Application of CRISPR/cas9-Directed Homologous Recombination to the Generation of Human Tumor Cells with Conditional Knockout of an X-Linked MicroRNA Locus

Aurélie Van Tongelen, Axelle Loriot, Olivier De Backer and Charles De Smet

Studying the cellular function of microRNAs requires genetic strategies to generate their loss-of-function. Recently, a novel approach of targeted genomic deletion was proposed, which is based on induction of site-specific DNA cuts with Cas9/gRNA ribonucleoprotein complexes, combined with homologous recombination-dependent insertion of cassettes that contain sequences for Cre-lox or FLP-FRT systems. Here, we provide a technical report describing application of this CRISPR/Cas9-directed homologous recombination procedure to the generation of human tumor cells in which conditional knockout of an X-linked cluster of microRNAs (miR-105/miR-767) can be induced. We describe the successive steps of genetic engineering and cell clone selection that allowed us to generate cells with the expected genome editing.