File:Cas9 stable cell line.png

CRISPR/Cas9 system used for genome engineering in molecular biology is composed of two components: sgRNA which is a combine of original trRNA and crRNA, and Cas9 endonuclease. By delivering Cas9 and sgRNA into a cell, Cas9 is targeted to a given locus based on sequence complementary between sgRNA and cell genome, and further induces a double strand break (DSB). In the presence of donor template, the DSB can be repaired by HDR (homology-directed repair) pathway enabling precise editing such as point mutation. When DNA repair template is not provided, the cell is forced to undergo NHEJ (non-homologous end joining) pathway resulting in indels (insertions or deletions). Apart from wild-type Cas9, a few variants have been developed for reducing off-target effects or for other applications. SpCas9-HF1 is a high-fidelity variant designed to reduce non-specific DNA contacts. https://www.creative-biogene.com/product/cas9-cell-line.html