KAPOSI?S SARCOMA-ASSOCIATED HERPESVIRUS GENE EXPRESSION

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。卡波西肉瘤相关疱疹病毒（KSHV） RTA转录因子通过与Notch介导的转录因子RBP-Jk相互作用被募集到其应答元件，表明RTA模仿细胞Notch信号转导激活病毒裂解基因表达。为了验证细胞Notch信号转导和RTA是否在功能上与病毒基因表达互换，我们在kshv感染的原发性分泌性淋巴瘤BCBL1细胞（TRExBCBL1-HNIC）中以四环素诱导的方式表达了构成性激活RBP-Jk转录因子活性的人Notch胞内（NIC）结构域。基因表达谱显示，与RTA一样，hNIC也能强烈诱导多种病毒基因的表达，包括病毒白细胞介素6 （viral interleukin 6, vIL-6）、K3和K5。然而，与RTA不同的是，hNIC不能够唤起裂解病毒基因表达的全部曲目，从而裂解病毒复制。为了进一步了解Notch信号转导在KSHV基因表达中的作用，我们选择了vIL-6生长因子和K5免疫调节基因进行详细分析。尽管存在多个RBP-Jk结合位点，但hNIC针对vIL-6和K5启动子区域的特定RBP-Jk结合位点来调节其基因表达。这些结果表明，细胞Notch信号转导不仅在激活病毒裂解基因表达方面与RTA部分可交换，而且还提供了一种新的KSHV生长和免疫失调基因的表达谱，这种表达谱可能不同于RTA独立的标准潜伏期程序和RTA依赖的裂解繁殖程序。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Kaposi's sarcom-associated herpesvirus (KSHV) RTA transcription factor is recruited to its responsive elements through interaction with a Notch-mediated transcription factor, RBP-Jk, indicating that RTA mimics cellular Notch signal transduction to activate viral lytic gene expression. To test whether cellular Notch signal transduction and RTA are functionally exchangeable for viral gene expression, human Notch intracellular (NIC) domain that constitutively activates RBP-Jk transcription factor activity was expressed in KSHV-infected primary effusion lymphoma BCBL1 cells (TRExBCBL1-HNIC) in a tetracycline-inducible manner. Gene expression profiling showed that like RTA, hNIC robustly induced expression of a number of viral genes, including viral interleukin 6 (vIL-6), K3 and K5. Unlike RTA, however, hNIC was not capable of evoking the full repertoire of lytic viral gene expression and thereby lytic replication. To further understand the role of Notch signal transduction in KSHV gene expression, vIL-6 growth factor and K5 immune modulator genes were selected for detailed analysis. Despite the presence of multiple RBP-Jk binding sites, hNIC targeted the specific RBP-Jk binding sites of vIL-6 and K5 promoter regions to regulate their gene expression. These results indicate that cellular Notch signal transduction not only is partially exchangeable with RTA in regard to activation of viral lytic gene expression, but also provides a novel expression profile of KSHV growth and immune deregulatory genes that is likely different from that of RTA-independent standard latency program as well as RTA-dependent lytic reproduction program.