Fig. 1: TRIM52 is required for cell fitness.

a Schematic representation of the lentiviral expression vectors used to modify RKO Cas9 cells for knock-out and cell competition assays. b RKO cells harbouring Dox-inducible Cas9 were transduced with sgRNA vectors targeting TRIM52 or the safe-harbour locus AAVS1. Cas9 was induced by Dox treatment for 5 days. Whole cell lysates (WCE) were analysed by WB. c Relative cell fitness of sgTRIM52-transduced cells compared to untransduced cells was determined by measuring the percentage of iRFP fluorescent cells over the indicated period and normalized to the fraction of sgAAVS1-transduced cells relative to untransduced cells. Data represent biological replicates as mean values +/- SD, n = 3. d Schematic representation of genetic modifier screen, grey and blue circles represent individual cells transduced with different sgRNAs. e RKO cells expressing Cas9 and transduced with a lentiviral genome-wide sgRNA library were further transduced with individual sgRNAs targeting TRIM52 or AAVS1. Following Cas9 induction, cells were grown for 12 doublings and integrated sgRNA-coding sequences were analysed by NGS analysis of gDNA, sgRNA enrichment calculated by MAGeCK analysis, and log2-fold change and adjusted p-value plotted relative to library representation determined in the unselected cell population. Factors on the left-hand side of the plot are identified as genes which lead to synthetic lethality upon ablation in TRIM52-targeted cells. Non-TRIM52-specific genes were filtered out by comparison with data from DGCR8-targeted cells. Factors involved in DNA-damage repair are marked in pink and labelled by name. f Filtered TRIM52 ablation-specific genes were selected and their Log2 fold change compared to AAVS1, plotted in a heatmap, and grouped by their function. g Relative cell fitness of sgTRIM52, sgNHEJ1 and sgTRIM52/sgNHEJ1 transduced cells compared to untransduced cells was determined by measuring the percentage of iRFP fluorescent cells over the indicated period. sgTRIM52 fractions were normalized to sgAAVS1/CCR5-transduced cells, relative to untransduced cells. Data represent biological replicates as mean values +/- SD, n = 3. Data analysed by unpaired two-sided t-test comparing means of TRIM52/AAVS1 and NHEJ1/TRIM52, with FDR adjustment using Benjamini, Krieger, and Yekutieli. Source data are provided as a Source Data file.