Entrainment of the Mammalian Cell Cycle by the Circadian Clock: Modeling Two Coupled Cellular Rhythms
Figure 13
Entrainment of the cell cycle by a circadian variation of growth factor (GF).
(A) In the continuous presence of GF at a constant value (GF = 1 µM), for t<120 h and t>280 h, cells proliferate with an autonomous period of 16 h. For 120 h<t<280 h, in the presence of a square wave variation of growth factor in which GF alternates every 12 h between the values 0 and 1 µM, the cell cycle readily entrains to the 24-h period of the square wave of GF. (B) Entrainment by the circadian variation of GF for t≥120 h also occurs when starting from a stable, quiescent state observed in the absence of GF [14]. Parameter values are listed in Table S2 of Ref. 14.