FIG. 7.

Inactive ARF deletion mutants, D6-10 and D21-25, import exogenous Mdm2 into nucleoli. NIH 3T3 cells were transfected with an expression vector encoding Mdm2 plus empty vector, ARF, or the indicated ARF mutants. The localization of ARF (red, top row) and Mdm2 (green, second row) was assayed by antibody (Ab) staining and confocal microscopy. Colocalization between ARF and Mdm2 was observed (merged images, third row) in the nucleoli of all cells for all mutants tested, except D1-62, which remained nucleoplasmic with Mdm2. Nucleolar localization was confirmed in parallel studies examining ARF with fibrillarin (data not shown).