Figure 7.
Effect of Src kinase inhibitor PP1 on primary murine MKs. Fresh bone marrow from C57BL/J mice was washed and resuspended in RPMI and 1% Nutridoma plus recombinant mTPO. DMSO alone (final concentration, 0.1%) or the Src inhibitor PP1, dissolved in DMSO, was added to the cells at the indicated final concentrations. After 72 hours of incubation, the entire cell culture was analyzed by flow cytometry for the presence of polyploid cells. The percentage of each ploidy class is expressed as a fold increase or decrease relative to no inhibitor (ie, no inhibitor = 1). Data are representative of 3 separate experiments. (B) Wild-type mice (C57BL/J) and lyn–/– mice were killed and femurs from 4 mice (of each type) were pooled, subjected to RBC lysis, and cultured under serum-free conditions with exogenous recombinant mTPO (37.5 ng/mL) for 72 hours. Nuclear ploidy was determined by flow cytometry and plotted on a semilog scale (500 000 events/sample). Bars mark the DNA contents of 2N, 4N, 8N, 16N, and 64N, respectively. *Anueploid cells.