Figure 4
From: LincRNA-p21 acts as a mediator of ING1b-induced apoptosis
ING1b directly binds to the lincRNA-p21 promoter and regulates its expression at the transcriptional level. (a and b) The effects of ING1b on lincRNA-p21 expression are independent of HuR, which regulates lincRNA-p21 stability. lincRNA-p21 expression was measured using qRT-PCR after Hs68 cells were transfected with control or HuR siRNAs for 8 h and treated with either Ad-GFP or Ad-ING1b for an additional 24 h. (c) ING1b binds to the lincRNA-p21 promoter at ~150–400 bp upstream of the first exon as demonstrated by ING1 chromatin immunoprecipitation (ChIP) of Hs68 cells treated with either GFP or ING1b adenoviruses. Binding of ING1b at the promoters of lincRNA-p21, PCNA (positive control) and Cyclin A (negative control) was detected using regular PCR and qRT-PCR. A parallel IgG ChIP was used as an additional background control. (d) ING1b enrichment at the human lincRNA-p21 promoter normalized to IgG in untreated or ADR-treated p53-null and p53-induced H1299 cells, as quantified by regular PCR and qRT-PCR. (e and f) ING1b-dependent expression of lincRNA-p21 promoter as measured by levels of luciferase activity normalized to β-galactosidase activity. Values are relative to untreated or ADR-treated H1299 cells transfected with empty vector controls. All experiments were carried out in triplicates. Asterisks represent significant comparisons (P<0.05)
