Fig. 2 |. A synthetic lethality CRISPR screen in TRF2-deficient ES cells.

a, Experimental outline of the CRISPR–Cas9 screen we performed. Trf2^f/f-creER ES cells were infected with a genome-wide gRNA library; a portion of the cells was collected after selection (day 0); and the remaining cells were either treated with OHT to induce TRF2 deletion (OHT) or left untreated (control), and collected two weeks later (day 14). Cells infected with gRNAs targeting essential genes are depicted in magenta; cells infected with gRNA against genes that are synthetically lethal with TRF2 are shown in blue; and the remaining cells are shown in black. b, Scatter plot showing the average essentiality scores (β-score) in OHT-treated (y axis) and control (x axis) ES cells for all the genes targeted (about 23,000). Genes with a β-score below −0.75 are considered essential. Genes that have previously been reported as essential in ES cells are labelled in magenta, and genes that we found to be synthetically lethal with TRF2 are labelled in blue. Oct4 is also known as Pou5fl. c, Growth of ES cells with the indicated genotypes was monitored by confluence in an Incucyte S3. Cells were monitored starting from time of OHT-mediated TRF2 deletion (day 0). Plots show the time between day 4 and day 11. Mean and s.d. are derived from the analysis of 49 images per condition. d, Clonogenic survival assay by crystal violet was performed on cells of the indicated genotypes and treatment.