Biallelic targeting of expressed genes in mouse embryonic stem cells using the Cas9 system

Gene targeting – homologous recombination between transfected DNA and a chromosomal locus – is greatly stimulated by a DNA break in the target locus. Recently, the RNA-guided Cas9 endonuclease, involved in bacterial adaptive immunity, has been modified to function in mammalian cells. Unlike other site-specific endonucleases whose specificity resides within a protein, the specificity of Cas9-mediated DNA cleavage is determined by a guide RNA...