小柯机器人

美国加州大学旧金山分校Jonathan S. Weissman、Luke A. Gilbert等研究人员合作发现，通过基于CRISPR的表观基因组编辑可实现全基因组范围的可编程转录记忆。相关论文于2021年4月12日在线发表于国际学术期刊《细胞》。

研究人员报道了CRISPRoff，一种可编程的表观遗传记忆书写技术，它由单个无活性的Cas9融合蛋白组成，该融合蛋白能够建立DNA甲基化和抑制性组蛋白修饰。瞬时CRISPRoff表达可启动高度特异性的DNA甲基化和基因抑制，这种抑制通过细胞分裂和干细胞向神经元的分化来维持。将CRISPRoff与全基因组筛选配对并分析染色质标记可建立可遗传基因沉默的规则。

研究人员发现，单个向导RNA（sgRNAs）能够沉默的大多数基因，包括那些缺乏经典CpG岛（CGI）的基因，并揭示了超出CGI以外的广泛靶向区域。CRISPRoff甚至在CGI之外也具有启动可遗传基因沉默的广泛能力，扩展了基于甲基化的沉默经典模型，并实现了多种应用，包括全基因组筛选、多重细胞工程、增强子沉默和表观遗传继承的机制探索。

据悉，可遗传地改变基因表达的通用方法具有实现许多发现和治疗的潜力。

附：英文原文

Title: Genome-wide programmable transcriptional memory by CRISPR-based epigenome editing

Author: James K. Nuez, Jin Chen, Greg C. Pommier, J. Zachery Cogan, Joseph M. Replogle, Carmen Adriaens, Gokul N. Ramadoss, Quanming Shi, King L. Hung, Avi J. Samelson, Angela N. Pogson, James Y.S. Kim, Amanda Chung, Manuel D. Leonetti, Howard Y. Chang, Martin Kampmann, Bradley E. Bernstein, Volker Hovestadt, Luke A. Gilbert, Jonathan S. Weissman

Issue&Volume: 2021-04-09

Abstract: A general approach for heritably altering gene expression has the potential to enablemany discovery and therapeutic efforts. Here, we present CRISPRoff—a programmableepigenetic memory writer consisting of a single dead Cas9 fusion protein that establishesDNA methylation and repressive histone modifications. Transient CRISPRoff expressioninitiates highly specific DNA methylation and gene repression that is maintained throughcell division and differentiation of stem cells to neurons. Pairing CRISPRoff withgenome-wide screens and analysis of chromatin marks establishes rules for heritablegene silencing. We identify single guide RNAs (sgRNAs) capable of silencing the largemajority of genes including those lacking canonical CpG islands (CGIs) and reveala wide targeting window extending beyond annotated CGIs. The broad ability of CRISPRoffto initiate heritable gene silencing even outside of CGIs expands the canonical modelof methylation-based silencing and enables diverse applications including genome-widescreens, multiplexed cell engineering, enhancer silencing, and mechanistic explorationof epigenetic inheritance.

DOI: 10.1016/j.cell.2021.03.025

Source: https://www.cell.com/cell/fulltext/S0092-8674(21)00353-6