环状RNA研究进展

环状RNA (circular RNA, circRNA)是一类不具有3’端poly(A)和5’端帽子结构的、以共价键首尾相连的单链内源闭合环状RNA。CircRNA具有广泛性、多样性、稳定性和保守性等特点,其具有转录调控和蛋白质翻译等功能。本文从circRNA的生物合成机制、分类、表达、生物学功能、与疾病的关系,以及鉴定与分析方法等方面对近年来的研究进展作一综述,并展望了circRNA的应用前景和研究方向。     

环状RNA研究进展

环状RNA(circRNA)出现在转录后的剪切过程中,单链的RNA分子通过共价结合形成一个环形。高通量测序技术的进步对线性非编码RNA(nocoding linear RNA,NCL)进行了全面的探究,这使得NCL重新走入研究者的视野中,尤其是环状RNA。环状RNA已被证实其丰富,高度表达,和进化保守等特性。一些环状RNA已经被证明能够影响microRNA对基因的调控,可以作为miRNA海绵体,并可能对亲本基因有转录调节的作用,有翻译以及其它的一些功能。并且对一些疾病有着重要的作用,对阿尔兹海默症、糖尿病、缺血性心脏病以及一些癌症都有着调控作用,既可以调节疾病的发展也可以作为一种生物标记物来对疾病进行检测。对环状RNA的形成机制、功能、检测方法、novel环状RNA的鉴定以及疾病相关性进行了总结与概述,并对未来研究进行了展望。     

环状RNA作为生物标志物的研究进展

环状RNA(circRNA)是一种共价闭合环状结构的非编码RNA,与线性RNA有显著差别。circRNA通过外显子或内含子的反向剪接进而环化形成完整的环形结构。近年研究已证实circRNA在基因的表达调控和肿瘤等疾病的发生和发展中发挥着重要作用,提示circRNA可能具有巨大的临床诊疗价值。就circRNA的形成、特征、功能,特别是其作为肿瘤生物标志物的研究进展做简要综述。     

环状RNA在人类疾病中的作用及研究进展

环状RNA（circular RNA,circRNA）是一类广泛表达于真核细胞的环形RNA,多起源于蛋白编码基因。近年来发现circRNAs可通过如miRNA“海绵”等作用模式在基因的表达中发挥重要的调控作用,存在器官组织特异性的表达谱,并且越来越多的证据表明circRNAs可能是一种潜在的疾病标志物和治疗靶点。本文将对circRNAs近年在疾病中的研究进展进行综述,具体分为以下几个方面：（1）circRNAs的基本特征;（2）circRNAs的合成调控;（3）环状RNA介导基因表达的调控机制;（4）circRNAs在肿瘤性疾病中的作用;（5）circRNAs在感染免疫相关性疾病中的作用;（6）circRNAs在心血管疾病中的作用;（7）研究展望。     

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.     

环状RNA在慢性病发病中作用机制的研究进展

环状RNA作为一种对基因表达进行精细调节的重要非编码RNA,不仅增加了非编码RNA介导的基因调控网络的复杂度,也加深了疾病发病机制研究的深度。虽然近年来环状RNA的功能研究有了长足的进步,确定了其作为ceRNA能够特异性吸附miRNA,解除相应miRNA对下游靶mRNA的抑制作用,此类研究也表明核外环状RNA介导的凋亡活化,增殖抑制和细胞与细胞间的交流在疾病发生发展过程中是至关重要的,但我们对环状RNA的了解还只是冰山一角,特别是病理状态下其作用的具体机制仍然需要我们不断探索。在此,本综述的主要目的是回顾目前关于环状RNA在心血管疾病、中枢神经系统疾病和癌症等慢性病领域的研究,探讨以上慢性病发病过程中环状RNA所起的作用以及展望未来环状RNA在疾病发病机制领域的研究。     

环状RNA翻译在癌症中的研究进展

环状RNA是一类有着独特环状结构的非编码RNA,它在生物体内有微小RNA分子海绵、蛋白质脚手架、调控基因转录、调控可变剪接、进入外泌体等多种经典功能机制。虽然环状RNA被定义成一种非编码RNA,但随着生物信息学和翻译组学的发展与应用,越来越多的研究发现,环状RNA是能够被翻译的。该文介绍了现在主要的环状RNA翻译的调控机制,总结了目前研究环状RNA翻译的常用数据库,汇总了环状RNA翻译的蛋白质和多肽在癌症中的最新发现,讨论了环状RNA翻译的应用前景和问题,旨在促进发现更多由环状RNA编码的与肿瘤相关的蛋白质和多肽。     

外泌体环状RNA在泌尿系统肿瘤中的研究进展

外泌体是一种包含了复杂RNA和蛋白质的膜性囊泡，其主要来源于细胞内溶酶体微粒内陷形成的多囊泡体，经多囊泡体外膜与细胞膜融合后释放到胞外基质中。外泌体在肿瘤微环境中介导细胞间通讯，其功能取决于来源的细胞类型。环状RNA是一类由前体mRNA反向剪接生成的非编码RNA，在外泌体中富集且稳定表达。外泌体环状RNA在疾病中发挥了重要的调控作用，其作为肿瘤标志物和治疗靶点的临床应用前景与价值现已成为研究热点。本文就外泌体环状RNA在泌尿系统肿瘤中的研究进展作一综述。     

circRNA在病毒感染及相关疾病诊断中的研究进展

环状RNA(circular RNA,circRNA)是一种新型非编码RNA,由mRNA在转录后加工过程中反向剪接形成。不同于线性RNA,circRNA是以共价键连接形成的闭合环状结构,缺少5?末端帽子和3?末端poly(A)尾巴结构。circRNA可作为miRNA(microRNA)的分子海绵,也可在细胞发生过程中发挥多种功能。此外,circRNA在机体免疫调控过程中也扮演了重要角色,参与了多种疾病的发生发展,因此对circRNA的深入探索可为治疗人类疾病提供重要的理论依据。该文就circRNA的生物合成、分类和功能作综述,重点讨论circRNA对病毒感染的调控机制以及circRNA作为病毒检测标记物和药物靶点的研究进展,从而为病毒性疾病的诊断提供新的参考依据和方向。     

环状RNA的产生、研究方法及功能

随着高通量测序技术的发展,环状RNA(circular RNAs,circRNAs)逐渐成为非编码RNA研究领域的热点。本文系统综述了环状RNA侧翼内含子自身互补配对驱动、RNA结合蛋白驱动以及套索驱动这3种环状RNA形成模型,并从高通量文库构建、生物信息学鉴别和常用的实验验证等3个方面对环状RNA的研究方法进行了介绍。同时,本文详细归纳了环状RNA作为microRNA(miRNA)或蛋白的海绵体、调控宿主基因的选择性剪接和表达、翻译成多肽等多种功能。最后通过系统综述植物环状RNA的特征及最新研究进展,为环状RNA在植物学中的进一步研究提供了新的视野。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV