scholarly journals Mapping QTL Associated with Resistance to Avian Oncogenic Marek’s Disease Virus (MDV) Reveals Major Candidate Genes and Variants

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1019
Author(s):  
Jacqueline Smith ◽  
Ehud Lipkin ◽  
Morris Soller ◽  
Janet E. Fulton ◽  
David W. Burt
Keyword(s):  
Candidate Genes ◽  
Disease Virus ◽  
Genome Wide Association Study ◽  
Animal Health ◽  
Genetic Selection ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Pure Lines

Marek’s disease (MD) represents a significant global economic and animal welfare issue. Marek’s disease virus (MDV) is a highly contagious oncogenic and highly immune-suppressive α-herpes virus, which infects chickens, causing neurological effects and tumour formation. Though partially controlled by vaccination, MD continues to have a profound impact on animal health and on the poultry industry. Genetic selection provides an alternative and complementary method to vaccination. However, even after years of study, the genetic mechanisms underlying resistance to MDV remain poorly understood. The Major Histocompatability Complex (MHC) is known to play a role in disease resistance, along with a handful of other non-MHC genes. In this study, one of the largest to date, we used a multi-facetted approach to identify quantitative trait locus regions (QTLR) influencing resistance to MDV, including an F6 population from a full-sib advanced intercross line (FSIL) between two elite commercial layer lines differing in resistance to MDV, RNA-seq information from virus challenged chicks, and genome wide association study (GWAS) from multiple commercial lines. Candidate genomic elements residing in the QTLR were further tested for association with offspring mortality in the face of MDV challenge in eight pure lines of elite egg-layer birds. Thirty-eight QTLR were found on 19 chicken chromosomes. Candidate genes, microRNAs, long non-coding RNAs and potentially functional mutations were identified in these regions. Association tests were carried out in 26 of the QTLR, using eight pure lines of elite egg-layer birds. Numerous candidate genomic elements were strongly associated with MD resistance. Genomic regions significantly associated with resistance to MDV were mapped and candidate genes identified. Various QTLR elements were shown to have a strong genetic association with resistance. These results provide a large number of significant targets for mitigating the effects of MDV infection on both poultry health and the economy, whether by means of selective breeding, improved vaccine design, or gene-editing technologies.

scholarly journals Mapping QTL associated with resistance to avian oncogenic Marek’s Disease Virus (MDV) reveals major candidate genes and variants

2020 ◽  
Author(s):  
Jacqueline Smith ◽  
Ehud Lipkin ◽  
Morris Soller ◽  
Janet E. Fulton ◽  
David W. Burt
Keyword(s):  
Candidate Genes ◽  
Disease Virus ◽  
Gene Editing ◽  
Selective Breeding ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Poultry Industry ◽  
Pure Lines

AbstractMarek’s Disease (MD) represents a significant global economic and animal welfare issue. Marek’s Disease Virus (MDV) is a highly contagious oncogenic and highly immune-suppressive alpha-herpes virus, which infects chickens, causing neurological effects and tumour formation. Though partially controlled by vaccination, MD continues to have a profound impact on animal health and on the poultry industry. Genetic selection provides an alternative and complementary method to vaccination. However, even after years of study, the genetic mechanisms underlying resistance to MDV remain poorly understood. The MHC is known to play a role in disease resistance, along with a handful of other. In this study, one of the largest to date, we used a multi-facetted approach to identify QTL regions (QTLR) influencing resistance to MDV, including an F6 population from a full-sib advanced intercross line (FSIL) between two elite commercial layer lines differing in resistance to MDV, RNA-seq information from virus challenged chicks, and genome wide association study (GWAS) from multiple commercial lines. Candidate genomic elements residing in the QTLR were further tested for association with offspring mortality in the face of MDV challenge in 8 pure lines of elite egg-layer birds. Thirty-eight QTLR were found on 19 chicken chromosomes. Candidate genes, miRNAs, lncRNAs and potentially functional mutations were identified in these regions. Association tests were carried out in 26 of the QTLR, using 8 pure lines of elite egg-layer birds. Numerous candidate genomic elements were strongly associated with MD resistance. Genomic regions significantly associated with resistance to MDV were mapped, and candidate genes identified. Various QTLR elements were shown to have strong genetic association with resistance. These results provide a large number of significant targets for mitigating the effects of MDV infection on both poultry health and the economy – whether by means of selective breeding, improved vaccine design or gene-editing technologies.Author summaryMarek’s Disease has a huge impact on the global poultry industry in terms of both animal welfare and economic cost. For many years, researchers have sought to identify the genes underlying resistance to Marek’s Disease Virus (MDV). However, this is a complex trait with each genetic locus having a small effect, so identifying causal genes and variants is no easy task. To date, it is known that the MHC confers differing susceptibility/resistance. A few other non-MHC genes have also been implicated in disease resistance, although based on experimental inbred lines and not representing real world commercial poultry. Using an F6 intercross population of birds with differences in MDV survival, we have identified many regions of the genome involved in resistance and highlighted candidate genes, miRNAs and lncRNA. Access to DNA from phenotyped birds spanning 15 generations of 8 elite commercial lines has provided a unique opportunity for us to show genetic association of markers in these transcripts with MDV survival. This genetic study, the largest to date, provides novel targets for mitigation of Marek’s Disease within the poultry industry. This could be through selective breeding strategies, improved vaccine design or future gene editing technologies.

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.

scholarly journals Comprehensive profiling analysis of the N6-methyladenosine-modified circular RNA transcriptome in cultured cells infected with Marek’s disease virus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aijun Sun ◽  
Rui Wang ◽  
Shuaikang Yang ◽  
Xiaojing Zhu ◽  
Ying Liu ◽  
...  
Keyword(s):  
Disease Virus ◽  
Cultured Cells ◽  
Circular Rna ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Circular Rnas ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Pathway Analyses ◽  
Profiling Analysis

AbstractMarek’s disease virus (MDV) induces severe immunosuppression and lymphomagenesis in the chicken, its natural host, and results in a condition that investigated the pathogenesis of MDV and have begun to focus on the expression profiling of circular RNAs (circRNAs). However, little is known about how the expression of circRNAs is referred to as Marek’s disease. Previous reports have is regulated during MDV replication. Here, we carried out a comprehensive profiling analysis of N6-methyladenosine (m6A) modification on the circRNA transcriptome in infected and uninfected chicken embryonic fibroblast (CEF) cells. Methylated RNA immunoprecipitation sequencing (MeRIP-Seq) revealed that m6A modification was highly conserved in circRNAs. Comparing to the uninfected group, the number of peaks and conserved motifs were not significantly different in cells that were infected with MDV, although reduced abundance of circRNA m6A modifications. However, gene ontology and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses revealed that the insulin signaling pathway was associated with the regulation of m6A modified circRNAs in MDV infection. This is the first report to describe alterations in the transcriptome-wide profiling of m6A modified circRNAs in MDV-infected CEF cells.

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