中文摘要：

Clustered regularly interspaced short palindromic repeats（CRISPR）/CRISPR-associated （Cas）系统是继锌指核酸酶（znic finger nuclease, ZFNs）及转录激活因子样效应物核酸酶（transcription activator-like effector nucleases, TALENs）技术之后一种新的对基因组进行高效定点修饰的技术。这种系统是细菌以及古细菌在进化过程中形成的可以降解外来病毒或核酸的具有免疫以及调节功能的系统。CRISPR/Cas系统共有3种类型,其中CRISPR/Cas类型II系统最为简单,目前在研究中使用得也最广泛。野生型CRISPR/Cas类型II系统由crRNA（CRISPR RNA, crRNA）、tracrRNA（trans-activating crRNA,tracrRNA）以及Cas9蛋白组成。其中crRNA识别入侵的同源序列,crRNA：tracrRNA复合物结合Cas9蛋白并引导其对DNA双链的切割。迄今,CRISPRI-Cas类型II系统在细菌、真核细胞（包括人类细胞）中的活性已经得到了验证。首先以CRISPR/Cas类型II系统为例介绍CRISPRI/Cas系统的结构特点、作用原理及其在基因组定点修饰方面的作用,然后对该技术潜在的广泛应用前景以及可能存在的问题进行深入的分析。

英文摘要：

CRISPR （Clustered regularly interspaced short palindromic repeats）/Cas（CRISPR-associated） system is another new technology for targeted genome editing in addition to ZFNs （zinc finger nuclease, ZFNs） and TALENs （Transcription activator-like effector nucleases, TALENs）. Bacteria and archaea have evolved this defense and regulatory system to cope with invading virus and plasmids. CRISPR/Cas has been classified into three types. Type Ⅱ is the simplest one among three CRISPR-Cas systems, and it is most widely used. The wild type Type Ⅱ system is composed of crRNA（CRISPR RNA）,tracrRNA （trans-activating RNA） and a Cas9 protein. During the interference phase, the individual crRNAs together with tracrRNA guide Cas proteins to cleave the cognate invading nucleic acids, and produce DSBs （Double strand breaks）. So far CRISPR/Cas system has been validated in bacteria and eukaryotic cell lines, including human cell lines. The structure of CRISPR/Cas system and how it operates during immunization was summarized, and how it works in targeted gene editing. and the prospected future and potential challenges of this technology was analyzed.