Progression of DNA replication.

<p>Analysis of the increase in DNA content in individual wild-type and <i>hpz1</i>Δ cells after two different methods for synchronization and release. A. DNA histograms of cells blocked in early S phase by HU-treatment for 4 hours, then washed and released into the cell cycle for the times indicated. B. Quantification of the cells (in A) with a 1C DNA or 2C DNA content after HU-treatment and release into the cell cycle for the times indicated. C. DNA histograms of <i>cdc10</i> cells that were synchronized in G1 phase, released into the cell cycle and incubated for the time indicated. D. Quantification of the cells (in panel C) with a 1C DNA or 2C DNA content after a <i>cdc10</i> block and release into the cell cycle and incubated for the times indicated. E. PreRC formation in wild-type and <i>hpz1</i>Δ cells as a function of time after release from a <i>cdc10</i> block.