RNA/DNA嵌合分子介导的高效基因修复

本文介绍了RNA/DNA嵌合分子介导的高效基因修复技术。这一技术是1996年开始发展起来的全新技术,它通过人工合成的双链开环RNA/DNA嵌合分子转染细胞而使特定基因靶位点产生单碱基改变,从而修复突变基因。这一技术高效（目前最高可达50％以上）、特异性强、安全、无随机插入致变的危险、无免疫反应、无明显毒性,能够用于定点突变、基因敲除、动植物功能基因组学、药物遗传学等很多方面的研究,在不久的将来能够应用于人类基因治疗,具有很高的应用价值和医学前景。 Abstract：We introduce a new technique?targeted gene correction directed by chimeric RNA/DNA oligonucleotides which began at 1996.It uses synthetic double?stranded non?circular RNA/DNA chimeric oligonucleotides to transfect cells and make a single?based change at the targeted site of the target gene.It is highly efficient (the highest efficiency is more than 50％),highly special,safe,without danger of mutation caused by random insertion,without immune response,and without obvious toxicity.It can be used to make point mutation,or gene knock?out plants and animals,and is very likely to be used in human gene therapy in the near future.It is also valuable in the study of functional genomics,pharmacogenetics,and medicine.     

RNA干扰机制研究进展

RNAi是多种生物体内由dsRNA介导的同源mRNA降解现象。这是一个高度特异化的过程,涉及多种蛋白质的共同参与。在这一过程中,siRNA的结构影响其两条链装配到RISC中去的能力。除了与RISC结合外,siRNA还引导了RITS复合物结合到同源染色质,介导异染色质化过程。干扰效应的扩散,即系统性沉默可能依赖于跨膜蛋白的转运,并且很可能是在多因素调控下完成的。Abstract: RNA interference (RNAi) is a phenomenon that the double-stranded RNA (dsRNA) intermediates the degradation of complementary mRNA found in many organisms. This is a specifically mechanism involved in kinds of proteins to complete the interference function. Structure of siRNA affects which strand will be assembled into RISC. Another role of siRNA is directing RITS complex to bind with homologue chromosome, and then induces heterochromatinization. Although systemic silence induced by dsRNA is observed in Caenorhabditis elegans and plants, this progress is probably transmembrane protein-dependent, and mostly, the systemic silencing is controlled by multi-factors.     

Optimization of parental RNAi conditions for hunchback gene in Locusta migratoria manilensis (Meyen)

An investigation on the optimization of parental RNA interference (RNAi) conditionsfor hunchback {hb) gene in Locusta migratoria manilensis (Meyen) was conducted.Double stranded RNA (dsRNA) corresponding to hb gene was injected into haemocoel offemale adults of L.migratoria manilensis.Embryos developed from the eggs laid by theinjected adults on the 7th day after eclosion showed observable effects of RNAi for hb.Thesilencing effect after delivery treatment of dsRNA for hb gene was maintained for moretha...     

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.     

GAMETOPHYTIC FACTOR 1, Involved in Pre-mRNA Splicing,Is Essential for Megagametogenesis and Embryogenesis in Arabidopsis

RNA biogenesis is essential and vital for accurate expression of genes. It is obvious that cells cannot continue normal metabolism when RNA splicing is interfered with. sgt13018 is such a mutant, with partial loss of function of GAMETOPHYTIC FACTOR 1 （GFA1）; a gene likely involved in RNA biogenesis in Arabidopsis. The mutant is featured in the phenotype of diminished female gametophyte development at stage FG5 and is associated with the arrest of early embryo development in Arabidopsis. Bioinformatics data showed that homologs of gene GFA1 in yeast and human encode putative U5 snRNPspecific proteins required for pre-mRNA splicing. Furthermore, the result of yeast two-hybrid assay indicated that GFA1 physically interacted with AtBrr2 and AtPrp8, the putative U5 snRNP components, of Arabidopsis. This investigation suggests that GFA1 is involved in mRNA biogenesis through interaction with AtBrr2 and AtPrp8 and functions in megagametogenesis and embryogenesis in plant.     

RNA介导的转基因沉默:原理及应用

RNA介导的转基因沉默是有dsRNA参与指导的,以外源和内源mRNA为降解目标的转基因沉默现象。本文对植物中RNA介导的转基因沉默的机理做了详细的阐述,并且将各种生物中在此过程中起关键作用的蛋白及其功能进行了总结,最后介绍dsRNA作为一种基因组学研究手段的优势和它实际的应用前景。 Abstract:RNA-based transgene silencing is a phenomenon that endogenous and exogenous mRNAs are degraded specifically directed by double-stranded RNA.Here we review the recent advances on its mechanism and summarize related proteins and expatiate their functions.Furthermore,we introduce the enormous potential of dsRNA as a tool in functional genomics research and practical biotechnology.     

RNA干涉的最新研究进展

RNA干涉 (RNAi)是将双链RNA(dsRNA)导入细胞引起特异基因mRNA降解的一种细胞反应过程 .它是转录后基因沉默 (PTGS)的一种 .RNAi在生物界中广泛存在 .RNAi发生过程主要分为 3个阶段 :起始阶段 ,扩增阶段 ,效应阶段 .RNAi在维持基因组稳定、保护基因组免受外源核酸侵入、基因表达调控等方面发挥重要生物学作用 .RNAi作为基因沉默的一个工具 ,已被广泛用于基因功能研究、基因治疗和新药研究与开发等方面 .     

基因枪在RNA干扰中的应用研究进展

RNA干扰（RNA interference,RNAi）是指双链RNA（double-strand RNA,dsRNA）特异性降解同源mRNA,从而引发基因转录后水平沉默的现象,是一种高效、高特异性抑制基因表达的途径。自1998年Fire等发现RNA干扰现象以来,其特异性降解目的基因的优势吸引了众多研究者的目光。本文在简要综述RNAi技术在基因功能研究、抗病毒治疗,肿瘤基因治疗等领域的应用后,重点归纳了基因枪技术在RNAi研究即siRNA导入细胞中的应用,并简单分析其优势与意义。     

RNA干涉技术(RNAi)应用研究进展

RNA干涉是通过双链RNA的介导特异性地降解相应序列的mRNA,从而导致转录后水平的基因沉默,这一过程在拟南芥、线虫和真菌等多种模式植物中发现。RNAi是研究多种生物基因功能的有效手段,本文综述了RNA干涉的分子机理及其应用研究进展。     

双链RNA在基因沉默中的作用

介绍依赖于同源识别的基因沉默 .依赖于同源识别的基因沉默 ,是指向生物体内导入外源核酸时引起相应序列的内源基因的表达被特异性抑制的一种基因调控现象 .基因沉默分为转录基因沉默和转录后基因沉默 ,二者都通过双链RNA介导 .它们是真核生物中普遍存在的抵抗病毒入侵、抑制转座子活动、调控基因表达的监控机制 .这些机制具有巨大的应用前景 .     

RNA干扰体内导入技术研究进展

RNA干扰(RNA interference,RNAi)是一种发展迅速并具有广阔应用前景的基因控制技术,它能特异性地沉默内源或外源性靶基因,已成为基因治疗的有效手段。然而,利用RNA干扰技术进行体内基因沉默的主要障碍是如何实现siRNA和miRNA的体内安全高效输送导入。该文结合国内外进展和本课题组在RNA干扰方面的研究成果,对RNA干扰体内导入技术作一综述。     

RNA干扰技术及其在细胞周期研究中的应用

RNA干扰(RNA interference,RNA i)是由双链RNA(doub le-stranded RNA,dsRNA)引发的转录后基因沉默(posttran-scridptional gene silenc ing,PTGS)。dsRNA经D icer酶降解成21-23nt的siRNA,并以其为模板,特定位点、特定间隔降解与之序列相应的mRNA。随着RNA i机制的深入研究与广泛应用,目前该技术已经普遍应用于细胞周期研究中,在阐明各种调控机制的同时也为基因治疗提供了新靶点。     

RNA interference for antiviral therapy

Silencing gene expression through a process known as RNA interference (RNAi) has been known in the plant world for many years. In recent years, knowledge of the prevalence of RNAi and the mechanism of gene silencing through RNAi has started to unfold. It is now believed that RNAi serves in part as an innate response against invading viral pathogens and, indeed, counter silencing mechanisms aimed at neutralizing RNAi have been found in various viral pathogens. During the past few years, it has been demonstrated that RNAi, induced by specifically designed double-stranded RNA (dsRNA) molecules, can silence gene expression of human viral pathogens both in acute and chronic viral infections. Furthermore, it is now apparent that in in vitro and in some in vivo models, the prospects for this technology in developing therapeutic applications are robust. However, many key questions and obstacles in the translation of RNAi into a potential therapeutic platform still remain, including the specificity and longevity of the silencing effect, and, most importantly, the delivery of the dsRNA that induces the system. It is expected that for the specific examples in which the delivery issue could be circumvented or resolved, RNAi may hold promise for the development of gene-specific therapeutics.     

RNA干扰与基因敲除

RNAi是指通过双链RNA介导特异性降解靶mRNA,导致转录后水平基因沉默的现象。其作用途径有RdRP依赖的RNAi的途径与非RdRP依赖的RNAi途径2种。利用RNAi的基因敲除技术在dsRNA序列选择、质粒或病毒为载体的dsRNA体内合成、发夹样siRNA的转录、dsRNA的导入方法等方面取得了很大进展,在研究人类或其他生物基因组中未知基因及蛋白质的功能等领域具有诱人的应用前景。