• PURPOSE

  This lentiviral vector can be used to assay Cas9 activity.

This lentiviral vector can be used to assay Cas9 activity. In the absence of Cas9, the cells are both resistant to puromycin and express EGFP. In the presence of functional levels of Cas9, the sgRNA expressed from the U6 cassette targets EGFP, and thus cells will still be puromycin-resistant, but will no longer express EGFP. The fraction of EGFP-positive and -negative cells can be accurately quantitated by flow cytometry. Please note that it is unlikely that 100% of cells will ever be EGFP-negative, as a fraction of cells are likely to have in-frame indels, and those the cells may still be green. This assay is best done with cells infected with pXPR_011 at an MOI <1.

Rational design of highly active sgRNAs for CRISPR-Cas9-mediated gene inactivation. Doench JG, Hartenian E, Graham DB, Tothova Z, Hegde M, Smith I, Sullender M, Ebert BL, Xavier RJ, Root DE. Nat Biotechnol. 2014 Sep 3. doi: 10.1038/nbt.3026. 10.1038/nbt.3026 PubMed 25184501