Moriuchi H, Moriuchi M, Pichyangkura R, Triezenberg S J, Straus S E, Cohen J I
Medical Virology Section, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA.
Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9333-7. doi: 10.1073/pnas.92.20.9333.
Varicella-zoster virus open reading frame 10 (ORF10) protein, the homolog of the herpes simplex virus protein VP16, can transactivate immediate-early promoters from both viruses. A protein sequence comparison procedure termed hydrophobic cluster analysis was used to identify a motif centered at Phe-28, near the amino terminus of ORF10, that strongly resembles the sequence of the activating domain surrounding Phe-442 of VP16. With a series of GAL4-ORF10 fusion proteins, we mapped the ORF10 transcriptional-activation domain to the amino-terminal region (aa 5-79). Extensive mutagenesis of Phe-28 in GAL4-ORF10 fusion proteins demonstrated the importance of an aromatic or bulky hydrophobic amino acid at this position, as shown previously for Phe-442 of VP16. Transactivation by the native ORF10 protein was abolished when Phe-28 was replaced by Ala. Similar amino-terminal domains were identified in the VP16 homologs of other alphaherpesviruses. Hydrophobic cluster analysis correctly predicted activation domains of ORF10 and VP16 that share critical characteristics of a distinctive subclass of acidic activation domains.
水痘-带状疱疹病毒开放阅读框10（ORF10）蛋白是单纯疱疹病毒蛋白VP16的同源物，可反式激活这两种病毒的立即早期启动子。一种称为疏水簇分析的蛋白质序列比较方法被用于识别一个以ORF10氨基末端附近的苯丙氨酸-28为中心的基序，该基序与围绕VP16苯丙氨酸-442的激活结构域序列非常相似。通过一系列GAL4-ORF10融合蛋白，我们将ORF10转录激活结构域定位到氨基末端区域（氨基酸5-79）。对GAL4-ORF10融合蛋白中苯丙氨酸-28的广泛诱变证明了该位置上芳香族或大体积疏水氨基酸的重要性，正如之前对VP16苯丙氨酸-442所显示的那样。当苯丙氨酸-28被丙氨酸取代时，天然ORF10蛋白的反式激活作用被消除。在其他α疱疹病毒的VP16同源物中也鉴定出了类似的氨基末端结构域。疏水簇分析正确地预测了ORF10和VP16的激活结构域，它们具有酸性激活结构域一个独特亚类的关键特征。
