scholarly journals The Transcriptional Landscape of Marek’s Disease Virus in Primary Chicken B Cells Reveals Novel Splice Variants and Genes

Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 264 ◽  
Author(s):  
Luca Bertzbach ◽  
Florian Pfaff ◽  
Viktoria Pauker ◽  
Ahmed Kheimar ◽  
Dirk Höper ◽  
...  
Keyword(s):  
B Cells ◽  
Disease Virus ◽  
Splice Variants ◽  
Transcriptome Assembly ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Target Cells ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Transcriptional Landscape

Marek’s disease virus (MDV) is an oncogenic alphaherpesvirus that infects chickens and poses a serious threat to poultry health. In infected animals, MDV efficiently replicates in B cells in various lymphoid organs. Despite many years of research, the viral transcriptome in primary target cells of MDV remained unknown. In this study, we uncovered the transcriptional landscape of the very virulent RB1B strain and the attenuated CVI988/Rispens vaccine strain in primary chicken B cells using high-throughput RNA-sequencing. Our data confirmed the expression of known genes, but also identified a novel spliced MDV gene in the unique short region of the genome. Furthermore, de novo transcriptome assembly revealed extensive splicing of viral genes resulting in coding and non-coding RNA transcripts. A novel splicing isoform of MDV UL15 could also be confirmed by mass spectrometry and RT-PCR. In addition, we could demonstrate that the associated transcriptional motifs are highly conserved and closely resembled those of the host transcriptional machinery. Taken together, our data allow a comprehensive re-annotation of the MDV genome with novel genes and splice variants that could be targeted in further research on MDV replication and tumorigenesis.

scholarly journals Marek’s disease virus prolongs survival of primary chicken B-cells by inducing a senescence-like phenotype

2021 ◽  
Vol 17 (10) ◽  
pp. e1010006
Author(s):  
Laëtitia Trapp-Fragnet ◽  
Julia Schermuly ◽  
Marina Kohn ◽  
Luca D. Bertzbach ◽  
Florian Pfaff ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cells ◽  
B Cell ◽  
Disease Virus ◽  
Cellular Responses ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Depth Analysis

Marek’s disease virus (MDV) is an alphaherpesvirus that causes immunosuppression and deadly lymphoma in chickens. Lymphoid organs play a central role in MDV infection in animals. B-cells in the bursa of Fabricius facilitate high levels of MDV replication and contribute to dissemination at early stages of infection. Several studies investigated host responses in bursal tissue of MDV-infected chickens; however, the cellular responses specifically in bursal B-cells has never been investigated. We took advantage of our recently established in vitro infection system to decipher the cellular responses of bursal B-cells to infection with a very virulent MDV strain. Here, we demonstrate that MDV infection extends the survival of bursal B-cells in culture. Microarray analyses revealed that most cytokine/cytokine-receptor-, cell cycle- and apoptosis-associated genes are significantly down-regulated in these cells. Further functional assays validated these strong effects of MDV infections on cell cycle progression and thus, B-cell proliferation. In addition, we confirmed that MDV infections protect B-cells from apoptosis and trigger an accumulation of the autophagy marker Lc3-II. Taken together, our data indicate that MDV-infected bursal B-cells show hallmarks of a senescence-like phenotype, leading to a prolonged B-cell survival. This study provides an in-depth analysis of bursal B-cell responses to MDV infection and important insights into how the virus extends the survival of these cells.

scholarly journals A Cell Culture System to Investigate Marek’s Disease Virus Integration into Host Chromosomes

2021 ◽  
Vol 9 (12) ◽  
pp. 2489
Author(s):  
Yu You ◽  
Tereza Vychodil ◽  
Giulia Aimola ◽  
Renato L. Previdelli ◽  
Thomas W. Göbel ◽  
...  
Keyword(s):  
Disease Virus ◽  
Marek's Disease Virus ◽  
Telomeric Repeat ◽  
Marek's Disease ◽  
Target Cells ◽  
Neoplastic Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Integration Mechanism

Marek’s disease virus (MDV) is a highly oncogenic alphaherpesvirus that causes a devastating neoplastic disease in chickens. MDV has been shown to integrate its genome into the telomeres of latently infected and tumor cells, which is crucial for efficient tumor formation. Telomeric repeat arrays present at the ends of the MDV genome facilitate this integration into host telomeres; however, the integration mechanism remains poorly understood. Until now, MDV integration could only be investigated qualitatively upon infection of chickens. To shed further light on the integration mechanism, we established a quantitative integration assay using chicken T cell lines, the target cells for MDV latency and transformation. We optimized the infection conditions and assessed the establishment of latency in these T cells. The MDV genome was efficiently maintained over time, and integration was confirmed in these cells by fluorescence in situ hybridization (FISH). To assess the role of the two distinct viral telomeric repeat arrays in the integration process, we tested various knockout mutants in our in vitro integration assay. Efficient genome maintenance and integration was thereby dependent on the presence of the telomeric repeat arrays in the virus genome. Taken together, we developed and validated a novel in vitro integration assay that will shed light on the integration mechanism of this highly oncogenic virus into host telomeres.

scholarly journals Characterization of a Novel Viral Interleukin 8 (vIL-8) Splice Variant Encoded by Marek’s Disease Virus

2021 ◽  
Vol 9 (7) ◽  
pp. 1475
Author(s):  
Yu You ◽  
Ibrahim T. Hagag ◽  
Ahmed Kheimar ◽  
Luca D. Bertzbach ◽  
Benedikt B. Kaufer
Keyword(s):  
Disease Virus ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Interleukin 8 ◽  
Target Cells ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Cxc Chemokine ◽  
Splice Forms

Marek’s disease virus (MDV) is a highly cell-associated oncogenic alphaherpesvirus that causes lymphomas in various organs in chickens. Like other herpesviruses, MDV has a large and complex double-stranded DNA genome. A number of viral transcripts are generated by alternative splicing, a process that drastically extends the coding capacity of the MDV genome. One of the spliced genes encoded by MDV is the viral interleukin 8 (vIL-8), a CXC chemokine that facilitates the recruitment of MDV target cells and thereby plays an important role in MDV pathogenesis and tumorigenesis. We recently identified a novel vIL-8 exon (vIL-8-E3′) by RNA-seq; however, it remained elusive whether the protein containing the vIL-8-E3′ is expressed and what role it may play in MDV replication and/or pathogenesis. To address these questions, we first generated recombinant MDV harboring a tag that allows identification of the spliced vIL-8-E3′ protein, revealing that it is indeed expressed. We subsequently generated knockout viruses and could demonstrate that the vIL-8-E3′ protein is dispensable for MDV replication as well as secretion of the functional vIL-8 chemokine. Finally, infection of chickens with this vIL-8-E3′ knockout virus revealed that the protein is not important for MDV replication and pathogenesis in vivo. Taken together, our study provides novel insights into the splice forms of the CXC chemokine of this highly oncogenic alphaherpesvirus.

scholarly journals The pp38 Gene of Marek's Disease Virus (MDV) Is Necessary for Cytolytic Infection of B Cells and Maintenance of the Transformed State but Not for Cytolytic Infection of the Feather Follicle Epithelium and Horizontal Spread of MDV

2005 ◽  
Vol 79 (7) ◽  
pp. 4545-4549 ◽  
Author(s):  
I. M. Gimeno ◽  
R. L. Witter ◽  
H. D. Hunt ◽  
S. M. Reddy ◽  
L. F. Lee ◽  
...  
Keyword(s):  
B Cells ◽  
Disease Virus ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Latently Infected ◽  
Feather Follicle ◽  
Pp38 Gene

ABSTRACT Marek's disease virus has a unique phosphoprotein, pp38, which is suspected to play an important role in Marek's disease pathogenesis. The objective of the present study was to utilize a mutant virus lacking the pp38 gene (rMd5Δpp38) to better characterize the biological function of pp38. This work shows that the pp38 gene is necessary to establish cytolytic infection in B cells but not in feather follicle epithelium, to produce an adequate level of latently infected T cells, and to maintain the transformed status in vivo.

Isolation and identification of Marek’s disease virus (MDV) from feather follicle epithelium and internal organs of diseased chickens in Dakahlia Governorate, Egypt

2019 ◽  
Vol 20 (2) ◽  
pp. 6-11
Author(s):  
Aly El-Kenawy ◽  
Mohamed El-Tholoth ◽  
Emad A
Keyword(s):  
Real Time ◽  
Disease Virus ◽  
Real Time Pcr ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Field Samples ◽  
Feather Follicle ◽  
Positive Results

In the present study, a total of 16 samples including feather follicle epithelium, ovary, spleen and kidney (4 samples for each organ) were collected from diseased chicken flocks suspected to be infected with Marek’s disease virus (MDV) at Dakahlia Governorate, Egypt during the period from October 2016 to October 2017. Each sample was pooled randomly from three to five birds (90 to 360 days old). The isolation of the suspected virus from the collected samples was carried out via chorioallantoic membranes (CAMs) of 12 days old embryonated chicken eggs (ECEs). Three egg passages were carried out for each sample. Hyperimmune serum was prepared against standard MDV. MDV in both field and egg passaged samples (after 3rd passage) was identified by agar gel precipitation test (AGPT) and indirect fluorescence antibody test (IFAT). Molecular identification of virus was carried out by conventional polymerase chain reaction (PCR) and real- time PCR in four selected samples. The results revealed that 14 samples (87.5%) including 4 (100%) samples from feather follicle epithelium, ovary and kidney and 2 (50%) samples from spleen, showed positive results in virus isolation after 3rd passage. The positive results percentage by AGPT for field samples were 50% (8 out of 16 samples), while after the 3rd passage in ECEs were 37.5% (6 out of 16 samples) and the positive results percentage by IFAT for field samples were 62.5% (10 out of 16 samples), while after the 3rd passage in ECEs were 81.25 % (13 out of 16 samples). Viral nucleic acid was detected in all selected samples by conventional and real- time PCR. The results indicate that feather follicle epithelium is the best organ for MDV detection. IFAT is superior over AGPT in virus detection. Conventional and real - time PCR could be efficiently used for molecular detection of the virus.

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