Figure 3.

Partitioning and equilibration of macromolecular content between mother and bud during yeast cell division. (a) Plot of the solution phase space of the final bud fraction, y, as a function of α and β. The blue line denotes the solution set for passive transfer assuming equal compartmental diffusion constants (D_b = D_m), free fractions (ϕ_b = ϕ_m), and final volumes (V_b = V_m, σ = 1). The red line gives the solution set more appropriate for the smaller final bud volume attained in S. cerevisiae budding ($V_b=\frac{2}{3}{V}_m$, $\sigma =\frac{2}{3}$). Specific symbols in the phase space specify particular solutions for which the corresponding full temporal trajectories have been given in Figure 2a,b. Solutions obtained for the simulation-based parameters of Zhou et al. [18] (■, y = 0.084) or for the actual parameters pertaining to the nuclear partitioning of episomes used in Gehlen et al. [28] (▲, y = 0.17) are also shown. The solution phase space is color-coded from low (purple) to high (blue) final bud fraction. (b) Phase space of the extent of equilibration. For each combination of α and β, the extent of equilibration was determined as the final bud concentration divided by the fully equilibrated bud concentration that would be obtained in the limit of extremely slow bud growth (see also Figure 2b,c). The solution phase space is color-coded from low (purple) to high (blue) extent of equilibration.