Figure 7.

G451E p55 does not enhance processive DNA synthesis of pol γ. Primer-extension reactions were performed as described in the “Subjects and Methods” section. Reactions contained p140 catalytic subunit (lanes 1–6), WT p55 (lanes 3 and 4), G451E p55 (lanes 5 and 6), and singly primed M13 DNA. Activity was measured at 0 mM NaCl (odd-numbered lanes) or 150 mM NaCl (even-numbered lanes). Lane 0 had no enzyme. Reaction products were resolved by denaturing polyacrylamide gel electrophoresis (A) and alkaline agarose gel electrophoresis (B). The arrows in panels A and B mark the unextended 35-mer primer. Markers indicate the number of nucleotides synthesized past the primer.