FIGURE 7.

Desumoylase SENP1 disrupts association of RFP-SUMO-1 with GFP-Nrf2 and with GFP-PML-I. HepG2 cells grown in MEM were transfected with 0.5 μg of expression plasmid for RFP-SUMO-1 along with 2 μg of pEGFP-Nrf2 (A–D) or expression plasmid for GFP-PML-I (2 μg) (E–H). Some cells were also transfected with 1 μg of pFLAG (vector) (A and E) or 1 μg of expression plasmid for SENP1 (B and F) or SENP1mt (C and G). After 24 h, all cells were harvested and processed for fluorescence microscope imaging as described under “Experimental Procedures.” Yellow dots in nuclei were counted in 34–36 cells per treatment group in A–D and in 44–47 cells per treatment group in E–H, and expressed as number of dots/nucleus for each group. Values plotted (D and H) are means ± S.E. Statistical analysis was performed with one-way analysis of variance with Tukey multiple comparison test. **, statistically different (p < 0.001). ***, statistically different (p < 0.0001). Scale bars, 5 μm.