Normal mouse BM cells retrovirally infected with Jak3 (BM-Jak3 cells) undergo accelerated G1 arrest following stimulation with GM-CSF.
Myeloblast-enriched BM cells from wild- type (C57/BL6) mice were infected with the retroviral vectors pMSCV-neo (A-C) or pMSCV-Jak3/neo (D-F). Cells were seeded in methylcellulose and selected in the presence of G418. Several colonies from each infection were expanded, transferred to liquid culture, and induced for differentiation with GM-CSF. At the indicated time points, aliquots of the cells were removed for FACS analysis. The cell cycle distribution of day 0 BM-Neo (A) and BM-Jak3 (D) cells is undistinguishable. In contrast to day 4 BM-Neo cells that showed no accumulation in G1 phase (B), BM-Jak3 cells (E) accumulated in G1 phase. By day 8, both BM-Neo (C) and BM-Jak3 (F) cells showed equivalent degree of G1 arrest.
