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Journal of Animal Science Jan 2023Avian leukosis virus subgroup E (ALVE) as a kind of endogenous retroviruses extensively exists in chicken genome. The insertion of ALVE has some effects on chicken...
Avian leukosis virus subgroup E (ALVE) as a kind of endogenous retroviruses extensively exists in chicken genome. The insertion of ALVE has some effects on chicken production traits and appearance. Most of the work on ALVEs has been done with commercial breeds. We present here an investigation of ALVE elements in seven Chinese domestic breeds and four standard breeds. Firstly, we established an ALVE insertion site dataset by using the obsERVer pipeline to identify ALVEs from whole-genome sequence data of eleven chicken breeds, seven Chinese domestic breeds, including Beijing You (BY), Dongxiang (DX), Luxi Game (LX), Shouguang (SG), Silkie (SK), Tibetan (TB) and Wenchang (WC), four standard breeds, including White Leghorn (WL), White Plymouth Rock (WR), Cornish (CS), and Rhode Island Red (RIR). A total of 37 ALVE insertion sites were identified and 23 of them were novel. Most of these insertion sites were distributed in intergenic regions and introns. We then used locus-specific PCR to validate the insertion sites in an expanded population with 18~60 individuals in each breed. The results showed that all predicted integration sites in 11 breeds were verified by PCR. Some ALVE insertion sites were breeds specific, and 16 out of 23 novel ALVEs were found in only one Chinese domestic chicken breed. We randomly selected three ALVE insertions including ALVE_CAU005, ALVE_ros127, and ALVE_ros276, and obtained their insertion sequences by long-range PCR and Sanger sequencing. The insertion sequences were all 7525 bp, which were full-length ALVE insertion and all of them were highly homologous to ALVE1 with similarity of 99%. Our study identified the distribution of ALVE in 11 chicken breeds, which expands the current research on ALVE in Chinese domestic breeds.
Topics: Animals; Chickens; Avian Leukosis Virus; DNA Transposable Elements; Polymerase Chain Reaction; Endogenous Retroviruses
PubMed: 36932970
DOI: 10.1093/jas/skad081 -
Journal of Virology Sep 2022The geographical spread and inter-host transmission of the subgroup J avian leukosis virus (ALV-J) may be the most important issues for epidemiology. An integrated...
The Emergence, Diversification, and Transmission of Subgroup J Avian Leukosis Virus Reveals that the Live Chicken Trade Plays a Critical Role in the Adaption and Endemicity of Viruses to the Yellow-Chickens.
The geographical spread and inter-host transmission of the subgroup J avian leukosis virus (ALV-J) may be the most important issues for epidemiology. An integrated analysis, including phylogenetic trees, homology modeling, evolutionary dynamics, selection analysis and viral transmission, based on the gp85 gene sequences of the 665 worldwide ALV-J isolates during 1988-2020, was performed. A new Clade 3 has been emerging and was evolved from the dominating Clade 1.3 of the Chinese Yellow-chicken, and the loss of a α-helix or β-sheet of the gp85 protein monomer was found by the homology modeling. The rapid evolution found in Clades 1.3 and 3 may be closely associated with the adaption and endemicity of viruses to the Yellow-chickens. The early U.S. strains from Clade 1.1 acted as an important source for the global spread of ALV-J and the earliest introduction into China was closely associated with the imported chicken breeders in the 1990s. The dominant outward migrations of Clades 1.1 and 1.2, respectively, from the Chinese northern White-chickens and layers to the Chinese southern Yellow-chickens, and the dominating migration of Clade 1.3 from the Chinese southern Yellow-chickens to other regions and hosts, indicated that the long-distance movement of these viruses between regions in China was associated with the live chicken trade. Furthermore, Yellow-chickens have been facing the risk of infections of the emerging Clades 2 and 3. Our findings provide new insights for the epidemiology and help to understand the critical factors involved in ALV-J dissemination. Although the general epidemiology of ALV-J is well studied, the ongoing evolutionary and transmission dynamics of the virus remain poorly investigated. The phylogenetic differences and relationship of the clades and subclades were characterized, and the epidemics and factors driving the geographical spread and inter-host transmission of different ALV-J clades were explored for the first time. The results indicated that the earliest ALV-J (Clade 1.1) from the United States, acted as the source for global spreads, and Clades 1.2, 1.3 and 3 were all subsequently evolved. Also the epidemiological investigation showed that the early imported breeders and the inter-region movements of live chickens facilitated the ALV-J dispersal throughout China and highlighted the needs to implement more effective containment measures.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; China; Phylogeny; Poultry Diseases; United States
PubMed: 35950858
DOI: 10.1128/jvi.00717-22 -
Frontiers in Cellular and Infection... 2021Avian leukosis virus subgroup J (ALV-J) is an oncogenic retrovirus that causes immunosuppression and neoplastic diseases in poultry. Cytokine signal-transduction...
Avian leukosis virus subgroup J (ALV-J) is an oncogenic retrovirus that causes immunosuppression and neoplastic diseases in poultry. Cytokine signal-transduction inhibitor molecule 3 (SOCS3) is an important negative regulator of the JAK2/STAT3 signaling pathway and plays certain roles in ALV-J infection. It is of significance to confirm the roles of in ALV-J infection and study how this gene affects ALV-J infection. In this study, we assessed the expression of the gene and , and investigated the roles of in ALV-J infection using overexpressed or interfered assays with the in DF-1 cells. The results showed that the expression of ALV-J infected chickens was different from uninfected chickens in the spleen, thymus and cecal tonsil. Further, is mainly expressed in the nucleus as determined by immunofluorescence assay. Overexpression of in DF-1 cells promoted the replication of ALV-J virus, and the expression of interferons ( and ), inflammatory factors ( and ) along with interferon-stimulating genes (, , , and ). Conversely, interference of showed the opposite results. We also observed that SOCS3 promoted ALV-J virus replication by inhibiting JAK2/STAT3 phosphorylation. In conclusion, promotes ALV-J replication inhibiting the phosphorylation of the JAK2/STAT3 signaling pathway. These results would advance further understanding of the persistent infection and the viral immune evasion of the ALV-J virus.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; Phosphorylation; Poultry Diseases; Virus Replication
PubMed: 34568100
DOI: 10.3389/fcimb.2021.748795 -
Poultry Science Nov 2022Subgroup K avian leukosis virus (ALV-K) is a new subgroup of avian leukosis virus (ALV) first identified in Chinese indigenous chickens in recent years. In this study,...
Subgroup K avian leukosis virus (ALV-K) is a new subgroup of avian leukosis virus (ALV) first identified in Chinese indigenous chickens in recent years. In this study, an ALV-K strain was isolated from Luhua chicken in Shandong province, China, and designated SD20LH01. The full-length genomic sequence of SD20LH01 was 7491 bp, which had the highest homology with ALV-K reference strains GDFX0601, GDFX0602 and GDFX0603. The nucleotide homology of env gene of SD20LH01 with reference strains of subgroup A, B, C, D, E, and J was ranged from 57.1 to 93.2%, while 94.1 to 99.4% with other ALV-K reference strains. The nucleotide difference of SD20LH01 mainly clustered with gp85 gene and U3 sequence when compared with the reference strain of ALV-K. In order to investigate the pathogenicity of SD20LH01, SPF chicken embryos were infected by yolk sac inoculation, and 1-day-old chickens were infected by intraperitoneal inoculation of SD20LH01. The results showed that yolk sac inoculation of SD20LH01 could induce persistent viremia, growth retardation and reduce the immune response to NDV and AIV-H9 vaccines. However, intraperitoneal inoculation in 1-day-old chickens could only induce a low level of viremia. In addition, no tumors were found in infected chickens during the animal experiments. This study enriched the genomic sequence data of ALV-K isolated in Chinese indigenous chickens, and laid a foundation for further study on the pathogenesis and prevention of ALV-K.
Topics: Chick Embryo; Animals; Avian Leukosis Virus; Chickens; Avian Leukosis; Virulence; Viremia; Poultry Diseases; Phylogeny; Nucleotides
PubMed: 36081235
DOI: 10.1016/j.psj.2022.102116 -
Viruses Oct 2022Hens infected with avian leukosis virus subgroup A (ALV-A) experience stunted growth, immunosuppression, and potentially, lymphoma development. According to past...
Hens infected with avian leukosis virus subgroup A (ALV-A) experience stunted growth, immunosuppression, and potentially, lymphoma development. According to past research, A20 can both promote and inhibit tumor growth. In this study, DF-1 cells were infected with ALV-A rHB2015012, and Gp85 expression was measured at various time points. A recombinant plasmid encoding the chicken A20 gene and short hairpin RNA targeting chicken A20 (A20-shRNA) was constructed and transfected into DF-1 cells to determine the effect on ALV-A replication. The potential signaling pathways of A20 were explored using bioinformatics prediction, co-immunoprecipitation, and other techniques. The results demonstrate that A20 and ALV-A promoted each other after ALV-A infection of DF-1 cells, upregulated A20, inhibited TRAF6 ubiquitination, and promoted STAT3 phosphorylation. The phosphorylated-STAT3 (p-STAT3) promoted the expression of proto-oncogene c-myc, which may lead to tumorigenesis. This study will help to further understand the tumorigenic process of ALV-A and provide a reference for preventing and controlling ALV.
Topics: Animals; Female; Avian Leukosis Virus; Avian Leukosis; TNF Receptor-Associated Factor 6; RNA, Small Interfering; Chickens; Ubiquitination; Proto-Oncogenes; Poultry Diseases
PubMed: 36298765
DOI: 10.3390/v14102210 -
Genomics May 2022The impact of Endogenous retroviruses (ERVs) on chicken disease is not well understood. Here, we systematically identified 436 relatively complete ChERVs from the...
The impact of Endogenous retroviruses (ERVs) on chicken disease is not well understood. Here, we systematically identified 436 relatively complete ChERVs from the chicken genome. Subsequently, ChERV transcriptomes were analyzed in chicken after subgroup J avian leukosis virus (ALV-J), avian influenza virus (AIV), Marek's disease virus (MDV) and avian pathogenic Escherichia coli (APEC) infection. We found that about 50%-68% of ChERVs were transcriptionally active in infected and uninfected-samples, although the abundance of most ChERVs is relatively low. Moreover, compared to uninfected-samples, 49, 18, 66 and 17 ChERVs were significantly differentially expressed in ALV-J, AIV, MDV and APEC infected-samples, respectively. These findings may be of significance for understanding the role and function of ChERVs to response the pathogenic microorganism infection.
Topics: Animals; Chickens; Endogenous Retroviruses; Avian Leukosis; Transcriptome; Poultry Diseases; Avian Leukosis Virus
PubMed: 35462029
DOI: 10.1016/j.ygeno.2022.110371 -
Viruses Sep 2016Infectious retrovirus particles contain two copies of unspliced viral RNA that serve as the viral genome. Unspliced retroviral RNA is transcribed in the nucleus by the... (Review)
Review
Infectious retrovirus particles contain two copies of unspliced viral RNA that serve as the viral genome. Unspliced retroviral RNA is transcribed in the nucleus by the host RNA polymerase II and has three potential fates: (1) it can be spliced into subgenomic messenger RNAs (mRNAs) for the translation of viral proteins; or it can remain unspliced to serve as either (2) the mRNA for the translation of Gag and Gag-Pol; or (3) the genomic RNA (gRNA) that is packaged into virions. The Gag structural protein recognizes and binds the unspliced viral RNA to select it as a genome, which is selected in preference to spliced viral RNAs and cellular RNAs. In this review, we summarize the current state of understanding about how retroviral packaging is orchestrated within the cell and explore potential new mechanisms based on recent discoveries in the field. We discuss the -acting elements in the unspliced viral RNA and the properties of the Gag protein that are required for their interaction. In addition, we discuss the role of host factors in influencing the fate of the newly transcribed viral RNA, current models for how retroviruses distinguish unspliced viral mRNA from viral genomic RNA, and the possible subcellular sites of genomic RNA dimerization and selection by Gag. Although this review centers primarily on the wealth of data available for the alpharetrovirus Rous sarcoma virus, in which a discrete RNA packaging sequence has been identified, we have also summarized the - and -acting factors as well as the mechanisms governing gRNA packaging of other retroviruses for comparison.
PubMed: 27657110
DOI: 10.3390/v8090257 -
Viruses Nov 2022The avian immunosuppressive and neoplastic diseases caused by Marek's disease virus (MDV), avian leucosis virus (ALV), and reticuloendotheliosis virus (REV) are...
The avian immunosuppressive and neoplastic diseases caused by Marek's disease virus (MDV), avian leucosis virus (ALV), and reticuloendotheliosis virus (REV) are seriously harmful to the global poultry industry. In recent years, particularly in 2020-2022, outbreaks of such diseases in chicken flocks frequently occurred in China. Herein, we collected live diseased birds from 30 poultry farms, out of 42 farms with tumour-bearing chicken flocks distributed in central China, to investigate the current epidemiology and co-infections of these viruses. The results showed that in individual diseased birds, the positive infection rates of MDV, ALV, and REV were 69.5% (203/292), 14.4% (42/292), and 4.7% (13/277), respectively, while for the flocks, the positive infection rates were 96.7% (29/30), 36.7% (11/30), and 20% (6/30), respectively. For chicken flocks, monoinfection of MDV, ALV, or REV was 53.3% (16/30), 3.3% (1/30), and 0% (0/30), respectively, but a total of 43.3% (13/30) co-infections was observed, which includes 23.3% (7/30) of MDV+ALV, 10.0% (3/30) of MDV+REV, and 10.0% (3/30) of MDV+ALV+REV co-infections. Interestingly, no ALV+REV co-infection or REV monoinfection was observed in the selected poultry farms. Our data indicate that the prevalence of virulent MDV strains, partially accompanied with ALV and/or REV co-infections, is the main reason for current outbreaks of avian neoplastic diseases in central China, providing an important reference for the future control of disease.
Topics: Animals; Chickens; Coinfection; Avian Leukosis; Neoplasms; Herpesvirus 2, Gallid; Reticuloendotheliosis virus; China; Poultry Diseases; Avian Leukosis Virus; Marek Disease
PubMed: 36560601
DOI: 10.3390/v14122599 -
Poultry Science Apr 2022Subgroup J Avian leukosis virus (ALV-J) is an important pathogen of poultry tumor diseases. Since its discovery, it has caused significant economic losses to the poultry...
Subgroup J Avian leukosis virus (ALV-J) is an important pathogen of poultry tumor diseases. Since its discovery, it has caused significant economic losses to the poultry industry. Thus, the rapid detection of molecular level with strong specificity is particularly important whether poultry are infected with ALV-J. In this study, we designed primers and probe for real-time fluorescent reverse-transcription recombinase-aided amplification assay (RT-RAA) based on the ALV-J gp85 sequence. We had established a real-time fluorescent RT-RAA method and confirmed this system by verifying the specificity and sensitivity of the primers and probe. In addition, repeatability tests and clinical sample regression tests were used for preliminary evaluation of this detection method. The sensitivity of established method was about 10 copies/μL, and the repeatability of the CV of the C value is 4%, indicating repeatability is good. Moreover, there was no cross-reactivity with NDV, IBV, IBDV, H9N2, MDV, and REV, and other avian leukosis virus subgroups, such as subgroups A, B, C, D, K and E. Importantly, the real-time fluorescent RT-RAA completed the test within 30 min at a constant temperature of 41°C. Forty-two clinical samples with known background were tested, and the test results were coincided with 100%. Overall, these results suggested that the real-time fluorescent RT-RAA developed in this study had strong specificity, high sensitivity, and good feasibility. The method is simple, easy, and portable, that is suitable for clinical and laboratory diagnosis, and provides technical support for the prevention and control of ALV-J.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; DNA Primers; Influenza A Virus, H9N2 Subtype; Poultry Diseases; Recombinases; Sensitivity and Specificity
PubMed: 35240352
DOI: 10.1016/j.psj.2022.101743 -
Journal of Virology Apr 2022The retroviral surface envelope protein subunit (SU) mediates receptor binding and triggers membrane fusion by the transmembrane (TM) subunit. SU evolves rapidly under...
The retroviral surface envelope protein subunit (SU) mediates receptor binding and triggers membrane fusion by the transmembrane (TM) subunit. SU evolves rapidly under strong selective conditions, resulting in seemingly unrelated SU structures in highly divergent retroviruses. Structural modeling of the SUs of several retroviruses and related endogenous retroviral elements with AlphaFold 2 identifies a TM-proximal SU β-sandwich structure that has been conserved in the orthoretroviruses for at least 110 million years. The SU of orthoretroviruses diversified by the differential expansion of the β-sandwich core to form domains involved in virus-host interactions. The β-sandwich domain is also conserved in the SU equivalent GP of Ebola virus although with a significantly different orientation in the trimeric envelope protein structure relative to the β-sandwich of human immunodeficiency virus type 1 gp120, with significant evidence for divergent rather than convergent evolution. The unified structural view of orthoretroviral SU and filoviral GP identifies an ancient, structurally conserved, and evolvable domain underlying the structural diversity of orthoretroviral SU and filoviral GP. The structural relationships of SUs of retroviral groups are obscured by the high rate of sequence change of SU and the deep-time divergence of retroviral lineages. Previous data showed no structural or functional relationships between the SUs of type C gammaretroviruses and lentiviruses. A deeper understanding of structural relationships between the SUs of different retroviral lineages would allow the generalization of critical processes mediated by these proteins in host cell infection. Modeling of SUs with AlphaFold 2 reveals a conserved core domain underlying the structural diversity of orthoretroviral SUs. Definition of the conserved SU structural core allowed the identification of a homologue structure in the SU equivalent GP of filoviruses that most likely shares an origin, unifying the SU of orthoretroviruses and GP of filoviruses into a single protein family. These findings will allow an understanding of the structural basis for receptor-mediated membrane fusion mechanisms in a broad range of biomedically important retroviruses.
Topics: Ebolavirus; Endogenous Retroviruses; Gene Products, env; Humans; Viral Envelope Proteins
PubMed: 35319227
DOI: 10.1128/jvi.00063-22