Expression of MnSOD protein in MnSODtet/tet cell lines. Western analysis (as described in Materials and Methods) was performed on cell lines from MnSOD+/+, MnSODtet/+, MnSODtet/tet demonstrating reduced MnSOD expression in MnSODtet/+ (1.8 ± 0.1-fold, P = 0.0125) and MnSODtet/tet (55.1 ± 2.5-fold, P = 0.0022) relative to MnSOD+/+ cells. Cells from a negative control, MnSOD−/− cells had no detectable reactive protein.