CRISPR/Cas9(clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9)系统具有高效、简单、易编辑等特性,在基因工程方面具有巨大潜能。在果蝇(Drosophila melanogaster)基因功能研究中,CRIS...CRISPR/Cas9(clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9)系统具有高效、简单、易编辑等特性,在基因工程方面具有巨大潜能。在果蝇(Drosophila melanogaster)基因功能研究中,CRISPR/Cas9系统也得到了广泛应用。然而利用传统的CRISPR/Cas9系统编辑果蝇基因时,Cas9与sgRNA表达元件往往分别存在于不同果蝇中,需要通过复杂的遗传杂交过程将Cas9与sgRNA整合到一个个体中,操作周期长且较为复杂。本研究在CRISPR/Cas9系统基础上引入tRNA-sgRNA系统和triplex元件,利用triplex元件连接Cas9和tRNA-sgRNA基因,稳定单转录本切割后Cas9 mRNA的末端,实现一个转录本可以同时表达Cas9蛋白和sgRNA,通过一次杂交即可得到相应表型的后代,简化了遗传操作过程。本研究利用这一新的条件性基因编辑系统,分别对果蝇眼部white(w)基因和翅成虫盘broad(br)基因进行条件性敲除,观察到与预期相符的对应表型。因此,该条件性基因编辑系统在高效性、可扩展性和易操作性等方面是对现有CRISPR/Cas9系统进行的重大改进。展开更多
目的设计并验证能够高效切割Hipp11位点的sgRNA,为在Hipp11位点定点敲入外源基因提供工作基础。方法使用预测软件对Hipp11位点的sgRNA进行预测并挑选脱靶效应较低的两个sgRNA。构建相应载体,通过CRISPR/Cas9活性检测试剂盒在体外检测sg...目的设计并验证能够高效切割Hipp11位点的sgRNA,为在Hipp11位点定点敲入外源基因提供工作基础。方法使用预测软件对Hipp11位点的sgRNA进行预测并挑选脱靶效应较低的两个sgRNA。构建相应载体,通过CRISPR/Cas9活性检测试剂盒在体外检测sgRNA的活性。选取活性较高的sgRNA体外转录,与Cas9 m RNA一并注射受精卵。检测出生后小鼠Hipp11位点切割效率,计算出sgRNA的体内活性。结果两个sgRNA的体外活性分别为19.2%和51.7%,使用体外活性高的2号sgRNA显微注射获得8只新生小鼠,其中62.5%(5/8)的小鼠中检测到Hipp11位点周围发生碱基插入或缺失。结论获得一个能够引导高效切割的Hipp11位点通用型sgRNA,从而为基因CRISPR技术在Hipp11位点定点插入外源基因奠定基础。sgRNA体外活性能够预测sgRNA在体内的切割活性,表明体外活性验证是筛选高活性sgRNA的有效手段。展开更多
CRISPR-Cas9 is a common tool for gene editing, and appropriate sg RNAs are the key factor for successful editing. In this study, the effect of sg RNA length and number on editing efficiency was analyzed in rice using ...CRISPR-Cas9 is a common tool for gene editing, and appropriate sg RNAs are the key factor for successful editing. In this study, the effect of sg RNA length and number on editing efficiency was analyzed in rice using CYP81 A6 as the target gene. A series of CRISPR-Cas9 plant expression vectors containing single sg RNAs with different lengths(17, 18, 19, 20, 21, 22, 23 nt) or two sg RNAs were constructed and introduced into rice cultivar Zhonghua11 by Agrobacterium-mediated transformation. Analysis of the editing status of 1283 transgenic rice plants showed that 371 were successfully edited with base preference.Single A or T insertions were the most frequent among the six edited types. The editing efficiency of transgenic rice with two sg RNAs was higher than that with a single sg RNA. Editing efficiency and sg RNA length showed a normal distribution with 20 nt sg RNA(25%) being the most efficient. The editing efficiency decreased slightly with decreases of 1–2 bases(19 nt 20%, 18 nt 21%), but decreased significantly with a decrease of 3 bases(17 nt 4.5%). Editing efficiency was significantly reduced by adding 1 to 3 bases(21 nt 16.8%, 22 nt 13%, 23 nt 13%) to the sg RNA. These results provide data for successful gene editing or rice by CRISPR-Cas9.展开更多
文摘CRISPR/Cas9(clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9)系统具有高效、简单、易编辑等特性,在基因工程方面具有巨大潜能。在果蝇(Drosophila melanogaster)基因功能研究中,CRISPR/Cas9系统也得到了广泛应用。然而利用传统的CRISPR/Cas9系统编辑果蝇基因时,Cas9与sgRNA表达元件往往分别存在于不同果蝇中,需要通过复杂的遗传杂交过程将Cas9与sgRNA整合到一个个体中,操作周期长且较为复杂。本研究在CRISPR/Cas9系统基础上引入tRNA-sgRNA系统和triplex元件,利用triplex元件连接Cas9和tRNA-sgRNA基因,稳定单转录本切割后Cas9 mRNA的末端,实现一个转录本可以同时表达Cas9蛋白和sgRNA,通过一次杂交即可得到相应表型的后代,简化了遗传操作过程。本研究利用这一新的条件性基因编辑系统,分别对果蝇眼部white(w)基因和翅成虫盘broad(br)基因进行条件性敲除,观察到与预期相符的对应表型。因此,该条件性基因编辑系统在高效性、可扩展性和易操作性等方面是对现有CRISPR/Cas9系统进行的重大改进。
文摘目的设计并验证能够高效切割Hipp11位点的sgRNA,为在Hipp11位点定点敲入外源基因提供工作基础。方法使用预测软件对Hipp11位点的sgRNA进行预测并挑选脱靶效应较低的两个sgRNA。构建相应载体,通过CRISPR/Cas9活性检测试剂盒在体外检测sgRNA的活性。选取活性较高的sgRNA体外转录,与Cas9 m RNA一并注射受精卵。检测出生后小鼠Hipp11位点切割效率,计算出sgRNA的体内活性。结果两个sgRNA的体外活性分别为19.2%和51.7%,使用体外活性高的2号sgRNA显微注射获得8只新生小鼠,其中62.5%(5/8)的小鼠中检测到Hipp11位点周围发生碱基插入或缺失。结论获得一个能够引导高效切割的Hipp11位点通用型sgRNA,从而为基因CRISPR技术在Hipp11位点定点插入外源基因奠定基础。sgRNA体外活性能够预测sgRNA在体内的切割活性,表明体外活性验证是筛选高活性sgRNA的有效手段。
基金supported by the Central Public-interest Scientific Institution Basal Research Fund。
文摘CRISPR-Cas9 is a common tool for gene editing, and appropriate sg RNAs are the key factor for successful editing. In this study, the effect of sg RNA length and number on editing efficiency was analyzed in rice using CYP81 A6 as the target gene. A series of CRISPR-Cas9 plant expression vectors containing single sg RNAs with different lengths(17, 18, 19, 20, 21, 22, 23 nt) or two sg RNAs were constructed and introduced into rice cultivar Zhonghua11 by Agrobacterium-mediated transformation. Analysis of the editing status of 1283 transgenic rice plants showed that 371 were successfully edited with base preference.Single A or T insertions were the most frequent among the six edited types. The editing efficiency of transgenic rice with two sg RNAs was higher than that with a single sg RNA. Editing efficiency and sg RNA length showed a normal distribution with 20 nt sg RNA(25%) being the most efficient. The editing efficiency decreased slightly with decreases of 1–2 bases(19 nt 20%, 18 nt 21%), but decreased significantly with a decrease of 3 bases(17 nt 4.5%). Editing efficiency was significantly reduced by adding 1 to 3 bases(21 nt 16.8%, 22 nt 13%, 23 nt 13%) to the sg RNA. These results provide data for successful gene editing or rice by CRISPR-Cas9.
