Patient-derived mutant forms of the FANCA protein bind and retain FANCG in the cytoplasm.

GM6914 fibroblasts (FA-A) were infected with the pMMP-FANCG retrovirus either alone (column 2) or in combination with the pMMP-FANCA wt (column 3), pMMP-FANCA-H1110P (column 4), pMMP-R1117G (column 5), or pMMP-FANCA-NLS-Mut2 (column 6) retrovirus. Pools of infected cells were stained with anti-FANCA (upper panels) or anti-FANCG antiserum (lower panel) and analyzed by immunofluorescence. The GM6914 cells express no FANCA protein (column 1, upper panel) and only low levels of FANCG, which were not detected by our anti-FANCG antibody (column 1, lower panel). The presence of the FANCG protein in the nucleus in panels 4, 5, and 6 may reflect the relative stability of the free (non–FANCA-bound) FANCG protein in fibroblasts compared to the lymphoblasts examined in Figures 3 and 4.