Visualization of the intracellular co-expression eGFP or mCherry tagged Vpr. Plasmid DNA (0.5 μg each) expressing the Vpr fusion proteins were cotransfected in HeLa cells. One day post transfection, images were recorded with an excitation at 488 nm and emission at 500–550 nm to monitor eGFP expression, and with an excitation at 568 nm and emission at 580–700 nm to monitor mCherry expression, respectively. In the merge images, co-localization of the two proteins is indicated in yellow. Each image is representative of the major phenotype. Note the accumulation of the Vpr fusion proteins at or close to the nuclear envelope.