Figure 4. The BER pathway protects cells from FdUrd but not 5-FU.

HT29 cells transfected with control (Luc) or XRCC1 siRNA were plated as single cells, exposed to the indicated concentrations of 5-FU or FdUrd for 24 h, washed, cultured for 10 d, and stained with Coomassie Blue. Transfected cells were also sequentially immunoblotted for XRCC1 and beta-actin (a loading control).