Relationship of the EBV Lytic Activator Zta to the bZIP Family of Cellular Transactivators
The Zta (BZLF1) transactivator is capable of reactivating lytic cycle expression when introducted into latently infected B-cells (1) and hence represents the pivotal viral protein in the reactivation process. In earlier studies we utilized a bacterially expressed Zta in DNAseI footprinting assays to identify six Zta binding sites in the BamHI-H divergent promoter (2). The sequences protected by Zta binding were TGTGTAA, TGAGCAA, TGTGCAA and TGTGTCA (3 copies). These sites resemble the AP-1 binding site (TGAGTCA) for the Jun/Fos cellular transcription factors and Zta binds equally well to an AP-1 site as a ZRE site (2,3). The sites identified not only bind Zta but when cloned into a normally non-responsive target, for example TK-CAT or A10-CAT, confer Zta responsiveness on these targets (2).
KeywordsLeucine Glutaraldehyde Phorbol Heptad
Unable to display preview. Download preview PDF.