CRISPR knockout requires expression of both a single-guide RNA (sgRNA) that targets the specific site for knockout, and expression of the Cas9 nuclease which cuts the DNA at the target site. Also, for studies using the CRISPRa or CRISPRi systems, cells need to express the corresponding dCas9 activator (e.g. dCas9-VPH or dCas9-VPR) or dCas9-repressor (e.g. dCas9-KRAB). For many CRISPR applications then, it is useful or necessary to have cells stably expressing one of the the Cas9 proteins.
After you let us know what Cas9 variant you want in what cell lines, Cellecta will transduce and test the target cells at multiple MOIs to produce healthy cells with optimal expression of the Cas9 protein. Cellecta not only makes stably expressing Cas9 or dCas9-activator/repressor cell lines, but we validate the activity of the Cas9 protein in the cells using the appropriate CRISPR-Test Cas9 Assay. You receive stable Cas9-expressing cells with the Cas9 activity level data.