Figure 4.

Zscan4 Activity Correlates with the Cell-Cycle Length

(A and B) Zscan4 is activated when the cell-cycle length is long. Zscan4 promoter activity represented by the delta of GFP intensity in the lineage trees was analyzed against the cell-cycle length in FCS/LIF culture conditions (A; n = 386 cell divisions in eight lineages from two independent experiments) or in 2i/LIF culture conditions (B; n = 283 cell divisions in four lineages from two independent experiments). Zscan4 activity became significantly high when the cell-cycle length became long.

(C and D) Expression of Zscan4 leads to shortening of the cell cycle at the next cell division. Total Zscan4 activity during a given cell cycle was analyzed against the difference between the lengths of that cell cycle and the next cell cycle in FCS/LIF culture conditions (C; n = 276 cell divisions in eight lineages from two independent experiments) or in 2i/LIF culture conditions (D; n = 255 cell divisions in four lineages from two independent experiments). Negative x axis means the cell cycle shortened. Bar graph represents the average with error bars of the SD. Student’s t test was used for statistical analysis.

^∗p < 0.05, ^∗∗p < 0.005, ^∗∗∗p < 0.001.