Extended Data Fig. 7: The Fanconi Anemia Pathway is required for growth of LINE-1⁺ cells.

(a) Behavior of sgRNAs targeting Fanconi Anemia pathway genes in the screen. Median values are depicted with 95% Confidence Intervals. (b) Western blot of DNA damage marker γH2A.X in chromatin-bound protein fractions of LINE-1⁺ cells with or without perturbations to the FA pathway. H3 was used as loading control. γH2A.X levels were quantified and graphed relative to NTC-treated, LINE-1⁺ cells. (c) Clonogenic assay (10 d). TP53^KD cells constitutively expressing Cas9 are treated with lentivirus encoding non-targeting-control (NTC) or FANCD2 sgRNA and then transfected with eGFP (pDA083) or the native LINE-1 sequence L1RP (pDA077). Left, representative images of colonies. Scale bar = 1 cm. Right, data are presented as the rate of LINE-1 per 100 eGFP colonies ± s.d. to control for transfection efficiency across samples, n = 3 independent experiments. P value obtained by unpaired two-sided t-test. (d) Quantification of FANCD2 foci in G1 and G2 phase (EdU-) HeLa cells. Number of cells per group: G1 untreated (n = 104), G1 HU (n = 352), G1 wildtype LINE-1 (n = 186), G1 RT (D702Y) (n = 138), G2 untreated (n = 60), G2 HU (n = 58), G2 wildtype LINE-1 (n = 42), G2 RT (D702Y) (n = 32). Two-sided t-tests were used for statistical comparisons. HU = hydroxyurea. RT = reverse transcriptase. ns = not significant.