本文2017年11月20日在线发表于Nature Plants，原文题目为：

A potent Cas9-derived gene activator for plant and mammalian cells

cDNA的过表达是最常用的功能获得的方法，以此来研究基因功能和操纵生物学特征。然而，由于基因克隆工作量的增加，有限的载体容量，需要多个启动子和终止子，以及转基因表达水平的变化，这种方法对于多基因表达具有挑战性和低效性。合成的转录激活因子通过可编程的DNA结合模块将自发转录激活结构域（TAD）连接到内源基因组基因座上的启动子上，为基因的激活提供了有希望的替代策略。在已知的DNA结合模块中，通过合成指导RNA和DNA之间的碱基配对识别特定DNA靶标的dCas9蛋白，性能要优于锌指蛋白和转录激活类效应子，后两者都通过蛋白质-DNA相互作用来靶向目标。最近，三种高效的基于dCas9的转录激活系统，即VPR，SAM和SunTag已经被开发用于动物细胞。然而，在植物细胞中仍然缺乏基于dCas9的转录激活系统。在这里，我们通过植物细胞筛选开发了一种名为dCas9-TV的新型强效dCas9-TAD。与植物和哺乳动物细胞中常规使用的dCas9-VP64激活相比，dCas9-TV赋予单个或多个靶基因更强的转录激活。

Overexpression of complementary DNA represents the most commonly used gain-of-function approach for interrogating gene functions and for manipulating biological traits. However, this approach is challenging and inefficient for multigene expression due to increased labour for cloning, limited vector capacity, requirement of multiple promoters and terminators, and variable transgene expression levels. Synthetic transcriptional activators provide a promising alternative strategy for gene activation by tethering an autonomous transcription activation domain (TAD) to an intended gene promoter at the endogenous genomic locus through a programmable DNA-binding module. Among the known custom DNA-binding modules, the nuclease-dead Streptococcus pyogenes Cas9 (dCas9) protein, which recognizes a specific DNA target through base pairing between a synthetic guide RNA and DNA, outperforms zinc-finger proteins and transcription activator-like effectors, both of which target through protein–DNA interactions. Recently, three potent dCas9-based transcriptional activation systems, namely VPR, SAM and SunTag, have been developed for animal cells. However, an efficient dCas9-based transcriptional activation platform is still lacking for plant cells. Here, we developed a new potent dCas9–TAD, named dCas9–TV, through plant cell-based screens. dCas9–TV confers far stronger transcriptional activation of single or multiple target genes than the routinely used dCas9–VP64 activator in both plant and mammalian cells.