Overproduction of Nup170C induces a cytoplasmic mislocalization of Nups. Nup82, Nup188, Pom34, and Nup2, all labeled with GFP at the C terminus by chromosomal integration, were expressed in the wild-type, nup170Δ, and GAL∷NUP170C-overproducing nup170Δ strains. Cells were grown in a raffinose-containing (SRC-Leu) medium to an OD600 of 0.7 before shift to a galactose-containing (synthetic galactose complete–Leu) medium for 10 h. Cells were inspected in the fluorescence microscope and viewed by Nomarski optics. Counting revealed that 28% of the cells showed mislocalized Nup188-GFP in cytoplasmic foci upon Nup170C overexpression, but only 5% exhibited this phenotype when GAL∷NUP170C was not induced. 17% of the cells showed Pom34-GFP mislocalized in a cytoplasmic spot upon GAL∷NUP170C induction versus 2% when GAL∷NUP170C was not induced. Bar, 2.5 µm.
