Fig. 2.
Effect of hydroxyurea on [3H]ara-C incorporation into DNA. Exponentially growing CCRF-CEM cells were treated without (○) or with 0.2 mmol/L hydroxyurea (•) 15 minutes before adding 0.6 nmol/L [3H]ara-C (1.5 × 10−2 μCi/mL) in the presence of 1.0 μmol/L BrdUrd and 10 nmol/L FdUrd for 13 hours as described in Fig 1. DNA isolation and CsCl ultracentrifugation were performed as described in Materials and Methods. Fractions of 0.2 mL were collected and diluted for the measurement of radioactivity.