线粒体基因转录调控机制与人类疾病

人类的线粒体DNA编码了37个基因,这些基因在氧化磷酸化作用中都发挥着重要的作用,而他们表达的失调与人类的疾病和衰老有着密切的联系.除了线粒体基因编码的13个mRNA、12S rRNA、16S rRNA和22个tRNA之外,其他调控线粒体基因的转录、翻译及RNA修饰的因子都由细胞核编码而后转运至线粒体基质中.本文详细讨...     

人类线粒体突变与线粒体疾病

线粒体是细胞内唯一存在于细胞核外又带有遗传物质的细胞器，由于这一特殊性，有关其进化和来源的问题曾有过很多争论。但因为与临床的关系过去不很明确，对它的生物学意义并未引起足够的重视。８０年代后随着线粒体的序列和基因组组成的测定，以及发现了线粒体ＤＮＡ（ｍ...     

线粒体核糖体蛋白与人类线粒体疾病

哺乳动物线粒体核糖体(mitochondrial ribosome,mitoribosome)在漫长的进化阶段经过一系列的结构重组,rRNA比例降低,新增了部分线粒体核糖体蛋白(mitochondrial ribosomal proteins,MRPs),成为蛋白含量最丰富的核糖体.所有MRPs均为核基因编码,在细胞质中合成,再转运到线粒体,与线粒体基因(mitochondrial DNA,mtDNA)编码的两种rRNA结合.mtDNA除编码tRNA和rRNA外,还编码组成线粒体呼吸链复合体的13种蛋白质.由于线粒体核糖体负责翻译这13种蛋白,MRPs和其他翻译工具的突变和缺陷可造成线粒体的相关疾病.     

线粒体DNA突变与人类疾病

近几年来，线粒体ＤＮＡ（ｍｔ ＤＮＡ）突变与人类疾病的关系越来越受到人们的重视。目前发现线粒体ＤＮＡ突变不但可累及脑、心脏、骨骼肌、肾脏和内分泌腺、造成人类多种疾病，而且还和人类的衰老过程有关。从分子水平上深入探讨ｍｔ ＤＮＡ突变的发生情况，阐明突变ｍｔ ＤＮＡ的传递规律及线粒体ＤＮＡ与核ＤＮＡ的相互关系，都有助于揭开线粒体病的本质，为人类诊断、预防和治疗这些疾病作出贡献。     

线粒体核糖体蛋白与线粒体疾病

近年来蛋白质组学技术和生物信息学方法的结合应用使人线粒体核糖体全部78个组成蛋白编码基因的序列及染色体定位得以明确.本文在此基础上总结了人线粒体核糖体蛋白基因突变与多种线粒体疾病之间存在的分子遗传学联系,提示人线粒体核糖体蛋白异常可能是线粒体疾病新的病因.     

RNA干扰分子机制研究进展

RNA干扰 (RNA interference,RNAi)即双链 RNA(double- stranded RNA,ds RNA)介导的同源m RNA特异性降解过程。作为一种简单有效的影响基因表达和一定程度上替代基因敲除的遗传学工具 ,RNAi已在秀丽新小杆线虫、黑腹果蝇、拟南芥、红色面包霉菌等多种模式生物体中得到广泛证实。同时 ,RNAi的分子机制的研究也不断取得进展 ,包括对基因转录后水平、翻译水平、基因组甲基化及沉默信号的传递等层次的研究。清晰地阐明 RNAi作用机理 ,将为大规模的基因系统筛查、新基因的发现、人类肿瘤及难治性疾病的基因治疗提供重要的理论依据和有力的工具。     

RNA干扰沉默Bax基因对线粒体途径软骨细胞凋亡的影响

 【摘要】 目的 利用体外培养的鼠软骨细胞,研究RNA干扰沉默Bax基因表达对经线粒体途径细胞凋亡的影响。方法 体外分离培养SD大鼠软骨细胞;Bax siRNA干扰沉默Bax基因表达。RT-PCR和Western blot检测mRNA及蛋白表达水平;MTT法检测细胞活力;Annexin V-FITC/PI双标记法检测细胞凋亡率;Western blot检测Bcl-2、Cytochrome C蛋白的表达。结果 Bax siRNA干扰24h后,Bax的mRNA和蛋白的表达水平均明显降低。细胞凋亡受到明显抑制,细胞存活率增高。并且,在Bax基因沉默的细胞中,Cytochrome C蛋白表达水平降低,同时Bcl-2蛋白表达水平升高。结论 RNA干扰沉默Bax基因可抑制鼠软骨细胞凋亡并且促进其存活,其机制可能与线粒体途径相关。     

RNA干涉：沉默基因的机制及应用研究新进展

RNA干涉（RNAinterference,RNAi)是一种由双链RNA（double-strandedRNA,dsRNA）始动的序列特异性基因沉默机制，广泛存在于各种生物，乃至人类；对RNAi分子机制及生物学意义研究不断深入，已发现了许多参与RNAi的基因和蛋白质（酶类），并证明了RNAi与细胞分化及生物发育密切相关。同时RNAi也是一种研究基因表达调控和基因功能强有力的工具，本就RNAi的分子机制，生物学意义及其应用研究方面的新进展做一介绍。     

Hepatitis B virus polymerase suppresses translation of pregenomic RNA via a mechanism involving its interaction with 5' stem-loop structure

The pregenomic RNA (pgRNA) of hepadnaviruses serves a dual role: as mRNA for the core (C) and polymerase (P) synthesis and as an RNA template for viral genome replication. A question arises as to how these two roles are regulated. We hypothesized that the P protein could suppress translation of the pgRNA via its interaction with 5' stem-loop structure (epsilon or encapsidation signal). Consistent with the hypothesis, we observed up-regulation of the C protein level in the absence of the P protein expression in a physiological context. Importantly, translational suppression depended on the 5' epsilon sequence. Furthermore, the impact of the P protein on ongoing translation of the C ORF was directly demonstrated by polysome distribution analysis. We conclude that the P protein suppresses translation of the pgRNA via a mechanism involving its interaction with the 5' epsilon sequence, a finding that implicates the coordinated switch from translation to genome replication.     

Mitochondrial delivery of antisense RNA by MITO-Porter results in mitochondrial RNA knockdown,and has a functional impact on mitochondria

Mitochondrial genome-targeting nucleic acids are promising therapeutic candidates for treating mitochondrial diseases. To date, a number of systems for delivering genetic information to the cytosol and the nucleus have been reported, and several successful gene therapies involving gene delivery targeted to the cytosol and the nucleus have been reported. However, much less progress has been made concerning mitochondrial gene delivery systems, and mitochondrial gene therapy has never been achieved. Here, we report on the mitochondrial delivery of an antisense RNA oligonucleotide (ASO) to perform mitochondrial RNA knockdown to regulate mitochondrial function. Mitochondrial delivery of the ASO was achieved using a combination of a MITO-Porter system, which contains mitochondrial fusogenic lipid envelopes for mitochondrial delivery via membrane fusion and D-arm, a mitochondrial import signal of tRNA to the matrix. Mitochondrial delivery of the ASO induces the knockdown of the targeted mitochondria-encoded mRNA and protein, namely cytochrome c oxidase subunit II, a component of the mitochondrial respiratory chain. Furthermore, the mitochondrial membrane potential was depolarized by the down regulation of the respiratory chain as the result of the mitochondrial delivery of ASO. This finding constitutes the first report to demonstrate that the nanocarrier-mediated mitochondrial genome targeting of antisense RNA effects mitochondrial function.     

非编码RNA与人类重大疾病的发生及其在生物医学领域内的应用

2003年人类基因组计划的完成开辟了人类遗传学、人类病理学等研究领域的新时代,然而近年来解析人类基因组意义过程遇到一系列的难题使人们认识到DNA序列本身并不能解释所有关于遗传信息传递、人类疾病生物学基础等问题.     

Splicing of goose parvovirus pre-mRNA influences cytoplasmic translation of the processed mRNA

Translation of goose parvovirus (GPV) 72 kDa Rep 1 is initiated from unspliced P9-generated mRNAs in ORF1 from the first in-frame AUG (537 AUG); however, this AUG is bypassed in spliced P9-generated RNA: translation of the 52 kDa Rep 2 protein from spliced RNA is initiated in ORF2 at the next AUG downstream (650 AUG). Usage of the 537 AUG was restored in spliced RNA when the GPV intron was replaced with a chimeric SV40 intron, or following specific mutations of the GPV intron which did not appear in the final spliced mRNA. Additionally, 650 AUG usage was gained in unspliced RNA when the GPV intron splice sites were debilitated. Splicing-dependent regulation of translation initiation was mediated in cis by GPV RNA surrounding the target AUGs. Thus, nuclear RNA processing of GPV P9-generated pre-mRNAs has a complex, but significant, effect on alternative translation initiation of the GPV Rep proteins.     

环状RNA及其在肝病中的作用

环状RNA（circRNA）是一种不具有5’末端帽子结构和3’末端的poly（A）尾巴的新型非编码RNA,是由非共价键形成的反向连接的闭合环状结构。circRNA由于其具有作为miRNA分子海绵及生物标志物的作用,可用于肝脏疾病的治疗和诊断,因此,circ RNA已逐渐成为当今的研究热点。我们针对circRNA以及circRNA在肝病中的研究进行了综述,以期对未来的肝脏疾病的研究和治疗提供理论基础和新思路。