Fig. 3. RA treatment triggers a subnuclear redistribution of TIF1ß in a subpopulation of F9 cells exhibiting a low proliferation rate and specific expression patterns for endodermal markers. (A-B) Bromodeoxyuridine preferentially labels the differentiated cells, exhibiting a diffuse nuclear staining of the TIF1ß protein. F9 cells treated with 1 µM RA for 6 days were pulse-labeled with BrdU, fixed and stained for TIF1ß (green) and BrdU (red) (see the Materials and Methods). The arrowhead points to a rare BrdU-positive cell with a TIF1ß nuclear dot pattern. (C-H) Endo A and laminin B1, but not fibronectin, are differentially expressed in the RA-treated F9 cells that exhibit a diffuse or a focal TIF1ß staining. F9 cells treated with RA for 6 days were processed for double-label immunofluorescence with antibodies against TIF1ß (C to H; green), fibronectin (D, red), Endo A (F, red) and laminin B1 (H, red). Bar, 20 µm.