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RNAi--一种抗病毒感染的新方法
RNAi又称之为转录后基因沉默(post transcription gene silencing,PTGS),是广泛存在于植物、线虫、果蝇、真菌和动物中的一种抗病毒机制,有如脊椎动物的免疫系统,它能特异地用于抗病毒感染,是一种有广泛应用前景的抗病毒感染的基因治疗方法,本文就近年来该方法在抗病毒感染方面的研究作一综述.
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番茄丛矮病毒p19蛋白抑制转录后基因沉默作用机制
RNA干扰(RNAinterference,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,这种转录后水平基因沉默(posttranscriptional gene silencing,PTGS)也称RNA沉默(RNA silencing)[1,2].人为地向细胞内导入dsRNA、siRNA,或者是它们的表达载体都可以诱发RNAi,有效地中止同源基因表达.这就为建立基因与表型之间的关系提供了可靠的手段.目前,RNAi技术正因其简捷高效性而广泛应用于功能基因组研究、疾病治疗研究,以及植物抗病毒研究等.
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RNA干扰号慢性疼痛的基因治疗
RNA干扰(RNA interference,BNAi)是1998年Fire等[1]首次发现并命名的,是由双链RNA(dsRNA)分子在细胞内特异性诱导与之同源mRNA降解或翻译抑制,导致基因沉默的现象,是一种典型的转录后基因沉默(post-transcriptional gene silencing,PTGS).RNAi主要的功能特点是其可以调节和关闭基因的表达,进而调控细胞的各种高级生命活动.RNAi技术已经成为模式生物、基因功能、基因治疗等研究领域中有力的工具,本文仅就RNAi在慢性疼痛研究中的进展作-介绍.
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RNA干扰:快速关闭基因表达新技术研究进展
在后基因组时代,基因功能的研究以前所未有的速度快速发展,各种研究基因功能的新技术不断涌现.RNA干扰(RNA interference, RNAi)作为一种新的、强有力的研究工具,在功能基因组学领域具有巨大的应用潜力.所谓RNAi就是利用双链RNA(double-stranded RNA, dsRNA)高效、特异的阻断体内特定基因表达,促使mRNA降解,使细胞表现出特定基因缺失表型的过程,即诱导序列特异的转录后基因沉默(post-transcriptional gene silencing, PTGS)[1].
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We hypothesized that RNA interference to silence Nogo-66 receptor gene expression in bone marrow mesenchymal stem cells before transplantation might further improve neurological function in rats with spinal cord transection injury. After 2 weeks, the number of neurons and BrdU-positive cells in the Nogo-66 receptor gene silencing group was higher than in the bone marrow mesenchymal stem cell group, and significantly greater compared with the model group. After 4 weeks, behavioral performance was signiifcantly enhanced in the model group. Af-ter 8 weeks, the number of horseradish peroxidase-labeled nerve ifbers was higher in the Nogo-66 receptor gene silencing group than in the bone marrow mesenchymal stem cell group, and signiifcantly higher than in the model group. The newly formed nerve ifbers and myelinated ner ve ifbers were detectable in the central transverse plane section in the bone marrow mesenchymal stem cell group and in the Nogo-66 receptor gene silencing group.
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Aquaporin-4 regulates water molecule channels and is important in tissue regulation and water transportation in the brain. Upregulation of aquaporin-4 expression is closely related to cel-lular edema after early cerebral infarction. Cellular edema and aquaporin-4 expression can be determined by measuring cerebral infarct area and apparent diffusion coefficient using diffu-sion-weighted imaging (DWI). We examined the effects of silencing aquaporin-4 on cerebral infarction. Rat models of cerebral infarction were established by occlusion of the right middle cerebral artery and siRNA-aquaporin-4 was immediately injectedvia the right basal ganglia. In control animals, the area of high signal intensity and relative apparent diffusion coefifcient value on T2-weighted imaging (T2WI) and DWI gradually increased within 0.5–6 hours after cerebral infarction. After aquaporin-4 gene silencing, the area of high signal intensity on T2WI and DWI reduced, relative apparent diffusion coefifcient value was increased, and cellular edema was ob-viously alleviated. At 6 hours after cerebral infarction, the apparent diffusion coefifcient value was similar between treatment and model groups, but angioedema was still obvious in the treat-ment group. These results indicate that aquaporin-4 gene silencing can effectively relieve cellular edema after early cerebral infarction; and when conducted accurately and on time, the diffusion coefifcient value and the area of high signal intensity on T2WI and DWI can relfect therapeutic effects of aquaporin-4 gene silencing on cellular edema.
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RNA干扰技术及其临床应用与进展
基因沉默是广泛存在于生物界的古老现象,是生物体抵御病毒或其它外来核酸入侵以及保持自身遗传稳定的保护性机制,广泛存在于真核生物细胞中.通常基因沉默发生在两种水平上:①由于DNA甲基化、异染色质化以及位置效应引起转录水平上的基因沉默(Transcriptional gene silencing,TGS);2在基因转录后水平上通过对目的RNA特异性降解而使基因失活的转录后基因沉默(Post transcriptional gene silencing,PTGS).RNA干扰 (RNA interference,RNAi)即属于转录后水平的基因沉默.随着近年来对RNA干扰机制和功能的深入研究,RNA干扰技术在人类多种疾病的治疗方面显示出了良好的应用前景.本文就RNA干扰技术及其临床应用现状和进展做一综述.
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RNAi技术在肝病研究领域中的进展
RNA和蛋白质在生物体中共同负责基因表达和基因表达的调控,在生命活动中具有重要的作用.RNA干扰(RNA interference,RNAi)是一种由小的双链RNA小分子干扰RNA片段(small interfering RNAs,siRNA)引起与其同源的mRNA的特异性降解和基因沉默现象,即序列特异性地转录后基因沉默(post transcriptional gene silencing,PTGS).RNAi现象是Fire等1998年偶然发现的,后来双链RNA成为一种有用的工具来抑制线虫及其他模式生物的基因表达[1~3].
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Objective:hTe purpose of this study is to examine expression of Vav3 and effect and mechanism of Vav3 gene to regulate inhibitor of apoptosis proteins in human gastri cancer cell line BGC823 is also explored.Methods: hTe expression of Vav3 in gastric cancer tissues and cell lines were detected. Specific siRNA targeting Vav3 were designed, synthesized, and transfected into BGC823. The expression of Vav3 was detected by real-time quantitative PCR and western blot Cytoactive was measured with MTT assay Cell apoptosis rate were determined by lfow cytometry (FCM). hTe expressions of Survivin, c-IAP1, c-IAP2, XIAP, Livin and Caspase-3 were also determined.Results:Vav3 was signiifcantly up-regulated in gastric cancer tissues and gastric cancer cell line (both P<0.01). Cell activity of BGC823 was inhibited after Vav3-siRNA was transfected into BGC823 (P<0.05). hTe apoptosis rate was higher after Vav3-siRNA transfected into BGC823 (P<0.05). hTe expressions of Survivin, c-IAP1, c-IAP2, XIAP were lower in BGC823 after Vav3-siRNA tansfected (both P0.05), and no obviously change was found in Livin (P<0.05). Conclusion:Vav3 gene silencing effectively promoted gastric cancer cell apoptosis.
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RNAi技术综述
RNA干扰(RNA interference,RNAi)现象是指内源性或外源性双链RNA(double strand RNA,dsRNA)介导的细胞内mRNA发生特异性降解,导致靶基因的表达沉默,产生相应的功能表型缺失[1].这一现象属于转录后的基因沉默机制(Posttranscriptional gene silencing,PTGS)[2].
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AIM:NLRP3 inflammasome was identified as the cellular machinery responsible for activation of inflammatory processes .The present study investigated whether the activation of NLRP 3 inflammasomes contributes to hyperhomocysteinemia ( HHcy)-induced in-flammation and atherosclerosis .METHODS:ApoE-/-mice were fed regular diet , high fat ( HF) diet or HF plus high methionine (HM) diet for 10 weeks.NLRP3 shRNA or scramble shRNA viral suspension was injected twice at the 2nd and the 6th weeks after HFHM treatment.The whole aortas and aortic root sections were stained with Oil Red O for atherosclerotic lesion .Plasma lipids, ho-mocysteine ( Hcy) , IL-1βand IL-18 levels were measured .We also examined the effect of Hcy on NLRP 3 inflammasomes activation in THP-1 differentiated macrophages in the presence or absence of NLRP 3 siRNA, caspase-1 inhibitor Z-WEHD-FMK, or antioxidant N-acetyl-L-cysteine ( NAC) .RESULTS:HFHM treatment induced HHcy in ApoE-/-mice.Increased plasma levels of IL-1βand IL-18, aggravated macrophage infiltration into atherosclerotic lesion , and accelerated development of atherosclerosis were detected in HHcy mice, which were associated with the activation of NLRP 3 inflammasomes.Silencing the NLRP3 gene significantly suppressed NLRP3 inflammasomes activation , reduced plasma levels of proinflammatory cytokines , attenuated macrophage infiltration , and improved HHcy-induced atherosclerosis .Moreover, we found that Hcy activated NLRP3 inflammasomes and promoted subsequent production of IL-1βand IL-18 in macrophages, which were blocked by NLRP3 gene silencing, Z-WEHD-FMK, or NAC.CONCLUSION:These data suggest that the activation of NLRP 3 inflammasomes contributes to HHcy-induced inflammation and atherosclerosis .Hcy activates NLRP3 inflammasomes in reactive oxygen species dependent pathway in macrophages .
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RNA干扰在鼻咽癌研究中的进展
RNA干扰(RNAi)是由双链RNA(dsRNA)分子介导的特异系列转录后基因沉默的机制,能高效、特异地抑制靶mRNA的表达.RNAi是一种典型的转录后基因调控方法,又称转录后基因沉默(post-transcriptional gene silencing, PTGS).RNAi现象自1998年被发现以来,研究者对其分子机制进行不断探索,目前其机制已经比较清楚.RNAi 特异效应发生在3个水平:转录后水平、转录水平和翻译水平.由3个效应RNA分子介导,分别为siRNA、shRNA、microRNA(miRNA).转录和转录后水平由siRNA/shRNA介导,翻译水平由miRNA介导.
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RNA干扰与卵巢癌的研究进展
卵巢癌是女性生殖系统常见的三大恶性肿瘤之一,由于缺乏早期诊断方法,手术、放化疗的治疗效果不佳,卵巢癌病死率居妇科恶性肿瘤首位。因而寻求新的方法已成为该领域亟待探讨的重要课题。 RNA 干扰(RNA interference,RNAi)是指在细胞内由双链 RNA (dsRNA)引发的高效特异靶基因表达沉默,通过降解特异mRNA,使细胞表现出相应基因表型缺失的现象。是转录后基因沉默(posttranscriptional gene silencing,PTGS)[1]。利用小干扰RNA 的分子疗法在基因异常表达或突变引起的疾病治疗方面显示出巨大的潜力。 RNAi技术可以特异性敲除特定基因的表达,已被广泛应用于恶性肿瘤的基因治疗领域。近几年应用RNAi技术在卵巢癌基因研究方面取得了突破性的进展。本文就RNAi与卵巢癌的研究进展、存在问题及展望做一简要综述。
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RNA干扰在肝癌治疗中的研究进展
RNA干扰(RNA interference,RNAi)是1998年由FIRE等[1]首次发现并命名的转录后水平基因沉默机制,即将与某一mRNA序列相对应的正义RNA和反义RNA组成的双链RNA(dsRNA)导入细胞,使相应的mRNA降解,抑制细胞特定基因的表达,又称为转录后基因沉默(posttranscriptional gene silencing,PTGS).RNAi技术已经成为研究基因功能、新基因筛选、基因治疗和寻找药物靶点的重要工具.
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RNAi技术的特征及应用前景
RNAi(RNA interference)即RNA干扰,是近几年发现和发展起来的一门新兴的在转录水平上的基因阻断技术.是一种双链RNA(double-stranded RNA,dsRNA)分子在mRNA水平上关闭相应序列基因的表达或使其沉默的过程,也就是序列特异性的转录后基因沉默(post-transcriptional gene silencing,PTGS).
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RNA干扰技术在肿瘤治疗中的应用
RNA干扰.(RNA interference,RNAi)是近年发现的一种重要的基因表达调控方式,是由转入细胞的小干扰双链RNA诱导同源mRNA特异性降解产生的一种转录后基因沉默现象(post transcription gene silencing,PTGS).
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RNA干扰--双链RNA诱导的基因沉默
转录后基因沉默(post-transcriptional gene silencing,PTGS)是分子生物学中热点之一.PTGS在植物和动物中都有发生,并在病毒防御和转座子沉默机制中起着关键作用.RNA干扰(RNA interference,RNAi)是双链RNA(double-stranded RNA,dsRNA)诱导的PTGS,在以线虫为对象的实验中发现并命名.它具有以下特点(以线虫为例):①阻断基因表达的是双链RNA,而不是单链反义RNA;②在转录后水平发挥作用;(实验证实dsRNA和基因外显子部分同源才发挥作用);③具有高度特异性,即只抑制与dsRNA同源的基因;④具有很高的效率,几个拷贝的dsRNA即可引起细胞内特异基因的表达大幅降低;⑤干扰作用可扩散,从一点注入dsRNA,作用可遍及全身;⑥能遗传给下一代,经过dsRNA处理后的线虫的子一代中仍然发生RNAi现象[1].