Fig. 6.

FF exposure activates AID to bind to and deaminate the TP53 gene but not other tumor suppressor genes of HGSC. (a) Immunofluorescence staining of AID in FE25 cells with or without 100 % FF (2 min, washed) checked after 45 min to 1 h (left) and 10 % FF (no wash) from 7–9 h (right) to identify the time of AID nuclear localization. Scale: 20 µm. (b) TP53 mRNA expression in FE25 cells treated with 100 % FF and 10 % FF to identify the time of TP53 active transcription. (c, e, f, g) ChIP-PCR in FE25 cells at AID nuclear localization time points with or without 100 % FF and 10 % FF treatment. Chromatin was immunoprecipitated with AID and IgG (control) antibodies, and PCR was used to detect AID-bound DNA, targeting the TP53 (c), PTEN (e), BRCA1 (f), and NF1 (g) genes. The red boxes with bands indicate AID binding to specific genes as positive, and the ones without bands indicate AID binding to specific genes as negative. (d) The relative level of uracil at TP53 exon 7 measured by uracil-qRT-PCR to check the deamination status after AID binding in FE25 cells treated with or without 100 % FF (left) and 10 % FF (right). * p < 0.05, ** p < 0.01, *** p < 0.001 by two-tailed paired Student's t-test.