Figure 8.

The effect of lamin A variants on SIGRUNB/NPR. Bax/Bak DKO MEFs were co-transfected with lamin A-RFP (WT) or the indicated lamin A mutants together with GFP-nucleolin. The cells were fixed 24 h later, stained with Hoechst 33258 dye and the distribution of lamin A variants in bubble-containing GFP/RFP-expressing cells were visualized by epi-fluorescence microscopy (A). Bar = 20 μm. To detect SIGRUNB/NPR (B) Bax/Bak DKO MEFs were transfected with RFP-nucleolin or co-transfected with RFP-nucleolin together with GFP-Bax, FLAG-Bax KASH or the indicated lamin A-RFP variants. The cells were fixed 24 h after transfection, stained with Hoechst 33258 dye and RFP-expressing cells were visualized by fluorescence microscopy. GFP/RFP-nucleolin distribution in the nucleus, bubbles and cytosol in the transfected cells was determined microscopically. The results are expressed as the percentage of GFP/RFP-nucleolin in the nuclei, bubbles and cytosol for each transfection out of the respective GFP/RFP-nucleolin-expressing cells (n = 300 cells; 3 independent experiments). Fisher's exact test of percentage of SIGRUNB/NPR (cells exhibiting GFP/RFP-nucleolin in bubbles and cells exhibiting cytosolic GFP/RFP-nucleolin) revealed significant differences (**p = 0.0001) between GFP-nucleolin or RFP-nucleolin to all other treatments; between lamin A-RFP and all the lamin A mutants examined.