Fig. 3

Identification of chromosome breaks in BA-treated NP69 cells. IPCR was employed to identify the AF9 gene cleavages in NP69 cells after exposed to BA. a Representative gel picture showing the AF9 gene cleavages identified by IPCR within: (a i) SAR region (a ii) Non-SAR region. NP69 cells were left untreated (a i, Lanes 1–5; a ii, Lanes 1–6) or treated for 1 h with 0.5 mM of BA at pH 7.4 (a i, Lanes 6–10; a ii, Lanes 7–12) and pH 5.8 (a i, Lanes 11–15; a ii, Lanes 13–18). Genomic DNA extraction and nested IPCR were performed as described in “Methods” section. The side bracket represents the IPCR bands derived from the AF9 cleaved fragments. M: 100 bp DNA marker. N: negative control for IPCR. b The average number of the AF9 gene cleavages identified in BA-treated NP69 cells. Data are expressed as means and SDs of two independent experiments. Each experiment consisted of two to four sets of IPCR carried out in three 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