Figure 7. Radiation-induced phosphorylation of c-Jun modulates its transcriptional activity.

(A) Radiation-increased AP-1 DNA binding ability was reduced by MEK kinase inhibitor U0126. To determine the effect of U0126 on c-Jun DNA binding ability, different nuclear extracts as indicated were incubated with the γ-³²p-labeled AP-1 consensus DNA probe. 5% acrylamide gel (0.5× TBE) was used to resolve the products of the binding reaction. Binding specificity is shown by the reaction only with BSA and competition with 50-fold excess non-radioactive consensus AP-1 oligonucleotide (cold AP-1 oligo). (B) BV2 cells were irradiated with 10 Gy dose with or without U0126. Cells were collected at the indicated time points and subsequently used to detect the expression of c-Jun target genes. Protein levels of COX-2 and cyclin D1 were examined by Western blot and transcription levels of TNFα, IL-1β, and IL-6 were examined by RT-PCR. (C) Real-time PCR was used to quantitatively analyze the expression of TNFα, IL-1β, and IL-6. Data represent mean ± SD, *p<0.05; **p<0.01.