Figure 3.

AICAR‐induced FANCD2 monoubiquitination requires FANCA. (A) AICAR‐induced FANCD2 monoubiquitination does not occur in transformed FANCA ^−/− fibroblasts originated from a patient with defective FANCA. Transformed FANCA ^−/− (GM06914B) or normal fibroblasts (GM00637I) were treated with 0.25 mm AICAR for 24 h, and monoubiquitinated FANCD2 (Ub‐FANCD2) was visualized by immunoblotting. (B) AICAR‐induced FANCD2 nuclear foci formation is abrogated in FANCA ^−/− fibroblasts. FANCD2 nuclear foci were visualized by immunofluorescence staining and confocal microscopy. (C) Knockdown of FANCA abolishes FANCD2 monoubiquitination after AICAR treatment in Caki‐1 cells. Caki‐1 cells were transfected with FANCA‐targeting siRNAs (siFANCA#5 or siFANCA#6), treated with AICAR and subjected to FANCD2 immunoblotting.