Sarmiento Cecilia, Nigul Lenne, Kazantseva Jekaterina, Buschmann Marju, Truve Erkki
Department of Gene Technology, Tallinn University of Technology, Estonia.
Plant Mol Biol. 2006 May;61(1-2):153-63. doi: 10.1007/s11103-005-0001-8.
RNA silencing is a mechanism involved in gene regulation during development and anti-viral defense in plants and animals. Although many viral suppressors of this mechanism have been described up to now, this is not the case for endogenous suppressors. We have identified a novel endogenous suppressor in plants: RNase L inhibitor (RLI) of Arabidopsis thaliana. RLI is a very conserved protein among eukaryotes and archaea. It was first known as component of the interferon-induced mammalian 2'-5' oligoadenylate (2-5A) anti-viral pathway. This protein is in several organisms responsible for essential functions, which are not related to the 2-5A pathway, like ribosome biogenesis and translation initiation. Arabidopsis has two RLI paralogs. We have described in detail the expression pattern of one of these paralogs (AtRLI2), which is ubiquitously expressed in all plant organs during different developmental stages. Infiltrating Nicotiana benthamiana green fluorescent protein (GFP)-transgenic line with Agrobacterium strains harboring GFP and AtRLI2, we proved that AtRLI2 suppresses silencing at the local and at the systemic level, reducing drastically the amount of GFP small interfering RNAs.
RNA沉默是植物和动物发育过程中参与基因调控以及抗病毒防御的一种机制。尽管到目前为止已经描述了许多这种机制的病毒抑制因子，但内源性抑制因子并非如此。我们在植物中鉴定出一种新型内源性抑制因子：拟南芥核糖核酸酶L抑制剂（RLI）。RLI是真核生物和古细菌中一种非常保守的蛋白质。它最初作为干扰素诱导的哺乳动物2'-5'寡腺苷酸（2-5A）抗病毒途径的组成部分为人所知。这种蛋白质在几种生物体中负责一些基本功能，这些功能与2-5A途径无关，比如核糖体生物合成和翻译起始。拟南芥有两个RLI旁系同源基因。我们已经详细描述了其中一个旁系同源基因（AtRLI2）的表达模式，它在不同发育阶段在所有植物器官中普遍表达。用携带绿色荧光蛋白（GFP）和AtRLI2的农杆菌菌株浸润本氏烟草绿色荧光蛋白转基因品系，我们证明AtRLI2在局部和系统水平上抑制沉默，大幅减少GFP小干扰RNA的量。
