Figure 7. .

Reverse mosaicism. Blood-derived cells from FA-D2 patients with reverse mosaicism of the hematopoietic system (patients 3 and 26, LCLs; patient 14, stimulated PBL; panel A, lanes 2, 3, and 4) reveal both FANCD2 bands at levels similar to a random normal control (lane 1) after exposure to MMC. In contrast, neither FANCD2 band was present in fibroblasts from the same patients, but only in the control (B). RAD50 was used as loading control in panels A and B. The LCLs and PBL used in panel A fail to show G2-phase arrest on flow cytometric cell cycle distributions in response to MMC (panel C) (black histograms indicate DAPI stain; control (CON), 8.0% G2; patient 3, 8.8% G2; patient 14, 8.8% G2; patient 26, 10.4% G2), whereas the corresponding cultured FA-D2 fibroblasts retain high G2-phase accumulations, which is again in contrast to the non-FA control (superimposed gray histograms; CON, 22.6% G2; patient 3, 53.2% G2; patient 14, 56.0% G2; patient 26, 54.8% G2). PBLs in panel A were stimulated with anti-CD3, anti-CD28, and Il-2 and, in panel B, with PHA.