以斑马鱼为模式动物研究器官的发育与再生

斑马鱼因其受精卵体外发育、胚胎透明、具有较强的再生能力以及适于大规模遗传筛选的优势, 成为研究脊椎动物器官发育与再生的新兴模式动物。通过数十年的探索, 科研工作者已经在斑马鱼中建立了一套成熟的研究方法, 并对斑马鱼胚胎发育早期的细胞命运决定和分化、组织器官的形态建成以及受损后的再生过程有了初步的认识。近年来, 随着遗传筛选技术的大规模开展和活体成像技术在斑马鱼中的深入应用, 许多在小鼠等模式动物中悬而未决的问题开始得到充分解答。随着研究的不断深化和技术的不断更新, 以斑马鱼为模式动物, 对脊椎动物器官发育与再生的研究将会更加深入, 相关的调控机制也会被逐步探明, 从而为临床相关疾病的防治提供富有价值的参考。文章通过对近年来发表的文章进行回顾, 总结了斑马鱼作为模式动物研究中枢神经系统、肝脏和胰腺、血液细胞和血管等重要器官早期发育过程及其调控机制的进展, 并阐述了以斑马鱼研究尾鳍、心脏、肝脏等器官再生的优势和初步发现。     

斑马鱼胚胎发育中细胞凋亡的研究进展

细胞凋亡是细胞在基因调控下发生的主动消亡过程,在脊椎动物胚胎发育过程中非常重要。斑马鱼作为一种十分理想的发育分子生物学研究模型,在有关细胞凋亡在诸如形态发生、性别分化等方面功能之活体在位研究中日益受到重视。目前,斑马鱼胚胎发育中主要凋亡通路研究已进行了不少工作,特别是caspase及其它凋亡调控基因在斑马鱼中已被成功克隆,通过转基因斑马鱼胚胎中胁迫诱导细胞凋亡并研究其信号通路以及斑马鱼胚胎形态发生的异常改变,为阐明这些凋亡调控基因与发育之间的关系提供了一个强有力的手段。     

鸡mir-17-92基因簇的结构、功能及其调控

mir-17-92基因簇(mir-17-92 cluster)是脊椎动物的一个保守miRNA基因簇,在哺乳动物细胞增殖、分化、凋亡及发育等多种生物学过程中起重要的调控作用.同时,mir- 17-92基因簇又是一个癌基因,在多种肿瘤中表达.尽管对mir-17-92基因簇的研究非常广泛,但其作用机制还不完全清楚.鸡mir- 17-92基因簇的结构组成特点、功能及其作用机制尚未见研究报道.该文根据同一miRNA基因簇的miRNAs在功能上相关的特点,以鸡mir- 17-92基因簇序列为研究对象,采用生物信息学研究方法和手段,开展了鸡mir- 17-92基因簇的基因组结构、miRNAs序列组成、靶生物学过程和信号通路以及miRNAs结合位点分布特点等分析研究.结果发现,鸡mir- 17-92基因簇调控MAPK、Wnt和TGF-β等多个重要细胞信号通路;miRNA结合位点分布分析显示,该miRNA基因簇多个成员共同作用于同一个靶基因,提示该基因簇的miRNAs成员以组合和协同的方式调控靶基因.该研究为深入了解mir-17-92基因簇如何调控癌症和发育中的关键细胞过程奠定了基础.     

心脏发育的基因调控

心脏发育是一个复杂的过程.在脊椎动物和无脊椎动物果蝇中驱动早期心脏分化的基因具有惊人的相似性.以果蝇、斑马鱼、小鼠等作为模式动物,以心脏的发育过程为主线,探讨了心脏发育的基因调控的研究进展.     

斑马鱼多能性因子的研究进展

哺乳动物多能性因子, 主要包括Pou5f1/Oct4、Sox2、Klf4、Nanog等转录因子, 不仅能够维持胚胎干细胞的未分化状态, 同时也参与使分化细胞重编程回多能性状态的过程。目前对脊椎动物多能性因子在体(in vivo)功能研究报道极少。斑马鱼是研究脊椎动物早期发育分化的理想模型, 它能够为多能性相关因子的功能研究提供在体环境, 因而可以更准确地了解多能性因子的作用信息。近年来, 已在斑马鱼中发现了多种哺乳动物多能性因子的同源基因, 如oct4、nanog等。文章主要介绍了斑马鱼中多能性因子的相关研究进展, 并与其它动物中的研究作一比较。     

miRNAs对动物肠道健康的调控作用

miRNAs(micro RNAs)是一类长约22 nt,参与mRNA转录后调控的非编码小分子RNA。作为基因表达的关键调控因子,其参与了各类细胞的增殖、分化、凋亡以及机体的生长发育等多种生命活动。肠道不仅是机体营养物质消化吸收的主要部位,也是重要的免疫器官。研究表明,miRNAs在肠道中的表达丰富,对肠道正常的发育及功能起重要的调控作用。文章结合本研究组的研究成果,对miRNAs的生物合成以及其对动物肠道功能的影响、肠道稳态的维持等方面的研究进展做简要综述,以期在分子营养学方面,为深入了解miRNAs对动物肠道健康的调控作用提供理论指导依据。     

模式动物斑马鱼在中枢神经系统疾病研究中的应用

斑马鱼作为一种新兴的模式动物,被广泛应用于神经、心血管、消化、造血等各生理系统的发育及相关疾病的研究。中枢神经系统(central nervous system,CNS)疾病是困扰人类健康的重大疾病之一。神经损伤后不易再生和修复等特点,导致了临床上诸多CNS疾病迄今仍无有效疗法。斑马鱼作为脊椎动物,因其与哺乳动物在遗传及生理上有很高的同源性和功能保守性,近年来成为研究CNS疾病的理想动物模型。基于斑马鱼构建的许多疾病研究模型对深入揭示CNS疾病的治病分子机制及对应疾病的靶向治疗等具有重要的启示作用。本文将综述近年来斑马鱼作为模式动物在CNS疾病研究中的应用进展。     

模式动物斑马鱼在组织屏障发育及功能研究中的进展

斑马鱼作为一种新型的模式动物,以其独特的优势,已经成为现代遗传学、发育生物学等研究的重要模式生物。与人类及其他高等脊椎动物相似,斑马鱼同样具有不同的组织屏障系统。近年来,此领域的研究者利用斑马鱼对血脑屏障等组织屏障的研究取得了重要的进展。这对揭示诸多生理屏障相关的人类疾病的发病机制,以及探讨通过调控组织屏障通透性来达到药物有效投递的可行性等研究具有重要的启示作用。本文将介绍近年来斑马鱼作为模式动物在血脑屏障、血-视网膜屏障、皮肤表皮屏障、肠黏膜上皮屏障等组织屏障发育和功能研究中的最新进展。     

MicroRNA与胚胎神经发育

胚胎神经发育过程中,众多基因时空性表达及其表达产物相互作用形成精确的调控,其中某些基因表达质或量的改变会引起胚胎发育异常,导致先天畸形的发生.这一精确的基因表达调控过程是在转录及转录后等不同水平进行的.MicroRNAs(miRNAs),是这个基因调控大家族中新的成员.目前研究表明miRNAs在神经干细胞的不同发育阶段和哺乳动物脑发育过程中有不同的表达模式,这表明miRNAs可能在胚胎神经发育过程中起作用.本文就miRNAs在胚胎神经发育过程中的表达及功能作一综述.     

MiR-183基因簇对动物感觉器官功能和发育及肿瘤发生的调控

MicroRNAs (miRNAs) 是一类长度约为22 nt的内源性非编码小RNA. 它们在后生动物基因组中普遍存在,通过抑制靶基因mRNA的翻译或将其降解,在转录后水平调控基因的表达. 越来越多的证据表明,miRNAs在动物发育和人类疾病发生中发挥重要作用. miR-183基因簇在后口动物和原口动物中高度保守,编码miR-182、miR-96和miR-183. miR-183基因簇在动物感觉器官中特异性表达,对动物感觉器官的发育和功能至关重要. miR-183基因簇还与人类的肺癌、肝癌、乳腺癌、胰腺癌和黑色素瘤等多种癌症相关. miR-183基因簇在多种肿瘤细胞中异常表达,它们通过调控与肿瘤细胞分裂和死亡相关基因,而起到促进或抑制肿瘤发生的作用. 本文对miR-183基因簇miRNAs在动物感觉器官功能和发育及人类肿瘤发生中的作用进行论述.     

The crucial role and regulations of miRNAs in zebrafish development

To comprehend the events during developmental biology, fundamental knowledge about the basic machinery of regulation is a prerequisite. MicroRNA (miRNAs) act as regulators in most of the biological processes and recently, it has been concluded that miRNAs can act as modulatory factors even during developmental process from lower to higher animal. Zebrafish, because of its favorable attributes like tiny size, transparent embryo, and rapid external embryonic development, has gained a preferable status among all other available experimental animal models. Currently, zebrafish is being utilized for experimental studies related to stem cells, regenerative molecular medicine as well drug discovery. Therefore, it is important to understand precisely about the various miRNAs that controls developmental biology of this vertebrate model. In here, we have discussed about the miRNA-controlled zebrafish developmental stages with a special emphasis on different miRNA families such as miR-430, miR-200, and miR-133. Moreover, we have also reviewed the role of various miRNAs during embryonic and vascular development stages of zebrafish. In addition, efforts have been made to summarize the involvement of miRNAs in the development of different body parts such as the brain, eye, heart, muscle, and fin, etc. In each section, we have tried to fulfill the gaps of zebrafish developmental biology with the help of available knowledge of miRNA research. We hope that precise knowledge about the miRNA-regulated developmental stages of zebrafish may further help the researchers to efficiently utilize this vertebrate model for experimental purpose.     

Targeted inhibition of miRNA maturation with morpholinos reveals a role for miR-375 in pancreatic islet development

Several vertebrate microRNAs (miRNAs) have been implicated in cellular processes such as muscle differentiation, synapse function, and insulin secretion. In addition, analysis of Dicer null mutants has shown that miRNAs play a role in tissue morphogenesis. Nonetheless, only a few loss-of-function phenotypes for individual miRNAs have been described to date. Here, we introduce a quick and versatile method to interfere with miRNA function during zebrafish embryonic development. Morpholino oligonucleotides targeting the mature miRNA or the miRNA precursor specifically and temporally knock down miRNAs. Morpholinos can block processing of the primary miRNA (pri-miRNA) or the pre-miRNA, and they can inhibit the activity of the mature miRNA. We used this strategy to knock down 13 miRNAs conserved between zebrafish and mammals. For most miRNAs, this does not result in visible defects, but knockdown of miR-375 causes defects in the morphology of the pancreatic islet. Although the islet is still intact at 24 hours postfertilization, in later stages the islet cells become scattered. This phenotype can be recapitulated by independent control morpholinos targeting other sequences in the miR-375 precursor, excluding off-target effects as cause of the phenotype. The aberrant formation of the endocrine pancreas, caused by miR-375 knockdown, is one of the first loss-of-function phenotypes for an individual miRNA in vertebrate development. The miRNA knockdown strategy presented here will be widely used to unravel miRNA function in zebrafish.     

Integrated analyses of zebrafish miRNA and mRNA expression profiles identify miR-29b and miR-223 as potential regulators of optic nerve regeneration

Background

Unlike mammals, zebrafish have the ability to regenerate damaged parts of their central nervous system (CNS) and regain functionality of the affected area. A better understanding of the molecular mechanisms involved in zebrafish regeneration may therefore provide insight into how CNS repair might be induced in mammals. Although many studies have described differences in gene expression in zebrafish during CNS regeneration, the regulatory mechanisms underpinning the differential expression of these genes have not been examined.

Results

We used microarrays to analyse and integrate the mRNA and microRNA (miRNA) expression profiles of zebrafish retina after optic nerve crush to identify potential regulatory mechanisms that underpin central nerve regeneration. Bioinformatic analysis identified 3 miRNAs and 657 mRNAs that were differentially expressed after injury. We then combined inverse correlations between our miRNA expression and mRNA expression, and integrated these findings with target predictions from TargetScan Fish to identify putative miRNA-gene target pairs. We focused on two over-expressed miRNAs (miR-29b and miR-223), and functionally validated seven of their predicted gene targets using RT-qPCR and luciferase assays to confirm miRNA-mRNA binding. Gene ontology analysis placed the miRNA-regulated genes (eva1a, layna, nefmb, ina, si:ch211-51a6.2, smoc1, sb:cb252) in key biological processes that included cell survival/apoptosis, ECM-cytoskeleton signaling, and heparan sulfate proteoglycan binding,

Conclusion

Our results suggest a key role for miR-29b and miR-223 in zebrafish regeneration. The identification of miRNA regulation in a zebrafish injury model provides a framework for future studies in which to investigate not only the cellular processes required for CNS regeneration, but also how these mechanisms might be regulated to promote successful repair and return of function in the injured mammalian brain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1772-1) contains supplementary material, which is available to authorized users.     

MicroRNAs与多潜能干细胞的研究进展

microRNAs(miRNAs)是一类内源性非编码小RNA,通过调控基因表达来参与生命过程中的一系列重要进程。越来越多的证据表明,miRNAs参与了几乎所有生物代谢过程,其胚胎干细胞的自我更新与分化和在多能干细胞(iPSCs)中的诱导调节作用也日益受到关注。该文介绍了miRNAs的生成、检测方法以及miRNAs对胚胎干细胞(ESCs)及诱导多能性干细胞的调控作用,并对miRNAs的应用前景进行了展望。