FIG. 4.
Induction of DNA synthesis in BALB/c/3T3 cells by the recombinant mature Hu HB-EGF, mature Mk HB-EGF, HBΔ-EGF, HBΔ-EGF(I117A/L148A), and HBΔ-EGF(Y138A/L148A) proteins. The serum-starved BALB/c/3T3 cells were stimulated with various concentrations of recombinant mature Hu HB-EGF (◊), mature Mk HB-EGF (□), HBΔ-EGF (▵), HBΔ-EGF(I117A/L148A) (○), or HBΔ-EGF(Y138A/L148A) (▿) for 3 days, and the amount of [3H]thymidine incorporation was measured as described in Materials and Methods. The average from duplicate wells was calculated and plotted. Results are representative of at least two separate experiments.