No abstract

Cytosine base editors (CBEs) enable programmable C-toT conversion without DNA doublestranded breaks and homology-directed repair in a variety of organisms, which exhibit great potential for agricultural and biomedical applications. However, all reported cases only involved C-toT substitution at a single targeted genomic site. Whether C-toT substitution is effective in multiple sites/loci has not been verified in large animals. Here, by using pigs, an important animal for agriculture and biomedicine, as the subjective animal, we showed that CBEs could efficiently induce C-toT conversions at multiple sites/loci with the combination of three genes, including DMD, TYR, and LMNA, or RAG1, RAG2, and IL2RG, simultaneously, at the embryonic and cellular levels. CBEs also could disrupt genes (pol gene of porcine endogenous retrovirus) with dozens of copies by introducing multiple premature stop codons. With the CBEs, pigs carrying single gene or multiple gene point mutations were generated through embryo injection or nuclear transfer approach.