Figure 1.

Comet assay of RTS and RECQL4 knockdown cells treated with H₂O₂. (A) Comet assay for RTS fibroblasts. Exponentially growing normal, MRC5, or RTS, AG5013, cells were treated with 500 µM H₂O₂ for 15 min on ice, and comet assay was performed as described in Materials and Methods. (B) Western blot analysis of U2OS cells treated with RECQL4 siRNA. Blot was probed with the indicated antibody. Western blot of U2OS whole cell extracts showing the knockdown effects of RECQL4 siRNA: (1) No treatment; (2) Negative control siRNA; (3) RECQL4 siRNA; (4) Purified RECQL4 protein (∼5 ng). (C) Comet assay for RECQL4 knockdown U2OS cells treated with H₂O₂. RECQL4 knockdown U2OS cells were treated with 500 µM H₂O₂ for 15 min and comet assay was performed as described in Materials and Methods. (D) Comet assay for RECQL4 knockdown cells with 3 h recovery after treatment with H₂O₂. Same as in (C), except cells were incubated for 3 h in fresh medium lacking H₂O₂ before comet assay was performed. Comet assay data was analyzed using Komet 5.5 software. Shown is the percentage of cells with the observed Olive Tail moment values. In order to graphically represent the OTMs, the data were binned into 10–12 segments and, unless otherwise noted, the median of the bin is displayed on the X-axis.