RAZ, A TRANSDOMINANT REPRESSOR, MODULATES EBV REACTIVATION

RAZ是一种新发现的EBV延迟立即早期基因蛋白， 通过BZLF-1的双顺反子mRNA的差异剪接而升高， 预测产生嵌合蛋白的BRLF-1 ORF，所述嵌合蛋白由以下部分组成： R蛋白的氨基末端和Z蛋白的羧基末端的连接， 蛋白 虽然Z的DNA结合和结构域的二聚化是不可能的， 保存的，在体外制造的RAZ不能结合到Z的同源结合位点（ZRE）。 此外，在与RAZ异源二聚化后，Z不能再与ZRE结合。 在瞬时转染试验中，RAZ化学计量地下调Z- 诱导早期启动子的反式激活。 在生物测试中，RAZ 减少了由Z. 自从RAZ 具有反式显性转录的结构和功能特征， 阻遏蛋白，它可能在EBV潜伏期或 重新激活 在下一阶段的工作中，我们将首先研究RAZ， 通过确定潜伏EBV的时间过程来重新激活潜伏EBV的细胞。 RAZ RNA和蛋白在细胞中的出现以及定量 转录物和蛋白质的水平。 第二，我们将研究 进一步研究了关键的生物学效应，即RAZ如何减弱病毒 重新激活 我们还将研究RAZ是否是一个过时的 参与初次感染的蛋白质。 以独立 生物学功能的评估，er将验证RAZ在病毒中的作用， 复制和潜伏周期的RAZ基因敲除病毒突变体的创建。 第三，我们将确定RAZ和翻译后的结构域， 修饰，特别是某些丝氨酸和酪氨酸磷酸化， 可能与阻遏物的功能有关。 最后， RAZ可能与潜伏和晚期启动子中ZRE以外的DNA位点结合 和异二聚体将细胞b-Zip样蛋白或与其他病毒 和与Z相互作用的细胞蛋白质将被检查， 定义RAZ功能的范围。

RAZ is a newly discovered EBV delayed immediate-early gene protein that rises by differential splicing of the bicistronic mRNAs for the BZLF-1 and BRLF-1 ORFs predicted to generate a chimeric protein composed of a portion of the amino terminus of the R protein and the carboxy terminus of the Z protein. Although the DNA-binding and dimerization of domains of Z are preserved, in vitro-made RAZ cannot bind to Z's cognate binding site (ZRE). Moreover upon heterodimerization with RAZ, Z can no longer bind to a ZRE. In transient transfection assays, RAZ stoichiometrically down-regulates Z- induced transactivation of early promoters. In biologic tests, RAZ diminishes viral reactivation of latent infection produced by Z. Since RAZ has structural and functional hallmarks of a transdominant transcriptional repressor protein, it may have a potential role in EBV latency or reactivation. In this next phase of work, we will first, study RAZ in cells in which latent EBV is reactivated by determining the time-course of the appearance of RAZ RNA and protein in the cell as well as quantitating the levels of the transcript and the protein. Second, we will study further the key biologic effect, namely, how RAZ attenuates viral reactivation. We will also examine whether RAZ is an encapsideated late protein that participates in primary infection. In an independent assessment of biologic function, er will verify RAZ's role in the viral replicative and latent cycles by creation of a RAZ knock-out viral mutant. Third, we will identify domains of RAZ and post-translational modifications, specifically, certain serine and tyrosine phosphorylations, that may be involved in the repressor function. Finally the possibility that RAZ may bind to DNA sites other than ZREs in latent and late promoters and heterodimerize will cellular b-Zip-like proteins or with other viral and cellular proteins that interact with Z will be examined in order to define the scope of RAZ function.