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bioRxiv · 10.64898/2026.11.12.766130

Engineered Miniature ParTasR Enables Efficient PAMless Genome Editing

Zhang, X.·Zhu, Q.·Zhang, Z.·Cao, Q.·Ma, X.·Zeng, Y.·Shang, M.
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Abstract

TIGR-Tas system holds great promise for genome-engineering applications owing to its compact size and PAMless targeting capability. However, its low editing efficiency in mammalian cells severely limits its broader utility. Here, we engineered a highly active variant of ParTasR, termed eTasR, through structure-guided rational design of ParTasR combined with fusion to the exonuclease TREX2. eTasR increased mammalian editing efficiency from the original 4.29% to 48.94% with an average 26.52-fold increase, significantly surpassing the efficiency of SpRY, a reported version of PAM-free nuclease. More importantly, single-AAV delivery enabled efficient Hpd disruption in vivo, resulting in robust phenotypic rescue. Thus, eTasR provides a compact, PAMless and highly efficient platform for genome editing and therapeutic applications.

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Zhang, X., Zhu, Q., Zhang, Z., Cao, Q., Ma, X., Zeng, Y., Shang, M.. 2026-11-13. Engineered Miniature ParTasR Enables Efficient PAMless Genome Editing. https://doi.org/10.64898/2026.11.12.766130

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