DNA damage-inducible colocalization of FANCJ helicase and RPA. (A) HeLa cells were treated with the DNA-damaging agents MMC (500 ng/mL) or hydroxyurea (2 mM) or exposed to 10 Gy IR as described in “Immunofluorescence cellular localization studies” After fixation and permeabilization, cells were incubated with anti-RPA (green) and anti-FANCJ (red) antibodies. After treatment with MMC, hydroxyurea, or IR, RPA localizes in nuclear foci that coincide with FANCJ foci as shown in the overlapped images. The yellow color results from the overlapping of the red and green foci in the merged images. In control untreated cells, RPA and FANCJ staining is diffuse. (B) Quantitation of FANCJ-RPA colocalizing foci as described in panel A. Percentages of RPA foci colocalizing with FANCJ are represented □, and percentages of FANCJ foci colocalizing with RPA are represented (▩). Experimental data are the mean of at least 3 independent experiments with standard deviations indicated by error bars. (C) FA-J vector and FA-J corrected cells were treated with the indicated DNA-damaging agents and processed for immunofluorescence as described above.