Fig. 2.

Cytokine-independent growth of D9 cells through JAK2 and STAT-activation. a A cell growth curve for D9 cells cultured in the presence of GM-CSF (GM, triangle) or Tet (circle) supplemented every other day, or in the absence of both GM-CSF and Tet (square). Cell numbers were counted daily for the indicated period, and growth relative to day 1 for each condition is shown. b At the same time, cell viability was also assessed using a dye exclusion assay, and representative samples are shown. c JAK2 and STAT activation upon JAK2V617F induction. Equal amounts of protein from cells treated with Tet for the indicated periods were analyzed by immunoblotting analysis with the indicated antibodies. Note that the level of JAK2V617F and phosphor-STATs were decreased in 48 and 72 h compared to 24 h due to degradation of Tet, which was only added in the media at time 0