Effects of EBV Type on Viral Reactivation

EBV 类型对病毒再激活的影响

基本信息

批准号：
10386815
负责人：
Shannon Celeste Kenney
金额：
$ 52.19万
依托单位：
UNIVERSITY OF WISCONSIN-MADISON
依托单位国家：
美国
项目类别：
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/10386815
关键词：
Amino Acids Antigens Applications Grants Automobile Driving B-Cell Activation B-Cell Antigen Receptor 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 Reporting Sampling Stimulus Telomerase Umbilical Cord Blood Undifferentiated Variant Viral Viral Genome Virus Virus Diseases cancer cell cell type gene product genomic locus humanized mouse infected B cell keratinocyte large cell Diffuse non-Hodgkin&apos s lymphoma latent infection malignant stomach neoplasm mouse model oral cavity epithelium paracrine plasma protein Z promoter public health relevance transcription factor transforming virus tumor

项目摘要

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.

项目概要/摘要 Epstein-Barr 病毒 (EBV) 引起传染性单核细胞增多症，是人类 B 细胞和上皮细胞癌。潜伏感染和裂解感染之间的转换是由两种病毒立即早期（IE）介导的蛋白质，BZLF1 (Z) 和 BRLF1 (R)。 EBV有两种类型，1型（T1）和2型（T2），但相对较少已知 T2 EBV。由于 T2 EBV 减少，体外转化 B 细胞的能力受损 EBV 癌蛋白 LMP1 的表达。然而，我们的初步研究表明 T2 EBV 会诱导人源化小鼠模型中的 B 细胞淋巴瘤具有高度溶解性，并且在口腔上皮细胞中也具有更强的溶解性。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 都具有相同的病毒启动子 (Zp) 变体 (Zp-V3)，控制 EBV 感染在 B 细胞中是潜伏感染还是裂解性感染，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，全部位于 245 个氨基酸蛋白质的重要功能区域内。 T1 和 T2 的功能都没有还比较了 Z 启动子的 T1 形式与 T2 形式的 Z 启动子的活性。均为T2形式据报道，Z 启动子的 Z 启动子和 Z 蛋白的 T2 形式在某些类型中表现过度 EBV 感染癌症的发生率与其在非恶性样本中的发生率相关，我们最近发现 T1/T2 杂交病毒（在其他 T1 EBV 病毒中包含 Z/R IE 位点的 T2 形式）过度- 代表从伯基特淋巴瘤 (BL) 分离的 EBV。我们还发现 T2，而不是 T1， Z启动子的形式增强了抗原刺激的B细胞中的裂解性EBV再激活，因为它能够结合 NFATC1 细胞转录因子，我们的初步结果表明 T2 Z/R 蛋白也诱导 B 细胞裂解再激活的能力增强。我们假设 T2 EBV 毒株有很多由于 Z 启动子、Z 和/或 R IE 蛋白的差异，比 T1 EBV 菌株更具裂解性，并且降低末次月经1。我们还假设杂交 T1/T2 EBV 毒株（包含 Z/R IE 位点的 T2 形式）具有相对于纯 T1 菌株，进入裂解性感染的能力有所增强，并且这种差异增强了它们的恶性潜能。我们的具体目标是 1) 使用人源化小鼠模型来定义 EBV 基因 B 细胞中 T2 EBV 感染的增强裂解表型，并确定是否存在杂交 T1/T2 EBV 病毒与人类 BL 中发现的类似杂交病毒相比，纯 T1 EBV 更具裂解性或更具转化性； 2）比较未分化和分化口腔上皮细胞中 T1、T2 和 T1/T2 杂交病毒的表型，以及 3) 体外比较 T1 与 T2 Z 和 R 蛋白以及 T1 与 T2 Z 和 R 启动子的功能 B 细胞和上皮细胞模型，并定义任何差异的机制。拟议的研究应该扩大我们对 T2 EBV 的理解，并可能揭示为什么 T1/T2 杂交 EBV 毒株在癌症。