Enhanced Cellular Uptake of Compact Cas Proteins: A Comparative Study of Cas12f and Cas9 in Human Cells

The clinical translation of CRISPR genome-editing therapies is often hindered by inefficient delivery of the CRISPR-Cas RNA-protein complex into target cells. The most widely used CRISPR-Cas9 system poses a significant challenge for efficient delivery into cells due to its large size (∼1.4 kDa). Recently reported compact Cas proteins, such as Cas12f (552 Da), Cas12k (639 Da), and Cas12m (596 Da) represent attractive alternatives as cargoes for delivery. In this brief research report, we employ efficient delivery vectors to evaluate the efficiency of cellular uptake of a compact Cas protein (Cas12f) compared to the widely used larger Cas9 in human cells. Our findings demonstrate that compact Cas proteins may facilitate more efficient cellular penetration and delivery, making them a promising alternative for the development of CRISPR-based therapies. Practical Application: Our study demonstrates that compact Cas proteins significantly enhance cellular uptake compared to larger Cas proteins. This improved uptake efficiency suggests that compact Cas proteins could be more effective for clinical application, where size constraints and delivery efficiency are critical challenges. Combined with the optimization and refinement of the editing efficiencies of compact Cas systems, our study provokes further exploration of compact Cas proteins in various therapeutic contexts to advance the development of more efficient CRISPR-based therapies.