脱氨酶介导的大肠杆菌多重基因组编辑。
Deaminase-mediated multiplex genome editing in Escherichia coli.
机构信息
Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Hyogo, Japan.
Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan.
出版信息
Nat Microbiol. 2018 Apr;3(4):423-429. doi: 10.1038/s41564-017-0102-6. Epub 2018 Feb 5.
In eukaryotes, the CRISPR-Cas9 system has now been widely used as a revolutionary genome engineering tool. However, in prokaryotes, the use of nuclease-mediated genome editing tools has been limited to negative selection for the already modified cells because of its lethality. Here, we report on deaminase-mediated targeted nucleotide editing (Target-AID) adopted in Escherichia coli. Cytidine deaminase PmCDA1 fused to the nuclease-deficient CRISPR-Cas9 system achieved specific point mutagenesis at the target sites in E. coli by introducing cytosine mutations without compromising cell growth. The cytosine-to-thymine substitutions were induced mainly within an approximately five-base window of target sequences on the protospacer adjacent motif-distal side, which can be shifted depending on the length of the single guide RNA sequence. Use of a uracil DNA glycosylase inhibitor in combination with a degradation tag (LVA tag) resulted in a robustly high mutation efficiency, which allowed simultaneous multiplex editing of six different genes. The major multi-copy transposase genes that consist of at least 41 loci were also simultaneously edited by using four target sequences. As this system does not rely on any additional or host-dependent factors, it may be readily applicable to a wide range of bacteria.
在真核生物中,CRISPR-Cas9 系统现已广泛用作革命性的基因组工程工具。然而,在原核生物中,由于其致死性,只能将核酸酶介导的基因组编辑工具用于已经修饰的细胞的负选择。在这里,我们报告了在大肠杆菌中采用脱氨酶介导的靶向核苷酸编辑(Target-AID)。将胞嘧啶脱氨酶 PmCDA1 与无核酸酶的 CRISPR-Cas9 系统融合,通过在不影响细胞生长的情况下在大肠杆菌中的靶位点引入胞嘧啶突变,实现了特异性的点突变。胞嘧啶到胸腺嘧啶的取代主要发生在间隔区邻近基序-远端靶序列的大约五个碱基的窗口内,其可以根据单指导 RNA 序列的长度而移动。在尿嘧啶 DNA 糖基化酶抑制剂与降解标签(LVA 标签)联合使用的情况下,可实现高效的突变,从而允许同时对六个不同的基因进行多重编辑。使用四个靶序列还可以同时编辑至少由 41 个基因组成的主要多拷贝转座酶基因。由于该系统不依赖于任何额外的或宿主依赖性的因素,它可能易于应用于广泛的细菌。