针对SARS冠状病毒重要蛋白的siRNA设计(英)

RNA干涉(RNA interference, RNAi)是一种特异性地导致转录后基因沉默的现象,在哺乳动物细胞中小分子干扰RNA双链体(small interfering RNA duplexes, siRNA duplexes)可以有效地诱导RNAi现象,为一些疾病的治疗开辟了新的途径.针对SARS冠状病毒(SARS coronavirus, SARS-CoV)中编码5个主要蛋白质的基因,用生物信息学的方法设计了348条候选siRNA靶标.在理论上,相应的siRNA双链体能特异地抑制SARS-CoV靶基因的表达,同时不会影响人体细胞基因的正常表达,这为进一步siRNA类药物的实验研究提供了理论基础.     

针对SARS冠状病毒重要蛋白的siRNA设计(英文)

NA干涉 (RNAinterference ,RNAi)是一种特异性地导致转录后基因沉默的现象 ,在哺乳动物细胞中小分子干扰RNA双链体 (smallinterferingRNAduplexes ,siRNAduplexes)可以有效地诱导RNAi现象 ,为一些疾病的治疗开辟了新的途径 .针对SARS冠状病毒 (SARScoronavirus ,SARS CoV)中编码 5个主要蛋白质的基因 ,用生物信息学的方法设计了3 48条候选siRNA靶标 .在理论上 ,相应的siRNA双链体能特异地抑制SARS CoV靶基因的表达 ,同时不会影响人体细胞基因的正常表达 ,这为进一步siRNA类药物的实验研究提供了理论基础     

RNA干扰技术及其在肝纤维化中的应用

RNA干扰(RNA interference,RNAi)是近几年发展起来的新技术,是外源和内源性双链RNA在生物体内诱导同源靶基因的mRNA特异性降解,因而抑制相应基因表达,导致转录后基因沉默的现象.尽管RNA干扰发现的时间较短,但由于其具有操作简单、成本低、特异性高和高效性等特点,因而发展迅速.小干扰RNA(small interfering RNA,siRNA)的可制备使RNAi在很多领域有了应用的前景,尤其是在复杂多变的肝脏疾病中.肝纤维化(hepatic fibrosis,HF)是多种慢性肝病发展的共同病理基础,RNAi技术在其基因治疗领域拥有广阔的前景.RNAi具有能够调节细胞增殖、抑制致病基因的表达、影响细胞的信号转导等方面的作用,可能成为肝纤维化有效的潜在治疗手段.     

RNA干扰技术在哺乳动物中的应用

RNA干扰(RNAi)是生物界普遍存在的一种抵御外来基因和病毒感染的进化保守机制.RNAi是由双链RNA触发的转录后基因沉默机制,具有序列特异性,在哺乳动物细胞中,RNAi由21～23个核苷酸组成的双链RNA引发.小干扰RNA(siRNA)可以在体外合成或通过表达载体在哺乳动物细胞内合成.由于RNAi技术具有快速、简单和特异性强等特点,在基因功能研究、抗病毒治疗和抗肿瘤治疗等方面有广泛的应用前景.     

人工 microRNA 技术研究进展

RNA干扰（RNAi）是由双链RNA触发的在mRNA水平进行的特异靶序列的基因沉默现象,广泛存在于动物、植物和病毒中,主要包括小干扰RNA（siRNA）及微小RNA（miRNA）两种作用途径。人工miRNA（amiRNA）是将天然miRNA的成熟序列替换成人工设计的靶向其他感兴趣基因的反义序列,通过天然miRNA的生成和作用途径达到RNAi的效果,具有干扰效果明显、作用迅速、毒性低等优点,拥有广阔的应用前景。我们对基于amiRNA的基因沉默技术进行了较为系统的介绍和总结,梳理了该技术的优缺点和适用范围,并展望了其进一步发展的方向和应用前景。     

RNA干涉及其应用前景

RNA干涉是指由特定双链RNA(dsRNA)引起的转录后基因沉默现象。研究表明,Dicer断裂dsRNA产生的小干涉RNA可以抑制哺乳动物体细胞和胚胎中的基因的表达。RdRP在扩增RNAi中起着关键性的作用,RdRP活性复制较长的触发性dsRNA或以一种非引物的方式复制短的siRNA,即以siRNA为引物的RdRP反应使靶mRNA转变为dsRNA,同时复制触发性dsRNA。所有的产物又可作为Dicer的底物,起始RdRP级联反应。本文综述了RNAi可能的作用机制,并对RNAi在分析功能基因组、药物治疗等方面的应用前景进行了展望。     

多靶向RNA干扰技术在基因治疗中的应用与前景

RNA干扰(RNA interference,RNAi)通过转录后基因沉默效应特异性抑制靶基因的表达,其沉默机制的高效性、特异性及稳定性使这项技术成为生物医学领域研究基因治疗的重要工具。阐述RNAi技术的特点和RNAi疗法的现状,特别是多靶小干扰RNA(small interference RNA,siRNA)目前的发展态势及其各种结构性修饰,通过使用这些结构修饰的siRNA提高基因沉默的效率,将有助于提高疗效。但该技术在广泛应用于临床之前,仍存在一些亟待解决的问题与面临的挑战,需进一步研究。     

RNA干扰的研究进展

RNA干扰(RNA interference,RNAi)是一种由双链RNA诱发的转录后水平的基因沉默现象,是近几年发展起来的基因表达调节新机制。RNAi广泛存在于真菌、植物和动物中,这种调控可以由siRNA、shRNA及miRNA等小分子RNA参与。在此主要对RNAi的研究进展如背景、分子调控机制、存在的问题和应用前景等进行了综述。     

Predicting siRNA activity based on back-propagation neural network

RNA interference (RNAi) is a phenomenon of gene silence induced by a double-stranded RNA (dsRNA) homologous to a target gene.RNAi can be used to identify the function of genes or to knock down the targeted genes.In RNAi technology,19 bp double-stranded short interfering RNAs (siRNA) with characteristic 3' overhangs are usually used.The effects of siRNAs are quite varied due to the different choices in the sites of target mRNA.Moreover,there are many factors influencing siRNA activity and these factors are usually nonlinear.To find the motif features and the effect on siRNA activity,we carried out a feature extraction on some published experimental data and used these features to train a backpropagation neural network (BP NN).Then,we used the trained BP NN to predict siRNA activity.     

Predicting siRNA activity based on back-propagation neural network

RNA interference (RNAi) is a phenomenon of gene silence induced by a double-stranded RNA (dsRNA) homologous to a target gene. RNAi can be used to identify the function of genes or to knock down the targeted genes. In RNAi technology, 19 bp double-stranded short interfering RNAs (siRNA) with characteristic 39 overhangs are usually used. The effects of siRNAs are quite varied due to the different choices in the sites of target mRNA. Moreover, there are many factors influencing siRNA activity and these factors are usually nonlinear. To find the motif features and the effect on siRNA activity, we carried out a feature extraction on some published experimental data and used these features to train a back-propagation neural network (BP NN). Then, we used the trained BP NN to predict siRNA activity. __________ Translated from Acta Biophysica Sinica, 2006, 22(6): 429–434 [译自: 生物物理学报]     

Inputs and outputs for chromatin-targeted RNAi

Plant gene silencing is targeted to transposons and repeated sequences by small RNAs from the RNA interference (RNAi) pathway. Like classical RNAi, RNA-directed chromatin silencing involves the cleavage of double-stranded RNA by Dicer endonucleases to create small interfering RNAs (siRNAs), which bind to the Argonaute protein. The production of double-stranded RNA (dsRNA) must be carefully controlled to prevent inappropriate silencing. A plant-specific RNA polymerase IV (Pol IV) initiates siRNA production at silent heterochromatin, but Pol IV-independent mechanisms for making dsRNA also exist. Downstream of siRNA biogenesis, multiple chromatin marks might be targeted by Argonaute-siRNA complexes, yet mechanisms of chromatin modification remain poorly understood. Genomic studies of siRNA target loci promise to reveal novel biological functions for chromatin-targeted RNAi.     

Interfering with disease: opportunities and roadblocks to harnessing RNA interference

RNA interference (RNAi) is an evolutionarily conserved mechanism for silencing gene expression by targeted degradation of mRNA. Short double-stranded RNAs, known as small interfering RNAs (siRNA), are incorporated into an RNA-induced silencing complex that directs degradation of RNA containing a homologous sequence. RNAi has been shown to work in mammalian cells, and can inhibit viral infection and control tumor cell growth in vitro. Recently, it has been shown that intravenous injection of siRNA or of plasmids expressing sequences processed to siRNA can protect mice from autoimmune and viral hepatitis. RNAi could provide an exciting new therapeutic modality for treating infection, cancer, neurodegenerative disease and other illnesses.     

Inhibition of genes expression of SARS coronavirus by synthetic small interfering RNAs

RNA interference (RNAi) is triggered by the presence of a double-stranded RNA (dsRNA), and results in the silencing of homologous gene expression through the specific degradation of an mRNA containing the same sequence, dsRNAmediated RNAi can be used in a wide variety of eucaryotes to induce the sequence-specific inhibition of gene expression.Synthetic 21-23 nucleotide (nt) small interfering RNA (siRNA) with 2 nt 3‘ overhangs was recently found to mediate efficient sequence-specific mRNA degradation in mammalian cells. Here, we studied the effects of synthetic siRNA duplexes targeted to SARS coronavirus structural proteins E, M, and N in a cell culture system. Among total 26 siRNAduplexes, we obtained 3 siRNA duplexes which could sequence-specifically reduce target genes expression over 80% at the concentration of 60 nM in Vero E6 cells. The downregulation effect was in correlation with the concentrations of the siRNA duplexes in a range of 0-450 nM. Our results also showed that many inactive siRNA duplexes may be brought to life simply by unpairing the 5‘ end of the antisense strands. Results suggest that siRNA is capable of inhibiting SARS coronavirus genes expression and thus may be a new therapeutic strategy for treatment of SARS.     

Inhibition of herpesvirus-6B RNA replication by short interference RNAs

RNA interference (RNAi) is a process of sequence-specific gene silencing, which is initiated by double-stranded RNA (dsRNA). RNAi may also serve as an antiviral system in vertebrates. This study describes the inhibition of herpesvirus-6B (HHV-6B) replication by short interference RNAs (siRNAs) that are targeted to the U38 sequence that encodes DNA polymerase. When virus-infected SupT1 cells were treated by siRNA, these cells blocked the cytopathic effect (CPE) and detected the HHV-6B antibody-negative in indirect immunofluorescence assays (IFA). Our result suggests that RNAi can efficiently block Herpesvirus-6B replication.     

RNA干扰作用(RNAi)研究进展

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     

siRNA binding proteins of microglial cells: PKR is an unanticipated ligand

Small interfering RNA (siRNA), double-stranded RNA (dsRNA) 21-23 nucleotides (nt) long with two nt 3' overhangs, has been shown to mediate powerful sequence-specific gene silence in mammalian cells through RNA interference (RNAi). Due to its high efficiency and high specificity siRNA has been used as a powerful post genomic tool and a potent therapeutic candidate. However, there is still a lot to learn about the mobility of siRNA inside cells and the cellular factors that might interfere with the specificity and activity of siRNA. Microglia are the brain's effector cells of the innate immune system and suitable targets in the development of novel therapeutic strategies. Here, we show the cellular uptake and intracellular distribution of siRNA in murine microglial N9 cells. siRNA was internalized by microglial N9 cells without transfection reagent and mainly localized to the endosomes However, no significant gene silencing effects were observed. Its cellular uptake and cellular distribution pattern were similar with that of a same length single stranded DNA (ssDNA). Further, cellular binding proteins of siRNA were purified and identified by mass spectrometry. Negative control siRNA and siRNA targeted to beta-actin were used in this part of experiment. Most of the siRNA binding proteins for negative control siRNA and siRNA targeted to beta-actin were dsRNA-binding proteins, such as dsRNA-dependent protein kinase R (PKR). Furthermore, both control siRNA and siRNA targeted to beta-actin activated PKR in N9 cells, which suggest that siRNA might cause off-target effects through activation of PKR.