I am planning to do a CRISPR activation screening. But I found there is no control sgRNAs in Feng Zhang's lentiSAM v2 library. Are the control sgRNAs not necessary for an activation screen?
Unfortunately we did not include control sgRNAs in the lentiSAM v2 library. The control sgRNAs are not necessary, but certainly very helpful for assessing the noise in your screen and whether the enrichment is significant. If this is your first time setting up a particular screen (and no one has published anything similar), I would recommend including non-targeting sgRNAs. You can use our custom sgRNA library cloning protocol in Joung Nat Protoc 2017 to clone the control sgRNAs.