Figure 3.

(a) Rendered confocal Z-stack of an organotypic culture of primary human keratinocytes grown on plastic, stained for the stem cell marker MCSP (green) and the marker of cell division Ki67 (red). Scale bar = 100 µm. Lower panel shows the basal layer in cross section along the dashed line, DAPI is shown in blue. (b) Cell lineage in the stem/CP model. Stem cells (S, green) give rise to committed progenitor cells (CP, red) that can independently maintain tissue through stochastic division giving rise to equal numbers of CP and post-mitotic (PM) cells. In addition to the lineage structure shown, the model assumes that stem cells adhere to one another, and that cell division is contact-inhibited. (c) Typical realization of the stem/CP cell model, obtained through a cellular automata simulation (see appendix). Cell colours correspond to the cell types in (b). (Online version in colour.)