MicroRNA与细胞分化及发育

microRNA（miRNA）能调控基因表达是近年来在动植物体内发现的一种新的调控基因表达的方式.在动物体内,通过基因敲除方法所进行的研究表明了miRNA参与了胚胎早期发育、神经发育、肌肉发育和淋巴细胞发育等动物发育的各个方面.这些研究提示,miRNA是动物发育过程中的重要调控因子,而且与很多人类的疾病相关.本文介绍了近期miRNA在细胞分化及发育中的研究进展.     

let-7 microRNA调控动物器官发育的研究进展

微小RNA（microRNA,miRNA）是一类在进化上高度保守、长度约20～24 nt的小分子非编码RNA,能通过与靶基因3′非翻译区相结合从而抑制靶基因的翻译或降解靶基因。let-7 microRNA是发现较早的一类miRNA,最早在线虫中发现能调控细胞分裂的时序。此后大量证据表明,let-7参与动物多个器官发育的调控过程,并与人类疾病发生密切相关。该文综述了近年来let-7调控动物脑、神经及心肺系统等器官发育的研究成果,初步阐述了let-7调控动物器官发育可能的作用机制,以期为深入研究let-7的功能奠定基础。     

miRNA对水稻生长发育的调控

MicroRNA(miRNA)是一类小的非编码RNA,它们主要在转录后水平对靶mRNA进行切割或抑制mRNA的翻译来调控基因的表达. miRNA通过对靶基因的调控参与植物的生长发育、胁迫应答和代谢过程.在水稻中,已经发现并初步验证了许多与生长发育相关的miRNA,它们对水稻不同器官和形态发育发挥着重要作用.本文综述了水稻miRNA的发生和调控机制、靶基因的预测,重点介绍了miRNA对水稻生长发育和形态建成的研究进展,并对研究过程中存在的问题进行了讨论.为更好地了解miRNA及其靶基因在提高水稻产量和品质方面的作用,进一步解析miRNA在水稻中的调控机制提供参考.     

miRNA在植物发育与环境适应性中的作用

植物miRNA是广泛分布于植物基因组的非编码小分子RNA．是真核生物基因表达的一类负调控因子,主要通过指导靶基因的切割或降低靶基因的翻译从转录后水平上来抑制植物基因表达．从而影响植物形态发生、发育过程和适应环境的能力。本文综述了植物miRNA形成、作用机理、功能等方面研究的最新进展,总结了现有miRNA研究方法的优缺点,提出了miRNA在植物适应养分和元素毒害胁迫过程中的调节作用．拓宽了该领域研究的思路。     

MicroRNA调控被子植物花发育的研究进展

MicroRNA（miRNA）是一类由内源基因编码的长度为21～23nt的非编码单链小RNA分子,通过与靶基因的互补位点结合而降解或抑制靶mRNA的翻译,从而在转录后水平上调控基因的活性。miRNA在调控植物发育方面发挥着广泛的作用。从成花诱导到花器官特征属性的形成,miRNA在整个花发育过程均发挥着关键作用。miRl72和miRl56／157参与由营养生长向生殖生长转换的调控,miRl72和miRl69在花发育的早期阶段通过界定靶基因的表达区域而调控花器官的属性,miR319、miRl59、miRl64以及miRl67在花发育的晚期阶段决定细胞的特化。文章综述了miRNA调控被子植物花发育的研究进展,为深入了解miRNA的作用机制奠定基础。     

miRNA在植物种子发育过程中的作用

MicroRNA(miRNA)是一类小分子非编码RNA,通过降解靶基因途径在转录后水平调控基因表达,参与植物生长、发育以及逆境胁迫应答等多种细胞代谢活动。种子是植物生长的基础要素,是农业生产的重要资料。与种子发育相关的miRNA已在多种植物中得到鉴定。文章综述了参与植物种子发育过程的miRNA及其在种子发育中的具体调控机制,旨在为利用miRNA提高种子遗传特性提供研究思路。     

人类miRNA上游转录因子及下游靶基因的基因本体分析

目的研究人类miRNA转录因子及靶基因之间的相关关系。方法利用生物信息学方法预测miR-NA的上游转录因子和下游靶基因,并对预测结果做基因本体分析,得到参与各生物学过程及分子功能的比例,用统计学软件PASW做相关性分析。结果人类382个miRNA参与应激、代谢、发育等10个生物学过程和行使转录调控、翻译调控、催化活性等12个分子功能,miRNA上游转录因子之间、下游靶基因之间以及上下游之间存在着广泛的正负相关关系。结论基因在参与生物学过程及行使分子功能的过程中,通过miRNA实现协同作用或隔离效应。     

MicroRNAs在动物皮肤和毛发发育中的调控作用

MicroRNAs(miRNAs)是近年来发现的一类由19～25个核苷酸组成的非编码单链小RNA分子,它们通过与靶基因mRNA的3′非编码区相互配对结合,在转录后水平负调控靶基因的表达.miRNA参与了包括细胞增殖、分化和凋亡及免疫系统应答在内的一系列发育调控和生物学过程.最近几年研究发现,miRNA在多种哺乳动物皮肤中均表达,并参与了哺乳动物皮肤及毛发发育的调控过程.本文综述了近几年来miRNA在各种动物皮肤及毛发发育中的表达谱以及miRNA在皮肤形态发生中的重要作用.     

MicroRNA及其在人和动物上的研究进展

MicroRNA是一种长约22nt的非编码RNA, 通过与靶基因的3′UTR区结合来调控靶基因的表达。目前已证实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。文章介绍了miRNA的特征、作用机制, 综述了关于miRNA的功能、miRNA基因的鉴定与靶基因预测的最新研究进展。     

microRNA:心血管发育及疾病中的重要调控因子

心脏是哺乳动物在胚胎发育时期最早形成的器官,心血管系统的正常发育及功能维持受到精确的调控。近年来,心血管疾病已成为危害人类生命的首要杀手之一,因此,对心血管的发育及疾病发生的机制研究一直是生命科学研究的热点问题。microRNA(miRNA)是一类长约18～25nt的单链非编码小RNA,主要通过结合于靶基因的3'非翻译区抑制靶基因的翻译或导致mRNA降解,从而抑制靶基因的表达。miRNA在许多生物学过程中发挥重要的调控作用,如细胞增殖、分化、凋亡、癌症发生等。最近研究表明,miRNA也参与调控心血管系统的发育和疾病发生过程。在此,该文对miRNA在心血管系统发育和疾病中的作用做一综述。     

睾丸发育和精子生成相关miRNA研究进展

MicroRNA(miRNA)是一类长约22nt的非编码小RNA, 广泛存在于各种生物中, 调节生物体生长、发育和凋亡等过程。研究表明, miRNA在人和动物睾丸发育及精子生成等过程也起着重要的调控作用。但miRNA在不同种属的睾丸组织及其不同发育时间段均存在特异性表达。此外, miRNA在动物精子生成过程中也存在时空特异性。文章综述了睾丸发育和精子生成过程中miRNA的差异性表达、表达调控以及一些miRNA对精子生成的调节作用, 旨在为睾丸miRNA的进一步研究提供参考, 为利用miRNA调控和促进种公畜精液品质提供研究思路。     

Role of miRNA and miRNA processing factors in development and disease

Mature microRNAs (miRNAs) are single-stranded RNA molecules of 17-24 nucleotides (nt) in length that are encoded in the genomes of plants and animals. The seminal discoveries of miRNA made in C. elegans have led the way to the rampant discoveries being made today in this field. Since each miRNA is predicted and in some cases confirmed to regulate multiple genes, the potential regulatory circuitry afforded by miRNAs is thought to be enormous and could amount to regulation of >30% of all human genes. Due to the sequences of many of the miRNAs being highly homologous among organisms, the huge potential of miRNAs to regulate gene expression, and the hints of miRNAs being useful in both diagnostics and therapeutics, it is no wonder these small RNAs are gaining such popularity in both the academic and industrial settings. It is now becoming clear that the miRNA gene class represents a very important gene regulatory network. This article reviews the initial discoveries of miRNA that began in the nematode C. elegans, and extends into what is known about miRNAs and miRNA processing factors in mouse development and human disease.     

microRNA在肌肉发育中的功能研究进展

microRNA(miRNA)是一类非编码的小RNA分子,它通过对靶mRNA的翻译抑制和降解对基因表达起负调节作用。现在人们已经清楚地知道miRNA参与了增殖、分化、凋亡、发育等许多生物过程。一些miRNA在肌肉中特异表达,参与肌肉发育。该文重点介绍了参与肌肉发育的miRNA。已有证据表明肌肉miRNA在肌肉的增殖和分化过程中起了重要的调节作用,miRNA的调节异常和肌肉疾病有关。因此,miRNA是一类新的肌肉调控因子,它有可能成为畜禽肉产量提高和肌肉相关疾病治疗的新型靶标。     

Altered microRNA expression in bovine skeletal muscle with age

Age‐dependent decline in skeletal muscle function leads to several inherited and acquired muscular disorders in elderly individuals. The levels of microRNAs (miRNAs) could be altered during muscle maintenance and repair. We therefore performed a comprehensive investigation for miRNAs from five different periods of bovine skeletal muscle development using next‐generation small RNA sequencing. In total, 511 miRNAs, including one putatively novel miRNA, were identified. Thirty‐six miRNAs were differentially expressed between prenatal and postnatal stages of muscle development including several myomiRs (miR‐1, miR‐206 and let‐7 families). Compared with miRNA expression between different muscle tissues, 14 miRNAs were up‐regulated and 22 miRNAs were down‐regulated in the muscle of postnatal stage. In addition, a novel miRNA was predicted and submitted to the miRBase database as bta‐mir‐10020. A dual luciferase reporter assay was used to demonstrate that bta‐mir‐10020 directly targeted the 3′‐UTR of the bovine ANGPT1 gene. The overexpression of bta‐mir‐10020 significantly decreased the DsRed fluorescence in the wild‐type expression cassette compared to the mutant type. Using three computational approaches – miranda , pita and rnahybrid – these differentially expressed miRNAs were also predicted to target 3609 bovine genes. Disease and biological function analyses and the KEGG pathway analysis revealed that these targets were statistically enriched in functionality for muscle growth and disease. Our miRNA expression analysis findings from different states of muscle development and aging significantly expand the repertoire of bovine miRNAs now shown to be expressed in muscle and could contribute to further studies on growth and developmental disorders in this tissue type.     

The development of Wilms tumor: From WT1 and microRNA to animal models

Wilms tumor recapitulates the development of the kidney and represents a unique opportunity to understand the relationship between normal and tumor development. This has been illustrated by the findings that mutations of Wnt/β-catenin pathway-related WT1, β-catenin, and WTX together account for about one-third of Wilms tumor cases. While intense efforts are being made to explore the genetic basis of the other two-thirds of tumor cases, it is worth noting that, epigenetic changes, particularly the loss of imprinting of the DNA region encoding the major fetal growth factor IGF₂, which results in its biallelic over-expression, are closely associated with the development of many Wilms tumors. Recent investigations also revealed that mutations of Drosha and Dicer, the RNases required for miRNA generation, and Dis3L2, the 3′–5′ exonuclease that normally degrades miRNAs and mRNAs, could cause predisposition to Wilms tumors, demonstrating that miRNA can play a pivotal role in Wilms tumor development. Interestingly, Lin28, a direct target of miRNA let-7 and potent regulator of stem cell self-renewal and differentiation, is significantly elevated in some Wilms tumors, and enforced expression of Lin28 during kidney development could induce Wilms tumor. With the success in establishing mice nephroblastoma models through over-expressing IGF₂ and deleting WT1, and advances in understanding the ENU-induced rat model, we are now able to explore the molecular and cellular mechanisms induced by these genetic, epigenetic, and miRNA alterations in animal models to understand the development of Wilms tumor. These animal models may also serve as valuable systems to assess new treatment targets and strategies for Wilms tumor.