FIG. 9.

Mta shuttles between the nucleus and the cytoplasm. In the heterokaryon assay, Flag-Mta was transfected into HeLa (the heterokaryon donor) cells. The Cos cell line TdRev, which is a stable producer of a Rev mutant incapable of nucleocytoplasmic shuttling, was used as the heterokaryon recipient. After heterokaryon formation, the cells were fixed and immunostained with anti-Flag (mouse monoclonal) and anti-Rev (rabbit polyclonal) primary antibodies. The secondary antibodies were TRITC-conjugated anti-mouse and FITC-conjugated anti-rabbit. The arrowheads point to two Mta-expressing cells in each panel. Note the even distribution of Mta between both donor (bottom arrow) and recipient (top arrow) cells.