Effects of heme on the Bach2 transcription network. (A) The 18-81 cells were transiently transfected with the Prdm1 promoter-MARE-luc reporter and pCMV-Bach2 as described previously.¹⁶  Concentrations of 1μM (lane 3) and 5μM heme (lane 4) were added to each cell culture for 4 hours at the end of culture. The data are presented as the mean ± SD of triplicate determinations. (B-D) The relative expression levels of Blimp-1, AID, and ALAS-N mRNA, respectively, in mouse splenic B220-positive B cells. B cells were stimulated with 20 μg/mL LPS (open bars) or LPS and 20 μM heme (filled bars) for the indicated periods. The transcription levels were analyzed by qPCR. The data are presented as the means ± SD of triplicate determinations.