Figure 4.

Hematopoietic support by GAS6-transfected 3T3 is not vitamin K dependent. (a) Effect of additional vitamin K on hematopoietic support by GAS6-3T3. (b) Effect of warfarin on hematopoietic support by GAS6-3T3. Vitamin K (4 μM menadione) and warfarin (1 μM) were present throughout the culture period and were added to the medium used to feed the cultures. Nonadherent CFU-c were assayed at the indicated times. Hematopoietic colonies were counted after 7–10 days in culture. The error bars indicate the standard deviation of the results (n = 4–6).