中文摘要：

CRISPR（clustered regulatory interspersed short palindromic repeat）序列源于原核生物的一种获得性免疫系统，协同Cas（CRISPR—associated）蛋白家族参与抵抗噬茵体或其它病毒的二次感染，广泛存在于细菌（60％）和古茵（90％）中．病菌和宿主的共同进化导致了CRISPR-Cas系统具有多样性，可分为3大类（I-Ⅲ），又分为10亚类．在Ⅱ型CRISPR-Cas系统基础上建立了RNA介导的CRISPR．Cas系统来修饰（删除、添加、激活、抑制）靶细胞中特定的基因序列，现已在人类细胞、小鼠、斑马鱼、酵母、细菌、果蝇、线虫、拟南芥中得以应用．本文主要介绍了Ⅱ型CRISPR—Cas系统的结构特点、作用机理及作为新型基因组定点修饰技术的研究进展，分析该技术优势，并展望CRISPR—Cas系统的应用前景．

英文摘要：

CRISPR（clustered regulatory interspersed short palindromic repeat）sequences originate from a kind of prokaryotie adaptive immune system to protect prokaryotes against viruses or conjugative plasmids. CRISPR sequences are widely distributed in the genomes of both bacteria （60%） and archaea （90%）. Host-parasite coevolution plays a central role in the diversity of CRISPR-Cas systems. There are three highly diverse types of CRISPR-Cas （type I-Ⅲ ） that display major functional and structural differences, and these three major types have been further divided into 10 subtypes. CRISPR-Cas interference machines are utilized to develop novel RNA-guided genome editing tools. The CRISPR-Cas system has been demonstrated for genome editing in human, mice, zebrafish, yeast, bacteria, Drosophila, nematode, Arabidopsis in laboratory. The review summarized the structure of type Ⅱ CRISPR sequences, mechanisms of function, applications in genome editing and their advantages.