The formation of UFB-containing unreplicated DNA does not result from DNA replication fork uncoupling.

<p>(A) Schematic representation of 10 hours of treatment with 2 pM CPT during the cell cycle; only cells treated during the S and G2 phases were analyzed in anaphase. (B) Mean number of UFBs per anaphase cell, for HeLa-Ctrl_(CDA) (black bars) and HeLa-shCDA (gray bars) cells left untreated or treated with 2 pM CPT. Error bars represent means ± SD from six independent experiments (> 230 cells per condition). (C) Mean number of UFBs per anaphase cell, for BS-Ctrl_(BLM) and BS-BLM cells left untreated or treated with 2 pM CPT. Error bars represent means ± SD from six independent experiments (> 150 cells per condition). (D) Schematic representation of 3 hours of treatment with 2 pM CPT during the cell cycle; only cells treated during G2 phase were analyzed in anaphase. (E) Mean number of UFBs per anaphase cell in untreated HeLa-Ctrl_(CDA) (black bars) and in HeLa-shCDA (gray bars) cells left untreated or treated for 10 or 3 hours with 2 pM CPT. Error bars represent means ± SD from three independent experiments (> 90 anaphase cells per condition). The significance of differences was assessed with Student’s <i>t</i>-test.