Figure 2.
Constitutive and ligand-induced activation of Δ5TpoR in primary myeloid progenitors. (A) Bone marrow cells were infected with retroviruses coding for wtTpoR or Δ5TpoR and sorted for equivalent GFP before plating. Cell-surface levels of wtTpoR (red) or Δ5TpoR (blue) were determined by FACS with anti-HA antibodies. Green indicates Ba/F3 cells (negative control). (B) Colony formation of hematopoietic progenitor cells expressing the wtTpoR or Δ5TpoR in the absence of Tpo (- Tpo). (C) Colony formation of hematopoietic progenitor cells expressing the wtTpoR or Δ5TpoR in the presence of 10 ng/mL Tpo (+ Tpo). Shown in panels B and C are averages of colony numbers (averages of triplicates ± SD) from 1 representative experiment. Data were similar among 3 independent experiments.