Fig. 4

FA cells divide despite MMC treatment and cell cycle arrest. a The number of mononucleated cells (upper panel), binucleated cells (middle panel) and tetranucleated cells (bottom panel) was quantified after exposure to MMC (24 h) and Citochalasin B (48 h). The number of basal binucleated and tetranucleated cells was counted without Citochalasin B treatment and rested from the total number (data not shown). b Despite G2 arrest FA cells arrive to mitosis and divide with unrepaired DNA damage as demonstrated by two independent DNA damage analyses, increased chromosome aberrations (upper panel) and increased micronuclei in cells that have reached one division (bottom panel) (n = 3 independent experiments, p < 0.05)