植物miRNA抗胁迫机理研究进展

植物microRNA（miRNA）是一类约有21个核苷酸组成的小RNA分子,属于非编码单链RNA家族。miRNA与靶mRNA互补配对结合,以抑制基因表达或切割mRNA的方式,实现基因的负调控。miRNA对植物基因表达、生长发育和抵抗胁迫等有十分重要的影响。综述了植物miRNA特点以及miRNA抗胁迫机理的最新研究进展。     

环状RNA:潜在的新型miRNA活性调控分子

环状RNA(circular RNA,circRNA)是近年来RNA领域最新的研究热点.它是一类由特殊的选择性剪切产生且在真核细胞中广泛表达的环形内源性RNA分子.研究发现,circRNA富含microRNA(miRNA)结合位点,可以发挥竞争性内源RNA作用,作为miRNA"海绵"来解除对其靶基因的抑制效应.近年来,circRNA作为一种新型调控分子调控miRNA功能的发挥,受到众多研究者的青睐.本文综述circRNA的产生机制,及其调控miRNA的最新研究进展与研究方法等.     

辐射相关microRNA研究进展

microRNA(miRNA)是一类由内源基因编码的长度约22核苷酸的非编码单链RNA分子,主要以碱基互补方式与靶基因mRNA的3'非翻译区特异性结合,通过降解mRNA或抑制蛋白翻译合成而实现对靶基因的转录后调控。研究发现,miRNA在电离辐射诱导的生物学反应中发挥重要作用。我们从以下层面概述辐射相关miRNA的研究进展,即辐射调节miRNA表达、miRNA对辐射后DNA损伤的调节、miRNA参与的辐射生物学效应。     

法国发现miRNA前体新功能

<正>法国图卢兹第三大学研究发现,植物中miRNA的初级转录本primiRNA能够编码一类具有调节功能的多肽,促进miRNA积累,调节基因表达。这一研究发现了pri-miRNA的新功能,为基因调控研究开辟了新的领域。成果在《自然》杂志在线发表。MicroRNA(miRNA)是一类具有调节作用的小RNA分子,能够通过结合和切割mRNA,抑制蛋白质翻译过程,从而特异性抑制靶向基因表达。细胞在形成成熟miRNA之前,会先转录出     

miRNA在细胞因子表达调控中的作用

最新研究表明miRNA在免疫系统的精细调节中发挥重要作用,本综述则重点探讨miRNA如何调节细胞因子基因的机制。细胞因子转录后水平的调节主要是通过使富含腺嘌呤/尿嘧啶元件(AU-rich element,ARE)稳定性降低,然而miRNA表达具有空间和时间上的特异性,使得其在上述过程中发挥了重要作用。深入理解miRNA调节免疫反应的机制,不仅有助于鉴定调节免疫反应的新靶标,还有助于建立基于miRNA的有效新疗法。     

miRNA,lncRNA与心血管疾病

近年来,心血管疾病在我国的发病率和致死率呈逐年上升趋势,已成为威胁我国公众健康的重要疾病之一.尽管长期的研究使人们对心血管疾病有了一定的了解,但是其发病机制尚未完全清楚.非编码RNA(non-coding RNA,ncRNA)是指转录组中不编码蛋白的功能性RNA分子,包括微小RNA(microRNA,miRNA)和长链非编码RNA(long non-coding RNA,lncRNA)等.miRNA是一类在进化上高度保守,具有转录后调节活性的单链非编码小分子RNA.而lncRNA是一类转录本长度超过200个核苷酸的功能性非编码RNA分子.研究表明,这些功能性ncRNA不但在细胞增殖、分化和衰老过程中发挥着重要作用,还参与了癌症、神经退行性疾病和心血管疾病等疾病的病理进程.本文将着重概述miRNA和lncRNA在心血管疾病中的作用及其最新研究进展.     

干扰小RNA与微RNA

干扰小RNA（small interfering RNA;siRNA）和微RNA（microRNA;miRNA）是两种序列特异性地转录后基因表达的调节因子,它们的相关性密切,既具有相似性,又具有差异性。该文主要介绍这两种小RNA分子的产生、作用机制,以及两者之间的联系与区别。     

miRNA体内作用靶标鉴定的策略

miRNAs是一类重要的基因表达调节因子,近年的研究表明miRNA在控制细胞的生长发育、分化、凋亡等过程中发挥着十分重要的作用。但对miRNA作用机制和分子功能的研究却进展缓慢,归其原因是miRNA和靶标之间非完全配对,缺乏快捷有效的靶标鉴定方法。因此,就miRNA靶标鉴定的策略作一综述。miRNA调节靶标的鉴定有助于揭示一些疾病的致病机理,发现可用于治疗的新分子靶标,为基因治疗奠定基础。     

小RNA家族的新成员—piRNA

microRNA (miRNA)和small interfering RNA(siRNA)在真核生物生命活动的基本过程中发挥着重要的调节作用。随着对siRNA和miRNA研究的不断深入, 最近科学家在研究大鼠雄性精子时发现哺乳动物睾丸内存在另一种新型的小RNA分子, 该分子在精子发生过程中起着重要的生理调节作用, 该种小分子RNA被命名为piRNA, 在功能、分布和分子特征等方面piRNA较miRNA和siRNA存在着显著的不同, 对piRNA深入研究有望揭示出机体内在的基因表达调节机制。     

MicroRNA研究进展

在多细胞生物的基因组中都存在一类非编码RNA基因,能够产生长度约为22个核苷酸的小分子RNA,称为microRNA(miRNA),具有调节其他基因表达活性的功能。miRNA的发现,为我们理解复杂的基因调节网络开辟了新的空间。本文概述了miRNA的产生过程、转录抑制机理、研究并预测miRNA的方法等。     

Reexamining assumptions about miRNA-guided gene silencing

MicroRNAs (miRNAs) are short endogenously expressed RNAs that have the potential to regulate the expression of any RNA. This potential has led to the publication of several thousand papers each year connecting miRNAs to many different genes and human diseases. By contrast, relatively few papers appear that investigate the molecular mechanism used by miRNAs. There is a disconnect between rigorous understanding of mechanism and the extraordinary diversity of reported roles for miRNAs. Consequences of this disconnect include confusion about the assumptions underlying the basic science of human miRNAs and slow development of therapeutics that target miRNAs. Here, we present an overview of investigations into miRNAs and their impact on gene expression. Progress in our understanding of miRNAs would be aided by a greater focus on the mechanism of miRNAs and a higher burden of evidence on researchers who seek to link expression of a particular miRNA to a biological phenotype.     

禾花鲤与建鲤肌间骨miRNAs测序与分析比较

为了研究禾花鲤(Rice flower carp)肌间骨柔软的分子调控机制,采集禾花鲤和建鲤(Jian carp)的肌间骨进行micro RNAs (miRNAs)的高通量测序,并进行了生物信息学分析。从禾花鲤肌间骨的小RNA文库测序获得18 32 nt的高质量miRNA序列25474895条、鉴定出成熟miRNAs 595种,而从建鲤文库获得miRNA序列24625715条、成熟miRNAs 570种。表达差异分析结果显示,与建鲤相比,禾花鲤肌间骨中84个miRNAs呈上调表达、267个呈下调表达。禾花鲤下调表达的miRNAs中有7条为已报道的促进人类成骨的miRNAs,上调表达的miRNAs中有6条为已报道的抑制人类成骨的miRNAs。因此推测禾花鲤可能是通过下调表达促进成骨的miRNAs及上调表达抑制成骨的miRNAs来抑制成骨过程,从而维持其肌间骨细小及柔软的特性。研究为国内首次开展禾花鲤肌间骨发育的分子调控机制研究,为水产动物肌间骨发育的研究奠定了基础。     

MicroRNA与细胞信号转导通路研究进展

成熟的microRNA(miRNA)是一种长约22 nt的非编码RNA,通过与靶基因的3′非翻译区(3′UTR)结合来调控靶基因的表达。直至目前,在不同物种中发现的miRNA达6 397个。miRNA的发现为基因表达调控研究打开了新的窗口。目前研究者不仅证实miRNA在生物体生长、发育和疾病发生等过程中发挥着重要的作用,而且开始进一步探寻其发挥作用的分子机理。综述了miRNA与细胞信号转导途径之间的关系,从而有助于从基因水平上理解疾病的发生机制,为疾病的诊断、治疗提供依据。     

microRNAs在骨形成中的作用——运动调控骨代谢的新机制

microRNAs(miRNAs)是一类具有组织或发育阶段特异性的小分子、非编码单链RNA,通过转录后与靶基因特定序列结合来发挥其调控作用. 作为骨中的最重要的两种重要细胞--成骨细胞和破骨细胞,其代谢平衡与骨形成密切相关.研究发现,miRNAs在调节成骨细胞和破骨细胞分化及功能发挥上具有重要作用,并且运动训练可通过调节miRNAs进而调控骨细胞分化. 一般来说,适宜强度运动训练可上调某些miRNAs表达来促进成骨细胞或破骨细胞分化及功能;当失重或过量运动时,则会产生抑制作用. 本文就miRNAs调控干细胞向成骨细胞和破骨细胞分化及功能发挥的分子生物学机制以及运动训练调节与骨代谢相关miRNAs表达的研究进展进行综述.     

Downregulation of miR-31, miR-155, and miR-564 in chronic myeloid leukemia cells

Background/Aims

MicroRNAs (miRNAs) are short non-coding regulatory RNAs that control gene expression and play an important role in cancer development and progression. However, little is known about the role of miRNAs in chronic myeloid leukemia (CML). Our objective is to decipher a miRNA expression signature associated with CML and to determine potential target genes and signaling pathways affected by these signature miRNAs.

Results

Using miRNA microarrays and miRNA real-time PCR we characterized the miRNAs expression profile of CML cell lines and patients in reference to non-CML cell lines and healthy blood. Of all miRNAs tested, miR-31, miR-155, and miR-564 were down-regulated in CML cells. Down-regulation of these miRNAs was dependent on BCR-ABL activity. We next analyzed predicted targets and affected pathways of the deregulated miRNAs. As expected, in K562 cells, the expression of several of these targets was inverted to that of the miRNA putatively regulating them. Reassuringly, the analysis identified CML as the main disease associated with these miRNAs. MAPK, ErbB, mammalian target of rapamycin (mTOR) and vascular endothelial growth factor (VEGF) were the main molecular pathways related with these expression patterns. Utilizing Venn diagrams we found appreciable overlap between the CML-related miRNAs and the signaling pathways-related miRNAs.

Conclusions

The miRNAs identified in this study might offer a pivotal role in CML. Nevertheless, while these data point to a central disease, the precise molecular pathway/s targeted by these miRNAs is variable implying a high level of complexity of miRNA target selection and regulation. These deregulated miRNAs highlight new candidate gene targets allowing for a better understanding of the molecular mechanism underlying the development of CML, and propose possible new avenues for therapeutic treatment.     

Expression profile analysis of microRNAs during hair follicle development in the sheep foetus

MicroRNAs (miRNAs) regulate the development and growth cycle of hair follicles (HFs). The molecular mechanism by which miRNAs determine the development of HFs in the sheep foetus remains elusive. In this study, the expression profiles of miRNAs at 11 development periods (45, 55, 65, 75, 85, 95, 105, 115, 125, 135 and 145 d) in sheep foetus skin were analysed by high-throughput sequencing and bioinformatics analysis. A total of 72 conserved miRNAs, 44 novel miRNAs and 32 known miRNAs were significantly differentially expressed. qRT-PCR results for 18 miRNAs were consistent with the sequencing data. 85 d of foetal development was the starting point for secondary hair follicle (SF) development according to tissue morphology and cluster analysis. In SF development, the prolactin signalling pathway and platelet activation played important roles, and 10 miRNAs were potential candidate miRNAs in SF initiation.     

Analysis of miRNA-seq combined with gene expression profile reveals the complexity of salinity stress response in <Emphasis Type="Italic">Oryza sativa</Emphasis>

High salinity is a major abiotic stressor that affects crop productivity and quality. While proper seedling growth is critical for crop reproduction under high salinity stress. Nowadays, genes/miRNAs expression is used for studying salinity stress response in rice seedlings. However, analysis of miRNA combined with gene expression is rare. To this end, we used miRNA-seq and gene expression profile to ascertain 6335 genes (3276 genes up-regulated, 3059 genes down-regulated) and 126 miRNAs (47 miRNAs up-regulated, 79 miRNAs down-regulated) that respond to salinity stress in rice seedlings. We then used these 126 miRNAs (including the novel miRNA osa-Chr12_1506) to identify 121 differentially expressed predicted target genes. In addition, we identified 34 miRNA-target RNA pairs, consisting of 9 differentially expressed miRNAs with complementary expression patterns. Combined with previous studies, we proposed a simple model for the molecular mechanism of a 12-h salinity stress response in rice seedlings. The findings lead to a deeper understanding of the function of miRNAs and genes that respond to salinity, and contributed to the elucidation of the complex mechanisms activated by salinity stress.     

Effects of vitamin E on expressions of eight microRNAs in the liver of Nile tilapia (Oreochromis niloticus)

Currently, microRNAs (miRNAs) are known to regulate cellular processes such as apoptosis, differentiation, cell cycle, and immune functions, and their expression can be altered by distinct stress conditions, such as oxidative stress. In immune systems of fish, vitamin E (VE) has a defined role as an antioxidant. In order to understand the molecular mechanism of vitamin E defending from oxidative stress, three groups of juvenile Nile tilapia (Oreochromis niloticus) (initial weight 3.25 ± 0.02 g) were fed to satiation with 3 semi-purified diets containing VE (dl-α-tocopherol acetate) of 0, 50, and 2500 mg/kg supplementation, respectively, with the expressions of eight miRNAs (miR-21, miR-223, miR-146a, miR-125b, miR-181a, miR-16, miR-155 and miR-122) in the liver of tilapia subsequently detected after 8-week growth experiment. Results showed that VE-deficient (0 mg/kg supplementation) decreased the activity of superoxide dismutase (SOD), and decreased the expressions of miR-223, miR-146a, miR-16 and miR-122, while excessive supplementation of VE (2500 mg/kg) decreased SOD activity and increased the expressions of all the eight miRNAs. The targets of the eight miRNAs were further predicated with bioinformatic approach and the possible regulating mechanisms of VE via miRNAs were analyzed. The present study confirmed that the differences in dietary VE affected expression of hepatic miRNAs which may partly demonstrate the molecular mechanism of VE, and the new idea of introducing miRNAs into research will provide the basic data for researches of molecular nutrition.     

miRNA的研究进展

微小RNAs(microRNAs,miRNAs)是一类长度在22nt左右、能调节mRNAs表达的非编码RNA基因产物。miRNAs最初在线虫体内被发现,广泛存在于真核生物体内,对于生物体的发育等诸多方面有调节作用,并在进化中保守。miRNAs作用机制尚不完全清楚,但已知其能通过与mRNAs的3′非翻译区结合而影响翻译水平。部分miRNAs可以行使类似siRNAs的作用。本文就miRNAs的生物发生、作用机制、应用方向等研究进展作一综述。相信对miRNAs的深入认识将为基因功能研究提供新思路,同时也将为基因操作技术提供新的手段。