新药研究与开发翻译作业.docVIP

RNA interference was first discovered in C.elegans. When long double-stranded (ds)RNAs were injected into a worms gonad (a standard way of introducing transgenes into worms), they blocked the expression of endogenous genes in a sequence-specific manner. 在线虫中首次发现了RNA干扰。当长的双链RNA（DS）注射到一个蠕虫的性腺（转基因引入到蠕虫的标准方法），他们以特异性的方式阻断内源性基因表达的序列。 In eukaryotes, most protein-coding genes are transcripted by RNA polymerase II, which generates pre-mRNAs that are then processed to form mature mRNAs. These mRNAs are then transported from the nucleus to the cytoplasm, where they are translated. 在真核生物中，RNA聚合酶II转录了大多数蛋白质编码基因，产生前体mRNA，然后形成成熟mRNA。这些mRNA从细胞核被运输到细胞质中进行翻译。 RNAi is a recently discovered process that can regulate endogenous gene expression.In plants, RNAi can be set in motion by genomically encoded short regulatory RNAs known as microRNAs. In algae, worms and flies, RNAi can be activated by endogenous transposition. RNAi是近年来发现的一种过程，它可以调节内源基因的表达。在植物中，RNAi可以通过短期调控RNA基因组编码进行运作，这些RNA被称为microRNAs。在藻类、蠕虫和苍蝇，RNA干扰可通过内源性换位激活。 In plants and cultured insect cells, RNAi also has a role in antiviral defense, in which viral dsRNAs are targeted for destruction by the RNAi machinery. 在植物和昆虫细胞中，RNAi在抗病毒防御中也发挥作用，它是通过RNAi机制对病毒的双链RNA进行有针对性的破坏。 When long dsRNAs enter a cell, they are recognized and cleaved by Dicer, which is a member of the RNase III family of dsRNA-specific endonucleases. Cleavage by Dicer creates short dsRNAs that are characterized by 2- nucleotide long -long 3 overhangs. These are called small interfering or (si) RNAs. 当长的双链RNA进入细胞，它们被Dicer酶识别和切割，这些酶是双链RNA特异性核酸内切酶RNaseⅢ家族中的一员。Dicer切割形成结构特征为2-3个核苷酸长的短的双链RNA。这些RNA被称为小干扰RNA或(si)RNAs。 In worms, flies and mammals, siRNAs can form a ribonucleoprotein complex called RISC (RNAi silencing complex). 在蠕虫，果蝇和哺乳动物中，小干扰RNA可形成一种被称为RISC（RNA沉默复合物）的核糖核蛋白复合物。 This complex includes an unidentified nuclease that has been nicknamed Slicer. RISC first mediates the unwinding of the siRNA duplex. A single stranded siRNA that is coupled to RISC, then binds