Figure 3
Cyclin content during the cell cycle. Extracts from cells of different ages were separated by SDS-PAGE. Cyclin contents were measured by immunoblotting (black bars). All protein signals were normalized to actin signal in the same lane. Each blot also included an extract from an exponentially growing culture, representing cells of all ages (open bars). This total sample is expected to yield an average cyclin content; in the three experiments shown here, this expectation is fulfilled. Starting from the upper right and proceeding counterclockwise, the three panels show cyclins B1, A, E, protein levels during the cell cycle. In the lower right, the best fit 6th order polynomial trendline for the three experiments are shown.