Fig. 4

Identification of chromosome breaks in BA-treated TWO4 cells. Genomic DNA was extracted from BA-treated TWO4 cells for nested IPCR as described in “Methods” section. a Representative gel picture showing the AF9 gene cleavages in BA-treated TWO4 cells detected within: (a i) SAR region (a ii) Non-SAR region. TWO4 cells were left untreated (Lanes 1–6) or treated for 3 h with 0.5 mM of BA at pH 7.4 (Lanes 7–12) and pH 5.8 (Lanes 13–18). The IPCR bands derived from the AF9 cleaved fragments were indicated by the side bracket. M: 100 bp DNA ladder. N: Negative control for IPCR. b The average number of AF9 gene cleavages detected by IPCR. Data represents means and SDs of three independent experiments. Each experiment consisted of at least two sets of IPCR assays performed in five to six replicates per set for each cell sample. Values are expressed as fold change normalised to the value of the untreated control. The differences between untreated control and treated groups were compared by using Student’s t test, * p < 0.05, ** p < 0.01. NS, no significant difference