A genome-wide CRISPR/Cas phenotypic screen for modulators of DUX4 cytotoxicity reveals screen complications

In pursuit of unraveling the underlying mechanism of FSHD we performed a genome-wide CRISPR/Cas9 phenotypic rescue screen in an inducible DUX4 transgenic cell line (DIE) to identify modulators of DUX4-induced apoptosis. Inducible DUX4 cells were spin transfected with viral Brunello particles containing a construct with both a spCas9 and a sgRNA. Cells were than maintained and passaged for 6 days, before treating a portion of cells with doxycycline. The remaining untreated cells were harvested. After the 24h doxycyline treatment and a recovery period, surviving cells were harvested, genomic DNA extracted, and samples processed for seuqencing.