FIGURE 5.

Induction of Mt1 by arsenic does not depend on zinc. A, effect of zinc depletion. MTF1 WT, MTF1 KO, and MTF1 KO cells stably transfected with pMTF1_1–675 were cultured in a normal medium (DMEM plus 10% FBS) or a zinc-depleted medium (DMEM plus 10% of Chelex 100-treated FBS) for 48 h. The cells were treated with arsenic (10 μm) for 5 h. Total RNA was blotted for Mt1 and actin. B, MRE-βGal induction. BHK3038 cells were cultured in a normal medium or a zinc-depleted medium for 48 h and were treated with arsenic (5 and 10 μm) or Zn²⁺ (100 μm) for 5 h. Cell lysate was assayed for β-gal activities. C, effect of EDTA. BHK3038 cells were treated with EDTA plus Cd²⁺ (10 μm), As³⁺ (2, 5, or 10 μm), or Zn²⁺ (100 μm) for 5 h, or the cells were pretreated with EDTA for 2 h, followed by washing with fresh medium and treating with Cd²⁺ 10 μm or As³⁺ at 2, 5, and 10 μm for 5 h. β-gal induction was measured.