FIGURE 4.

Effect of metal exposure on the sumoylation level of MTF-1. SUMO-1 and MTF-1-His₆ were co-expressed in CHO K1 cells and MTF-1-His₆ was immunoprecipitated (IP) with anti-His₆ antibodies after exposing the cells to 25, 50, 75, and 100 μm zinc (A) or 2, 5, and 10 μm cadmium (B) for 3 h. The level of sumoylation on MTF-1 was detected by Western blotting with SUMO-1 antibodies. C, cells transfected with SUMO-1 and MTF-1-His₆ were exposed to 100 μm zinc for 3 or 6 h. The level of sumoylation on MTF-1 was detected by Western blotting (IB).