Flemington E, Speck S H
Division of Tumor Virology, Dana-Farber Cancer Institute, Boston, MA.
Proc Natl Acad Sci U S A. 1990 Dec;87(23):9459-63. 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.
爱泼斯坦-巴尔病毒（EBV）的BZLF1基因产物ZEBRA有两个区域与c-Fos存在序列同源性，其中一个区域对应于c-Fos的DNA结合结构域。然而，ZEBRA并不包含亮氨酸拉链蛋白二聚化结构域中存在的亮氨酸七肽重复序列。本文表明，ZEBRA以同二聚体形式结合其识别位点，且与碱性DNA结合结构域相邻的区域对二聚化至关重要。该区域包含一个主要由疏水残基组成的4-3重复序列，相对于碱性DNA结合结构域，该序列与亮氨酸拉链蛋白中存在的疏水七肽重复序列精确对齐。对ZEBRA的突变分析支持了一种涉及卷曲螺旋相互作用的二聚化模型。这些结果表明，亮氨酸七肽重复序列并非转录因子形成卷曲螺旋二聚体的结构必需条件。
