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1.
微小核糖核酸(microRNA,miRNA)是一种由内源基因编码长度约为22个核苷酸的非编码RNA,其能抑制靶基因蛋白质表达,有多种生物学功能。越来越多的研究表明,miRNA在多种肿瘤中异常表达,参与肿瘤发生、发展过程。幽门螺杆菌(Helicobacter pylori,Hp)作为胃癌的主要致病因素,可通过调节miRNA的表达,在胃癌中起促进或抑制作用。现就Hp相关miRNA在胃癌中的作用作一概述。  相似文献   

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microRNA是一类由内源基因编码的长度约为18-25个核苷酸的非编码单链RNA分子,可以与靶基因mRNA的3'非编码区结合,通过降解靶m RNA或(和)抑制靶m RNA转录后翻译调节靶蛋白的生成,从而发挥其生物学作用。目前,在人体基因组内发现的microRNA已经超过2500多个,可能调节着人类1/3的基因,在维持正常干细胞功能、调控细胞增殖分化及恶性肿瘤发生过程中均起重要作用。既往的研究表明microRNA与基因之间相互调控的失衡导致肿瘤的发生。从分子水平上研究microRNA与肿瘤发生的关系,检测microRNA与肿瘤相关基因表达情况的改变,分析肿瘤组织和血清中microRNA表达量与肿瘤分型的关系,将有利于肿瘤的病因学研究,早期发现和肿瘤治疗及预后判断。本文主要就microRNA在肿瘤发生发展和诊断中作用的研究进展进行了综述。  相似文献   

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microRNA是植物和动物基因组编码的小分子非编码RNA.这种高度保守、长21~25个碱基RNA分子通过与mRNA的3'非编码区结合来调控基因组表达.microRNA通过其转录后调控机制在胚胎发育、细胞增殖,细胞分化、细胞死亡及细胞凋亡中发挥调控作用.近期研究发现,microRNA的异常表达可导致心脏疾病的发生、发展.现对microRNA在心脏发育、心肌肥厚和心肌重构、心力衰竭和心律失常等过程中的作用进行综述.  相似文献   

4.
Zuo Q  Xu JJ 《生理科学进展》2011,42(4):261-268
MicroRNA是一类内源性的非编码RNA,在mRNA转录后水平调节靶基因的表达.近年来国内外研究表明,生理条件下microRNA在神经系统存在特异性表达并发挥重要作用.而在神经系统损伤后,多种microRNA的分布和表达发生改变,从而对神经再生过程产生影响.microRNA的这一作用对临床诊断和治疗神经系统损伤意义重大.  相似文献   

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microRNA是近年来发现的与基因表达调控相关的一类非编码小分子单链RNA,长度约21-22个碱基对构成,通过与靶mRNA碱基对特异结合,引起靶mRNA降解或翻译抑制,调控基因转录后的表达。microRNA通过干预基因表达,从而对细胞的分化、增殖、凋亡、新陈代谢等多项生命活动进行调控。microRNA的表达异常可以引起细胞的分化、增殖、凋亡的异常,这与肿瘤的发生、发展关系密切。其作为一个新的分子生物学标志,在肿瘤的诊断、治疗中有着重要的潜在价值。  相似文献   

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microRNA(miRNA)是一类对基因具有调控功能的内源性非编码小分子RNA,通过与靶mRNA完全或不完全互补配对,引起mRNA降解或翻译抑制,从而对基因转录后水平进行调控.目前认为miRNA在多种生物学过程中起着至关重要的作用,包括细胞增殖、分化、凋亡等.研究显示miRNA的表达异常能导致疾病甚至肿瘤的发生,有类似于抑癌基因或癌基因的功能.本文就miRNA在肿瘤发生和诊断方面的研究进展作一综述.  相似文献   

7.
王世华  边春景  赵春华 《遗传》2008,30(12):1545-1549
摘要: 胚胎干细胞是一类具有自我更新能力和多向分化潜能的细胞, 其自我更新和多向分化过程都在遗传和表观遗传的严格调控下进行的。越来越多的研究表明microRNA 也在这一过程中发挥重要的作用。microRNA是一类内源性的非编码RNA, 能够通过与靶mRNA特异性的结合而导致靶mRNA降解或抑制其翻译, 从而对基因进行转录后调控。文章就microRNA在胚胎干细胞中的表达及其作用的研究进展做一综述。主要讨论一些在胚胎干细胞中特异性表达的microRNA, 以及这些microRNA 对胚胎干细胞自我更新和未分化状态的维持和继续分化增殖的调控作用。  相似文献   

8.
马清珠  季昆  王焱 《生物信息学》2023,21(3):226-232
本研究旨在总结整理已有胃癌研究的基础上,进一步挖掘出非编码基因在胃癌的进展及预后中起的关键作用。通过胃癌患者编码及非编码基因的表达数据,结合已知胃癌致病基因,进行编码基因与非编码基因的共表达计算,识别出由miRNA介导的并且与已知胃癌基因互作的lncRNA,挖掘出三者(mRNA-miRNA-lncRNA)相互作用的模块,进而对模块进行筛选,并对疾病相关的显著模块的基因进行生存分析。除已知的胃癌相关基因外,研究也使用了差异表达的胃癌基因,这些基因显著的富集在细胞增殖、细胞粘附、肌肉收缩、血管重塑、细胞分裂、染色体分离等生物过程,这些生物过程都与胃的基础功能及胃癌发生发展密切相关。分值最高的三元组模块内核心基因BGN在胃癌患者中显著高表达,而且和胃癌患者的预后显著相关;同时也发现该模块内的miRNA has-miRNA-153-5p和has-miRNA-5001-5p均为已证实的胃癌相关基因;模块内的mRNA和miRNA的表达异常可能是由于与他们显著相关的lncRNA的表达异常导致的。本研究为胃癌已知致病基因的表达异常研究找到了新突破口,潜在的胃癌相关的非编码基因的发现为胃癌预防与治疗提供了新的靶点,为未来的临床应用提供了依据。  相似文献   

9.
microRNA是一种内源性的大小在20nt左右的一类非编码RNAs,其通过下调靶基因的表达或翻译而参与调节细胞的发育、增殖、分化、凋亡.近期研究发现microRNA具有癌基因和抑癌基因的作用,已发现miR-21,miR-191,miR-223,let-7a microRNA,miR-106b-25亚群等与胃癌的发生,let-7 microRNA,miR-155与胃癌的侵袭与转移相关,miR-15,miR-16则参与胃癌的耐药机制.对其相应的调控机制和靶基因E2F1,PRL-3,HMGA2,BCL-2等的研究也已有了一些进展,为胃癌的研究开辟了一条新途径.本文就胃癌相关MicrRNA的研究进展予以综述.  相似文献   

10.
MicroRNA是一组长度约为21 nt的非编码蛋白质的短序列RNA,能通过碱基互补配对的方式指导降解靶基因mRNA或抑制靶基因的翻译。MicroRNA的主要功能是调控基因的表达,在生物体的生长、发育及疾病发生中扮演着重要的角色。本文介绍了利用microRNA实现基因沉默的作用原理,人工合成microRNA,构建转基因载体,实现对目的基因的沉默及这种工具在生命科学领域的应用前景。  相似文献   

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It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

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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  相似文献   

17.
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.  相似文献   

18.
Microbial resistance to antibiotics is an unresolved global concern, which needs urgent and coordinated action. One of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat antibiotic resistance is the development of new antibiotics to treat drug-resistant bacteria. In our effort to find new antibiotics, we report the synthesis and antimicrobial studies of 30 new pyrazole derivatives. These novel molecules have been synthesized by using readily available starting materials and benign reaction conditions. Some of these molecules have shown activity with MIC values as low as 0.78?µg/mL against four bacterial strains; Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Acinetobacter baumannii. Furthermore, active molecules are non-toxic to mammalian cell line.
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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.  相似文献   

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