3f). Finally, we tested whether Ku70 was required to maintain resistance of short-term (ST) HSCs to aldehydes by exposing bone marrow cells to acetaldehyde in vitro before injecting them into lethally irradiated recipients. Fancafl/-Ku70−/− Vav1-iCre ST-HSCs were much more sensitive to acetaldehyde than either of the single mutant ST-HSCs (Fig. 3g). These results indicate that in the mouse haematopoietic system, in the absence of Fanconi anaemia repair, NHEJ is required to provide resistance to endogenous and acetaldehyde-induced DNA damage. This result contrasts with the reported negative impact of active NHEJ on the viability of Fanconi anaemia-deficient chicken DT40 cells and worms.
