Figure 1.

Prp17 is required for G₁/S and G₂/M transitions. FACS analysis of DNA content in prp17::LEU2 cells assayed in various arrest/release protocols. The peaks representing 1N or 2N DNA content are labeled. Indicated to the right of each data plot are the time points shown here. CYC denotes a 23°C cycling culture of prp17::LEU2. (A) Terminal arrest phenotypes in a prp17::LEU2 culture grown at 23°C and shifted to 37°C at time point 0 h. (B) Arrest phenotype in G₁-synchronized prp17::LEU2 cells grown at non-permissive temperatures. α-Factor-treated cells were released at time 0 h to either permissive (23°C, left) or non-permissive temperatures (37°C, right). Plots show cellular DNA content in aliquots withdrawn at the indicated time points. (C) prp17::LEU2 cells grown at 23°C were synchronized in early S phase with hydroxyurea (time point 0 h). Cells were then released to 23 and 37°C, and DNA content was monitored. (D) G₁-synchronized prp17::LEU2 cells were generated as in (B). These cells were first released for growth at 23°C for 2 h. At this stage, marked time point 0 h, half the culture was shifted to 37°C. DNA content in cells withdrawn subsequently at 2, 4 and 6 h is plotted.