In the past few years, several types of artificial transcriptional activator, based on CRISPR-Cas9, have been developed and refined. Of these, in synergistic activation mediator and SunTag systems, the effector proteins, expressed in trans, can be recruited to the target sites via the MS2 RNA-binding system and GCN4-scFv antibody system, respectively. Here, we report a strong transcriptional activation system achieved by fusing GCN4 repeat to MS2 coat protein to accumulate numbers of activators, fused to scFv antibodies. By targeting the CDH1 gene, we show that our novel system, named "TREE," results in a greater effect of activating exogenous reporter and endogenous gene. Moreover, by targeting another gene, RANKL, we consistently show the superiority of the TREE system with fewer single-guide RNAs compared to conventional systems. Our TREE system is a promising tool for transcriptional activation and can potentially contribute to other dCas9-mediated technologies such as epigenome editing and chromosome visualization.

中文翻译：

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用于增强表达的三成分重新利用技术：通过分支标签阵列的高度可复制转录激活因子。

在过去的几年中，已经开发和改进了几种基于CRISPR-Cas9的人工转录激活剂。其中，在协同激活介体和SunTag系统中，反式表达的效应蛋白可以分别通过MS2 RNA结合系统和GCN4-scFv抗体系统募集到靶位点。在这里，我们报道了一个强大的转录激活系统，该系统通过将GCN4重复序列融合到MS2外壳蛋白上来积累与scFv抗体融合的激活剂数量而实现。通过针对CDH1基因，我们表明，我们的新系统，名为“ TREE”，导致激活外源报告基因和内源基因的更大作用。此外，通过靶向另一个基因RANKL，我们始终显示出TREE系统与传统系统相比具有更少的单向导RNA的优越性。