Figure 3: p53-induced expression of ISG15-conjugating system is independent of type-I IFNs.
From: Positive feedback regulation of p53 transactivity by DNA damage-induced ISG15 modification
In P1 reporter vectors (see Fig. 2), RE3 of the ISG15 gene (a), RE1/RE2 of UBE1L (b), RE1 of UBCH8 (c) and RE1/RE2 of EFP (d) were mutated as shown in Supplementary Fig. 5 and the mutated REs were marked by the asterisks. ISREs of the genes were also mutated and marked by the asterisks. After transfection of the vectors, p53 were expressed in p53−/− HCT116 cells or 1,000 U ml−1 of interferon-α (IFNα) was treated to the cells (left panels). p53+/+ HCT116 cells transfected with the same reporter vectors were treated with and without IFNα or ultraviolet (UV; right panels). The cells were then subjected to assay for the luciferase activity. The activity seen without any expression or treatment was expressed as 1.0 and the others were expressed as its relative values. Error bar, ±s.d. (n=3).
