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通过实验手段向细胞内导入长的双链RNA或者转基因可以产生一些短片段的双链RNA,这些短片段的双链RNA可以通过促使特定基因的mRNA降解来高效、特异地阻断体内特定基因的表达,使细胞出现特定基因缺失的表型,称为RNA干扰(RNA interference,RNAi)。SiRNA(small interference RNA)就是这种短片段双链RNA分子,能够以序列同源互补的mRNA为靶目标,降解特定的mRNA。基本上所有的生物体内也都存在一种内源的小分子RNA,为单链RNA,由基因组转录生成,但是不编码蛋白质,它们的功能在于调节mRNA的翻译,称为miRNA,是由具有发夹结构的前体剪切产生的。RNAi的发现具有划时代的意义,它不仅揭示了细胞内基因沉默的机制,而且有望成为后基因组时代基因功能分析的有力工具,极大地促进了人类揭示生命奥秘的进程。 相似文献
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Fruit ripening is a complex process and is regulated by many factors.Ethylene and polygalacturonase (PG),lipoxygenase (LOX),expansin (EXP) are all critical regulating factors in fruit ripening and softening process.With antisense,ACS tomato,Nr mutant tomato and cultivated tomato as materials,Northern blot hybridization showed that PG,LeEXP1 and LOX expressed differently in different parts of cultivated tomato fruit during ripening,which was related to fruit ripening.The ripening process of columella and radial pericarp was faster than pericarp.In both Nr mutant and antisense ACS transgenic tomato fruit,expression levels of PG,LeEXP1 and LOX were generally lower than those in cultivated fruit but still related to fruit ripening.The expression levels of PG,LeEXP1 and LOX increased in the mature green tomato fruits after 0.5 h treatment with ethylene ( 100 μL/L).These results indicate that gene expression of PG,LeEXP1 and LOXwere positively regulated by ethylene.The time and cumulative effect of the concentration exists in the expression of PG regulated by ethylene.The regulation of LOX expression mainly depended on the fruit development after great amount of ethylene was produced.PG played a major role in ripening and softening of tomato fruit,and cooperated with the regulation of EXP and LOX. 相似文献
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长链非编码RNA（IncRNAs）是真核细胞中转录本长度超过200nt的非编码RNA。近年来的研究表明lncRNAs具有一系列的重要功能,包括影响转录、RNA剪切、翻译、核因子转运、基因重排及染色质修饰等,lncRNAs的异常表达常与肿瘤、神经退行性疾病、心血管系统疾病等的发生发展密切相关,因此对lncRNAs的研究将有助于对机体生理病理反应的内在机制形成更为系统的认识。该文就lncRNAs的研究策略及其在神经退行性疾病中的研究进展进行了综述,以期为神经系统调控网络的建立及神经退行性疾病的防治提供新的思路。 相似文献
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增殖细胞核抗原(proliferating cell nuclear antigen,PCNA),也称周期蛋白或DNA聚合酶的辅助蛋白,是真核细胞合成所必需的核蛋白,在DNA复制中起重要作用。前期实验发现日本七鳃鳗肝脏cDNA文库的表达序列标签(Expressed Sequence Tag,EST)中存在与高等脊椎动物pcna基因同源的序列。提取日本七鳃鳗(Lampetra japonica)肝脏组织RNA,通过RT-PCR方法扩增七鳃鳗pcna基因,对其进行生物信息学分析,并将Lj-pcna基因成功构建到pGFP-N2真核表达载体上,重组质粒PGFP-N2-Lj-pcna转染人Hela细胞,荧光显微镜下观察有荧光蛋白的表达。日本七鳃鳗pcna基因的真核表达载体成功构建和转染,为探讨七鳃鳗pcna基因功能研究及其它七鳃鳗相关研究提供条件。 相似文献
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The focus of this Research Experience for Undergraduates (REU) project was on RNA secondary structure prediction by using a lattice walk approach. The lattice walk approach is a combinatorial and computational biology method used to enumerate possible secondary structures and predict RNA secondary structure from RNA sequences. The method uses discrete mathematical techniques and identifies specified base pairs as parameters. The goal of the REU was to introduce upper-level undergraduate students to the principles and challenges of interdisciplinary research in molecular biology and discrete mathematics. At the beginning of the project, students from the biology and mathematics departments of a mid-sized university received instruction on the role of secondary structure in the function of eukaryotic RNAs and RNA viruses, RNA related to combinatorics, and the National Center for Biotechnology Information resources. The student research projects focused on RNA secondary structure prediction on a regulatory region of the yellow fever virus RNA genome and on an untranslated region of an mRNA of a gene associated with the neurological disorder epilepsy. At the end of the project, the REU students gave poster and oral presentations, and they submitted written final project reports to the program director. The outcome of the REU was that the students gained transferable knowledge and skills in bioinformatics and an awareness of the applications of discrete mathematics to biological research problems. 相似文献
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MicroRNAs (miRNAs or miRs) are endogenous non-coding RNAs that negatively regulate gene expression by binding to the 3′ non-coding regions of target mRNAs, resulting in their cleavage or blocking their translation. miRNAs may have an impact on cell differentiation, proliferation, and survival, and their deregulation can be inclined to diseases and cancers, including thyroid tumors. The purpose of this review is to summarize the existing findings of deregulated miRNAs in different types of thyroid tumors and to exhibit their potential target genes, especially to demonstrate those involved in tumor invasion and metastasis. In addition, new findings of circulating miRNA expression profiles, single nucleotide polymorphism (SNP) in thyroid tumors, and the correlation of somatic mutations with deregulated miRNA expression in thyroid tumors were all included in this review. 相似文献
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核糖体是细胞生长所需的蛋白质合成的动力工厂,每一个核糖体的大小为4兆而顿,有18S、5．8S、28S和5S四种RNA及80S等蛋白质组成,细胞中约有50％的RNA是核糖体RNA,这些RNA直接或间接地参与形成数百万的核糖体,因此,核糖体RNA基因的转录调控机制一直是细胞生长和细胞周期调控研究的热点,细胞通过进化已经形成一套完整的配合RNA聚合酶共同完成的核糖体RNA转录调控机制。本文从核糖体RNA基因结构出发,就染色质重塑、组蛋白乙酰化及细胞周期三个方面探讨核糖体RNA转录调控机制。 相似文献
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Wen-biao CHEN Jian-rong HUANG Xiang-qi YU Xiao-cong LIN Yong DAI 《Journal of Zhejiang University. Science. B》2015,16(3):235-250,166
目的:寻找来源于Alport综合征患者与正常对照者的多能干细胞差异性表达的microR NA,并对差异性表达的microR NA靶基因进行预测。创新点:本研究不同于一般的试验标本,试验标本是来源于尿肾脏管细胞诱导而成的多能干细胞。基于Alport综合征是遗传疾病,我们对一遗传家系进行了系统的分析。寻找特异性的差异性表达microR NA及其靶基因,从基因水平对Alport综合征进行研究。方法:在前期工作中,成功地从实验者与对照者的尿肾脏管细胞诱导成多能干细胞。运用高通量测序技术分析并发现实验者与对照者之间差异性表达的microR NA。对差异性表达的microR NA靶基因进行预测,并进行靶基因聚集分析,研究靶基因主要参与的生物学过程。同时进行靶基因信号传导通路的分析,研究靶基因主要参与的细胞信号传导通路。结论:在实验组与对照组之间,发现了30个具有显著差异性表达的microR NAs,包括19个上调表达与11个下调表达。差异性表达的microR NA的靶基因主要聚集在细胞膜和细胞代谢过程;靶基因主要参与嘌呤代谢通路与丝裂原活化蛋白激酶(MAPK)通路。 相似文献
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孙亮先 《泉州师范学院学报》2004,22(2):94-99
对GenBank中9215条来源于水稻(Oryza sativa L.ssp．Indica)胚乳cDNA库的3’EST进行了分析，获得20个淀粉合成相关基因的表达丰度信息，研究发现淀粉合成的5个关键酶的编码基因，ADPG焦磷酸化酶基因、ADP—葡萄糖淀粉合成酶、淀粉分支酶、淀粉去分支酶、蜡质基因的表达丰度极高，表明该时期水稻胚乳内淀粉合成反应非常强烈，研究发现在淀粉合成途径中存在功能相关的基因协同表达的现象，章结合所获得的基因表达信息对淀粉合成的分子机理进行了探讨。 相似文献
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Qiao-ling GU Yan ZHANG Xi-mei FU Zhao-lian LU Yao YU Gen CHEN Rong MA Wei KOU Yong-mei LAN 《Journal of Zhejiang University. Science. B》2020,21(1):77-86
目的:通过3-溴丙酮酸(3-BrPA)处理秀丽隐杆线虫(Caenorhabditis elegans),观察3-BrPA对线虫的毒性和生存周期的影响。通过秀丽隐杆线虫RNA干扰(RNAi)和突变株,分析3-BrPA对线虫糖酵解途径己糖激酶家族和药物代谢的关键酶细胞色素P450(cytochrome P450,CYP)家族的影响。创新点:首次报道了3-BrPA对秀丽隐杆线虫有毒性作用,己糖激酶是3-BrPA对线虫作用的重要靶点,而CYP-35A家族是线虫代谢3-BrPA的主要酶类。方法:用不同浓度的3-BrPA处理秀丽隐杆线虫,每24 h监测一次存活率;用实时荧光定量聚合酶链反应(qPCR)检测代谢相关基因的表达;通过RNAi沉默己糖激酶家族基因hxk-1、hxk-2和hxk-3;计算3-BrPA处理hxk家族RNAi株和细胞色素P450 cyp-35家族突变株后的致死中浓度(LC50)。结论:3-BrPA对线虫有明显的毒性效应(图1);与对照组比较,3-BrPA处理组的线虫平均寿命明显缩短(图2);3-BrPA处理线虫后hxk-1、hxk-2和hxk-3的信使RNA(mRNA)表达明显升高(P<0.05,图5);3-BrPA处理hxk RNAi株后的LC50均减小(P<0.05,表5);3-BrPA处理cyp-35突变株后的LC50也均减小(P<0.05,表6)。综上所述,3-BrPA的毒性与其对秀丽隐杆线虫己糖激酶代谢的影响密切相关;CYP-35家族在线虫中对3-BrPA代谢中起着关键作用。 相似文献
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核糖体是细胞生长所需的蛋白质合成的动力工厂,每一个核糖体的大小为4兆而顿,有18S、5.8S、28S和5S四种RNA及80S等蛋白质组成,细胞中约有50%的RNA是核糖体RNA,这些RNA直接或间接地参与形成数百万的核糖体,因此,核糖体RNA基因的转录调控机制一直是细胞生长和细胞周期调控研究的热点,细胞通过进化已经形成一套完整的配合RNA聚合酶共同完成的核糖体RNA转录调控机制。本文从核糖体RNA基因结构出发,就染色质重塑、组蛋白乙酰化及细胞周期三个方面探讨核糖体RNA转录调控机制。 相似文献
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Salt stress affects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and analyzed them using the technique for order preference by similarity to ideal solution analysis to select the optimal trehalose concentration for treatment. We also determined the contents of sugar and abscisic acid(ABA) and detected the expression of genes involved in the metabolism of sugar and ABA by quantitative real-time PCR. Results showed that the optimal trehalose concentration was 2 mmol/L for tomato seedlings under salt stress. Exogenous trehalose decreased the starch content and increased the soluble sugar content by affecting the expression of genes related to the metabolism of starch and soluble sugar. Exogenous trehalose altered the accumulation and distribution of sugar by inducing the upregulation of sugar transporter genes. Furthermore, trehalose increased the ABA content to induce salt stress response by regulating the expression of genes related to the synthesis and metabolism of ABA. In conclusion, trehalose can effectively alleviate salt stress and enhance salt tolerance of tomato. These findings provide a novel perspective and a better resource to investigate the salt tolerance mechanism and a new method for alleviating salt stress in tomato. 相似文献
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吴建桥 《孝感职业技术学院学报》2007,10(3):105-109
miRNA是一类高度保守的非编码RNA,为21-25nt的单链型RNA(ssRNAs),由70-90nt的可形成发夹状的内源性转录前体pri-miRNA加工而成,miRNA与靶mRNA的3'-UTR碱基配对,通过抑制mRNA的翻译或直接使mRNA降解,在转录后水平使基因产生沉默,研究发现人类全部基因的三分之一都受到miRNA的调控,这表明miRNA分子实际上是基因调控网络中的核心成分。近来研究发现miRNA与人类的某些疾病密切相关。文章综述了miRNA的基因调控原理和临床研究进展。 相似文献
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RNAi是与靶基因序列同源的双链RNA（dsRNA）所诱导的一种特异性基因沉默现象。RNAi是生物体进化过程中抵御外来基因和病毒感染的进化保守机制,是真核生物中存在的一种抗病毒入侵、抑制转座子活动、调控基因表达的监控机制,具有重大生物学意义。RNA干扰技术的发现及其作为基因敲除工具在模式生物、哺乳动物细胞和体内的成功应用的例子确保了它在药学研究中的作用。越来越多的研究显示RNAi在药物研发中显示出极大潜力,目前已有部分RNAi药物进入临床试验阶段。本文将从两个方面来论述RNAi在药学的应用：一是RNAi在药物靶点鉴定中的运用;二是siRNAs作为药物在疾病治疗中的作用。 相似文献
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Lia Midori Nascimento Meyer Gilberto Cafezeiro Bomfim Charbel Niño El-Hani 《Science & Education》2013,22(2):345-374
It is widely acknowledged in the literature on philosophy of biology and, more recently, among biologists themselves that the gene concept is currently in crisis. This crisis concerns the so-called “classical molecular concept”, according to which a gene is a DNA segment encoding one functional product, which can be either a RNA molecule or a polypeptide. In this paper, we first describe three categories of anomalies that challenge this way of understanding genes. Then, we discuss proposals for revising the gene concept so as to accommodate the increasingly known complexity of genomic architecture and dynamics. Our intention is to provide an informative overview of recent proposals concerning how we should conceive of genes, which are probably not very familiar to many science educators and teachers, but can bring relevant contributions to genetics teaching, in particular, to a more critical treatment of genes and their role in living systems. 相似文献
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在SL反式剪接过程中,生物利用SL RNA分子上的SD位点和pre-mRNA分子上的SA位点,在剪接体的作用下,将SL作为小型外显子加到pre-mRNA上形成成熟的mRNA。SL反式剪接这一古老的生物学过程在那些进化缓慢的分子中被完整地保留了下来。不同生物间的SL在大小和组成上有时差别很大;个别生物中还存在着组成完全不同的两种SL,它们在pre-mRNA的加工过程中有着不同的作用。几乎所有的SL RNA在结构上有着惊人的相似之处,包括5’末端的TMG帽子结构、保守的SD位点、Sm位点、SL RNA二级结构等。由于pre-mRNA在转录过程中丢失了SA位点或获得了SD位点,大多数脊椎动物在进化过程中丢失了SL反式剪接方式,而这种丢失可能是导致脊椎动物C值增高的原因之一。 相似文献