Functional interaction of Oct transcription factors with the family of repeats in Epstein-Barr virus oriP.

The family of repeats (FR) is a major upstream enhancer of the Epstein-Barr virus (EBV) latent C promoter (Cp) that controls transcription of six different latent nuclear proteins following interaction with the EBV nuclear protein EBNA1. Here, it was shown that Cp could also be activated by octamer-binding factor (Oct) proteins. Physical binding to the FR by the cellular transcription factors Oct-1 and Oct-2 was demonstrated by using an electrophoretic mobility-shift assay. Furthermore, Oct-1 in combination with co-regulator Bob.1, or Oct-2 alone, could drive transcription of a heterologous thymidine kinase promoter linked to the FR in both B cells and epithelial cells. Cp controlled by the FR was also activated by binding of Oct-2 to the FR. This may have direct implications for B cell-specific regulation of Cp.