FIGURE 4.

Comparison of IOP1 and IOP2 knockdown on aconitase activity in HeLa cells. HeLa cells were transfected with the indicated siRNAs. A, total RNA was isolated from cells and analyzed by real-time PCR for IOP2 mRNA (means ± S.D.) and normalized to that ofβ-actin. The levels of IOP2 mRNA following IOP2-A or IOP2-B siRNA treatment are 13 and 11% of control, respectively. B, extracts (20 μg) were analyzed by Western blotting using antibodies against IOP2 or actin, as indicated. C-D, cytosolic or mitochondrial extracts were assayed for aconitase activity. Some cells were also treated with 100 μm DFO for 20 h prior to harvest, as indicated. Shown are the means ± S.D., n = 3. ^*, p < 0.01.