CRISPR/Cas9 technology and its application in horticultural crops

Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated 9(CRISPR/Cas9)system has recently become one popular technology due to its efficiency,precision,and simplicity compared with other genome editing tools such as Zinc Finger Nucleases(ZFNs)and Transcription Activator Like Effector Nucleases(TALENs).Horticultural crops provide energy and health-keeping nutrients to humankind.Genome-editing technology has become widely adopted in horticultural breeding with the increasing demand for high yield and better-quality horticultural crops.Here,we describe the CRISPR/Cas9 system construction,its optimization,including sgRNA promoter,sgRNA design,Cas9 protein promoter,SpCas9 variants and orthologs,and vector delivery methods.We also summarized the application of this technology in horticultural plants for stress responses enhancement,fruit quality improvement,and cultivation traits modification.This detailed review was compiled to help establish comprehensive understanding of the CRISPR/Cas9 systems and provide a reference for further developing this technology to manipulate horticultural plant traits effectively.

Use of gene-editing technology to introduce targeted modifications in pigs

Pigs are an important resource in agriculture and serve as a model for human diseases. Due to their physiological and anatomical similarities with humans, pigs can recapitulate symptoms of human diseases, making them a useful model in biomedicine. However, in the past pig models have not been widely used partially because of the difficulty in genetic modification. The lack of true embryonic stem cells in pigs forced researchers to utilize genetic modification in somatic cells and somatic cell nuclear transfer(SCNT) to generate genetically engineered(GE) pigs carrying site-specific modifications. Although possible, this approach is extremely inefficient and GE pigs born through this method often presented developmental defects associated with the cloning process. Advancement in the gene-editing systems such as Zinc-Finger Nucleases(ZFNs), Transcription activator-like effector nucleases(TALENs), and the Clustered regularly interspaced short palindromic repeat(CRISPR)/CRISPR-associated 9(Cas9) system have dramatically increased the efficiency of producing GE pigs. These gene-editing systems, specifically engineered endonucleases, are based on inducing double-stranded breaks(DSBs) at a specific location, and then site-specific modifications can be introduced through one of the two DNA repair pathways: non-homologous end joining(NHEJ) or homology direct repair(HDR).Random insertions or deletions(indels) can be introduced through NHEJ and specific nucleotide sequences can be introduced through HDR, if donor DNA is provided. Use of these engineered endonucleases provides a higher success in genetic modifications, multiallelic modification of the genome, and an opportunity to introduce site-specific modifications during embryogenesis, thus bypassing the need of SCNT in GE pig production. This review will provide a historical prospective of GE pig production and examples of how the gene-editing system, led by engineered endonucleases, have improved GE pig production. We wil also present some of our current progress related to the optimal use of CRISPR/Cas9 system during embryogenesis.

CRISPR／Cas9系统在现代生物学研究和临床试验中的应用

规律成簇间隔短回文重复结构(clustered regularly interspaced short palindromic repeats,CRISPR)/CRISPR相关蛋白9(CRISPR-associated protien 9,Cas9)系统在生物医学研究中被广泛应用于基因编辑及探索基因的功能。这种基因编辑技术越来越多地运用在人类疾病的治疗中,包括巴斯综合征、杜氏肌萎缩症、血友病、地中海贫血和囊性纤维化。CRISPR/Cas 9基因编辑系统可以在体外细胞实验和体内动物实验上修复突变的DNA序列,也能改变CCR5、PD-1/L1、CAR-T等基因序列,用于控制HIV病毒的入侵及提高肿瘤免疫治疗的疗效。该技术还被运用于诱导多能干细胞(induced pluripotent stem cells,iPS)分化,形成某些具有功能的器官用于器官移植。本文综述了CRISPR/Cas 9系统的来源、结构和作用原理,以及其在现代生物学研究和基因治疗领域的应用。

Addressing challenges in the clinical applications associated with CRISPR/Cas9 technology and ethical questions to prevent its misuse

The recently developed RNA-guided clustered regularly interspaced short palindromic repeat （CRISPR）/CRISPR-associated 9 （Cas9） nuclease system has progressed to be an invaluable technology for genome manipulation in somatic cell types and germline model organisms. While the unprecedented advance in human embryo gene editing research has great potential in next-generation therapeutics, it raises various ethical concerns that need to be addressed before being translated for clinical use. Here, we discuss the current and potential applications of CRISPR/Cas9 technology and its limitations in clinical applications, as well as ethical and legal considerations in the treatment, disease prevention or disability in somatic cells or human embryo via gene editing.

Using a novel cellular platform to optimize CRISPR/CAS9 technology for the gene therapy of AIDS

Dear Editor,Despite tremendous effort devoted to the development of antiretroviral therapies to combat HIV over the past decades, AIDS remains one of the most important global infectious diseases. According to UNAIDS report on the global AIDS epidemic in 2016, the estimated number of people living with HIV rose from 7.5 million in 2010 to 36.7 million in 2015. Furthermore, drug-resistance HIV strains have recently been reported （Wensing et al., 2017）. Therefore, it is important to develop new therapies to eliminate HIV in the patients. Immortalized cell lines representing the major targets of HIV in human are important for HIV research and therapeutic development.

Regulating CRISPR/Cas9 Using Streptavidin-Biotin Interactions

Comprehensive Summary Currently,CRISPR/Cas9 technology has found widespread applications across various domains.However,the utility of CRISPR/Cas9 is encumbered by issues pertaining to its reliability and safety,primarily stemming from the uncontrolled activity of the system.Therefore,the design and development of CRISPR/Cas9 systems with controllable activity is of paramount importance.Biotin,characterized by its small molecular weight,and streptavidin,distinguished by its substantial spatial steric hindrance,can be harnessed as an ideal OFF switch(termed a"bioactivity brake")due to their interaction characteristics.In this work,we present a strategy that employs the streptavidin-biotin interaction as a"brake system"for CRISPR/Cas9,effectively allowing for the shutdown of the enzymatic activity of CRISPR/Cas9.

盘状结构域受体1对实验性结肠炎小鼠肠道炎症及纤维化的影响

目的探究盘状结构域受体1(discoidin domain receptors,DDR1)在慢性结肠炎小鼠肠道炎症及肠纤维化中的功能。方法针对DDR1基因exon4设计并合成gRNA序列,与编码Cas9的mRNA混合显微注射入C57BL/6小鼠受精卵内,构建DDR1基因突变小鼠。选择F4代基因敲除纯合子小鼠(DDR1^(-/-))和野生型C57BL/6小鼠,通过葡聚糖硫酸钠(DSS)诱导慢性结肠炎模型。比较两组小鼠疾病活动指数(DAI)、体质量、结肠长度及组织病理学变化。ELISA法检测外周血细胞因子的含量,Western blot法检测小鼠结肠纤维化相关蛋白表达。结果PCR法检测结果显示利用CRISPR/Cas9技术成功构建DDR1^(-/-)小鼠;循环饮用DSS后,与野生型小鼠相比,DDR1^(-/-)小鼠体质量下降减缓,DAI评分及肠组织病理学评分降低,结肠短缩减轻(5.81±0.11 cm vs 5.19±0.05 cm,P<0.05);血清IL-1β、TNF-α及TGF-β水平下调(P<0.01);Masson染色胶原容积评分显示肠纤维化减轻(DSS-WT vs DSS-DDR1,41.43±0.08 cm vs 21.37±0.07 cm,P<0.01);肠组织TGF-β、α-SMA和COL1A1的蛋白表达下降。结论DDR1参与慢性结肠炎的发生,敲除DDR1基因可减轻慢性结肠炎肠道炎症及纤维化的症状和疾病进程。

罕见病的基因治疗应用与展望

罕见病发病率极低、但大多病情严重且好发于儿童时期,多由遗传变异所引起。因患者数少、市场需求低,罕见病药物的研发成本极高,有药可治的罕见病仅不足1%。随着基因诊断技术进步,基因治疗凭借其“一次性彻底治愈”的特点,为遗传性罕见病患者带来了希望。本文介绍罕见病的基因治疗现状,论述传统基因递送技术和以CRISPR-Cas 9为代表的基因编辑技术在罕见病中的应用及发展。

Current Status of Conventional and Molecular Interventions for Blast Resistance in Rice

Pyricularia oryzae anamorph of Magnaporthe oryzae is one of the most notorious fungal pathogens causing severe economic loss in rice production worldwide. Various methods, viz. cultural, biological and molecular approaches, are utilized to counteract this pathogen. Moreover, some tolerant or resistant rice varieties have been developed with the help of breeding programmes. Isolation and molecular characterization of different blast resistance genes now open the gate for new possibilities to elucidate the actual allelic variants of these genes via various molecular breeding and transgenic approaches. However, the behavioral pattern of this fungus breakups the resistance barriers in the resistant or tolerant rice varieties. This host-pathogen barrier will be possibly countered in future research by comparative genomics data from available genome sequence data of rice and M. oryzae for durable resistance. Present review emphasized fascinating recent updates, new molecular breeding approaches, transgenic and genomics approaches(i.e. mi RNA and genome editing) for the management of blast disease in rice. The updated information will be helpful for the durable, resistance breeding programme in rice against blast pathogen.

Genome Editing Strategies Towards Enhancement of Rice Disease Resistance

The emerging pests and phytopathogens have reduced the crop yield and quality, which hasthreatened the global food security. Traditional breeding methods, molecular marker-based breedingapproaches and use of genetically modified crops have played a crucial role in strengthening the foodsecurity worldwide. However, their usages in crop improvement have been highly limited due to multiplecaveats. Genome editing tools like transcriptional activator-like effector nucleases and clustered regularlyinterspaced short palindromic repeats (CRISPR)-associated endonuclease Cas9 (CRISPR/Cas9) haveeffectively overcome limitations of the conventional breeding methods and are being widely accepted forimprovement of crops. Among the genome editing tools, the CRISPR/Cas9 system has emerged as themost powerful tool of genome editing because of its efficiency, amicability, flexibility, low cost andadaptability. Accumulated evidences indicate that genome editing has great potential in improving thedisease resistance in crop plants. In this review, we offered a brief introduction to the mechanisms of differentgenome editing systems and then discussed recent developments in CRISPR/Cas9 system-based genomeediting towards enhancement of rice disease resistance by different strategies. This review also discussed thepossible applications of recently developed genome editing approaches like CRISPR/Cas12a (formerlyknown as Cpf1) and base editors for enhancement of rice disease resistance.

大豆NIN和NLP基因生物信息学分析及敲除载体构建

为促进大豆NLP家族基因突变大豆材料的获得及大豆NIN和NLP基因功能的研究,本研究对大豆NIN和NLP基因进行生物信息学分析,通过CRISPR/Cas 9基因编辑技术构建基因敲除载体,并且通过大豆毛根转化实验验证靶点的有效性。结果表明:大豆基因组中一共存在4个NIN基因和10个NLP基因家族成员,这些基因都具有RWP-RK和PB1两个保守结构域。亚细胞定位预测表明所有成员都定位在细胞核中,此外GmNIN1b和GmNIN2a还定位于叶绿体。GmNIN1a/b、GmNIN2a/b、GmNLP2a/b及GmNLP3b在根瘤中的表达量相对较高,推测这些基因可能对结瘤过程具有重要的调控功能。成功构建了NLP4和NLP5两个敲除载体,得到可敲除GmNLP4a/b的3个有效靶点和敲除GmNLP5a/b的2个有效靶点。本研究获得了大豆NIN和NLP基因家族的生物信息学依据和创制GmNLP4a/b和GmNLP5a/b基因突变体的技术依据。

Targeting lactate dehydrogenase A (LDHA) exerts antileukemic effects on T-cell acute lymphoblastic leukemia

Background:T-cell acute lymphoblastic leukemia(T-ALL)is an uncommon and aggressive subtype of acute lymphoblastic leukemia(ALL).In the serum of T-ALL patients,the activity of lactate dehydrogenase A(LDHA)is increased.We proposed that targeting LDHA may be a potential strategy to improve T-ALL outcomes.The current study was conducted to investigate the antileukemic effect of LDHA gene-targeting treatment on T-ALL and the underlying molecular mechanism.Methods:Primary T-ALL cell lines Jurkat and DU528 were treated with the LDH inhibitor oxamate.MTT,colony formation,apoptosis,and cell cycle assays were performed to investigate the effects of oxamate on T-ALL cells.Quantitative real-time PCR(qPCR)and Western blotting analyses were applied to determine the related signaling pathways.A mitochondrial reactive oxygen species(ROS)assay was performed to evaluate ROS production after T-ALL cells were treated with oxamate.A T-ALL transgenic zebrafish model with LDHA gene knockdown was established using CRISPR/Cas9 gene-editing technology,and then TUNEL,Western blotting,and T-ALL tumor progression analyses were conducted to investigate the effects of LDHA gene knockdown on T-ALL transgenic zebrafish.Results:Oxamate significantly inhibited proliferation and induced apoptosis of Jurkat and DU528 cells.It also arrested Jurkat and DU528 cells in G0/G1 phase and stimulated ROS production(all P<0.001).Blocking LDHA significantly decreased the gene and protein expression of c-Myc,as well as the levels of phosphorylated serine/threonine kinase(AKT)and glycogen synthase kinase 3 beta(GSK-3β)in the phosphatidylinositol 3′-kinase(PI3K)signaling pathway.LDHA gene knockdown delayed disease progression and down-regulated c-Myc mRNA and protein expression in T-ALL transgenic zebrafish.Conclusion:Targeting LDHA exerted an antileukemic effect on T-ALL,representing a potential strategy for T-ALL treatment.