Supplementation of pantothenate corrects the cell cycle phenotypes of S. pombe liz1Δ mutants. S. pombe cells were grown in media containing a low (1.68 μM) or high (1 mM) concentration of pantothenate (PAN), freshly diluted into the same media, and 10 mM HU was added. Cells were stained with calcofluor to visualize septa and with DAPI to visualize nuclei. At least 200 cells were examined for each time point. All strains analyzed were prototrophic for uracil and were grown in media lacking uracil. ▪, wild type; ▵, liz1Δ; □, hus1Δ. In panel A, the percentages of cells showing the cut phenotype are given, and in panel B, the percentages of cells showing septa (i.e., cells in S phase) are given. Inpanel C, the DNA content of asynchronous wild-type or liz1Δ cells was determined by FACS analysis. Samples were obtained after growth in media with low (L) or high (H) concentrations of pantothenate, as described above. Where indicated, the cells were treated for 2 h with 10 mM HU. Approximately 2,000 cells were fixed, stained with propidium iodide, and analyzed.