HER cells were transfected with either pGFPHis (a) or pPODGFPHis (b), plasmids expressing His-tagged GFP or POD-GFP fusion proteins respectively. Whereas GFP localizes to the cytoplasm and nucleus (a), POD-GFP localizes primarily to the nucleus (b). Furthermore, POD-GFP appears to be concentrated in sub nuclear compartments (b, arrowheads). BF, brightfield. Color version of this figure appears online.