RAZ, A TRANSDOMINANT REPRESSOR, MODULATES EBV REACTIVATION

RAZ是一种新发现的EBV延迟型即刻早期基因蛋白 BZLF-1和BZLF-1的双顺反子mRNA的差异剪接 BRLF-1 ORF预测产生由一部分组成的嵌合蛋白 R蛋白的氨基末端和Z的羧基末端 蛋白。尽管Z结构域的DNA结合和二聚化是 保存的体外制造的RAZ不能与Z的同源结合位点(ZRE)结合。 此外，当Z与RAZ发生异二聚化时，Z不再与ZRE结合。 在瞬时转染法中，Raz化学计量学下调Z- 诱导早期启动子的反式激活。在生物测试中，拉兹 减少Z.自Raz以来产生的潜伏感染的病毒重新激活 具有跨显性转录的结构和功能特征 抑制子蛋白，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，研究拉兹在 通过确定潜伏的EBV的时间进程而重新激活的细胞 Raz RNA和蛋白质在细胞中的出现及其定量 转录本和蛋白质的水平。第二，我们将研究 进一步的关键生物效应，即Raz如何减弱病毒 重新激活。我们还将检查Raz是否是被封装的Late 参与原发感染的蛋白质。在一个独立的 对生物功能的评估，呃将证实Raz在病毒中的作用 通过创建Raz基因敲除病毒突变体的复制和潜伏周期。 第三，我们将确定RAZ和翻译后领域 修饰，特别是某些丝氨酸和酪氨酸的磷酸化， 可能与抑制物功能有关的基因。最后一种可能性是 在潜伏期和晚期启动子中，RAZ可能与ZRE以外的DNA位点结合 异源二聚体将细胞内的b-Zip样蛋白或与其他病毒 与Z相互作用的细胞蛋白质将被检测，以便 定义RAZ函数的作用域。

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.