Optimising CRISPR: A Robust New Framework for Stem Cell Editing

CRISPR/Cas9 has revolutionised genetic research, yet achieving consistent gene knockouts in human pluripotent stem cells (hPSCs) remains a technical hurdle. Standard systems often display variable efficiency, and selecting effective single-guide RNAs (sgRNAs)—the molecules that direct the Cas9 enzymes—can be hit-or-miss. To solve this, researchers developed a doxycycline-inducible Cas9 system, systematically refining critical parameters to boost performance.

The results were striking: the optimised system achieved stable insertion and deletion efficiencies of 82–93 per cent for single genes and over 80 per cent for double-gene knockouts. Furthermore, the team used this robust framework to evaluate three common algorithms for predicting sgRNA success, ultimately finding that Benchling provided the most accurate forecasts. The study also offered a cautionary tale regarding the targeted ACE2 gene: one sgRNA caused mutations in 80 per cent of cells, yet the protein was still expressed. This highlights the importance of verifying protein loss rather than relying solely on DNA sequencing data, offering practical guidance for future gene editing experiments.