Figure 2. Gene Expression of well-characterized cell cycle genes. The expression profiles are shown for twenty well-characterized genes whose expression peaks in each phase of the cell cycle. Data are shown for each of the five time courses (114 total arrays). The purple bars above each column represent S phase and the arrows indicate mitoses as estimated by Flow cytometry or BrdU labeling. In each time course, RNA was collected for points (typically every 1 - 2 hrs) for 30 hrs (Thy-Thy1), 44 hrs (Thy-Thy2), 46 hrs (Thy-Thy3), 36 hrs (Thy-Noc) or 14 hrs (Shake) after the synchronous arrest, at the intervals indicated. The four genes representing each cell cycle phase were averaged to create five different "ideal expression profiles" (G1/S, S, G2, G2/M and M/G1).