Precise large genomic deletions in mammalian cells and mice by dCas9 controlled CRISPR Cas3

Cas9 and Cas12a systems are widely used for genome editing. However, the Cas9 and Cas12a systems are limited in their ability to make large deletions. Although type I E CRISPR mediates broad and unidirectional DNA degradation, the size of the large deletions could not be controlled in previous studies. Here, we first demonstrate that dCas9 could control the size of Cas3 mediated DNA deletions in mammalian cells and mice. In addition, the elimination of the Y chromosome and precise retention of Sry in mice by using CRISPR Cas3 and dCas9 controlled CRISPR Cas3 were performed respectively. In conclusion, CRISPR Cas3-mediated precise large deletions targeting chromosomes provide a new approach to generate animal models with chromosome elimination and a potential therapeutic strategy for human aneuploidy diseases involving additional chromosomes.