Minimizing far-extending chromatin perturbation in genome editing preserves stem cell identity

Although CRISPR-Cas9 holds therapeutic promise, broader application demands an understanding of complications in vast non-coding regions. We found that CRISPR-Cas9 can cause premature differentiation of neural stem cells in vivo and mouse embryonic stem cells in vitro, even when cleavage occurred at distant sites tens of kilobases away from the nearest regulatory elements. To investigate this, we employed an integrated assay for transposase-accessible chromatin (ATAC)/RNA sequencing (AR-seq) approach and identified editing-induced chromatin accessibility changes, with their scale varying by cell type. Cells with stemness are most affected, experiencing perturbations that extend over a hundred kilobases. Furthermore, even local DNA perturbations can disrupt CTCF- and condensate-associated chromatin architecture, causing distal transcriptional rewiring and, ultimately, loss of stemness identity. To minimize chromatin perturbations and preserve cell identity, we refined gene-editing strategies, including distance-aware sgRNA design, pharmacological attenuation of DNA resection, and alternative editing systems. This work paves the way for the safer and broader application of genome-editing technologies.