Cohen J I, Heffel D, Seidel K
Medical Virology Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
J Virol. 1993 Jul;67(7):4246-51. doi: 10.1128/JVI.67.7.4246-4251.1993.
Varicella-zoster virus (VZV) open reading frame 62 (ORF62) encodes an immediate-early protein that transactivates expression of VZV, herpes simplex virus (HSV), and cellular genes in transient expression assays. VZV ORF62 is homologous to HSV ICP4 and pseudorabies virus immediate-early (IE180) proteins. All three viral proteins have conserved DNA binding domains that recognize similar sites in their corresponding promoters. Here, we show that the transcriptional activation domain of ORF62 is located near the amino terminus of the protein and is not conserved with the activation domain of ICP4. A 161-amino-acid activation domain of ORF62 activates transcription to a level comparable to that of the potent HSV VP16 activation domain; much of the activity is contained in the first 90 amino acids of ORF62. Deletion of the activation domain from full-length ORF62 markedly reduced transactivating activity. These experiments indicate that while VZV ORF62 and HSV ICP4 have conserved amino acid sequences, including their DNA binding domains, the transcriptional activation domains are poorly conserved.
水痘带状疱疹病毒（VZV）开放阅读框62（ORF62）编码一种立即早期蛋白，该蛋白在瞬时表达试验中可反式激活VZV、单纯疱疹病毒（HSV）及细胞基因的表达。VZV ORF62与HSV ICP4及伪狂犬病病毒立即早期（IE180）蛋白同源。这三种病毒蛋白均具有保守的DNA结合结构域，可识别其相应启动子中的相似位点。在此，我们表明ORF62的转录激活结构域位于该蛋白的氨基末端附近，且与ICP4的激活结构域不保守。ORF62的一个161个氨基酸的激活结构域可将转录激活至与强效HSV VP16激活结构域相当的水平；大部分活性存在于ORF62的前90个氨基酸中。从全长ORF62中缺失激活结构域会显著降低反式激活活性。这些实验表明，虽然VZV ORF62和HSV ICP4具有保守的氨基酸序列，包括它们的DNA结合结构域，但转录激活结构域的保守性较差。
