RNAi技术研究新进展

RNA干扰(RNAi)是指双链RNA在细胞内特异性地诱导同源互补的mRNA降解,从而阻断相应基因表达的现象。RNAi在生物界中广泛存在,其发生过程主要分为3个阶段:起始阶段、扩增阶段和效应阶段。它在维持基因组稳定、基因表达调控等方面发挥重要生物学作用。随着人们对RNAi研究的不断深入,目前RNA干扰技术作为基因沉默的一个工具,已被广泛用于基因功能研究、疾病的靶点治疗和寻找新的药物靶标等方面的研究。     

RNA干涉与干细胞

RNA干涉(RNAi)现象普遍存在于生物体细胞中,在理论上已清楚其分子机制,为干细胞研究提供了新的方法。现从RNAi的分子机制、干细胞中的RNAi现象、研究干细胞RNAi效应的方法以及小分子干涉RNA(siRNA)干涉干细胞特异功能基因的检测方法等方面进行了综述。表明应用RNAi技术研究基因功能和干细胞维持及定向分化的调控具有广阔的发展前景。     

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。     

RNAi技术研究进展及其在医学中的应用前景

将双链RNA导入细胞内会引起与其同源基因的沉默,这种现象称为RNA干扰（RNAinterference,RNAi）。就RNAi技术的定义、发现过程、作用机制、产生机理等方面的研究进展作一综述,同时对RNAi技术在医学领域中的应用和存在问题进行了展望。     

RNA干扰的机制及其应用

RNA干扰(RNA interference,RNAi)是真核生物中高度保守的,由小分子干扰RNA(small interfering RNA,si RNA)介导的转录后基因沉默现象,在基因功能的研究中得到了非常广泛的应用,并有望成为小核酸药物在疾病治疗中发挥重要作用。现对近年来RNAi的作用机制、si RNA的产生途径、引起RNAi副作用的原因以及RNAi表达载体的设计这四个方面的国内外研究进展进行了总结,对RNAi与CRISPR技术在应用中的关系进行了探讨,展望了RNAi技术未来的发展。     

RNAi作用机制及应用研究进展

RNA干扰(RNA interference,RNAi)是由小非编码RNA(small non-coding RNA,snc RNA)诱发的基因沉默现象,广泛存在于真核生物中。RNAi现象自发现以来,很快成为生物学研究的热点,并取得了一定成果。就RNAi的作用机制、作用过程的关键因子及其应用的研究进展进行综述,以期为RNAi的进一步研究提供参考。     

RNA干扰技术及其应用

RNA干扰（RNAi)是利用具有同源性的双链RNA诱发序列特异的转录后基因沉默的现象。它可以通过抑制蛋白表达模拟基因敲除技术,从利用体外合成双链RNA到通过质粒稳定表达小型干扰RNA诱发RNA干扰现象,这项技术被不断完善,并被广泛的应用,尽管RNAi的作用机制仍不清楚,但实验证实在RNA干扰过程中,外源的双链RNA在体内会被切割成小片段,新的双链RNA被合成,从而RNAi的作用机制假说正被逐步修正,由于RNAi技术的高效性和特异性,它已经成为基因功能研究的一种新方法。     

RNA干扰在疾病治疗上的应用

RNA干扰(RNA interference,RNAi)是一种双链RNA分子在mRNA水平上引发的特异性基因沉默现象。RNAi在基因治疗方面表现出了光明的前景,已成功地应用于多种疾病的临床治疗。本文主要介绍了RNAi在疾病治疗上的应用及研究进展。     

甲壳动物RNAi技术研究与应用进展

RNA干扰(RNA interference,RNAi)是指由双链RNA(double-stranded RNA,ds RNA)诱发的一种使特定基因沉默的现象。作为一种研究基因功能、发现新基因和抗病毒的新型手段,近年来RNAi技术在昆虫、真菌、植物和哺乳动物等的研究中已被广泛应用,但是在甲壳动物研究中尚处于起步阶段。对甲壳动物RNAi技术实施方法做了简要介绍;着重综述了RNAi技术在甲壳动物CHH家族神经肽类基因功能、蜕皮和生长调控机制、配子及性腺发育调控和甲壳动物抗病毒机制研究上的应用进展。     

昆虫RNAi技术及其应用

RNAi是近几年发展起来的抑制基因表达的新技术。部分昆虫存在RNAi信号的系统性传播现象,可以将dsRNA直接注射进昆虫的卵、血腔或局部组织,引发远距离靶基因的特异性沉默,建立起了Embryo RNAi,Larval RNAi,Adult RNAi,Parental RNAi,Feeding RNAi和基于转基因技术的可遗传RNAi等昆虫RNAi技术,使RNAi迅速成为了研究昆虫尤其是非模式昆虫基因功能的主要方法。文章拟就RNAi的系统性、昆虫RNAi技术及其应用进行综述。     

RNA干扰(RNAi)文库研究进展

RNAi是由双链RNA(dsRNA)引发的转录后基因沉默现象,由dsRNA产生的小分子siRNA会导致生物体内同源转录产物特异性降解,是基因表达调控的重要方式之一。目前RNAi技术已发展成为遗传分析强有力的工具,在基因功能分析鉴定方面发挥越来越大的作用。构建大规模的RNAi文库进而转变成RNAi突变体库是功能基因组学研究的重要手段,因此如何利用简单经济的方法构建特定物种的高效RNAi文库就成为关键问题。综述了目前构建RNAi文库的不同方法以及每种构建方法的优点和存在的不足,为不同研究目的的RNAi文库的构建提供参考。     

Gene silencing in Xenopus laevis by DNA vector-based RNA interference and transgenesis

A vector-based RNAi expression system was developed using the Xenopus tropicalis U6 promoter, which transcribes small RNA genes by RNA polymerase Ⅲ. The system was first validated in a Xenopus laevis cell line, designing a short hairpin DNA specific for the GFP gene. Co-transfection of the vector-based RNAi and the GFP gene into Xenopus XR1 cells significantly decreased the number of GFP-expressing cells and overall GFP fluorescence. Vector-based RNAi was subsequently validated in GFP transgenic Xenopus embryos. Sperm nuclei from GFP transgenic males and RNAi construct-incubated-sperm nuclei were used for fertilization, respectively. GFP mRNA and protein were reduced by -60% by RNAi in these transgenic embryos compared with the control. This transgene-driven RNAi is specific and stable in inhibiting GFP expression in the Xenopus laevis transgenic line. Gene silencing by vector-based RNAi and Xenopus transgenesis may provide an alternative for ＇repression of gene function＇ studies in vertebrate model systems.     

Development of a heat shock inducible and inheritable RNAi system in silkworm

A heat shock inducible and inheritable RNA interference (RNAi) system was developed in the silkworm (Bombyx mori). RNAi transgenic silkworms were generated by injecting silkworm eggs with a piggyBac transposon plasmid carrying RNAi sequence against target gene driven by the Drosophila heat shock protein 70 (HSP70) promoter and the helper plasmid expressing piggyBac transposase. The transgenic EGFP gene and the endogenous eclosion hormone (EH) gene were chosen respectively as the target genes. In the RNAi transgenic silkworms, heat shock at 42 degrees C significantly and specifically reduced the expression of EGFP or EH gene in silkworms according to the corresponding RNAi targeting sequence but not in silkworms with the irrelevant RNAi sequence demonstrating the efficiency and specificity of the RNAi effect. Heat shock in the pupal stage hampered pupal-adult eclosion and reduced egg fertility in EH RNAi transgenic silkworms but not in the wild type or EGFP RNAi transgenic silkworms. The establishment of this heat inducible and inheritable conditional RNA interference system in silkworms provided an approach for the first time to dissect the functions of target genes in silkworms at different stages.     

Gene silencing in Caenorhabditis elegans by transitive RNA interference

When a cell is exposed to double-stranded RNA (dsRNA), mRNA from the homologous gene is selectively degraded by a process called RNA interference (RNAi). Here, we provide evidence that dsRNA is amplified in Caenorhabditis elegans to ensure a robust RNAi response. Our data suggest a model in which mRNA targeted by RNAi functions as a template for 5' to 3' synthesis of new dsRNA (termed transitive RNAi). Strikingly, the effect is nonautonomous: dsRNA targeted to a gene expressed in one cell type can lead to transitive RNAi-mediated silencing of a second gene expressed in a distinct cell type. These data suggest dsRNA synthesized in vivo can mediate systemic RNAi.     

Vectors for RNAi technology in poplar

Abstract: The potential of double-stranded RNA interference (RNAi) technology was studied for down-regulation of gene expression in poplar. A set of vectors was constructed generating RNAs capable of duplex formation of sequences specific for the β-glucuronidase (GUS) reporter gene system. These gene cassettes are driven by the CaMV-35S promoter. To address the question of gene silencing, we tested the functionality of these vectors, both in transient assays by transforming protoplasts with the RNAi constructs, and in stably transformed GUSexpressing poplar plants. Agrobacterium -mediated transformation of those GUS-expressing plants with a GUS-specific RNAi construct showed a strong down-regulation of the reporter gene. From these results we conclude that RNAi is also functional in poplar.