Figure 6. Delineation of the SMC1-dependent repression to the 41-bp region (−257/−217-bp) of the CYP2B6 promoter.

Various deletion constructs of the −1.8-kb CYP2B6 promoter, shown in the left panel, were co-transfected with phRL-TK and pcDNA3.1 or pcDNA3.1-SMC1 N-coiled coil (N-c) into Ym17 cells. The transfected cells were incubated with TCPOBOP (250 nM), OA (10 nM) or TCPOBOP plus OA for 48 h, harvested and assayed for luciferase activity. Fold induction was calculated by taking the control activity (DMSO) as 1. (B) Fold inhibition of the treatment-dependent promoter activities by the N-coiled coil in the presence or absence of SMC1. The fold inductions in the absence of SMC1 were divided by those in the presence of SMC1. Numbers were calculated by subtracting one from those inhibition rates to make the baseline to zero. The values shown with less than zero indicate no inhibition.