CRISPR-Cas9 has quickly become the method of choice for genome editing, with multiple publications describing technical advances and novel applications. It has been widely adopted as a tool for basic research and has significant translational and clinical potential. However, its usage has outpaced the establishment of essential and rigorous controls for unwanted off-target effects, manifested as small mutations, large deletions of target loci, or large-scale chromosomal rearrangements. A common application of CRISPR-Cas9 is as a tool for creating isogenic cell-line models to study the effects of precise mutations, or variants, on disease traits. Here, we describe the effect of standard CRISPR-Cas9 mutagenesis protocols on well characterized cancer cell lines. We demonstrate that commonly used methods for detecting correctly mutated clones fail to uncover large-scale rearrangements. We show that simple cytogenetic methods can be used to identify clones carrying chromosomal abnormalities and large mutations at target loci. These methods are quick and cost-efficient, and we suggest that such controls should be performed prior to publication of studies based on novel CRISPR-Cas9 mutated cancer cell lines.

中文翻译：

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CRISPR-Cas9 导致癌细胞系染色体不稳定和重排，可通过细胞遗传学方法检测到。


CRISPR-Cas9 已迅速成为基因组编辑的首选方法，有多篇出版物描述了技术进步和新颖的应用。它已被广泛采用作为基础研究的工具，并具有显着的转化和临床潜力。然而，其使用速度超过了针对不良脱靶效应（表现为小突变、靶基因座大量删除或大规模染色体重排）建立必要且严格的控制的速度。 CRISPR-Cas9 的一个常见应用是作为创建同基因细胞系模型的工具，以研究精确突变或变异对疾病性状的影响。在这里，我们描述了标准 CRISPR-Cas9 诱变方案对已明确表征的癌细胞系的影响。我们证明，检测正确突变克隆的常用方法无法发现大规模重排。我们表明，简单的细胞遗传学方法可用于识别在目标位点携带染色体异常和大突变的克隆。这些方法快速且经济高效，我们建议在基于新型 CRISPR-Cas9 突变癌细胞系的研究发表之前进行此类对照。