Figure 4.

Effect of CYP1A2 on the interaction between GFP-HO-1 and POR-Rluc.A, HEK 293T/17 cells were transfected with plasmids coding for GFP-HO-1 and POR-Rluc in the absence and presence of untagged CYP1A2. BRET generated by the GFP-HO-1•POR-Rluc pair was measured 24 h after transfection in the presence (red) and absence (blue) of 2 μg of vector coding for untagged CYP1A2. Cotransfected CYP1A2 DNA did not significantly alter the BRET signal generated by the GFP-HO-1•POR-Rluc pair. Error bars represent the SD of triplicate measurements of cells from a single transfection and generally do not exceed the size of the points. Each experiment was repeated with small adjustments to transfection conditions for optimization of protein expression, generating similar results. B, total protein expression was estimated from the sum of the fluorescence of the GFP and luminescence of the Rluc tags. BRET, bioluminescence resonance energy transfer; GFP, green fluorescent protein; HO-1, heme oxygenase 1; POR, NADPH-cytochrome P450 reductase.