HIP1/PDGFβR transforms Ba/F3 cells to factor independence. Two independent infections of Ba/F3 cells were performed. To assess protein expression and phosphorylation, lysates were immunoprecipitated with anti-PDGFβR antibody (tail; Pharmingen), separated on 8% polyacrylamide gel electrophoresis (PAGE), and blotted onto nitrocellulose. Proteins were detected with anti-PDGFβR peptide antibody directed against the C-terminus (part a) and HRP-conjugated anti-phosphotyrosine 4G10 monoclonal antibody (part b). Lanes 1 and 2 are the HIP1/PDGFβR stable infectants, and lanes 3 and 4 are neomycin-resistant controls. (C) The G418-resistant cells growing in IL-3 were seeded in 96-well trays with 2 × 10⁴ cells per 200 μL per well in RPMI 1640 and 10% fetal calf serum media with or without IL-3. Cells were assessed for number and viability (trypan blue) in triplicate at 24-hour intervals. Each point is the average of the triplicate samples, with standard deviations ranging from 1% to 3% of the number of cells counted each day.