Fig. 6. elg1Δ mutants display DNA replication defects. (A) Progression through S phase. Wild-type or elg1Δ cells were arrested in G₁ (t = 0) and released synchronously into the cell cycle. Samples were removed at the indicated times and analyzed by flow cytometry. The shaded histograms represent the cell cycle distribution of the asynchronous cultures before the G₁ arrest. Overlaid histograms represent the cell cycle distribution at the indicated times after release from the G₁ arrest. The positions of cells with 1C and 2C DNA contents are indicated. (B) Plasmid loss in wild-type, elg1Δ and ctf19Δ. The probability of plasmid loss per generation is plotted, and error bars span 1 SD. (C) Suppression of elg1Δ MMS sensitivity by PCNA overexpression. Serial dilutions of wild-type or elg1Δ cells carrying empty vector (v) or GAL1-POL30 plasmid (POL30) were plated on synthetic medium with 2% glucose (Glu; uninduced) or 2% galactose + 2% raffinose (Gal; induced), plus or minus 0.01% MMS.