Intra- and intercellular RNA interference in Arabidopsis thaliana requires components of the microRNA and heterochromatic silencing pathways
Intra- and intercellular RNA interference in Arabidopsis thaliana requires components of the microRNA and heterochromatic silencing pathways
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DOI：
10.1038/ng2081
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发表时间：
2007-07-01
期刊：
影响因子：
30.8
通讯作者：
Voinnet, Olivier
中科院分区：
文献类型：
--
作者：
Dunoyer, Patrice;Himber, Christophe;Voinnet, Olivier
在RNA干扰（RNAi）中，双链RNA（dsRNA）被加工成短干扰RNA（siRNA）来介导序列特异性基因敲除。植物RNAi的遗传学尚不清楚，也不清楚它在细胞之间传播的基础。在这里，我们解开了拟南芥中指导RNA干扰的siRNAs的生物发生和作用的要求，并展示了在极端的双链RNA剂量下，替代途径如何冗余地介导这一过程。我们发现，细胞间而非细胞内RNAi所需的SMD 1和SMD 2分别与RDR2和NRPD 1a等位，先前通过DCL 3和AGO 4的作用参与siRNA指导的异染色质形成。然而，非细胞自主RNAi既不需要DCL3也不需要AGO4，揭示了受体细胞中RNAi传播或检测的新途径。最后，我们表明RNAi的遗传学与抗病毒沉默不同，并提出这种实验沉默途径具有直接的内源性植物对应物。
In RNA interference ( RNAi), double- stranded RNA ( dsRNA) is processed into short interfering RNA ( siRNA) to mediate sequence-specific gene knockdown. The genetics of plant RNAi is not understood, nor are the bases for its spreading between cells. Here, we unravel the requirements for biogenesis and action of siRNAs directing RNAi in Arabidopsis thaliana and show how alternative routes redundantly mediate this process under extreme dsRNA dosages. We found that SMD1 and SMD2, required for intercellular but not intracellular RNAi, are allelic to RDR2 and NRPD1a, respectively, previously implicated in siRNA- directed heterochromatin formation through the action of DCL3 and AGO4. However, neither DCL3 nor AGO4 is required for non - cell autonomous RNAi, uncovering a new pathway for RNAi spreading or detection in recipient cells. Finally, we show that the genetics of RNAi is distinct from that of antiviral silencing and propose that this experimental silencing pathway has a direct endogenous plant counterpart.