scholarly journals Direct Evidence of Abortive Lytic Infection-Mediated Establishment of Epstein-Barr Virus Latency During B-Cell Infection

2021 ◽  
Vol 11 ◽  
Author(s):  
Tomoki Inagaki ◽  
Yoshitaka Sato ◽  
Jumpei Ito ◽  
Mitsuaki Takaki ◽  
Yusuke Okuno ◽  
...  
Keyword(s):  
Epstein Barr Virus ◽  
Direct Evidence ◽  
Lytic Infection ◽  
Viral Gene ◽  
Cell Infection ◽  
Gene Expressions ◽  
Lytic Gene ◽  
Barr Virus ◽  
Epstein Barr ◽  
Latent Phase

Viral infection induces dynamic changes in transcriptional profiles. Virus-induced and antiviral responses are intertwined during the infection. Epstein-Barr virus (EBV) is a human gammaherpesvirus that provides a model of herpesvirus latency. To measure the transcriptome changes during the establishment of EBV latency, we infected EBV-negative Akata cells with EBV-EGFP and performed transcriptome sequencing (RNA-seq) at 0, 2, 4, 7, 10, and 14 days after infection. We found transient downregulation of mitotic division-related genes, reflecting reprogramming of cell growth by EBV, and a burst of viral lytic gene expression in the early phase of infection. Experimental and mathematical investigations demonstrate that infectious virions were not produced in the pre-latent phase, suggesting the presence of an abortive lytic infection. Fate mapping using recombinant EBV provided direct evidence that the abortive lytic infection in the pre-latent phase converges to latent infection during EBV infection of B-cells, shedding light on novel roles of viral lytic gene(s) in establishing latency. Furthermore, we find that the BZLF1 protein, which is a key regulator of reactivation, was dispensable for abortive lytic infection in the pre-latent phase, suggesting the divergent regulation of viral gene expressions from a productive lytic infection.

scholarly journals Direct evidence of abortive lytic infection-mediated establishment of Epstein-Barr virus latency during B-cell infection

2020 ◽  
Author(s):  
Tomoki Inagaki ◽  
Yoshitaka Sato ◽  
Jumpei Ito ◽  
Mitsuaki Takaki ◽  
Yusuke Okuno ◽  
...  
Keyword(s):  
Viral Infection ◽  
Epstein Barr Virus ◽  
Lytic Infection ◽  
Lytic Gene ◽  
Barr Virus ◽  
Ebv Infection ◽  
Infected Cells ◽  
Epstein Barr ◽  
Viral Responses ◽  
Latent Phase

AbstractViral infection induces dynamic changes in transcriptional profiles. Virus-induced and anti-viral responses are intertwined during the infection. Epstein-Barr virus (EBV) is a human gammaherpesvirus that provides a model of herpesvirus latency. To measure the transcriptome changes during the establishment of EBV latency, EBV-negative Akata cells were infected with EBV-EGFP and observed by transcriptome sequencing (RNA-seq) at 0, 2, 4, 7, 10, and 14 days after infection. We found transient downregulation of mitotic division-related genes, reflecting reprograming of cell growth by EBV. Moreover, a burst of viral lytic gene expression was detected in the early phase of infection. Experimental and mathematical investigations demonstrated that infectious virions were not produced in the pre-latent phase, suggesting the presence of an abortive lytic infection. Finally, we conducted fate mapping using recombinant EBV, enabling the noninvasive, continuous observation of infected cells during EBV infection. Our tracking analysis provided direct evidence that the abortive lytic infection in the pre-latent phase converges to latent infection during EBV infection of B-cells, shedding light on novel roles of viral lytic gene(s) in establishing latency.Author summaryViral infection is a complex process that activates both virus-triggered and host anti-viral responses. This process has classically been studied by snapshot analysis such as microarray and RNA-seq at discrete time points as population averages. Snapshot data lead to invaluable findings in host-pathogen interactions. However, these “snapshot” omics, even from a single cell, lack temporal resolution. Because the behavior of infected cells is highly dynamic and heterogenous, continuous analysis is required for deciphering the fate of infected cells during viral infection. Here, we exploited fate mapping techniques with recombinant Epstein-Barr virus (EBV) to track the infected cells and recorded a log of lytic gene expression during EBV infection. Our continuous observation of infected cells revealed that EBV established latency in B-cells via an abortive lytic infection in the pre-latent phase.

scholarly journals A Genome-Wide Epstein-Barr Virus Polyadenylation Map and Its Antisense RNA to EBNA

2018 ◽  
Vol 93 (2) ◽  
Author(s):  
Vladimir Majerciak ◽  
Wenjing Yang ◽  
Jing Zheng ◽  
Jun Zhu ◽  
Zhi-Ming Zheng
Keyword(s):  
Cell Lines ◽  
Epstein Barr Virus ◽  
Lytic Infection ◽  
Viral Gene ◽  
Human Pathogen ◽  
Antisense Transcripts ◽  
Barr Virus ◽  
Genome Wide ◽  
A Genome ◽  
Epstein Barr

ABSTRACTEpstein-Barr virus (EBV) is a ubiquitous human pathogen associated with Burkitt's lymphoma and nasopharyngeal carcinoma. Although the EBV genome harbors more than a hundred genes, a full transcription map with EBV polyadenylation profiles remains unknown. To elucidate the 3′ ends of all EBV transcripts genome-wide, we performed the first comprehensive analysis of viral polyadenylation sites (pA sites) using our previously reported polyadenylation sequencing (PA-seq) technology. We identified that EBV utilizes a total of 62 pA sites in JSC-1, 60 in Raji, and 53 in Akata cells for the expression of EBV genes from both plus and minus DNA strands; 42 of these pA sites are commonly used in all three cell lines. The majority of identified pA sites were mapped to the intergenic regions downstream of previously annotated EBV open reading frames (ORFs) and viral promoters. pA sites lacking an association with any known EBV genes were also identified, mostly for the minus DNA strand within the EBNA locus, a major locus responsible for maintenance of viral latency and cell transformation. The expression of these novel antisense transcripts to EBNA were verified by 3′ rapid amplification of cDNA ends (RACE) and Northern blot analyses in several EBV-positive (EBV+) cell lines. In contrast to EBNA RNA expressed during latency, expression of EBNA-antisense transcripts, which is restricted in latent cells, can be significantly induced by viral lytic infection, suggesting potential regulation of viral gene expression by EBNA-antisense transcription during lytic EBV infection. Our data provide the first evidence that EBV has an unrecognized mechanism that regulates EBV reactivation from latency.IMPORTANCEEpstein-Barr virus represents an important human pathogen with an etiological role in the development of several cancers. By elucidation of a genome-wide polyadenylation landscape of EBV in JSC-1, Raji, and Akata cells, we have redefined the EBV transcriptome and mapped individual polymerase II (Pol II) transcripts of viral genes to each one of the mapped pA sites at single-nucleotide resolution as well as the depth of expression. By unveiling a new class of viral lytic RNA transcripts antisense to latent EBNAs, we provide a novel mechanism of how EBV might control the expression of viral latent genes and lytic infection. Thus, this report takes another step closer to understanding EBV gene structure and expression and paves a new path for antiviral approaches.

scholarly journals Epstein–Barr Virus: How Its Lytic Phase Contributes to Oncogenesis

2020 ◽  
Vol 8 (11) ◽  
pp. 1824
Author(s):  
Quincy Rosemarie ◽  
Bill Sugden
Keyword(s):  
Epstein Barr Virus ◽  
Tumor Formation ◽  
Gene Products ◽  
Lytic Gene ◽  
Barr Virus ◽  
Oncogenic Pathways ◽  
Epstein Barr ◽  
Latent Phase

Epstein–Barr Virus (EBV) contributes to the development of lymphoid and epithelial malignancies. While EBV’s latent phase is more commonly associated with EBV-associated malignancies, there is increasing evidence that EBV’s lytic phase plays a role in EBV-mediated oncogenesis. The lytic phase contributes to oncogenesis primarily in two ways: (1) the production of infectious particles to infect more cells, and (2) the regulation of cellular oncogenic pathways, both cell autonomously and non-cell autonomously. The production of infectious particles requires the completion of the lytic phase. However, the regulation of cellular oncogenic pathways can be mediated by an incomplete (abortive) lytic phase, in which early lytic gene products contribute substantially, whereas late lytic products are largely dispensable. In this review, we discuss the evidence of EBV’s lytic phase contributing to oncogenesis and the role it plays in tumor formation and progression, as well as summarize known mechanisms by which EBV lytic products regulate oncogenic pathways. Understanding the contribution of EBV’s lytic phase to oncogenesis will help design ways to target it to treat EBV-associated malignancies.

scholarly journals The Epstein-Barr Virus Protein Kinase BGLF4 and the Exonuclease BGLF5 Have Opposite Effects on the Regulation of Viral Protein Production

2009 ◽  
Vol 83 (21) ◽  
pp. 10877-10891 ◽  
Author(s):  
Regina Feederle ◽  
Anja M. Mehl-Lautscham ◽  
Helmut Bannert ◽  
Henri-Jacques Delecluse
Keyword(s):  
Protein Kinase ◽  
Viral Protein ◽  
Epstein Barr Virus ◽  
Protein Production ◽  
Opposite Effect ◽  
Viral Gene ◽  
Virus Protein ◽  
Barr Virus ◽  
Viral Genes ◽  
Epstein Barr

ABSTRACT The Epstein-Barr virus BGLF4 and BGLF5 genes encode a protein kinase and an alkaline exonuclease, respectively. Both proteins were previously found to regulate multiple steps of virus replication, including lytic DNA replication and primary egress. However, while inactivation of BGLF4 led to the downregulation of several viral proteins, the absence of BGLF5 had the opposite effect. Using recombinant viruses that lack both viral enzymes, we confirm and extend these initial observations, e.g., by showing that both BGLF4 and BGLF5 are required for proper phosphorylation of the DNA polymerase processivity factor BMRF1. We further found that neither BGLF4 nor BGLF5 is required for baseline viral protein production. Complementation with BGLF5 downregulated mRNA levels and translation of numerous viral genes, though to various degrees, whereas BGLF4 had the opposite effect. BGLF4 and BGLF5 influences on viral expression were most pronounced for BFRF1 and BFLF2, two proteins essential for nuclear egress. For most viral genes studied, cotransfection of BGLF4 and BGLF5 had only a marginal influence on their expression patterns, showing that BGLF4 antagonizes BGLF5-mediated viral gene shutoff. To be able to exert its functions on viral gene expression, BGLF4 must be able to escape BGLF5's shutoff activities. Indeed, we found that BGLF5 stimulated the BGLF4 gene's transcription through an as yet uncharacterized molecular mechanism. The BGLF4/BGLF5 enzyme pair builds a regulatory loop that allows fine-tuning of virus protein production, which is required for efficient viral replication.

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