Precise genome editing is a powerful tool for analysis of gene function. However, in spermatogonial stem cells (SSCs), this still remains a big challenge mainly due to low efficiency and complexity of currently available gene editing techniques. The CRISPR-Cas9 system from bacteria has been applied to modifying genome in different species at a very high efficiency and specificity. Here we describe CRISPR-Cas9-mediated gene editing via nonhomologous end joining (NHEJ) or homology-directed repair (HDR) in SSCs. This protocol provides guidelines for derivation of SSCs, nucleofection of SSCs with the CRISPR-Cas9 system, transplantation of the gene-modified SSCs into the recipient testes, and production of mice using transplanted SSC-derived round spermatids.
Keywords: CRISPR-Cas9; Embryo transfer; Nucleofection; Round spermatid injection (ROSI); Spermatogonial stem cells; Transplantation.