Mouse interleukin 3

Mouse embryo fibroblast cells, NIH 3T3 (ATCC no. CRL‐1658), were obtained from American Type Culture Collection (ATCC, Manassas, VA, USA). NIH 3T3 cells were cultivated in Dulbecco's modified Eagle's medium without sodium pyruvate (Thermo Fisher Scientific, Waltham, MA, USA) supplemented with 10% fetal bovine serum (Thermo Fisher Scientific) and antibiotics (100 U·mL⁻¹ penicillin, 100 μg·mL⁻¹ streptomycin). A murine pro B cell line, BA/F3, was purchased from Leibniz Institute DSMZ‐German Collection of Microorganisms and Cell Cultures (DSMZ, Braunschweig, Germany), and a BA/F3 FGFR1c cell line stably transfected with the FGFR1 gene (isoform IIIc) was provided by D. M. Ornitz (Washington University, St Louis, MO, USA). Both, BA/F3 and BA/F3 FGFR1c cells were cultivated in RPMI‐1640 medium (Thermo Fisher Scientific) supplemented with 10% newborn bovine calf serum (Thermo Fisher Scientific), antibiotics (100 U·mL⁻¹ penicillin, 100 μg·mL⁻¹ streptomycin), β‐mercaptoethanol (50 nm) and mouse interleukin 3 (PeproTech, New Jersey, NJ, USA).