Durations (h) of each cell-cycle phase in exponentially growing HeLa-Fucci cells.

1) From Fig 1A, G1-phase duration was determined from the red-phase duration. S+G2-phase duration was determined from the green-phase duration. Values represent means from 150 cells. Mitotic cells were identified morphologically. Total cell-cycle time was calculated from the duration between one M phase and the next M phase, as determined by time-lapse imaging.
2) Each cell-cycle phase duration was calculated from the proportion of each cell cycle phase (Fig 1B), assuming an exponential distribution according to the equations as described by Watanabe and Okada [29]. Values in parenthesis were derived from Fucci analysis.
3) Durations of S and G2 phases were directly determined from the curve in Fig 1C, as described in Materials and Methods. G1-phase duration was determined by subtracting the S+G2+M duration from the total cell-cycle time.
4) The actual culture doubling time obtained from growth curves was 17–18 h.
Durations (h) of each cell-cycle phase in exponentially growing HeLa-Fucci cells.