Immunoprecipitation analysis of P. furiosus DNA polymerases. The total cell extracts were immunoprecipitated with three kinds of antiserum, anti-Pfu Pol I, anti-Pfu DP1, and anti-Pfu Pol II (DP1 + DP2). Immunoprecipitated fractions were separated by SDS/7.5% PAGE and then analyzed by Western blotting with anti-Pfu Pol I antiserum (A), anti-Pfu DP1 antiserum (B), and anti-Pfu Pol II antiserum (C). In each panel, lane 1 shows total cell extracts without immunoprecipitation; lane 2 shows total cell extracts precipitated with PBS; lane 3 shows total cell extracts precipitated with anti-Pfu Pol I; lane 4 shows total cell extracts precipitated with anti-Pfu DP1; and lane 5 shows total cell extracts precipitated with anti-PI-PfuI (negative control). The closed, open, and shaded arrowheads correspond to DP1, DP2, and Pol I, respectively. A nonspecific band (∗) found in all of the immunoprecipitated samples probably corresponds to IgG judging by its molecular size.