Figure 2.

An HGF pulse is able to stimulate a sustained migratory response. (A) Hypothetical input functions to the gene regulatory network. Blue: pulse; black: constant; green: oscillatory; yellow: nonlinear increase; red: exponential decay. (B) A short HGF input pulse is able to induce a sustained migratory response. HGF-induced migration distance of HaCaT cells for untreated (control), prolonged incubation (30 h), prolonged incubation (30 h) with actinomycin D inhibition (5 μg/ml) and short time (1.5 h) incubation with 10 ng/ml recombinant human HGF is shown (from left to right). For short time treatment, cultures were washed extensively after stimulation and media were replaced. Error bars denote ±s.d. of the mean migration distance from three independent experiments. Note that migratory responses for a constant and pulsed stimulus are almost indistinguishable.