Cas9 is a RNA-guided double stranded DNA nuclease that participates in the CRISPR/Cas9 system. Wide-type Cas9 directly silences the expression of target gene by gene splicing. The engineered dCas9 protein with the mutation at D10A and H840A lacks the Cas9' s endonuclease function but keeps its DNA binding activity. dCas9 can activate special genes by fusing with transcription activator. Meanwhile,it can inhibit the gene transcription by directly binding to the target gene and stop gene transcrip?tion. Combination of light sensitive structures and CRISPR can produce light-inducible CRISPR/Cas9 system for control of gene expres?sion. This system is able to activate or inhibit gene expression via the use of controlling blue light(470 nm). In this review,we mainly discuss the development of the light inducible CRISPR/Cas9 system as well as its application in the control of gene expression.%Cas9是CRISPR/Cas9系统中RNA引导的可切割双链DNA的核酸酶,野生型Cas9可通过基因剪切直接导致目的基因表达沉默.将Cas9蛋白D10A和H840A位点突变,可获得失去切割活性但仍保留与DNA结合能力的dCas9,其与转录激活因子连接后结合到DNA特定位点可实现转录激活;若dCas9直接与靶基因特定位点结合则可阻碍目的基因的转录.将光可调节物质引入CRISPR/Cas9可设计成光诱导CRISPR/Cas9系统.此系统在蓝光(470 nm)诱导下作用于靶DNA可实现人为可控的基因表达激活和抑制.本文主要介绍了光诱导CRISPR/Cas9系统的特性及其在基因表达调控中的运用.
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