Expanded targeting scope and enhanced base editing efficiency in rabbit using optimized xCas9(3.7).

Evolved xCas9(3.7) variant with broad PAM compatibility has been reported in cell lines, while its editing efficiency was site-specific. Here, we show that xCas9(3.7) can recognize a broad PAMs including NGG, NGA, and NGT, in both embryos and Founder (F0) rabbits. Furthermore, the codon-optimized xCas9-derived base editors, exBE4 and exABE, can dramatically improve the base editing efficiencies in rabbit embryos. Our results demonstrated that the optimized xCas9 with expanded PAM compatibility and enhanced base editing efficiency could be used for precise gene modifications in organisms.