高温胁迫下可变剪切调控拟南芥miRNA400加工机理研究

MicroRNAs (miRNAs) have emerged as a class of regulators of gene expression through post-transcriptional degradation or translational repression in living cells. Increasing evidence points to the important relationship between miRNAs and environmental stress responses or plant development, but the regulatory mechanisms of miRNAs themselves in plants are poorly understood. Recently, we found that alternative splicing act as a novel regulatory mechanism linking miRNA and stress. A 100bp fragment was excised, the stress-induced AS event thus resulted in greater accumulation of miR400 primary transcripts and a low level of mature miR400. We suggest that the splicing signals and factors could play important roles in miRNA regulation. Therefore, in this study, the biological role and molecular mechanism of AS in the regulation of miRNA will be identified. Furthermore, we will determine the interaction factors in the miRNA AS events including the AS regulating protein and signals, which will be very helpful to gain new insights into the complex regulation mechanisms of miRNAs.

MicroRNA是近年来备受关注的基因表达调控因子，其作用涉及动植物的生长发育及外界逆境响应等多种生物学过程，具有重要的生物学功能。但人们对于miRNA自身功能调控的机制却知之甚少。我们近期研究首次发现高温胁迫诱导的可变剪切可以作为一种新的调节机制调控植物中miRNA的加工，可变剪切发生导致miRNA400所在内含子3′末端出现100bp碱基丢失，直接影响miR400成熟体加工，初步分析发现可变剪切信号和剪切调控因子可能在加工过程中起重要作用。到目前为止，可变剪切调控miRNA的机制却未见报道。因此本项目通过深入研究可变剪切对miRNA400功能的影响、明确不同剪切信号对miRNA400加工和功能的作用，结合突变体、ChIP技术等筛选miR400的剪切调节蛋白，阐明高温胁迫下可变剪切对miR400的分子调控机制，为深入理解miRNA的作用机理提供全新的理论依据和应用工具。

高温已成为影响作物产量形成的重要环境因素。microRNA是近年来备受关注的基因表达调控因子，其作用涉及动植物的生长发育及外界逆境响应等多种生物学过程，具有重要的生物学功能。PPRP在植物生长发育和胁迫响应过程中具有非常重要的生物学功能，但植物应答高温胁迫的miRNA和PPRP及其作用机制尚未见报道。我们的研究表明拟南芥miR400的表达受高温抑制，miR400超表达对高温敏感而突变体对高温有明显抗性，初步分析发现miR400的靶基因是PPR1和PPR2。近期研究首次发现高温胁迫诱导的可变剪切可以作为一种新的调节机制调控植物中miRNA的加工，可变剪切发生导致miRNA400所在内含子3′末端出现100bp碱基丢失，直接影响miR400成熟体加工，初步分析发现可变剪切信号和剪切调控因子可能在加工过程中起重要作用。因此本项目通过深入研究可变剪切对miRNA400功能的影响、明确不同剪切信号对miRNA400加工和功能的作用，结合突变体、ChIP技术等筛选miR400的剪切调节蛋白，阐明高温胁迫下可变剪切对miR400的分子调控机制。为深入理解miRNA的作用机理提供全新的理论依据和应用工具。