Fig 3.

Overexpression of exogenous BCL-6 down-regulates the endogenous gene. The heavy-metal-inducible pMEP4-HA-BCL-6 and control pMEP4 plasmids were stably transfected into Ly7 (A) and BT549 (B) cells. Representative results from three independent inductions are shown. In each experiment, cells were sampled before and at various time points after induction and analyzed by Northern blot for expression of both the endogenous and exogenous BCL-6 transcripts. Results were quantitated and normalized by the GAPDH signal. Plotted in the bar graph are ratios of various BCL-6 signals vs. the endogenous BCL-6 mRNA in the control cells, which was set as 1.0. All signals were first normalized to GAPDH for loading.