PDF(Sci-hub)
Abstract：
Reactivation of Kaposi\'s sarcoma-associated herpesvirus (KSHV) from latency requires the viral transactivator Rta to contact the host protein Jκ recombination signal-binding protein (RBP-Jκ or CSL). RBP-Jκ normally binds DNA sequence-specifically to determine the transcriptional targets of the Notch-signaling pathway, yet Notch alone cannot reactivate KSHV. We previously showed that Rta stimulates RBP-Jκ DNA binding to the viral genome. On a model viral promoter, this function requires Rta to bind to multiple copies of an Rta DNA motif (called \"CANT\" or Rta-c) proximal to an RBP-Jκ motif. Here, high-resolution ChIP/deep sequencing from infected primary effusion lymphoma cells revealed that RBP-Jκ binds nearly exclusively to different sets of viral genome sites during latency and reactivation. RBP-Jκ bound DNA frequently, but not exclusively, proximal to Rta bound to single, but not multiple, Rta-c motifs. To discover additional regulators of RBP-Jκ DNA binding, we used bioinformatics to identify cellular DNA-binding protein motifs adjacent to either latent or reactivation-specific RBP-Jκ-binding sites. Many of these cellular factors, including POU class homeobox (POU) proteins, have known Notch or herpesvirus phenotypes. Among a set of Rta- and RBP-Jκ-bound promoters, Rta transactivated only those that also contained POU motifs in conserved positions. On some promoters, POU factors appeared to inhibit RBP-Jκ DNA binding unless Rta bound to a proximal Rta-c motif. Moreover, POU2F1/Oct-1 expression was induced during KSHV reactivation, and POU2F1 knockdown diminished infectious virus production. Our results suggest that Rta and POU proteins broadly regulate DNA binding of RBP-Jκ during KSHV reactivation.
摘要：
卡波西肉瘤相关疱疹病毒（KSHV）从潜伏期的再激活需要病毒反式激活因子Rta与宿主蛋白Jκ重组信号结合蛋白（RBP-Jκ或CSL）接触。RBP-Jκ通常与DNA序列特异性结合，以确定Notch信号通路的转录靶标，然而仅靠Notch无法重新激活KSHV。我们先前表明Rta刺激RBP-JκDNA与病毒基因组的结合。在模型病毒启动子上，此功能要求Rta与RBP-Jκ基序附近的RtaDNA基序(称为“CANT”或Rta-c)的多个拷贝结合。这里,对感染的原发性积液性淋巴瘤细胞进行高分辨率ChIP/深度测序显示,在潜伏期和再激活期间,RBP-Jκ几乎只与不同组的病毒基因组位点结合.RBP-Jκ经常结合DNA，但不限于此,靠近Rta绑定到单个，但不是多个，Rta-c图案。为了发现RBP-JκDNA结合的其他调节因子，我们使用生物信息学来鉴定与潜伏或再激活特异性RBP-Jκ结合位点相邻的细胞DNA结合蛋白基序。许多这些细胞因子，包括POU类同源异型盒（POU）蛋白，具有已知的Notch或疱疹病毒表型。在一组结合Rta和RBP-Jκ的启动子中，Rta仅激活在保守位置也包含POU基序的那些。在一些发起人身上，除非Rta与近端Rta-c基序结合，否则POU因子似乎会抑制RBP-JκDNA结合。此外，POU2F1/Oct-1表达在KSHV再激活过程中被诱导，POU2F1敲除减少了传染性病毒的产生。我们的结果表明，在KSHV再激活过程中，Rta和POU蛋白广泛调节RBP-Jκ的DNA结合。
