Project description:Current methods can illuminate the genome-wide activity of CRISPR-Cas9 nucleases, but are not easily scalable to the throughput needed to fully understand the principles that govern Cas9 specificity. Here we describe 'circularization for high-throughput analysis of nuclease genome-wide effects by sequencing' (CHANGE-seq), a scalable, automatable tagmentation-based method for measuring the genome-wide activity of Cas9 in vitro. We applied CHANGE-seq to 110 single guide RNA targets across 13 therapeutically relevant loci in human primary T cells and identified 201,934 off-target sites, enabling the training of a machine learning model to predict off-target activity. Comparing matched genome-wide off-target, chromatin modification and accessibility, and transcriptional data, we found that cellular off-target activity was two to four times more likely to occur near active promoters, enhancers and transcribed regions. Finally, CHANGE-seq analysis of six targets across eight individual genomes revealed that human single-nucleotide variation had significant effects on activity at ~15.2% of off-target sites analyzed. CHANGE-seq is a simplified, sensitive and scalable approach to understanding the specificity of genome editors.
Project description:We recently developed CHANGE-seq (Circularization for High-throughput Analysis of Nuclease Genome-wide Effects by Sequencing), a fast, streamlined, Tn5 tagmentation-based assay for measuring the genome-wide activity of Cas9 in vitro that is easily scalable to many targets and samples. In this study, we directly compare CIRCLE-seq to CHANGE-seq and systematically evaluate Cas9 genome-wide activity on 110 targets across 13 therapeutically-relevant loci leveraging CHANGE-seq. We validate the sensitivity of CHANGE-seq for identifying sites of bona fide cellular off-target mutations using GUIDE-seq and sensitive targeted tag sequencing. Additionally, we sought to evaluate the impact of chromatin accessibility on cellular off-target activity by comparing CHANGE-seq with matched GUIDE-seq cellular off-target, chromatin, and transcriptional profiles generated from the same human primary T-cells.
Project description:We recently developed CHANGE-seq (Circularization for High-throughput Analysis of Nuclease Genome-wide Effects by Sequencing), a fast, streamlined, Tn5 tagmentation-based assay for measuring the genome-wide activity of Cas9 in vitro that is easily scalable to many targets and samples. In this study, we directly compare CIRCLE-seq to CHANGE-seq and systematically evaluate Cas9 genome-wide activity on 110 targets across 13 therapeutically-relevant loci leveraging CHANGE-seq. We validate the sensitivity of CHANGE-seq for identifying sites of bona fide cellular off-target mutations using GUIDE-seq and sensitive targeted tag sequencing. Additionally, we sought to evaluate the impact of chromatin accessibility on cellular off-target activity by comparing CHANGE-seq with matched GUIDE-seq cellular off-target, chromatin, and transcriptional profiles generated from the same human primary T-cells.
Project description:We recently developed CHANGE-seq (Circularization for High-throughput Analysis of Nuclease Genome-wide Effects by Sequencing), a fast, streamlined, Tn5 tagmentation-based assay for measuring the genome-wide activity of Cas9 in vitro that is easily scalable to many targets and samples. In this study, we directly compare CIRCLE-seq to CHANGE-seq and systematically evaluate Cas9 genome-wide activity on 110 targets across 13 therapeutically-relevant loci leveraging CHANGE-seq. We validate the sensitivity of CHANGE-seq for identifying sites of bona fide cellular off-target mutations using GUIDE-seq and sensitive targeted tag sequencing. Additionally, we sought to evaluate the impact of chromatin accessibility on cellular off-target activity by comparing CHANGE-seq with matched GUIDE-seq cellular off-target, chromatin, and transcriptional profiles generated from the same human primary T-cells.
