Nucleocytoplasmic shuttling of UAP56 (A) and URH49 (B) in transfected HeLa cells.

<p>HeLa cells were cotransfected with expression plasmids for FLAG-UAP56 (panel A) or FLAG-URH49 (panel B) and one of the internal control plasmids as indicated (a–d, + CFNrev-βGal; e–f, + CFN-βGal). The transfected cells were subjected to an interspecies heterokaryon assay as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0022671#s4" target="_blank">Materials and Methods</a> section. In order to detect and discriminate the respective proteins, double immunofluorescence analysis was performed using polyclonal anti-FLAG serum (b and f) and monoclonal anti-β-galactosidase antibody (c and g). DAPI, counterstaining of the nuclei (a and e); Phase, phase contrast image of the heterokaryon (d and h); murine nuclei are indicated by arrows.