Figure 3.

Monitoring Zscan4 Promoter Activity

(A) The intensity of the chemiluminescence (represents Rex1 activity) and the logarithm of GFP intensity were converted to a gray scale and green scale, respectively, using a handmade program written in Microsoft VBA (Data S1). Due to the long half-life of EGFP (Figure S2B), GFP positive does not necessarily mean Zscan4 active. To evaluate Zscan4 promoter activities, the GFP intensities were converted to the increment of the intensity (delta indicated in the green scale; i.e., GFP(t + 1) − GFP(t)) as shown in the red scale. The actual image of the cell that showed upregulation of Zscan4 is shown together with the green and red scales. Bar, 7.5 μm. See also Figure S4B.

(B) The lineage trees in Figure 2B were converted to delta signal. Subtle Zscan4 activity emerged (red arrows). See also Figure S5.

(C) Rex1 and Zscan4 promoter activities obtained from the intensities of Luciferase and GFP, respectively, were calculated as the average per hour within each cell cycle (n = 391 cell divisions in eight lineages from two independent experiments). There was no correlation (R² = 0.0279).