A cancer-associated Epstein-Barr virus BZLF1 promoter variant enhances lytic infection
Fig 4
The longer Zp-V3 probe contains a cooperative NFAT/AP1 binding motif.
EBV-negative BJAB nuclear extracts, with or without exposure to 6 hours of anti-IgM, were incubated with radiolabeled probes in EMSA assays. (A) A radiolabeled AP1 consensus probe was incubated with nuclear extract obtained from untreated or anti-IgM treated BJAB cells and EMSA performed. Cold competitor DNA containing consensus binding sites for the AP1 or NFAT transcription factors was added in some conditions. (B) Radiolabeled probes containing the Zp-V3 sequences (either from -155 to -127, or from -155 to -120 as indicated) were incubated with nuclear extract obtained from untreated or anti-IgM treated BJAB cells and EMSA performed. Cold competitor DNA containing consensus binding sites for the AP1 or NFAT transcription factors was added in some conditions. Arrows depict bands representing NFAT binding alone and NFAT plus AP1 binding. (C) A radiolabeled probe containing the Zp-V3 sequence from -155 to -120 was incubated with nuclear extract obtained from untreated or anti-IgM treated BJAB cells and EMSA performed. In some conditions, antibodies against cFos or XBP1 were added to the nuclear extract (prior to the addition of the labeled probe) as shown. Arrows depict bands representing NFAT binding alone, NFAT plus AP1 binding, and the NFAT plus AP1 band that is supershifted by the cFos antibody.