Mourrain P, Béclin C, Elmayan T, Feuerbach F, Godon C, Morel J B, Jouette D, Lacombe A M, Nikic S, Picault N, Rémoué K, Sanial M, Vo T A, Vaucheret H
Laboratoire de Biologie Cellulaire, Institut National de la Recherche Agronomique, Versailles, France.
Cell. 2000 May 26;101(5):533-42. doi: 10.1016/s0092-8674(00)80863-6.
Posttranscriptional gene silencing (PTGS) in plants resuits from the degradation of mRNAs and shows phenomenological similarities with quelling in fungi and RNAi in animals. Here, we report the isolation of sgs2 and sgs3 Arabidopsis mutants impaired in PTGS. We establish a mechanistic link between PTGS, quelling, and RNAi since the Arabidopsis SGS2 protein is similar to an RNA-dependent RNA polymerase like N. crassa QDE-1, controlling quelling, and C. elegans EGO-1, controlling RNAi. In contrast, SGS3 shows no significant similarity with any known or putative protein, thus defining a specific step of PTGS in plants. Both sgs2 and sgs3 mutants show enhanced susceptibility to virus, definitively proving that PTGS is an antiviral defense mechanism that can also target transgene RNA for degradation.
植物中的转录后基因沉默（PTGS）是由mRNA降解引起的，在现象学上与真菌中的基因压制和动物中的RNA干扰相似。在此，我们报告了在PTGS中受损的拟南芥sgs2和sgs3突变体的分离。我们建立了PTGS、基因压制和RNA干扰之间的机制联系，因为拟南芥SGS2蛋白类似于一种依赖RNA的RNA聚合酶，如控制基因压制的粗糙脉孢菌QDE-1和控制RNA干扰的秀丽隐杆线虫EGO-1。相反，SGS3与任何已知或推测的蛋白质都没有明显的相似性，从而确定了植物中PTGS的一个特定步骤。sgs2和sgs3突变体都对病毒表现出增强的易感性，明确证明PTGS是一种抗病毒防御机制，也可以靶向转基因RNA进行降解。
