scholarly journals The Role of Marek’s Disease Virus UL12 and UL29 in DNA Recombination and the Virus Lifecycle

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 111 ◽  
Author(s):  
Renato Previdelli ◽  
Luca Bertzbach ◽  
Darren Wight ◽  
Tereza Vychodil ◽  
Yu You ◽  
...  

Marek’s disease virus (MDV) is an oncogenic alphaherpesvirus that infects chickens and integrates its genome into the telomeres of latently infected cells. MDV encodes two proteins, UL12 and UL29 (ICP8), that are conserved among herpesviruses and could facilitate virus integration. The orthologues of UL12 and UL29 in herpes simplex virus 1 (HSV-1) possess exonuclease and single strand DNA-binding activity, respectively, and facilitate DNA recombination; however, the role of both proteins in the MDV lifecycle remains elusive. To determine if UL12 and/or UL29 are involved in virus replication, we abrogated their expression in the very virulent RB-1B strain. Abrogation of either UL12 or UL29 resulted in a severe impairment of virus replication. We also demonstrated that MDV UL12 can aid in single strand annealing DNA repair, using a well-established reporter cell line. Finally, we assessed the role of UL12 and UL29 in MDV integration and maintenance of the latent virus genome. We could demonstrate that knockdown of UL12 and UL29 does not interfere with the establishment or maintenance of latency. Our data therefore shed light on the role of MDV UL12 and UL29 in MDV replication, DNA repair, and maintenance of the latent virus genome.

2020 ◽  
Author(s):  
Tereza Vychodil ◽  
Andelé M. Conradie ◽  
Jakob Trimpert ◽  
Amr Aswad ◽  
Luca D. Bertzbach ◽  
...  

Marek's disease virus (MDV) is an oncogenic alphaherpesvirus of chickens. The MDV genome consists of two unique regions that are both flanked by inverted repeat regions. These repeats harbor several genes involved in virus replication and pathogenesis, but it remains unclear why MDV and other herpesviruses harbor these large sequence duplications. In this study, we set to determine if both copies of these repeat regions are required for MDV replication and pathogenesis. Our results demonstrate that MDV mutants lacking the entire internal repeat region (ΔIRLS) efficiently replicate and spread from cell-to-cell in vitro. However, ΔIRLS replication was severely impaired in infected chickens and the virus caused significantly less frequent disease and tumors compared to the controls. In addition, we also generated recombinant viruses that harbor a deletion of most of the internal repeat region, leaving only short terminal sequences behind (ΔIRLS-HR). These remaining homologous sequences facilitated rapid restoration of the deleted repeat region, resulting in a virus that caused disease and tumors comparable to the wild type. Therefore, ΔIRLS-HR represents an excellent platform for rapid genetic manipulation of the virus genome in the repeat regions. Taken together, our study demonstrates that MDV requires both copies of the repeats for efficient replication and pathogenesis in its natural host. IMPORTANCE Marek's disease virus (MDV) is a highly oncogenic alphaherpesvirus that infects chickens and causes losses in the poultry industry of up to $2 billion per year. The virus is also widely used as a model to study alphaherpesvirus pathogenesis and virus-induced tumor development in a natural host. MDV and most other herpesviruses harbor direct or inverted repeats regions in their genome. However, the role of these sequence duplications in MDV remains elusive and has never been investigated in a natural virus-host model for any herpesvirus. Here, we demonstrate that both copies of the repeats are needed for efficient MDV replication and pathogenesis in vivo, while replication was not affected in cell culture. With this, we further dissect herpesvirus genome biology and the role of repeat regions in Marek's disease virus replication and pathogenesis.


2021 ◽  
Author(s):  
Yu You ◽  
Andelé M. Conradie ◽  
Ahmed Kheimar ◽  
Luca D. Bertzbach ◽  
Benedikt B. Kaufer

Marek’s disease virus (MDV) is a highly oncogenic alphaherpesvirus of chickens that causes lymphomas in various organs. Most MDV genes are conserved among herpesviruses, while others are unique to MDV and may contribute to pathogenesis and/or tumor formation. High transcript levels of the MDV-specific genes MDV082, RLORF11 and SORF6 were recently detected in lytically infected cells; however, it remained elusive if the respective proteins are expressed and if they play a role in MDV pathogenesis. In this study, we first addressed if these proteins are expressed by inserting FLAG tags at their N- or C- terminus. We could demonstrate that among the three genes tested, MDV082 is the only gene that encodes a protein and is expressed very late in MDV plaques in vitro. To investigate the role of this novel MDV082 protein in MDV pathogenesis, we generated a recombinant virus that lacks expression of the MDV082 protein. Our data revealed that the MDV082 protein contributes to the rapid onset of Marek’s disease, but is not essential for virus replication, spread and tumor formation. Taken together, this study sheds light on the expression of MDV-specific genes and unravels the role of the late protein MDV082 in MDV pathogenesis. Importance Marek’s disease virus (MDV) is a highly oncogenic alphaherpesvirus that causes Marek’s disease in chickens. The virus causes immense economic losses in poultry industry due to the high morbidity and mortality, but also cost of the vaccination. MDV encodes over 100 genes that are involved in various processes of the viral lifecycle. Functional characterization of MDV genes is an essential step towards understanding the complex virus lifecycle and MDV pathogenesis. Here, we have identified a novel protein encoded by MDV082 and two potential non-coding RNAs (RLORF11 and SORF6). The novel MDV082 protein is not needed for efficient MDV replication and tumor formation. However, our data demonstrate that the MDV082 protein is involved in the rapid onset of Marek’s disease.


2012 ◽  
Vol 60 (3) ◽  
pp. 333-342
Author(s):  
Mitsutaka Ikezawa ◽  
Jun Sasaki ◽  
Masanobu Goryo

To demonstrate the relationship between tumour development and virus replication, eight specific-pathogen-free pullets of line P2 (Group P; 14 weeks old) and five adult chickens (Group A; 96 weeks old) were inoculated with virulent Marek’s disease virus (vMDV). Five chickens of Group P died or were euthanised due to moribund condition following the development of neoplastic lesions between days 53 and 91. On histopathological examination, these lesions were characterised by the proliferation of lymphoid cells of variable size. On analysis by polymerase chain reaction (PCR), the MDVmeqgene was detected in Group P from day 21, and it was continuously identified in five chickens until they died or were euthanised. Abnormal signs and histopathological changes were not observed in chickens of Group A. The MDVmeqgene was temporarily detected in some chickens of Group A, but it remained almost undetectable throughout the experimental period. In older chickens inoculated with vMDV, the onset of MD lymphoma development tended to be delayed as compared with the young chicks. The relationship between MD lymphoma development and virus replication in older chickens has been suggested. Our data might indicate the underlying existence of an age-related resistance to vMDV challenge.


2019 ◽  
Vol 93 (9) ◽  
Author(s):  
Xue Lian ◽  
Chenyi Bao ◽  
Xueqi Li ◽  
Xunhai Zhang ◽  
Hongjun Chen ◽  
...  

ABSTRACT Oncogenic virus replication often leads to genomic instability, causing DNA damage and inducing the DNA damage response (DDR) pathway. The DDR pathway is a cellular pathway that senses DNA damage and regulates the cell cycle to maintain genomic stability. Therefore, the DDR pathway is critical for the viral lifecycle and tumorigenesis. Marek’s disease virus (MDV), an alphaherpesvirus that causes lymphoma in chickens, has been shown to induce DNA damage in infected cells. However, the interaction between MDV and the host DDR is unclear. In this study, we observed that MDV infection causes DNA strand breakage in chicken fibroblast (CEF) cells along with an increase in the DNA damage markers p53 and p21. Interestingly, we showed that phosphorylation of STAT3 was increased during MDV infection, concomitantly with a decrease of Chk1 phosphorylation. In addition, we found that MDV infection was enhanced by VE-821, an ATR-specific inhibitor, but attenuated by hydroxyurea, an ATR activator. Moreover, inhibition of STAT3 phosphorylation by Stattic eliminates the ability of MDV to inhibit Chk1 phosphorylation. Finally, we showed that MDV replication was decreased by Stattic treatment. Taken together, these results suggest that MDV disables the ATR-Chk1 pathway through STAT3 activation to benefit its replication. IMPORTANCE MDV is used as a biomedical model to study virus-induced lymphoma due to the similar genomic structures and physiological characteristics of MDV and human herpesviruses. Upon infection, MDV induces DNA damage, which may activate the DDR pathway. The DDR pathway has a dual impact on viruses because it manipulates repair and recombination factors to facilitate viral replication and also initiates antiviral action by regulating other signaling pathways. Many DNA viruses evolve to manipulate the DDR pathway to promote virus replication. In this study, we identified a mechanism used by MDV to inhibit ATR-Chk1 pathways. ATR is a cellular kinase that responds to broken single-stranded DNA, which has been less studied in MDV infection. Our results suggest that MDV infection activates STAT3 to disable the ATR-Chk1 pathway, which is conducive to viral replication. This finding provides new insight into the role of STAT3 in interrupting the ATR-Chk1 pathway during MDV replication.


Virus Genes ◽  
1994 ◽  
Vol 8 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Koichi Makimura ◽  
Fang-Yu Peng ◽  
Miho Tsuji ◽  
Saori Hasegawa ◽  
Yuri Kawai ◽  
...  

2021 ◽  
Vol 17 (2) ◽  
pp. e1009307
Author(s):  
Yifei Liao ◽  
Blanca Lupiani ◽  
Mohammad AI-Mahmood ◽  
Sanjay M. Reddy

Marek’s disease virus (MDV) is a potent oncogenic alphaherpesvirus that elicits a rapid onset of malignant T-cell lymphomas in chickens. Three MDV types, including GaHV-2 (MDV-1), GaHV-3 (MDV-2) and MeHV-1 (HVT), have been identified and all encode a US3 protein kinase. MDV-1 US3 is important for efficient virus growth in vitro. To study the role of US3 in MDV replication and pathogenicity, we generated MDV-1 US3-null virus and chimeric viruses by replacing MDV-1 US3 with MDV-2 or HVT US3. Using MD as a natural virus-host model, we showed that both MDV-2 and HVT US3 partially rescued the growth deficiency of MDV-1 US3-null virus. In addition, deletion of MDV-1 US3 attenuated the virus resulting in higher survival rate and lower MDV specific tumor incidence, which could be partially compensated by MDV-2 and HVT US3. We also identified chicken histone deacetylase 1 (chHDAC1) as a common US3 substrate for all three MDV types while only US3 of MDV-1 and MDV-2 phosphorylate chHDAC2. We further determined that US3 of MDV-1 and HVT phosphorylate chHDAC1 at serine 406 (S406), while MDV-2 US3 phosphorylates S406, S410, and S415. In addition, MDV-1 US3 phosphorylates chHDAC2 at S407, while MDV-2 US3 targets S407 and S411. Furthermore, biochemical studies show that MDV US3 mediated phosphorylation of chHDAC1 and 2 affect their stability, transcriptional regulation activity, and interaction network. Using a class I HDACs specific inhibitor, we showed that MDV US3 mediated phosphorylation of chHDAC1 and 2 is involved in regulation of virus replication. Overall, we identified novel substrates for MDV US3 and characterized the role of MDV US3 in MDV pathogenesis.


2020 ◽  
Vol 95 (2) ◽  
pp. e01645-20
Author(s):  
Aurélien Chuard ◽  
Katia Courvoisier-Guyader ◽  
Sylvie Rémy ◽  
Stephen Spatz ◽  
Caroline Denesvre ◽  
...  

ABSTRACTViral tropism and transmission of herpesviruses are best studied in their natural host for maximal biological relevance. In the case of alphaherpesviruses, few reports have focused on those aspects, primarily because of the few animal models available as natural hosts that are compatible with such studies. Here, using Marek’s disease virus (MDV), a highly contagious and deadly alphaherpesvirus of chickens, we analyze the role of tegument proteins pUL47 and pUL48 in the whole life cycle of the virus. We report that a virus lacking the UL48 gene (vΔUL48) is impaired in growth in cell culture and has diminished virulence in vivo. In contrast, a virus lacking UL47 (vΔUL47) is unaffected in its growth in vitro and is as virulent in vivo as the wild-type (WT) virus. Surprisingly, we observed that vΔUL47 was unable to be horizontally transmitted to naive chickens, in contrast to the WT virus. In addition, we show that pUL47 is important for the splicing of UL44 transcripts encoding glycoprotein gC, a protein known as being essential for horizontal transmission of MDV. Importantly, we observed that the levels of gC are lower in the absence of pUL47. Notably, this phenotype is similar to that of another transmission-incompetent mutant ΔUL54, which also affects the splicing of UL44 transcripts. This is the first study describing the role of pUL47 in both viral transmission and the splicing and expression of gC.IMPORTANCE Host-to-host transmission of viruses is ideally studied in vivo in the natural host. Veterinary viruses such as Marek’s disease virus (MDV) are, therefore, models of choice to explore these aspects. The natural host of MDV, the chicken, is small, inexpensive, and economically important. MDV is a deadly and contagious herpesvirus that can kill infected animals in less than 4 weeks. The virus naturally infects epithelial cells of the feather follicle epithelium from where it is shed into the environment. In this study, we demonstrate that the viral protein pUL47 is an essential factor for bird-to-bird transmission of the virus. We provide some molecular basis to this function by showing that pUL47 enhances the splicing and the expression of another viral gene, UL44, which is essential for viral transmission. pUL47 may have a similar function in human herpesviruses such as varicella-zoster virus or herpes simplex viruses.


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