FANCD2 and Fanconi anemia: An increased LINE-1 expression and activity was reported in case of defect in Fanconi anemia factors, SLX4/FANCP and FANCD2 [39] In addition, FANCD2 activates the ubiquitin ligase RAD18 leading to the monoubiquitination of the proliferating cell nuclear antigen protein, which interacts with LINE-1 ORF2 during retrotransposition and may therefore inhibit LINE-1 insertion [40].