Morphology and megakaryocytic lineage‐specific gene transcription in the UT‐7/GM clones under treatment with thrombopoietin (TPO). The mock (M‐1 and M‐4) and TEL‐overexpressing (T‐5 and T‐6) UT‐7/GM clones cultured in the presence of TPO (100 ng/mL) were harvested at each time point indicated (days 0, 7, 10, 14, 28). (a) Cytospin preparations of M‐4 and T‐5 at day 28. Wright‐Giemsa staining, ×100. (b–d) Total mRNA was extracted and subjected to northern analysis with GPIIb (b), PF 4 (c) and GAPDH (d) probes. Signal ratios between day 0 and the indicated time points were quantified and presented below each lane.