Effects of EBV Type on Viral Reactivation

EBV 类型对病毒再激活的影响

• 批准号: 9815163
• 负责人: Shannon Celeste Kenney
• 金额: $ 51.96万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-17 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9815163
• 关键词: Amino Acids; Antigens; Applications Grants; Automobile Driving; B-Cell Lymphomas; B-Lymphocytes; BZLF1 gene; Binding; Burkitt Lymphoma; Carcinoma; Cell model; Cells; EBNA2 protein; Early Promoters; Epithelial Cells; Epstein-Barr Virus Infections; Frequencies; Genes; Genetic Transcription; Genome; Geographic Locations; Goals; Hodgkin Disease; Human; Human Herpesvirus 4; Hybrids; Immediate-Early Genes; Immediate-Early Proteins; Impairment; In Vitro; Individual; Infectious Mononucleosis; LMP1; Lead; Lymphoma; Lytic; Lytic Phase; Lytic Virus; Malignant - descriptor; Malignant Neoplasms; Maps; Mediating; Modeling; Nasopharynx Carcinoma; Non-Malignant; Oncoproteins; Oral; Patients; Phenotype; Product R; Production; Proteins; Receptor Activation; Receptors, Antigen, B-Cell; Reporting; Sampling; Stimulus; Telomerase; Umbilical Cord Blood; Undifferentiated; Variant; Viral; Viral Genome; Virus; Virus Diseases; cancer cell; cell type; gene product; humanized mouse; infected B cell; keratinocyte; large cell Diffuse non-Hodgkin' s lymphoma; latent infection; malignant stomach neoplasm; mouse model; paracrine; plasma protein Z; promoter; public health relevance; transcription factor; transforming virus; tumor

PROJECT SUMMARY / ABSTRACT Epstein-Barr virus (EBV) causes infectious mononucleosis and is an important cause of human B-cell and epithelial cell cancers. The switch between latent and lytic infection is mediated by two viral immediate-early (IE) proteins, BZLF1 (Z) and BRLF1 (R). There are two types of EBV, type 1 (T1) and type 2 (T2), but relatively little is known about T2 EBV. T2 EBV is impaired for the ability to transform B cells in vitro due to decreased expression of an EBV oncoprotein, LMP1. However, our preliminary studies demonstrate that T2 EBV induces B-cell lymphomas in a humanized mouse model that are highly lytic, and is also more lytic in oral epithelial cells. Thus, we hypothesize that enhanced lytic infection is a major phenotype of T2 EBV. Our analysis of publically available EBV genomes indicates that all T2 EBV share the same variant (Zp-V3) of the viral promoter (Zp) that governs whether EBV infection is latent or lytic in B cells, and also contain the same variants of the Z and R IE proteins. The T2-encoded Z protein contains 9 amino acid (aa) differences compared to Z encoded by T1 viruses, all located within functionally important regions of the 245 aa protein. Neither the functions of the T1 versus T2 forms of Z, nor the activities of theT1 versus T2 forms of the Z promoter, have been compared. Both the T2 form of the Z promoter, and the T2 form of the Z protein, have been reported to be over-represented in certain types of EBV-infected cancers relative to their frequency in non-malignant samples, and we have recently discovered that T1/T2 hybrid viruses (containing the T2 form of the Z/R IE locus within otherwise T1 EBV viruses) are over- represented in EBV isolated from Burkitt lymphomas (BLs). We have also discovered that the T2, but not T1, form of the Z promoter confers enhanced lytic EBV reactivation in antigen-stimulated B cells due to its ability to bind the NFATC1 cellular transcription factor, and our preliminary results indicate that the T2 Z/R proteins also have an enhanced ability to induce lytic reactivation in B cells. We hypothesize that T2 EBV strains are much more lytic than T1 EBV strains due to differences in the Z promoter, the Z and/or R IE proteins, and decreased LMP1. We also hypothesize that hybrid T1/T2 EBV strains (containing the T2 form of the Z/R IE locus) have an increased ability to enter lytic infection relative to pure T1 strains, and that this difference enhances their malignant potential. Our Specific Aims are to 1) use a humanized mouse model to define EBV genes contributing to the enhanced lytic phenotype of T2 EBV infection in B cells, and to determine if a hybrid T1/T2 EBV virus resembling hybrid viruses found in human BLs is more lytic, or more transforming, than pure T1 EBV; 2) compare the phenotypes of T1, T2, and T1/T2 hybrid viruses in undifferentiated and differentiated oral epithelial cells, and 3) compare the functions of the T1 versus T2 Z and R proteins, and T1 versus T2 Z and R promoters, in vitro in B cell and epithelial cell models, and define mechanism(s) for any differences. The proposed studies should expand our understanding of T2 EBV, and may reveal why T1/T2 hybrid EBV strains are over-represented in cancers.

项目摘要 /摘要 爱泼斯坦 - 巴尔病毒（EBV）引起感染性单核细胞增多症，是人类B细胞和 上皮细胞癌。潜在感染和裂解感染之间的切换是由两个立即的病毒（即）介导的（IE） 蛋白质，BZLF1（Z）和BRLF1（R）。 EBV有两种类型，类型1（T1）和类型2（T2），但相对较少 关于T2 EBV已知。 T2 EBV因减少而在体外转化B细胞的能力受损 EBV癌蛋白LMP1的表达。但是，我们的初步研究表明T2 EBV诱导了 在人源性小鼠模型中，B细胞淋巴瘤高度裂解，并且在口腔上皮细胞中也更裂解。 因此，我们假设增强的裂解感染是T2 EBV的主要表型。我们对公开的分析 可用的EBV基因组表明，所有T2 EBV具有与病毒启动子（ZP）相同的变体（ZP-V3） 控制EBV感染是B细胞中的潜在还是裂解，并且还包含Z和R IE的相同变体 蛋白质。与T1病毒编码的Z相比，T2编码的Z蛋白包含9个氨基酸（AA）差异， 所有这些都位于245 AA蛋白的功能重要区域内。 T1与T2的功能都不 已经比较了Z的形式，也比较了Z启动子的Thet1与T2形式的活性。两种T2形式 据报道，Z启动子和Z蛋白的T2形式在某些类型中的代表性过高 EBV感染的癌症相对于非恶性样本中的频率而言，我们最近发现 T1/T2混合病毒（在T1 EBV病毒中包含Z/R IE基因座的T2形式）是过度的 在Burkitt淋巴瘤（BLS）中分离出的EBV中。我们还发现T2而不是T1 Z启动子的形式赋予抗原刺激的B细胞中增强的裂解EBV重新激活，因为它的能力 结合NFATC1细胞转录因子，我们的初步结果表明T2 Z/R蛋白也 具有增强的B细胞诱导裂解再活化的能力。我们假设T2 EBV菌株很多 由于Z启动子，Z和/或R IE蛋白质的差异，比T1 EBV菌株更裂解，并且减少了 LMP1。我们还假设混合T1/T2 EBV菌株（包含Z/R IE基因座的T2形式）具有一个 相对于纯T1菌株，进入裂解感染的能力提高了，这种差异可以增强其 恶性潜力。我们的具体目的是1）使用人源化的鼠标模型来定义造成贡献的EBV基因 到B细胞中T2 EBV感染的增强的裂解表型，并确定杂交T1/T2 EBV病毒是否 与纯T1 EBV相比，在人类BLS中发现的类似于裂解或更转化的杂种病毒。 2）比较 未分化和分化的口腔上皮细胞中T1，T2和T1/T2杂交病毒的表型，以及 3）在体外比较T1与T2 Z和R蛋白的功能，T1与T2 Z和R启动子的功能。 B细胞和上皮细胞模型，并为任何差异定义机制。拟议的研究应 扩展我们对T2 EBV的理解，并可能揭示为什么T1/T2混合EBV菌株代表过多 癌症。