Genome editing with the CRISPR‐Cas system: an art,ethics and global regulatory perspective

Over the last three decades, the development of new genome editing techniques, such as ODM, TALENs, ZFNs and the CRISPR‐Cas system, has led to significant progress in the field of plant and animal breeding. The CRISPR‐Cas system is the most versatile genome editing tool discovered in the history of molecular biology because it can be used to alter diverse genomes (e.g. genomes from both plants and animals) including human genomes with unprecedented ease, accuracy and high efficiency. The recent development and scope of CRISPR‐Cas system have raised new regulatory challenges around the world due to moral, ethical, safety and technical concerns associated with its applications in pre‐clinical and clinical research, biomedicine and agriculture. Here, we review the art, applications and potential risks of CRISPR‐Cas system in genome editing. We also highlight the patent and ethical issues of this technology along with regulatory frameworks established by various nations to regulate CRISPR‐Cas‐modified organisms/products.     

CRISPR/Cas9介导的基因组定点编辑技术在丝状真菌中的研究进展

CRISPR/Cas9技术是在特定的RNA引导下,利用特异的核酸酶实现对基因组进行编辑的新技术。自2013年该技术体系建立起来已成功应用于动物、植物及真菌中。本文简述了3种基于核酸酶的基因编辑技术及其应用,概述了CRISPR/Cas9系统的组成及其作用机理,总结了CRISPR/Cas9在模式真菌酿酒酵母及丝状真菌中的应用,并就在丝状真菌中应用该技术时sg RNA表达盒的设计、Cas9表达盒的优化、抗性标记的筛选、受体的选择等方面提出具体的研究方法。另外,针对该技术应用过程中出现的脱靶效应、Cas9核定位信号的添加、启动子的选择及多个靶基因的编辑等问题提出了建议与展望,希望能够为初次涉足该领域的科研人员提供理论参考和技术支持。     

CRISPR/Cas9 system: a powerful technology for in vivo and ex vivo gene therapy

CRISPR/Cas9 is a versatile genome-editing tool which is widely used for modifying the genome of both prokaryotic and eukaryotic organisms for basic research and applications. An increasing number of reports have demonstrated that CRISPR/Cas9-mediated genome editing is a powerful technology for gene therapy. Here, we review the recent advances in CRISPR/Cas9-mediated gene therapy in animal models via different strategies and discuss the challenges as well as future prospects.     

植物基因组编辑检测方法

以CRISPR/Cas9技术为代表的基因组编辑在生物领域的革命性应用使得生命科学研究迈入新篇章。该技术以其灵活性、易用性且扩展性强等优势,大大加快了基因工程研究,也加速了植物分子育种的步伐。但是,遗传转化过程中产生大量潜在的基因编辑植株,使得早期高通量快速筛选和检测目标编辑植株面临很大挑战。本文综述了近年来植物基因组编辑检测的各种方法,比较了其优缺点和适用范围;同时,还对近几年植物基因组编辑检测方法的发展趋势进行了深入分析和展望,以期对基因组编辑技术在植物中的应用提供参考。     

植物CRISPR基因组编辑技术的新进展

在过去的4年中,CRISPR/Cas9基因组编辑技术成为生命科学领域的革命性工具,为植物学基础研究和农作物遗传改良提供了高效、快速而又廉价的遗传操作工具。利用CRISPR/Cas9系统可以实现精准的knock-out和knock-in等遗传操作,也可用于靶向激活或抑制基因的表达。在CRISPR/Cas9被广泛地用于基因组编辑的同时,它的编辑能力、效率和精确度也在不断地改进和完善,特别是CRISPR/Cpf1系统的发掘和单碱基编辑技术的创建,使CRISPR系统正逐步成为一个理想的遗传工程技术平台。此外,利用CRISPR/Cas9技术改良的农作物品种也已经涌现,这必将推动精准基因组编辑技术在农作物遗传改良中的应用和发展。     

DNA-free genome editing methods for targeted crop improvement

Evolution of the next-generation clustered, regularly interspaced, short palindromic repeat/Cas9 (CRISPR/Cas9) genome editing tools, ribonucleoprotein (RNA)-guided endonuclease (RGEN) RNPs, is paving the way for developing DNA-free genetically edited crop plants. In this review, I discuss the various methods of RGEN RNPs tool delivery into plant cells and their limitations to adopt this technology to numerous crop plants. Furthermore, focus is given on the importance of developing DNA-free genome edited crop plants, including perennial crop plants. The possible regulation on the DNA-free, next-generation genome-edited crop plants is also highlighted.     

CRISPR/CAS9, the king of genome editing tools

The discovery of CRISPR/Cas9 brought a hope for having an efficient, reliable, and readily available tool for genome editing. CRISPR/Cas9 is certainly easy to use, while its efficiency and reliability remain the focus of studies. The review describes the general principles of the organization and function of Cas nucleases and a number of important issues to be considered while planning genome editing experiments with CRISPR/Cas9. The issues include evaluation of the efficiency and specificity for Cas9, sgRNA selection, Cas9 variants designed artificially, and use of homologous recombination and nonhomologous end joining in DNA editing.     

Agrobacterium-mediated delivery of CRISPR/Cas reagents for genome editing in plants enters an era of ternary vector systems

Lack of appropriate methods for delivery of genome-editing reagents is a major barrier to CRISPR/Cas-mediated genome editing in plants. Agrobacterium-mediated genetic transformation(AMGT) is the preferred method of CRISPR/Cas reagent delivery,and researchers have recently made great improvements to this process. In this article, we review the development of AMGT and AMGT-based delivery of CRISPR/Cas reagents. We give an overview of the development of AMGT vectors including binary vector, superbinary vector, dual binary vector, and ternary vector systems. We also review the progress in Agrobacterium genomics and Agrobacterium genetic engineering for optimal strains. We focus in particular on the ternary vector system and the resources we developed. In summary, it is our opinion that Agrobacterium-mediated CRISPR/Cas genome editing in plants is entering an era of ternary vector systems, which are often integrated with morphogenic regulators. The new vectors described in this article are available from Addgene and/or MolecularCloud for sharing with academic investigators for noncommercial research.     

CRISPR/Cas in Arabidopsis: overcoming challenges to accelerate improvements in crop photosynthetic efficiencies

The rapid and widespread adoption of clustered regularly interspaced short palindromic repeats (CRISPR)/Cas technologies has allowed genetic editing in plants to enter a revolutionary new era. In this mini review, we highlight the current CRISPR/Cas tools available in plants and the use of Arabidopsis thaliana as a model to guide future improvements in crop yields, such as enhancing photosynthetic potential. We also outline the current socio‐political landscape for CRISPR/Cas research and highlight the growing need for governments to better facilitate research into plant genetic‐editing technologies.     

Recent Progress in CRISPR/Cas9 Technology

The clustered regularly interspaced short palindromic repeats(CRISPR)/Cas9 system, a simple and efficient tool for genome editing, has experienced rapid progress in its technology and applicability in the past two years. Here, we review the recent advances in CRISPR/Cas9 technology and the ways that have been adopted to expand our capacity for precise genome manipulation. First, we introduce the mechanism of CRISPR/Cas9, including its biochemical and structural implications. Second, we highlight the latest improvements in the CRISPR/Cas9 system, especially Cas9 protein modifications for customization. Third, we review its current applications, in which the versatile CRISPR/Cas9 system was employed to edit the genome, epigenome, or RNA of various organisms. Although CRISPR/Cas9 allows convenient genome editing accompanied by many benefits, we should not ignore the significant ethical and biosafety concerns that it raises. Finally, we discuss the prospective applications and challenges of several promising techniques adapted from CRISPR/Cas9.     

CRISPR/Cas9技术在非模式植物中的应用进展

基因组编辑技术的出现对植物遗传育种及作物性状的改良产生了深远意义。CRISPR/Cas(clustered regularly interspaced short palindromic repeat)是由成簇规律间隔短回文重复序列及其关联蛋白组成的免疫系统,其作用是原核生物(40%细菌和90%古细菌)用来抵抗外源遗传物质(噬菌体和病毒)的入侵。该技术实现了对基因组中多个靶基因同时进行编辑,与前两代基因编辑技术:锌指核酶(ZFNs)和转录激活因子样效应物核酶(TALENs)相比更加简单、廉价、高效。目前CRISPR/Cas9基因编辑技术已在拟南芥(Arabidopsis thaliana)、烟草(Nicotiana benthamiana)、水稻(Oryza sativa)、小麦(Triticum aestivum)、玉米(Zea mays)、番茄(tomato)等模式植物和多数大作物中实现了定点基因组编辑,其应用范围不断地向各类植物扩展。但与模式植物和一些大作物相比,CRISPR/Cas9基因编辑技术在非模式植物,尤其在一些小作物的应用中存在如载体构建、靶点设计、脱靶检测、同源重组等问题有待进一步完善。该文对CRISPR/Cas9技术在非模式植物与小作物研究的最新研究进展进行了总结,讨论了该技术目前在非模式植物、小作物应用的局限性,在此基础上提出了相关改进策略,并对CRISPR/Cas9系统在非模式植物中的研究前景进行了展望。     

CRISPR/Cas植物基因组编辑技术及其在玉米中的应用*

CRISPR/Cas 系统具有操作简单、效率高等优势,为植物功能基因研究和作物遗传改良提供了重要支撑。介绍了CRISPR/Cas植物基因组编辑技术的研究进展,并对CRISPR/Cas系统及其衍生技术进行了详细比较;结合案例综述了CRISPR/Cas9基因编辑技术在玉米产量、品质、抗逆性改良,以及雄性不育系创制和单倍体诱导等方面的应用;同时针对CRISPR/Cas系统未来需要迫切解决的一些问题进行了分析和展望。     

CRISPR/Cas9基因组编辑技术在癌症研究中的应用

CRISPR/cas9基因组编辑技术因其设计简单以及操作容易,使其在基因编辑的研究中越来越受到欢迎。利用该技术,科研人员可以实现在碱基的水平对基因组进行定点修饰。CRISPR系统现已经被广泛地应用到多个物种的基因组编辑以及癌症的相关研究中。本文在最新研究进展的基础上,结合对癌症研究及基因组编辑技术的理解,对CRISPR/Cas9技术在癌症研究中的应用进行了综述。     

Delivery of CRISPR/Cas9 for therapeutic genome editing

The clustered, regularly‐interspaced, short palindromic repeat (CRISPR)‐associated nuclease 9 (CRISPR/Cas9) is emerging as a promising genome‐editing tool for treating diseases in a precise way, and has been applied to a wide range of research in the areas of biology, genetics, and medicine. Delivery of therapeutic genome‐editing agents provides a promising platform for the treatment of genetic disorders. Although viral vectors are widely used to deliver CRISPR/Cas9 elements with high efficiency, they suffer from several drawbacks, such as mutagenesis, immunogenicity, and off‐target effects. Recently, non‐viral vectors have emerged as another class of delivery carriers in terms of their safety, simplicity, and flexibility. In this review, we discuss the modes of CRISPR/Cas9 delivery, the barriers to the delivery process and the application of CRISPR/Cas9 system for the treatment of genetic disorders. We also highlight several representative types of non‐viral vectors, including polymers, liposomes, cell‐penetrating peptides, and other synthetic vectors, for the therapeutic delivery of CRISPR/Cas9 system. The applications of CRISPR/Cas9 in treating genetic disorders mediated by the non‐viral vectors are also discussed.     

基于CRISPR/Cas9技术的基因敲入/敲除策略

成簇的规律间隔性短回文序列(CRISPR)基因编辑系统,因其设计简单操作方便和无种属限制,已成为一种广泛应用的基因组定点编辑工具,在复杂的基因组编辑,例如基因的人源化改造以及条件等位基因的构建中有所应用。在自然界中,CRISPR系统拥有多种类别。其中,CRISPR/Cas9系统是研究最深入、应用最成熟的一种。本文针对CRISPR/Cas9系统,分别从基因敲入/敲除片段的大小、同源臂长短、构型即递送方式等技术环节进行综述,阐述不同设计及操作条件下由CRISPR/Cas9系统介导的基因敲入/敲除的效率差异。     

CRISPR/Cas9基因组编辑技术在HIV-1感染治疗中的应用进展

基因治疗是将外源正常基因通过一定方式导入人体靶细胞以纠正或补偿因基因缺陷和异常引起的疾病,从而达到治疗目的。因此,基因治疗的技术方法在研究持续感染HIV-1或潜伏感染HIV-1原病毒患者的治疗中具有重大的现实意义。目前,现有的基因治疗方法存在识别靶向位点有限及脱靶几率大等主要问题。最新研究表明来源于细菌和古菌的规律间隔成簇短回文重复序列及其相关核酸酶9系统[Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9), CRISPR/Cas9]已被成功改造成基因组定点编辑工具。因此,如何利用CRISPR/Cas9系统实现对HIV-1病毒基因组进行高效靶向修饰,从而达到治疗HIV-1感染病患的目的已经成为当前研究的热点。本文参考最新国内外研究成果,重点介绍了 CRISPR/Cas9基因组编辑技术在HIV-1感染疾病治疗中的应用,主要包括CCR5基因编辑、清除HIV-1原病毒以及活化HIV-1原病毒,以期为HIV-1感染疾病的预防与治疗提供重要研究参考。