Paper of the field n°2

Click to find out how the regulation of p53 and cell proliferation during editing can contribute to the development of safer gene editing protocols for therapeutic applications!

Abstract for General public

The CRISPR-Cas9 system has revolutionized gene editing and its clinical applications by allowing precise modification of the genome. CRISPR-Cas9 are molecular scissors that cleaves DNA at specific locations. It is able to delete specific DNA segments (e.g., to inactivate genes) or replace them with alternative sequences to correct a mutation responsible for pathology. However, the CRISPR-Cas9 nuclease can lead to DNA damage and potentially dangerous rearrangements of the genome at the target site (on-target). Therefore, a better characterization of the CRISPR-Cas9 nuclease outcomes at the target site is essential to assess the risk of genomic instability. In this study, the authors propose more appropriate and sensitive methods to assess the occurrence of unwanted toxic events at the on-target site.  These events are often underestimated when using standard methods such as PCR. To address this issue, the researchers present two Fluorescence-Assisted Megabase-scale Rearrangements Detection (FAMReD) systems. These systems enable the detection, quantification, and sorting of edited cells that experience large-scale loss of heterozygosity (LOH), a genetic alteration associated with the Cas9-nuclease activity. This work shows that the occurrence of LOH is influenced by the rate of cell division during editing and the p53 status, a crucial gene involved in cell division regulation. The occurrence of LOH can be suppressed by the use of inhibitors of cell division without compromising the efficiency of the correction. Furthermore, suggest that p53 status and cell division rate should be considered to develop safer clinical trials.

Abstract written by Steicy Sobrino from Imagine Institute (France)

Cullot, G., et al. « Cell Cycle Arrest and P53 Prevent ON-Target Megabase-Scale Rearrangements Induced by CRISPR-Cas9 ». 
Nature Communications, vol. 14, no 1, juillet 2023, p. 4072.

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