β1分别与UPF1（NMD核心因子）以及MARVELD1（NMD潜在的负调控因子）相互作用，而且importin β1表达沉默导致NMD通路活性显著降低，推测importin β1可能是NMD机制的潜在调控因子。为证实该假说，本课题拟利用NMD经典报告质粒系统、转录组学分析、蛋白质相互作用分析、RNA-FISH等技术，深入研究importin β1调控NMD机制的分子机制。完成本项目有助于完善我们对基因表达的表观遗传学调控机制的理解。

Nonsense-mediated RNA decay (NMD) is one of the quality- and quantity-control mechanisms in eukaryotic cells. The molecular mechanism of NMD, which is coupled to RNA processing and protein translation, is extremely complicated. In previous study, we found that importin β1 interacts with UPF1 (a core factor of NMD) and MARVELD1 (a potential negative regulator of NMD). And knockdown of importin β1 expression repressed NMD activities remarkably. These results indicated that importin β1 may be another potential regulator of NMD. To prove this hypothesis, the classical NMD reporter plasmids, transcriptomics analysis, protein interaction analysis and RNA-FISH will be applied in this project to uncover the molecular mechanism. The completion of this project will contribute to improve the understanding of epigenetic regulation of gene expression in mammalian cells.