成簇的规则间隔的短回文重复和相关的Cas蛋白(CRISPR-Cas),一个强大的基因组编辑工具,彻底改变了基因功能研究,并显示出巨大的临床应用潜力。CRISPR-Cas介导的基因敲除已经成为研究实验室的常规方法。然而,在过去的几年里,越来越多的证据表明,被CRISPR-Cas敲除的基因可能没有真正沉默.在这样的敲除生物体中可以产生功能性残留蛋白以补偿推定的功能损失。本文称为敲除逃逸。与此相符,一些CRISPR-Cas介导的基因敲除筛查发现的异常表型比预期少得多.敲除逃逸是如何发生的,以及它发生的频率还没有得到系统的审查。不知道这一点,基因敲除结果很容易被误解.在这次审查中,我们总结了这些证据,并提出了两种允许敲除逃逸的主要机制。为了避免淘汰赛逃跑造成的混乱,讨论了几种策略及其优缺点。另一方面,敲除逃逸也为研究必需基因和治疗单基因疾病如Duchenne肌营养不良提供了方便的工具,最后讨论。
Clustered regularly interspaced short palindromic repeats and associated Cas protein (CRISPR-Cas), a powerful genome editing tool, has revolutionized gene function investigation and exhibits huge potential for clinical applications. CRISPR-Cas-mediated gene knockout has already become a routine method in research laboratories. However, in the last few years, accumulating evidences have demonstrated that genes knocked out by CRISPR-Cas may not be truly silenced. Functional residual proteins could be generated in such knockout organisms to compensate the putative loss of function, termed herein knockout escaping. In line with this, several CRISPR-Cas-mediated knockout screenings have discovered much less abnormal phenotypes than expected. How does knockout escaping happen and how often does it happen have not been systematically reviewed yet. Without knowing this, knockout results could easily be misinterpreted. In this review, we summarize these evidences and propose two main mechanisms allowing knockout escaping. To avoid the confusion caused by knockout escaping, several strategies are discussed as well as their advantages and disadvantages. On the other hand, knockout escaping also provides convenient tools for studying essential genes and treating monogenic disorders such as Duchenne muscular dystrophy, which are discussed in the end.