Fig 1. 11E6 and 16E6 proteins regulate cell cycle progression, saturation density and differentiation of human keratinocytes.

(A) Schematic diagram of the FUCCI system. (B) Typical field of view showing cells transduced with empty vectors (EV) or plasmids stably expressing either 11E6 or 16E6. At similar densities (10,000 cells/field), the expression of 11E6 or 16E6 increased geminin positive cells and decreased K10 expression. Red: Cdt1-mKO2 (G1 phase); Green: Geminin-mAG (S/G2/M phase); Blue: DAPI; Cyan: K10. (Original magnification, x20. Scale bar = 200 μm) (C) Three-dimensional graph displaying % geminin-positive cells, % K10 positive cells against number of cells per field in EV-transduced, 11E6-expressing or 16E6-expressing NIKS cell populations. Each data point is a 3.78 mm² field of view. Significant differences of the cell saturation density and % cells in cycle at saturation across three cell populations were presented by the graphs on the right. Kruskal-Wallis tests were performed with Dunn’s correction. ***, P ≤0.001; ****, P ≤0.0001. (D) 2D images showing the effect of E6 expression on cells in cycle vs. cell density and differentiation commitment vs. cell density.