FIGURE 4.

Nuclear extracts from human primary macrophages fail to repair substrate at physiological dNTP concentrations. Nuclear extracts from macrophages from two donors (d1 and d2), which were normalized to 2 μg/μl total protein, were incubated with substrate i for 30, 60, 90, or 120 min at 60 nm (M), 2.5 μm (T), or 250 μm (S) dNTP. The unrepaired 20-mer upstream primer and the fully repaired 50-mer product are indicated. B, nuclear extracts from macrophages from two donors were incubated with substrate ii containing the 3′-end-labeled unligated downstream primer at 250 μm dNTP and with (+) or without (−) 2 mm ATP. The 51-mer ligated product is indicated. C, control.