Figure 4.

Myc target genes follow the kinetics of Myc expression. (A) Myc expression was blocked by treating lymphoma cells with 2 μg/ml of doxycycline for 12 h. Cells were than extensively washed and replated in normal medium. At indicated time points, an aliquot of cells was taken and analyzed for mRNA expression of Myc regulated genes. Pa2g4, Picalm, Timm10, Lap3, Gsto1 and Sod2 followed kinetic of Myc (expression after 8 h of Myc activation), while Umps and Hells showed later expression (24 h or later). β-actin was used as a control. Data presenting representative results are shown. (B) Cells were incubated for 12 h in the presence (panel ‘12 h DOX pretreatment’) or absence (‘control’) of doxycycline. Subsequently, cells were extensively washed, resuspended in RPMI and stained for 5 min with 2 μM of vital dye CFSE. Cells were replated in cell culture medium and one aliquot of both treated and untreated cells was used for FACS analysis at indicated time points. In addition, sample of cells continuously that was treated with doxycycline was included. Reduction of CFSE fluorescence indicates proliferation of cells.