FIG. 6.

Mislocalizations of nucleolar proteins by expressing truncated hNopp140. HeLa cells were transfected with FLAG-tagged hNopp140-partial constructs F-hNopp140N382 (A to D), F-hNopp140N605 (E), F-hNopp140C285 (F and G), F-hNopp140M204-398 (H), F-NLS-hNopp140M204-383 (I and J), and F-hNopp140N204 (K and L). After 48 h of transfection, cells were examined by indirect double immunofluorescence. Ectopic expression of FLAG-tagged mutants of hNopp140 was monitored by anti-FLAG antibody, whereas the endogenous hNopp140, RNA polymerase I (pol I), fibrillarin, and nucleolin were visualized with their specific antibodies as indicated. Nuclear DNA was stained with Hoechst 33258. Arrows in panels A to D indicate the crescent-shaped structures formed in nucleoli of cells expressing large amounts of F-hNopp140N382; arrowheads in panel A point out one cell expressing only a small amount of F-hNopp140N382 without forming the crescents. The transfected cells in images in panels F, G, I, J, K, and L are marked by arrows. Untransfected cells are those stained by antibodies to nucleolar protein but not by anti-FLAG (e.g., arrowheads in images in panel J). Bars, 10 μm.