CRISPR/Cas系统在感染性疾病诊断中的应用

成簇规律间隔短回文重复序列(CRISPR)/CRISPR相关蛋白(Cas)系统,作为原核生物的适应性免疫防御系统,近年来已经被开发成为一种高效的分子诊断工具,其特异、灵敏、快速、便捷等优势使得其在分子诊断领域,尤其是在感染性疾病的诊断上有着极佳的发展前景。本文旨在对CRISPR/Cas系统在感染性疾病诊断的应用现状、优势和局限以及未来的研究方向做一介绍和探讨。     

基于CRISPR/Cas系统诊断平台的研究进展

目前核酸检测技术已被广泛应用于临床实验室诊断,常规检测技术如实时荧光定量PCR技术耗时长且依赖特定的仪器设备。成簇规律间隔短回文重复序列(CRISPR)/CRISPR相关蛋白(Cas)系统是细菌和古细菌在与病毒斗争过程中获得的适应性免疫防御机制,已被发展成强大的基因组编辑技术。最近CRISPR领域的先驱团队基于Cas13a、Cas12a和新发现的Cas14蛋白开发出SHERLOCK、DETECTR等新型核酸检测工具,在传染性疾病的快速诊断、癌症中基因突变的检测和基因分型等方面意义重大,其灵敏度高、特异性强且快速经济,在临床分子诊断领域具有巨大潜力。本文综述了CRISPR/Cas系统的作用机制及新型诊断平台的原理和应用进展,总结了新型检测技术的优缺点并对其发展前景进行展望。     

CRISPR/Cas12系统在肿瘤检测中的应用

快速、灵敏、特异的检测方法对于提高肿瘤患者的生存率并改善预后至关重要。除了在基因编辑领域的贡献，近年来成簇规律间隔短回文重复序列(CRISPR)/CRISPR相关蛋白(Cas)系统以其特有的靶标核酸识别切割能力和反式切割活性为特点，已成为新一代核酸检测工具被广泛应用于病原体、肿瘤和转基因等检测领域。基于此，该文对CRISPR/Cas12系统原理及其在不同肿瘤标志物中的检测应用进展作一综述，并对其应用前景进行展望，以期为CRISPR/Cas系统更好地应用于肿瘤筛查和诊断提供参考及借鉴。     

基因魔剪CRISPR/Cas:核酸精准检测的新宠和利器

规则成簇间隔短回文重复序列及其相关蛋白(CRISPR/Cas)系统是存在于大多数细菌及古细菌中的一种获得性免疫系统。作为一种高效的基因定点编辑工具,CRISPR/Cas系统不仅在基因敲出、基因治疗及基因修饰等领域炙手可热,而且正在发展成为核酸精准检测领域的新利器。随着众多研究者的不断探索,便携、快速、低成本、灵敏度高、特异性强的CRISPR/Cas核酸精准检测技术不断涌现。本文就CRISPR/Cas技术在核酸快速精准检测领域的最新成果作一概述,并总结展望其面临的困难和挑战。     

基于CRISPR-Cas12a蛋白的副溶血弧菌及tdh基因检测分析

目的 将重组酶介导等温核酸扩增技术(RAA)与成簇的规律间隔短回文重复序列(CRISPR)系统相结合,建立一种快速检测并分型副溶血弧菌的检测方法.方法 通过纯化CRISPR相关蛋白Cas12a,设计和合成RAA引物、crRNA和单链DNA报告分子,建立副溶血弧菌的荧光和试纸条检测方法.采用煮沸法提取细菌核酸,经RAA扩...     

CRISPR/Cas系统在新型冠状病毒肺炎快速诊断中的应用

近年来,基于规律成簇间隔的短回文重复序列（ clustered regularly interspaced short palindromic repeats, CRISPR）及其相关蛋白（ CRISPR-associated protein, Cas）系统的新型分子诊断工具,为病原体的诊断开辟了新的机遇。该文将关注现有和正在研究的 CRISPR/Cas系统用于新型冠状病毒肺炎（coronavirus disease 2019, COVID-19）快速诊断的潜在能力,并重点探讨其在临床中的应用和面临的挑战。     

CRISPR/Cas技术在病原体检测中的应用

1987 年在大肠埃希菌基因组中首次发现了成簇间隔短回文重复序列(CRISPR),具有切割外来入侵病毒核酸的获得性免疫功能[1].CRISPR及其相关蛋白(CRISPR/Cas)系统是由编码 Cas 蛋白基因和由启动子加上重复序列与入侵核酸同源的间隔序列交替而构成[2].该系统的获得性免疫机制可以分为 3 个阶段:获得...     

CRISPR-Cas13a系统在基因编辑和分子诊断领域中的研究进展

成簇的规律间隔的短回文重复序列(CRISPR)-CRISPR相关蛋白(Cas)系统是一个强大的基因编辑工具。相对于Cas9,Cas13a可靶向多基因转录产物,从而调控基因功能表达,填补了Cas9仅限于DNA水平的编辑及脱靶效应等缺陷。不仅如此,利用Cas13a靶向RNA的特性,该系统被成功地改造成下一代核酸诊断工具。文章概述了CRISPR-Cas13系统在基因编辑及分子诊断领域的最新研究进展,并对该系统的应用前景进行了展望。     

基于CRISPR/Cas蛋白的副溶血弧菌检测方法的研究

目的利用规律间隔性成簇短回文重复序列（CRISPR）免疫原理及Cas12a酶的特点构建一种快速检测副溶血弧菌（VP）的方法,实现对病原菌准确快速的检测和识别。方法本研究通过制备纯化Cas12a蛋白,筛选构建VP的gRNA,建立CRISPR-VP荧光检测系统,根据最终荧光扩增曲线判定CRISPR-VP检测方法的有效性。结果在CRISPR-VP检测方法中只在VP的序列存在时才会产生明显的荧光信号。结论本实验初步建立了基于CRISPR/Cas蛋白的VP的检测方法,为后续简易检测试剂的研制提供理论依据。     

核酸检测和基因编辑的新工具：CRISPR/Cas13系统

成簇的规律间隔的短回文重复序列(clustered regularly interspaced short palindromic repeats,CRISPR)/CRISPR相关蛋白(CRISPR-associated proteins, Cas)系统是目前基因编辑、基因表达研究的热点,其中,研究较成熟的为CRISPR/Cas9系统,其在单链RNA的引导下可特异地切割靶DNA的特定位点,实现DNA水平的操作。而靶向RNA的CRISPR/Cas13系统开启了在RNA水平研究、诊疗的新时代。活化的Cas13具有独特的核酸酶活性,可特异性地切割靶向RNA,同时非特异性地切割周围环境中的RNA,利用以上特性可实现体外核酸检测。通过活性位点突变可产生无核酸酶活性但可与RNA结合的dCas13(dead Cas13),将dCas13与其他功能性蛋白质进行融合可进一步扩大dCas13的应用范围。该文主要概括了CRISPR/Cas13系统在核酸检测以及在RNA水平作为基因编辑工具的新进展。     

规律成簇的间隔短回文重复序列中间隔序列的噬菌体来源研究

目的 发现在现有的全基因组测序完成的原核生物中规律成簇的间隔短回文重复序列(CRISPR)系统中间隔序列分布规律以及间隔序列中噬菌体来源情况. 方法 整理现有CRISPR数据库中2762株细菌基因组中的CRISPR系统和其中的间隔序列数据,整理GenBank数据库中发表的1444个噬菌体基因组数据.利用BLASTN软件对间隔序列数据与噬菌体基因组进行相似性比较,计数资料比较使用2检验. 结果 在2762个细菌基因组中整理出1940个基因组存在确定或可能的CRISPR结构和90 096条间隔序列,多数基因组具有1~50条间隔序列(1414/1940,72.9%),间隔序列数量250条的仅有58个基因组(58/1940,3.0%).其中古细菌13株(13/150,8.6%),真细菌45株(45/2612,1.7%),差异有统计学意义(2=29.98,P 0.01).相似性比较结果共发现245个细菌基因组的1055条间隔序列,成功比对上363个噬菌体,比对成功率仅为0.12%. 结论 细菌基因组中的CRISPR系统中间隔序列数量存在较大差异,古细菌基因组中CRISPR系统存在更多的间隔序列.相似性比较中噬菌体来源的间隔序列所占比例低,提示与细菌和噬菌体基因组发现较少相关,进一步深入研究可以大幅度提高成功率.     

Personalized therapeutic strategies for patients with retinitis pigmentosa

Introduction: Retinitis pigmentosa (RP) encompasses many different hereditary retinal degenerations that are caused by a vast array of different gene mutations and have highly variable disease presentations and severities. This heterogeneity poses a significant therapeutic challenge, although an answer may eventually be found through two recent innovations: induced pluripotent stem cells (iPSCs) and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas genome editing.

Areas covered: This review discusses the wide-ranging applications of iPSCs and CRISPR–including disease modelling, diagnostics and therapeutics – with an ultimate view towards understanding how these two technologies can come together to address disease heterogeneity and orphan genes in a novel personalized medicine platform. An extensive literature search was conducted in PubMed and Google Scholar, with a particular focus on high-impact research published within the last 1 – 2 years and centered broadly on the subjects of retinal gene therapy, iPSC-derived outer retina cells, stem cell transplantation and CRISPR/Cas gene editing.

Expert opinion: For the retinal pigment epithelium, autologous transplantation of gene-corrected grafts derived from iPSCs may well be technically feasible in the near future. Photoreceptor transplantation faces more significant unresolved technical challenges but remains an achievable, if more distant, goal given the rapid pace of advancements in the field.     

Progress in the application of CRISPR: From gene to base editing

The system of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated endonucleases (Cas) has been utilized for genome editing with great accuracy and high efficiency in generating gene knockout, knockin, and point mutations in eukaryotic genomes. However, traditional CRISPR/Cas9 technology introduces double-stranded DNA breaks (DSBs) at a target locus as the first step to make gene corrections, which easily results in undesired mutations. Thus, it is necessary to develop new methods for correcting the unwanted mutations. In this review, we summarize the recent developments and a new approach to genome and base editing by using CRISPR/Cas9. This methodology renders a conversion of one target base into another, for example, C to T (or G to A), and A to G (or T to C) without producing DSBs, requiring a donor DNA template, or generating excessive insertions and deletions. Furthermore, CRISPR/Cas9-derived base editing also improves efficiency in repairing point mutations in the genome.     

The ABCs of CRISPR in Tephritidae: developing methods for inducing heritable mutations in the genera Anastrepha,Bactrocera and Ceratitis

Tephritid fruit flies are destructive agricultural pests that are the targets of expensive population eradication and suppression efforts. Genetic pest management is one of the strategies for reducing or eliminating tephritid populations, relying upon the genetic manipulation of insects to render them sterile or capable of transmitting deleterious traits through gene drive. Currently, radiation, chemical mutagenesis, and transgenic techniques are employed to generate agents for genetic pest management, but new methods must be explored and developed for all tephritid pest species. Targeted mutagenesis induced by nonhomologous end join repair of clustered regularly interspaced short palindromic repeats and the CRISPR associated protein 9 (Cas9) (commonly known as CRISPR/Cas9) has been demonstrated to be an efficient method for creating knock‐out mutants and can be utilized to create germline mutations in Tephritidae. In this paper, we describe detailed methods to knockout the white gene in three tephritid species in the genera Anastrepha, Bactrocera and Ceratitis, including the first demonstration of CRISPR/Cas9 induced mutations in the genus Anastrepha. Lastly, we discuss the variables in tephritid systems that directed method development as well as recommendations for performing injections in remote containment facilities with little molecular biology capabilities. These methods and recommendations combined can serve as a guide for others to use in pursuit of developing CRISPR/Cas9 methods in tephritid systems.