Deleris Angélique, Gallego-Bartolome Javier, Bao Jinsong, Kasschau Kristin D, Carrington James C, Voinnet Olivier
Institut de Biologie Moléculaire des Plantes, CNRS Unité Propre de Recherche (UPR) 2357, 12, rue du Général Zimmer, 67084 Strasbourg Cedex, France.
Science. 2006 Jul 7;313(5783):68-71. doi: 10.1126/science.1128214. Epub 2006 Jun 1.
The mechanisms underlying induction and suppression of RNA silencing in the ongoing plant-virus arms race are poorly understood. We show here that virus-derived small RNAs produced by Arabidopsis Dicer-like 4 (DCL4) program an effector complex conferring antiviral immunity. Inhibition of DCL4 by a viral-encoded suppressor revealed the subordinate antiviral activity of DCL2. Accordingly, inactivating both DCL2 and DCL4 was necessary and sufficient to restore systemic infection of a suppressor-deficient virus. The effects of DCL2 were overcome by increasing viral dosage in inoculated leaves, but this could not surmount additional, non-cell autonomous effects of DCL4 specifically preventing viral unloading from the vasculature. These findings define a molecular framework for studying antiviral silencing and defense in plants.
在持续的植物 - 病毒军备竞赛中，RNA沉默诱导和抑制的潜在机制仍知之甚少。我们在此表明，拟南芥中类似Dicer 4（DCL4）产生的病毒衍生小RNA可编程一种效应复合物，赋予抗病毒免疫力。病毒编码的抑制因子对DCL4的抑制揭示了DCL2的次要抗病毒活性。因此，使DCL2和DCL4都失活对于恢复缺乏抑制因子的病毒的系统感染是必要且充分的。通过增加接种叶片中的病毒剂量可克服DCL2的作用，但这无法克服DCL4的额外非细胞自主性效应，即特异性阻止病毒从脉管系统卸载。这些发现为研究植物中的抗病毒沉默和防御定义了一个分子框架。
