长链非编码RNA在头颈部肿瘤中的研究进展

长链非编码RNA(long noncoding RNA,lncRNA)是一类长度大于200个核苷酸的、缺少特异完整的开放阅读框、极少有蛋白编码功能的非编码RNA。研究表明lncRNA是参与基因表达的关键调控分子,从表观遗传、转录及转录后等多种水平调控相关靶基因的表达。近年来lncRNA在头颈部疾病中的研究开始受到关注。现就lncRNA在头颈部肿瘤中的研究进展作一综述。     

生物节律基因非编码RNA调控机制

节律性的振荡不仅存在于生物节律中枢也存在于外周器官、组织及细胞中,其产生依赖于节律基因的转录、转录后及翻译后水平调控。近几年,生物节律转录后水平调控机制研究成为热点。非编码RNA(ncRNAs)调控组分小RNA(microRNA)与长链非编码RNA(lncRNA)作为参与转录后调控的重要分子,已有研究表明microRNA与lncRNA调控节律基因mRNA与蛋白的相位及振幅。本文概述microRNA与lncRNA参与昼夜节律中枢与外周调控的研究进展,为生物节律转录后调控机制的进一步研究提供参考。     

长链非编码RNA的作用机制

长链非编码RNA(long non-coding RNA,lncRNA)是一大类不编码蛋白质或者编码微肽的RNA转录本。研究表明,lncRNA通过不同的作用机制在表观遗传学、转录、转录后水平调控基因的表达,且其功能异常与多种疾病的发生发展密切相关。了解lncRNA的作用机制,有利于进一步解析lncRNA的生物学功能,并为lncRNA的相关研究提供思路。此外,lncRNA研究中存在的问题也值得探讨。     

长非编码RNA

人类基因组序列的约5%～10%被稳定转录,蛋白质编码基因仅约占1%,其余4%～9%的序列虽能转录,但转录物功能尚不明确。尽管如此,已确证在非蛋白质编码转录物中,含有具备调节功能的非编码RNA(noncoding RNA,ncRNA)。与具有调节功能的短链非编码RNA[如微RNA(microRNA)、小干扰RNA(siRNA),、Piwi-RNA]相比,长非编码RNA(long noncoding RNA,lncRNA)在数量上占大多数。lncRNA通过多种方式产生,以多种途径调节靶基因表达,参与调控生物体生长、发育、衰老、死亡等过程;lncRNA功能异常往往导致疾病发生。本文综述了lncRNA的起源、分类、作用分子机制及lncRNA异常与疾病的相关性等内容,旨在充分了解这一重要新型调控分子。     

RNA修饰对长链非编码RNA的调控作用

长链非编码RNA (lncRNA)能在表观遗传、转录以及转录后水平上调控基因表达,与疾病的发生、发展和防治有着密切的联系。RNA修饰介导的表观转录组学调控是表观遗传的新领域,可以在转录后水平调控基因表达,并且可以作为一种重要的修饰手段对lncRNA进行调控。RNA修饰可以通过对lncRNA表达水平、剪切方式及二级结构的调控,影响各种生物学进程。现回顾和展望RNA修饰对lncRNA的调控作用和其潜在的生物学功能。     

长链非编码RNA在神经系统疾病中的作用

转录本长度超过200个核苷酸(nt)的非编码RNA被称为长链非编码RNA(lncRNA)。lncRNA可在转录和转录后水平调控基因的表达,并作为信号分子、蛋白质复合物支架、分子诱饵实现其生物功能;lncRNA的表达与多种疾病的发生密切相关。现将综述lncRNA的功能及其在神经系统疾病中的研究进展,以期了解这些疾病的发病机制,并为治疗提供新的思路。     

长链非编码RNA在神经系统发育及神经性疾病中的作用

长链非编码RNA(long non-coding RNA,lncRNA)是一类转录本长度在200至数千个核苷酸序列,且不具有蛋白质编码潜能的非编码RNA。相较于研究较多的微小RNA(microRNA,miRNA)和干扰小RNA(small interfering,siRNA)等非编码小RNA,lncRNA的许多功能仍尚不清楚。但越来越多的研究发现,lncRNA可通过多种方式调控中枢神经系统发育,包括表观遗传组蛋白甲基化、转录辅因子调控、可变剪接调控等途经。而以上途经的异常均与多种人类重大疾病的发生密切相关,例如,阿尔兹海默症(Alzheimer’s disease,AD)、自闭症(autism spectrum disorder,ASD)、精神分裂症(schizophrenia,SZ)等。本文就lncRNA在表观遗传水平、转录水平、转录后水平和翻译水平上调控神经系统发育以及其在人类神经性疾病中的作用进行综述。     

不同亚细胞结构中的长非编码RNA

长非编码RNA (long non-coding RNA,lncRNA)是长度大于200 nt的非编码RNA,最初被认为是不具有生物学功能的转录"垃圾".随着研究的深入,发现lncRNA参与了许多生物学调控过程,例如染色体沉默、染色质修饰、转录激活与干扰等.这些生物学调控过程与lncRNA的结构及时空特异性表达密切相关...     

长链非编码RNA的功能及其作用机制

近年来,随着高通量深度测序技术的飞速发展,大量长链非编码RNA(lncRNA)在真核生物体内不断被发现。lncRNA是一类长度大于200 nt,生物学功能丰富,高级结构保守的非编码RNA(ncRNA)分子,能直接与蛋白质、微小RNA(microRNA)等分子作用,在表观遗传水平、转录水平、转录后水平上调控靶基因的表达。主要就lncRNA的分类标准、调控基因表达模式及其与蛋白质、miRNA的相互作用进行综述,旨在为更好地理解和研究lncRNA生物学功能提供参考。     

长链非编码RNA在胃癌中的研究进展

长链非编码RNA(Long non-coding RNA,lncRNA)是一类长度大于200个核苷酸的转录本,其转录本没有或少有蛋白质编码功能,参与调控多种生物生理功能。lncRNA可在表观遗传学、转录及转录后等多层面调控基因表达,对个体生长发育及肿瘤发生、发展过程至关重要。近年来,有诸多的研究发现lncRNA参与胃癌的发生、发展及转移等多个过程,且与患者的预后相关。对lncRNA在胃癌增殖、凋亡、侵袭和转移中的调控作用进行了综述,以期为胃癌临床诊断与治疗提供新的思路。     

Embryo and Endosperm Function and Failure inSolanumSpecies and Hybrids

Although the importance of the endosperm as a food store inmany angiosperm seeds is well known, its significance duringearly embryogenesis has been neglected. In many interspecifichybrids, and in some other situations, embryos do not developfully and abort. It has often been stated that this is causedby the endosperm failing to conduct sufficient nutrients tothe embryo, but seldom has it been suggested that the endospermactively controls most of the early stages of morphogenesisof the embryo. Information gleaned from a broad survey of theliterature, combined with additional evidence presented here,obtained fromSolanum incanumand interspecific hybrids, indicatethat the endosperm is dynamic and very active in regulatingearly embryo development. This requires highly integrated geneticcontrol of rapidly changing metabolism in the endosperm. Ininterspecific hybrids, lack of coordination may cause unbalancedproduction of growth regulating substances by the endospermand hence abortion of the embryo, or even unregulated productionof nucleases and proteases resulting firstly in autolysis ofthe endosperm and then digestion of the embryo. The endospermmay thus serve to detect inappropriate hybridization of speciesor ploidy levels and so prevent waste of resources by producingseeds that would result in sterile hybrids or unthrifty subsequentgenerations. This discriminatory function of the endosperm hasdiminished during evolution and domestication of the crop plantSolanummelongenaL.Copyright 1998 Annals of Botany Company Solanum, embryo morphogenesis, endosperm, hybrid, seed development.     

环腺苷酸应答元件结合蛋白与学习记忆

环腺苷酸(cAMP)应答元件结合蛋白(cAMP response element binding protein,CREB)是一种核转录因子,可与cAMP反应元件结合,调节基因转录,具有调节精子生成,昼夜节律,学习记忆等功能.近年来关于其在学习记忆中的作用成为医学研究热点.CREB是神经元内多条信息传递途径的汇聚点,参与长时记忆形成和突触可塑性.长时记忆(long-term memory)形成需依赖CREB介导的基因转录,干扰或抑制CREB活性可破坏长时记忆.长时程增强(long-term potentiation,LTP)是研究学习记忆的理想模型,在LTP诱导和维持过程中均可观察到CREB活性持续升高.但增龄过程中,海马CREB活性下降,影响学习记忆功能,与许多神经退行性疾病发生有关.     

HIFs and tumors--causes and consequences

For most organisms oxygen is essential fo life. When oxygen levels drop below those required to maintain the minimum physiological oxygen requirement of an organism or tissue it is termed hypoxia. To counter act possible deleterious effects of such a state, an immediate molecular response is initiated causing adaptation responses aimed at cell survival. This response is mediated by the hypoxia-inducible factor-1 (HIF-1), which is a heterodimer consisting of an alpha- and a beta-subunit. HIF-1 alpha protein is stabilized under hypoxic conditions and therefore confers selectivity to this response. Hypoxia is characteristic of tumors, mainly because of impaired blood supply resulting from abnormal growth. Over the past few years enormous progress has been made in the attempt to understand how the activation of the physiological response to hypoxia influences neoplastic growth. In this review some aspects of HIF-1 pathway activation in tumors and the consequences for pathophysiology and treatment of neoplasia are discussed.     

Pragmatic Women and Body Politics and Maternities and Modernities: Colonial and Postcolonial Experiences in Asia and the Pacific

Pragmatic Women and Body Politics. Margaret Lock and Patricia A. Kaufert. eds. Cambridge, UK: Cambridge University Press, 1998. xii +364 pp.
Maternities and Modernities: Colonial and Postcolonial Experiences in Asia and the Pacific. Kalpana Ram and Margaret Jolly. eds. Cambridge, UK: Cambridge University Press, 1998. xiv. 305 pp.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.