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Frontiers in Immunology 2022Avian leukosis virus (ALV) causes various diseases associated with tumor formation and decreased fertility. Moreover, ALV induces severe immunosuppression, increasing... (Review)
Review
Avian leukosis virus (ALV) causes various diseases associated with tumor formation and decreased fertility. Moreover, ALV induces severe immunosuppression, increasing susceptibility to other microbial infections and the risk of failure in subsequent vaccination against other diseases. There is growing evidence showing the interaction between ALV and the host. In this review, we will survey the present knowledge of the involvement of host factors in the important molecular events during ALV infection and discuss the futuristic perspectives from this angle.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; Virus Replication
PubMed: 35693802
DOI: 10.3389/fimmu.2022.907287 -
Frontiers in Immunology 2022Avian Leukosis Virus Subgroup J (ALV-J) is a tumorigenic virus with high morbidity and rapid transmission. N6-methyladenosine (mA) is a common epigenetic modification...
Avian Leukosis Virus Subgroup J (ALV-J) is a tumorigenic virus with high morbidity and rapid transmission. N6-methyladenosine (mA) is a common epigenetic modification that may be closely related to the pathogenicity of ALV-J. Currently, there are no reports on whether mA modification is related to ALV-J induced tumor formation. In this study, we used methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) to examine the differences in mA methylation and gene expression in normal livers and ALV-J-induced tumor livers systematically, with functional enrichment and co-expression analysis. The results identified 6,541 mA methylated peaks, mainly enriched in CDS, and more than 83% of the transcripts contained 1-2 mA peaks. For RNA-seq, 1,896 and 1,757 differentially expressed mRNAs and lncRNAs were identified, respectively. Gene enrichment analysis indicated that they may be involved in biological processes and pathways such as immunology-related and apoptosis. Moreover, we identified 17 lncRNAs, commonly existing in differently expressed methylome and transcriptome. Through co-expression analysis, 126 differentially expressed lncRNAs, and 18 potentially mA-related methyltransferases were finally identified and connected, suggesting that mA modifications might affect gene expression of lncRNAs and play a role in ALV-J induced tumor formation. This study provides the first comprehensive description of the mA expression profile in tumor livers induced by ALV-J infection in chickens, which provides a basis for studying the role of mA modification in ALV-J induced tumorigenesis. This study provides clues for studying the epigenetic etiology and pathogenesis of ALV-J.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Carcinogenesis; Chickens; Liver; Methylation; RNA, Long Noncoding; Transcriptome
PubMed: 35529873
DOI: 10.3389/fimmu.2022.868892 -
Virologica Sinica Apr 2022Subgroup J avian leukosis virus (ALV-J) is a highly oncogenic retrovirus that has been devastating the global poultry industry since the late 1990s. The major infection...
Subgroup J avian leukosis virus (ALV-J) is a highly oncogenic retrovirus that has been devastating the global poultry industry since the late 1990s. The major infection model of ALV-J is vertical transmission, which is responsible for the congenital infection of progeny from generation to generation. Increasing evidence has suggested that extracellular vesicles (EVs) derived from virus-infected cells or biological fluids have been thought to be vehicles of transmission for viruses. However, the role of EVs in infection and transmission of ALV-J remains obscure. In the present study, semen extracellular vesicles (SE) were isolated and purified from ALV-J-infected rooster seminal plasma (SE-ALV-J), which was shown to contain ALV-J genomic RNA and partial viral proteins, as determined by RNA sequencing, reverse transcription-quantitative PCR and Western blotting. Furthermore, SE-ALV-J was proved to be able to transmit ALV-J infection to host cells and establish productive infection. More importantly, artificial insemination experiments showed that SE-ALV-J transmitted ALV-J infection to SPF hens, and subsequently mediated vertical transmission of ALV-J from the SPF hens to the progeny chicks. Taken together, the results of the present study suggested that ALV-J utilized host semen extracellular vesicles as a novel means for vertical transmission, enhancing our understanding on mechanisms underlying ALV-J transmission.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; Extracellular Vesicles; Female; Male; Poultry Diseases; Semen
PubMed: 35527223
DOI: 10.1016/j.virs.2022.01.026 -
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 Apr 2022MicroRNAs (miRNAs) are a group of regulatory noncoding RNAs, serving as major regulators with a sequence-specific manner in multifarious biological processes. Although a...
MicroRNAs (miRNAs) are a group of regulatory noncoding RNAs, serving as major regulators with a sequence-specific manner in multifarious biological processes. Although a series of viral families have been proved to encode miRNAs, few reports were available regarding the function of ALV-J-encoded miRNA. Here, we reported a novel miRNA (designated ALV-miRNA-p19-01) in ALV-J-infected DF-1 cells. We found that ALV-miRNA-p19-01 is encoded by the genome of the ALV-J SCAU1903 strain (located at nucleotides site 779 to 801) in a classic miRNA biogenesis manner. The transfection of DF-1 cells with ALV-miRNA-p19-01 enhanced ALV-J replication, while the blockage of ALV-miRNA-p19-01 suppressed ALV-J replication. Furthermore, our data showed that ALV-miRNA-p19-01 promotes ALV-J replication by directly targeting the cellular gene dual specificity phosphatase 6 through regulating ERK2 activity.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; Dual Specificity Phosphatase 6; MicroRNAs; Virus Replication
PubMed: 35458535
DOI: 10.3390/v14040805 -
Poultry Science May 2022Avian leukosis virus (ALV) induces multiple tumors in chicken and is still prevalent in a lot of local flocks in China. In this study, we analyzed the ALV infection...
Avian leukosis virus (ALV) induces multiple tumors in chicken and is still prevalent in a lot of local flocks in China. In this study, we analyzed the ALV infection status in an Anyi tile-like gray chicken flock by DF1-cells isolation, virus identification, and genome sequencing. Results showed a 29% (29/100) ALV positive rate in this flock. Homology analysis based on env genes illustrated that all these stains belong to subgroup J (92-100% identities) and can be further divided into 5 batches, suggesting a higher diversity of ALV-J within the same flock. The whole-genome analysis of representative stains from each batch confirmed the close relationship between these isolated strains with previously reported strains from different regions (Guangxi, Shandong, and Heilongjiang), revealing the enrichment of different strains in Anyi tile-like grey chickens. This study provides the epidemiological data of ALV-J in a special chicken flock and a reference for the further eradication of ALV in China.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; China; Poultry Diseases
PubMed: 35381497
DOI: 10.1016/j.psj.2022.101764 -
BMC Veterinary Research Apr 2022Co-infection with the avian leukosis virus subgroup J (ALV-J) and the reticuloendotheliosis virus (REV) increases mutual viral replication, causing a more serious...
BACKGROUND
Co-infection with the avian leukosis virus subgroup J (ALV-J) and the reticuloendotheliosis virus (REV) increases mutual viral replication, causing a more serious pathogenic effect by accelerating the progression of neoplasia and extending the tumor spectrum. However, the molecular mechanism underlying the synergistic replication of ALV-J and REV remains unclear.
RESULTS
Here, we performed this study to compare the differentially expressed proteins among CEF cells infected with ALV-J, REV or both at the optimal synergistic infection time using TMT-based quantitative proteomics. We identified a total of 719 (292 upregulated and 427 downregulated) and 64 (35 upregulated and 29 downregulated) proteins by comparing co-infecting both viruses with monoinfecting ALV-J and REV, respectively. GO annotation and KEGG pathway analysis showed the differentially expressed proteins participated in virus-vector interaction, biological adhesion and immune response pathways in the synergistic actions of ALV-J and REV at the protein levels. Among the differentially expressed proteins, a large number of integrins were inhibited or increased in the co-infection group. Further, eight integrins, including ITGα1, ITGα3, ITGα5, ITGα6, ITGα8, ITGα9, ITGα11 and ITGβ3, were validated in CEF cells by qRT-PCR or western blot.
CONCLUSIONS
These findings proved that integrins may be key regulators in the mechanism of synergistic infection of REV and ALV-J, which will provide more insight into the pathogenesis of synergism of REV and ALV-J at protein level.
Topics: Animals; Avian Leukosis Virus; Chickens; Integrins; Proteomics; Reticuloendotheliosis virus
PubMed: 35379256
DOI: 10.1186/s12917-022-03207-6 -
Viruses Mar 2022Retroviruses package two copies of their genomic RNA (gRNA) as non-covalently linked dimers. Many studies suggest that the retroviral nucleocapsid protein (NC) plays an...
Retroviruses package two copies of their genomic RNA (gRNA) as non-covalently linked dimers. Many studies suggest that the retroviral nucleocapsid protein (NC) plays an important role in gRNA dimerization. The upper part of the L3 RNA stem-loop in the 5' leader of the avian leukosis virus (ALV) is converted to the extended dimer by ALV NC. The L3 hairpin contains three stems and two internal loops. To investigate the roles of internal loops and stems in the NC-mediated extended dimer formation, we performed site-directed mutagenesis, gel electrophoresis, and analysis of thermostability of dimeric RNAs. We showed that the internal loops are necessary for efficient extended dimer formation. Destabilization of the lower stem of L3 is necessary for RNA dimerization, although it is not involved in the linkage structure of the extended dimer. We found that NCs from ALV, human immunodeficiency virus type 1 (HIV-1), and Moloney murine leukemia virus (M-MuLV) cannot promote the formation of the extended dimer when the apical stem contains ten consecutive base pairs. Five base pairs correspond to the maximum length for efficient L3 dimerization induced by the three NCs. L3 dimerization was less efficient with M-MuLV NC than with ALV NC and HIV-1 NC.
Topics: Animals; Avian Leukosis Virus; Base Sequence; Dimerization; HIV-1; Humans; Mice; Moloney murine leukemia virus; Nucleic Acid Conformation; Nucleocapsid; Nucleocapsid Proteins; RNA, Viral
PubMed: 35337013
DOI: 10.3390/v14030606 -
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 -
Archives of Virology Apr 2022The current prevalence of avian leukosis virus (ALV) in fancy chickens in Germany is unknown. Therefore, 537 cloacal swabs from 50 purebred fancy-chicken flocks in...
The current prevalence of avian leukosis virus (ALV) in fancy chickens in Germany is unknown. Therefore, 537 cloacal swabs from 50 purebred fancy-chicken flocks in Saxony were tested for the presence of the ALV p27 protein using a commercial antigen-capture ELISA. The detection rate was 28.7% at the individual-animal level and 56.0% at the flock level. Phylogenetic analysis of PCR products obtained from 22 different flocks revealed the highest similarity to ALV subtype K. When classifying breeds by their origin, ALV detection rates differed significantly. Evaluation of questionnaire data revealed no significant differences between ALV-positive and negative flocks regarding mortality.
Topics: Animals; Avian Leukosis; Avian Leukosis Virus; Chickens; Germany; Phylogeny
PubMed: 35301570
DOI: 10.1007/s00705-022-05404-y