The expression of G1/S transition genes (repressed by Nrm1) from the MBF pathway is not activated in <i>dpb2-103</i> cells under replication stress.

<p>(<b>A)</b> quantitative RT-PCR analysis of <i>TOS2</i>, <i>TOS4</i>, <i>MCD1</i>, <i>CDC21</i> transcripts in wild-type (solid line) and <i>dpb2-103</i> (dashed line) cells under unperturbed growth conditions (green) or under replication stress generated by 200 mM HU (red). Transcript levels were normalized to G1-synchronized wild-type cells. Yeast cultures were synchronized in G1 and released from α-factor in YNBD or YNBD 200 mM HU. Samples were taken at time 0 (G1 arrest), 30, 60, 90, 120 and 180 minutes after release from G1 block. Standard deviations were omitted for clarity and are presented in <b><a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1006572#pgen.1006572.s006" target="_blank">S1 Table</a></b>. (<b>B)</b> Flow cytometry analysis of DNA content (cell cycle progression) at 0, 30, 60, 90, 120 and 180 minutes time points in wild-type (solid line) and <i>dpb2-103</i> (dashed line) cells under unperturbed growth conditions (green) or under replication stress generated by 200 mM HU (red). <b>(C and D)</b> Deletion of <i>NRM1</i> gives viable <i>dpb2-103 ddc1Δ nrm1Δ</i> cells. <b>(C)</b> Deletion of <i>DDC1</i> in <i>dpb2-103</i> cells carrying plasmid pMJDPB2 (source of <i>DPB2</i>). Transformants were were grown exponentially and dilutions were spotted on YNBD or YNBD with 5-FOA. <b>(D)</b> Tetrad analysis of a <i>dpb2-103</i>/<i>DPB2</i>, <i>ddc1Δ</i>/<i>DDC1 nrm1Δ/ nrm1Δ</i> strain.