Tyler J K, Everett R D
MRC Virology Unit, Glasgow, UK.
Nucleic Acids Res. 1994 Mar 11;22(5):711-21. doi: 10.1093/nar/22.5.711.
The product of varicella-zoster virus gene 62 (VZV 140k) is the functional counterpart of the major transcriptional regulatory protein of herpes simplex virus type 1 (HSV-1), ICP4. We have found that the purified bacterially expressed DNA binding domain of VZV 140k (residues 417-647) is a stable dimer in solution. As demonstrated by the appearance of a novel protein--DNA complex of intermediate mobility in gel retardation assays, following in vitro co-translation of a pair of differently sized VZV 140k DNA binding domain peptides, the 140k DNA binding domain peptide binds to DNA as a dimer. In addition, the DNA binding domain peptide of HSV-1 ICP4 readily heterodimerizes with the VZV 140k peptide on co-translation, indicating that HSV-1 ICP4 and VZV 140k possess very similar dimerization interfaces. It appears that only one fully wild type subunit of the dimer is sufficient to mediate sequence specific DNA recognition in certain circumstances. Co-immunoprecipitation analysis of mutant DNA binding domain peptides, co-translated with an epitope-tagged ICP4 DNA binding domain, shows that the sequence requirements for dimerization are lower than those necessary for DNA binding.
水痘带状疱疹病毒基因62产物（VZV 140k）是1型单纯疱疹病毒（HSV - 1）主要转录调节蛋白ICP4的功能对应物。我们发现，纯化的经细菌表达的VZV 140k的DNA结合结构域（第417 - 647位氨基酸残基）在溶液中是稳定的二聚体。在凝胶阻滞试验中，通过出现一种具有中等迁移率的新型蛋白质 - DNA复合物得以证明，在体外共翻译一对不同大小的VZV 140k DNA结合结构域肽段后，140k DNA结合结构域肽段以二聚体形式与DNA结合。此外，HSV - 1 ICP4的DNA结合结构域肽段在共翻译时很容易与VZV 140k肽段形成异源二聚体，这表明HSV - 1 ICP4和VZV 140k具有非常相似的二聚化界面。似乎在某些情况下，二聚体中只有一个完全野生型亚基就足以介导序列特异性DNA识别。对与带有表位标签的ICP4 DNA结合结构域共翻译的突变DNA结合结构域肽段进行的共免疫沉淀分析表明，二聚化的序列要求低于DNA结合所需的序列要求。
