Evidence for coiled-coil dimer formation by an Epstein-Barr virus transactivator that lacks a heptad repeat of leucine residues

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 87; no. 23; pp. 9459 - 9463
• Main Authors: FLEMINGTON, E, SPECK, S. H
• Format: Journal Article
• Language: English
• Published: Washington, DC National Acad Sciences 01-12-1990; National Academy of Sciences of the United States of America
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Binding and carrier proteins; Biological and medical sciences; DNA-Binding Proteins - genetics; DNA-Directed RNA Polymerases - metabolism; Fundamental and applied biological sciences. Psychology; Genes, Viral; Herpesvirus 4, Human - genetics; Leucine; Molecular Sequence Data; Mutagenesis, Site-Directed; Plasmids; Protein Biosynthesis; Proteins; Repetitive Sequences, Nucleic Acid; Sequence Homology, Nucleic Acid; Trans-Activators - genetics; Transcription, Genetic; Viral Proteins; Gammaherpesvirinae; Virus; Herpesviridae; Site directed mutagenesis; DNA binding protein; Crosslinking; Epstein Barr virus; Mutation; Dimerization; Aminoacid sequence
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.87.23.9459

Two regions of the Epstein-Barr virus (EBV) BZLF1 gene product, ZEBRA, share sequence homology with c-Fos, one of which corresponds to the DNA binding domain of c-Fos. ZEBRA does not, however, contain the heptad repeat of leucines present in the dimerization domains of leucine zipper proteins. Here it is shown that ZEBRA binds its recognition sites as a homodimer and that the region adjacent to the basic DNA binding domain is essential for dimerization. This region contains a 4-3 repeat of predominantly hydrophobic residues, which is precisely in register with the hydrophobic heptad repeat present in the leucine zipper proteins with respect to the basic DNA binding domain. A mutational analysis of ZEBRA supports a model for dimerization involving a coiled-coil interaction. These results indicate that a heptad repeat of leucines is not a structural requirement for formation of coiled-coil dimers by transcription factors.