美国北卡罗来纳大学教堂山分校Nathaniel A. Hathaway、西奈山伊坎医学院Jian Jin等研究人员合作利用CRISPR和小分子，通过招募内源性染色质机器来剂量依赖性激活基因表达。2019年11月11日《自然—生物技术》杂志在线发表了这项成果。

研究人员报道了化学表观遗传修饰器（CEM），其能够通过招募内源染色质激活机器来激活目标基因的表达，从而不需要外源转录激活蛋白。该系统分为两个部分：与FK506结合蛋白（FKBP）形成复合体的无催化作用的Cas9（dCas9），以及一个含有FK506并连接一个能够与细胞表观机器相互作用的CEM。研究人员发现表明，CEM能够将靶基因上调至内源性基因的20倍或更多，具体取决于基因。研究人员还证明了转录激活的剂量依赖性调控、多个不同基因的功能、CEM活性的可逆性以及整个基因组中同类最佳CEM的特异性。

据了解，使用CRISPR-Cas9系统能够激活或抑制基因表达。但是，目前缺少能够在不使用外源转录调节蛋白的情况下实现剂量依赖性激活基因表达的工具。

附：英文原文

Title: Dose-dependent activation of gene expression is achieved using CRISPR and small molecules that recruit endogenous chromatin machinery

Author: Anna M. Chiarella, Kyle V. Butler, Berkley E. Gryder, Dongbo Lu, Tiffany A. Wang, Xufen Yu, Silvia Pomella, Javed Khan, Jian Jin, Nathaniel A. Hathaway

Issue&Volume: 2019-11-11

Abstract: Gene expression can be activated or suppressed using CRISPR-–Cas9 systems. However, tools that enable dose-dependent activation of gene expression without the use of exogenous transcription regulatory proteins are lacking. Here we describe chemical epigenetic modifiers (CEMs) designed to activate the expression of target genes by recruiting components of the endogenous chromatin-activating machinery, eliminating the need for exogenous transcriptional activators. The system has two parts: catalytically inactive Cas9 (dCas9) in complex with FK506-binding protein (FKBP) and a CEM consisting of FK506 linked to a molecule that interacts with cellular epigenetic machinery. We show that CEMs upregulate gene expression at target endogenous loci up to 20-fold or more depending on the gene. We also demonstrate dose-dependent control of transcriptional activation, function across multiple diverse genes, reversibility of CEM activity and specificity of our best-in-class CEM across the genome.

DOI: 10.1038/s41587-019-0296-7

Source: https://www.nature.com/articles/s41587-019-0296-7