Fig. 3

ING1b expression is correlated to p53-mediated p21 and Bax transcriptional activity. a Firefly luciferase promoter reporters for CDKN1A (encoding p21) or BAX and Renilla luciferase control reporters were co-transfected in YD-9 and YD-8 cells 48 h post-transfection with either control or ING1b expression plasmid. Dual luciferase assay was performed 24 h post-transfection of luciferase reporters. Data was normalized to Renilla luciferase. Error bars, SD. *P < 0.05. b Firefly luciferase promoter reporters for CDKN1A (encoding p21) or BAX and Renilla luciferase control reporters were co-transfected in YD-9 and YD-8 cells stably transduced with control or ING1b shRNA. Dual luciferase assay was performed 24 h post-transfection of luciferase reporters. Data was normalized to Renilla luciferase. Error bars, SD. *p < 0.05. c Chromatin immunoprecipitation assay (ChIP) shows direct binding of acetylated-p53 to both CDKN1A and BAX promoters, which was significantly more following transient overexpression of ING1b. Error bars, SD. *p < 0.05. d ChIP assay performed with primers specific to downstream of promoters of CDKN1A and BAX did not show any enrichment and was used as a control to rule out false-positive in results obtained in c due to incomplete DNA fragmentation. Error bars, SD. e ChIP confirmed ING1b mediates p53-mediated transcriptional activation of CDKN1A and BAX. Significant attenuation of direct interaction with either promoter was observed in YD-9 and YD-8 cells stably transduced with ING1b shRNA. Error bars, SD. *pP < 0.05. f ChIP assay performed with primers specific to downstream of promoters of CDKN1A and BAX did not show any enrichment and was used as a control to rule out false-positive in results obtained in e due to incomplete DNA fragmentation. Error bars, SD