Figure 1.

(A) Activation of the APE-1 gene in HeLa cells by HOCl. (a) Logarithmic-phase HeLa cells were treated with 0 (lane 1), 130 (lane 2), 260 (lane 3), or 850 (lane 4) nM HOCl for 1 h, and then fed with fresh medium. After 9 h, total RNA was extracted and Northern blot analysis was performed with APE-1 cDNA probes. (b) Kinetics of APE-1 mRNA activation. HeLa cells were treated with 130 nM HOCl, and at 0, 3, 6, 9, and 12 h after treatment (lanes 1–5, respectively), the cells were harvested from individual dishes for RNA analysis as in a. (B) Activation of the APE-1 gene by γ-rays. (a) Effect of radiation dose. Logarithmic-phase HeLa S3 cells were exposed to 0, 1, 2, 4, or 8 Gy of radiation 9 h before cells were harvested and RNA was extracted for Northern blot analysis (lanes 1 through 5, respectively). (b) Kinetics of APE-1 mRNA activation. HeLa cells were exposed to 2 Gy of γ-rays and harvested 0, 3, 6, 9, 12, or 18 h after irradiation. RNA from these cells was loaded for Northern analysis in lanes 1 through 6, respectively. All blots were reprobed for 18S ribosomal RNA (Lower), which was used as an internal control to correct for unequal RNA loading.