Figure 3.

Determination of the amount of PCNA in the nuclear extract (GM1310B) used for the in vitro repair assays. Nuclear extract (75 μg) (lane 1) and different amounts of histidine-tagged PCNA protein (lane 2, 25 μg; lane 3, 50 μg; lane 4, 100 μg; lane 5, 200 μg) were electrophoresed on 4–12% SDS-PAGE and transferred to PVDF membrane per manufacturer instructions. PCNA was immunologically detected using an anti-human mouse monoclonal antibody to PCNA. The values for the standards were linear.