Figure 1. PML promotes TNFα-induced expression of NF-κB target genes.

(A) Microarray mRNA expression data from wild type (WT) and PML^−/− MEFs untreated (−) or treated (+) with TNFα (10 ng/ml) for 3 hours were analysed by K-means clustering. Red represents TNFα-stimulated gene induction and green represents repression. Data is normalised on a per row basis relative to untreated WT cells. Clusters 1, 2 and 3 indicate genes expressed at reduced in PML^−/− cells relative to wild type (WT). The average fold induction of each cluster in WT (orange) and PML^−/− (blue) cells following TNFα treatment is presented. For each cluster the most significantly enriched transcription factor binding site within −2 to +2 kb of the transcriptional start sites were identified. Shown is the sequence logo for the RELA, NFKB1 and NF-kappaB matrix models in the JASPAR CORE database of transcription factor binding sites. (B) WT and PML^−/− MEFs were stimulated with TNFα (10 ng/ml) for the indicated time points and IL-6, NFKBIA, CXCL2 and ICAM1 mRNA levels assessed by QPCR. mRNA levels are expressed relative to unstimulated WT MEFs. (C) WT MEFs were transfected with control and PML specific siRNA prior to stimulation with TNFα (10 ng/ml) for the indicated time points. IL-6, NFKBIA, CXCL2 and ICAM1 mRNA levels were assessed by QPCR and expressed relative to unstimulated control siRNA transfected WT MEFs. (D) Immunoblot analysis of WT MEF cells transfected with control or PML siRNA using anti-PML and anti-β-actin antibodies. Data presented are mean ± SEM of triplicate cultures and representative of three independent experiments. Statistical significance determined by two-way ANOVA; p < 0.05 (*), p < 0.01 (**), p < 0.001 (***).