Dual regulation of Arabidopsis AGO2 by arginine methylation
Dual regulation of Arabidopsis AGO2 by arginine methylation
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DOI：
10.1038/s41467-019-08787-w
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发表时间：
2019-02-19
影响因子：
16.6
通讯作者：
Jin, Hailing
中科院分区：
文献类型：
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作者：
Hu, Po;Zhao, Hongwei;Jin, Hailing
Argonaute（AGO）蛋白是RNA干扰（RNAi）的核心成分，但其调控机制，特别是在翻译后水平的调控机制尚不清楚。在拟南芥的10种AGO中，只有AGO 2是由细菌感染诱导的，并且已知其正调节免疫。在这里，我们表明，AGO 2的N-末端结构域富含精氨酸-甘氨酸RG/GR重复序列，这是由蛋白质精氨酸甲基转移酶5（PRMT 5）甲基化。精氨酸甲基化在AGO 2调节中具有双重功能。甲基化精氨酸残基可以促进AGO 2蛋白降解，并且还与Tudor结构域蛋白（TSN）结合，TSN可以降解AGO 2相关的小RNA（sRNA）。PRMT 5在感染过程中下调，并且prmt 5突变体对细菌更具抗性。我们推测PRMT 5在感染过程中的表达减少可能导致AGO 2的精氨酸甲基化减少，从而导致AGO 2的积累，并通过减少与TSN的相互作用，积累AGO 2相关的sRNA，以促进植物免疫。这些结果表明，精氨酸甲基化写入器（PRMT 5）和读取器（TSNs）都可以调节AGO 2介导的RNAi。
Argonaute (AGO) proteins are core components of RNA interference (RNAi) but the mechanisms of their regulation, especially at the post-translational level, remain unclear. Among the ten AGOs in Arabidopsis, only AGO2 is induced by bacterial infection and is known to positively regulate immunity. Here we show that the N-terminal domain of AGO2 is enriched with arginine-glycine RG/GR repeats, which are methylated by protein arginine methyltransferase5 (PRMT5). Arginine methylation has dual functions in AGO2 regulation. Methylated arginine residues can promote AGO2 protein degradation and are also bound by Tudor-domain proteins (TSNs), which can degrade AGO2-associated small RNAs (sRNAs). PRMT5 is down-regulated during infection and the prmt5 mutant is more resistant to bacteria. We speculate that reduced PRMT5 expression during infection may lead to reduced arginine methylation of AGO2, resulting in accumulation of both AGO2 and, via reduced interaction with TSNs, accumulation of AGO2-associated sRNAs, to promote plant immunity. These results reveal that both the arginine methylation writer (PRMT5) and readers (TSNs) can regulate AGO2-mediated RNAi.