共查询到20条相似文献,搜索用时 125 毫秒
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dsRNA介导的RNAi普遍存在于各种生物中的一种特异的转录后基因沉默现象。dsRNA在细胞内降解为siRNA是传统RNAi作用中不可缺少的重要环节。新近发现。体外合成siRNA可直接触发RNAisi,尤其是在特异性抑制哺乳动物基因方面,有着广阔的应用前景。 相似文献
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RNA干涉分子机制研究进展 总被引:13,自引:0,他引:13
RNA干涉(RNA interference,RNAi)是生物体内的一种通过双链RNA(dsRNA)来抵抗病毒入侵和抑制转座子活动的自然机制.双链RNA与同源mRNA互补结合而使特定基因失活,这一过程已经在包括拟南芥、线虫和真菌等多种模式生物中得到揭示.近来研究表明,21~25 nt的小干涉RNA(small interference RNA, siRNA)可介导哺乳动物细胞特异性基因沉默.RNAi具有高效性和高度特异性,可能成为关闭基因的新技术而在基因功能研究和疾病基因治疗中发挥重要作用. 相似文献
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RNA干扰作用(RNAi)研究进展 总被引:25,自引:4,他引:21
RNA干扰作用 (RNAi)是生物界一种古老而且进化上高度保守的现象 ,是基因转录后沉默作用 (PTGS)的重要机制之一 .RNAi主要通过dsRNA被核酸酶切割成 2 1~ 2 5nt的干扰性小RNA即siRNA ,由siRNA介导识别并靶向切割同源性靶mRNA分子而实现 .RNAi要有多种蛋白因子以及ATP参与 ,而且具有生物催化反应特征 .RNAi是新发现的一种通过dsRNA介导的特异性高效抑制基因表达途径 ,在后基因组时代的基因功能研究和药物开发中具有广阔应用前景 相似文献
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RNA干扰(RNA interference,RNAi)是真核生物体内由双链RNA(double—stranded RNA)介导的同源RNA降解现象。在细胞内,长的dsRNA被Dicer酶切割成21~26核苷酸(nucleotide,nt)的小干扰RNA(small interfering RNA或short interfering RNA,siRNA);siRNA与多种蛋白结合后形成RNA诱导沉默复合物(RNA—induced silencing complex,RISC),同时解链;有活性的RISC可在siRNA的指引下与互补的转录物结合,并导致RNA的降解, 相似文献
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Huarong Li Andrew J. Bowling Premchand Gandra Murugesan Rangasamy Heather E. Pence Robert E. McEwan Chitvan Khajuria Blair D. Siegfried Kenneth E. Narva 《Insect Science》2018,25(1):45-56
Western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) is highly sensitive to orally delivered double‐stranded RNA (dsRNA). RNAi in WCR is systemic and spreads throughout the insect body. This raises the question whether transitive RNAi is a mechanism that functions in WCR to amplify the RNAi response via production of secondary siRNA. Secondary siRNA production is achieved through RNA‐dependent RNA polymerase (RdRP) activity in other eukaryotic organisms, but RdRP has not been identified in WCR and any other insects. This study visualized the spread of the RNAi‐mediated knockdown of Dv v‐ATPase C mRNA throughout the WCR gut and other tissues using high‐sensitivity branched DNA in situ hybridization. Furthermore, we did not detect either secondary siRNA production or transitive RNAi in WCR through siRNA sequence profile analysis. Nucleotide mismatched sequences introduced into either the sense or antisense strand of v‐ATPase C dsRNAs were maintained in siRNAs derived from WCR fed with the mismatched dsRNAs in a strand specific manner. The distribution of all siRNAs was restricted to within the original target sequence regions, which may indicate the lack of new dsRNA synthesis leading to production of secondary siRNA. Thus, the systemic spread of RNAi in WCR may be derived from the original dsRNA molecules taken up from the gut lumen. These results indicate that the initial dsRNA dose is important for a lethal systemic RNAi response in WCR and have implications in developing effective dsRNA traits to control WCR and in resistance management to prolong the durability of RNAi trait technology. 相似文献
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On the role of RNA amplification in dsRNA-triggered gene silencing. 总被引:155,自引:0,他引:155
T Sijen J Fleenor F Simmer K L Thijssen S Parrish L Timmons R H Plasterk A Fire 《Cell》2001,107(4):465-476
We have investigated the role of trigger RNA amplification during RNA interference (RNAi) in Caenorhabditis elegans. Analysis of small interfering RNAs (siRNAs) produced during RNAi in C. elegans revealed a substantial fraction that cannot derive directly from input dsRNA. Instead, a population of siRNAs (termed secondary siRNAs) appeared to derive from the action of a cellular RNA-directed RNA polymerase (RdRP) on mRNAs that are being targeted by the RNAi mechanism. The distribution of secondary siRNAs exhibited a distinct polarity (5'-->3' on the antisense strand), suggesting a cyclic amplification process in which RdRP is primed by existing siRNAs. This amplification mechanism substantially augments the potency of RNAi-based surveillance, while ensuring that the RNAi machinery will focus on expressed mRNAs. 相似文献
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RNA interference (RNAi) is a gene-silencing mechanism by which a ribonucleoprotein complex, the RNA-induced silencing complex (RISC) and a double-stranded (ds) short-interfering RNA (siRNA), targets a complementary mRNA for site-specific cleavage and subsequent degradation. While longer dsRNA are endogenously processed into 21- to 24-nucleotide (nt) siRNAs or miRNAs to induce gene silencing, RNAi studies in human cells typically use synthetic 19- to 20-nt siRNA duplexes with 2-nt overhangs at the 3′-end of both strands. Here, we report that systematic synthesis and analysis of siRNAs with deletions at the passenger and/or guide strand revealed a short RNAi trigger, 16-nt siRNA, which induces potent RNAi in human cells. Our results indicate that the minimal requirement for dsRNA to trigger RNAi is an ~42 Å A-form helix with ~1.5 helical turns. The 16-nt siRNA more effectively knocked down mRNA and protein levels than 19-nt siRNA when targeting the endogenous CDK9 gene, suggesting that 16-nt siRNA is a more potent RNAi trigger. In vitro kinetic analysis of RNA-induced silencing complex (RISC) programmed in HeLa cells indicates that 16-nt siRNA has a higher RISC-loading capacity than 19-nt siRNA. These results suggest that RISC assembly and activation during RNAi does not necessarily require a 19-nt duplex siRNA and that 16-nt duplexes can be designed as more potent triggers to induce RNAi. 相似文献
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Expression of small interfering RNAs targeted against HIV-1 rev transcripts in human cells 总被引:142,自引:0,他引:142
Lee NS Dohjima T Bauer G Li H Li MJ Ehsani A Salvaterra P Rossi J 《Nature biotechnology》2002,20(5):500-505
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Analysis of gene function in somatic mammalian cells using small interfering RNAs 总被引:175,自引:0,他引:175
RNA interference (RNAi) is a highly conserved gene silencing mechanism that uses double-stranded RNA (dsRNA) as a signal to trigger the degradation of homologous mRNA. The mediators of sequence-specific mRNA degradation are 21- to 23-nt small interfering RNAs (siRNAs) generated by ribonuclease III cleavage from longer dsRNAs. Twenty-one-nucleotide siRNA duplexes trigger specific gene silencing in mammalian somatic cells without activation of the unspecific interferon response. Here we provide a collection of protocols for siRNA-mediated knockdown of mammalian gene expression. Because of the robustness of the siRNA knockdown technology, genomewide analysis of human gene function in cultured cells has now become possible. 相似文献