Figure 4. State representation of human myelomonocytic leukaemia cell transcriptional network under phorbol myristate acetate (PMA) stimulus.

(a,b) State trajectories before and after PMA stimulation¹⁵, respectively. Step functions (0 → 1 to module B₁ and 1 → 0 to module B₂) were supplied to mimic THP-1 cell differentiation under PMA stimulation. States of modular network structure are shown in checkerboards, where upper row, from left to right, indicates states of A₁, B₁, C₁ and D₁ modules, and lower row indicates states of A₂, B₂, C₂ and D₂ modules (see Fig. 3). Modules in checkerboards are coded as ‘active’ (yellow) or ‘inactive’ (black). α_fin indicates states that mimic the final expression pattern as determined by qRT-PCR; α₀ indicates states that mimic the initial expression pattern. (c) Variation of state measured by bit before and after PMA stimulation. Variation of state was calculated over eight units of time. (d) Robustness before and after PMA stimulation.