Resolution:
## Figure 1.
Effect of PARP-1 knockout on the susceptibility of mouse 3T3 fibroblasts to the lethal
effect of NCS. A (top). Cytotoxicity of NCS against PARP-1
^{+/+ }and PARP-1^{-/- }3T3s. The growth assays were performed as described under Methods. For PARP-1^{-/- }3T3s, the data were fitted to an exponential equation, S = e^{-α [NCS] }where S is the surviving fraction (α = 0.398 ± 0.019 nM^{-1}). For PARP-1^{+/+ }3T3s, a linear-quadratic equation was used in order to smooth the curve and gave the
same value of α. The insert shows the response of PARP-1^{+/+ }and PARP-1^{-/- }3T3s in the low range of NCS concentration. The amount of NCS (LC_{37}) required to reduce cell survival to 1/e of that in control was 1.79 and 2.48 nM
for PARP-1^{+/+ }and PARP-1^{-/-}3T3, respectively. B (bottom). Comparison of the response of PARP-1^{-/- }3T3s from a unique isolate transduced with a pBabe-puro retroviral vector carrying
the full-length PARP-1 cDNA (pBabe^{PARP-1}) or the void vector (pBabe^{void}). Both cell lines showed the same exponentially-dependent response to NCS (α = 0.566
± 0.044 nM^{-1}).
Noël |