FIG. 2.

Analysis of Pap1 modification detected in cells blocked with hydroxyurea. Cells containing the HA-Ub construct were grown in selective medium at 25°C (without copper induction) and then blocked at S phase with hydroxyurea. Cells were released into fresh medium lacking hydroxyurea. Extracts from cells taken from a log-phase yeast culture (lane 1), from cells treated with hydroxyurea (H) (lane 2), and from cells removed at various time points (in minutes) after release from the hydroxyurea block (lanes 3 to 6) were immunoprecipitated with anti-Pap1 antibody, separated by SDS-PAGE, and then probed with anti-Pap1 antibody (α-Pap1) (lanes 1 to 6). The positions of molecular mass markers (in kilodaltons) are indicated to the left of the gel.