The maintenance of a stable stem cellpopulation in the epidermis is important for robust regenerationof the stratified epithelium. The population size is usuallyregulated by cell secreted extracellular signalling molecules aswell as intracellular molecules. In this paper, a simple modelincorporating both levels of regulation is developed to examinethe balance between growth and differentiation for the stem cellpopulation. In particular, the dynamics of a known differentiationregulator c-Myc, its threshold dependent differentiation, andfeedback regulation on maintaining a stable stem cell populationare investigated.
