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Avian retrovirus

Shun Chen, Miao Zeng, Peng Liu, Chao Yang, Mingshu Wang, Renyong Jia, Dekang Zhu, Mafeng Liu, Qiao Yang, Ying Wu, Xinxin Zhao, Anchun Cheng
The Tembusu virus (TMUV) is an avian pathogenic flavivirus that causes a highly contagious disease and catastrophic losses to the poultry industry. The myxovirus resistance protein (Mx) of innate immune effectors is a key antiviral “workhorse” of the interferon (IFN) system. Although mammalian Mx resistance against myxovirus and retrovirus was witnessed for decades, whether or not bird Mx has anti-flavivirus activity remains unknown. In this study, we found that the transcription of goose Mx (goMx) was obviously driven by TMUV infection, both in vivo and in vitro, and that the titers and copies of TMUV were significantly reduced by goMx overexpression...
July 6, 2018: Viruses
Xiaoyu Xu, Huayao Zhao, Zhen Gong, Guan-Zhu Han
The deep history and early diversification of retroviruses remains elusive, largely because few retroviruses have been characterized in vertebrates other than mammals and birds. Endogenous retroviruses (ERVs) documented past retroviral infections and thus provide 'molecular fossils' for studying the deep history of retroviruses. Here we perform a comprehensive phylogenomic analysis of ERVs within the genomes of 92 non-avian/mammalian vertebrates, including 72 fishes, 4 amphibians, and 16 reptiles. We find that ERVs are present in all the genomes of jawed vertebrates, revealing the ubiquitous presence of ERVs in jawed vertebrates...
June 2018: PLoS Pathogens
Duane P Grandgenett, Hideki Aihara
Integration of the reverse-transcribed viral cDNA into the host's genome is a critical step in the lifecycle of all retroviruses. Retrovirus integration is carried out by integrase (IN), a virus-encoded enzyme that forms an oligomeric 'intasome' complex with both ends of the linear viral DNA to catalyze their concerted insertions into the backbones of the host's DNA. IN also forms a complex with host proteins, which guides the intasome to the host's chromosome. Recent structural studies have revealed remarkable diversity as well as conserved features among the architectures of the intasome assembly from different genera of retroviruses...
2018: Sub-cellular Biochemistry
Wencheng Lin, Zhouyi Xu, Yiming Yan, Huanmin Zhang, Hongxin Li, Weiguo Chen, Feng Chen, Qingmei Xie
Avian leukosis virus subgroup J (ALV-J) is an oncogenic retrovirus that causes immunosuppression and enhances susceptibility to secondary infection, resulting in great economic losses. Although ALV-J-induced immunosuppression has been well established, the underlying molecular mechanism for such induction is still unclear. Here, we report that the inhibitory effect of ALV-J infection on type I interferon expression is associated with the down-regulation of transcriptional regulator NF-κB in host cells. We found that ALV-J possess the inhibitory effect on type I interferon production in HD11 cells and that ALV-J causes the up-regulation of IκBα and down-regulation of NF-κB p65, and that ALV-J blocks the phosphorylation of IκBα on Ser32/36 amino acid residues...
2018: Frontiers in Microbiology
Xiaoman Wang, Yongzhen Zhao, Ling Li, Ziqiang Cheng, Guihua Wang
TRIM62 is a member of the tripartite interaction motif (TRIM) family and exerts crucial roles in innate immune response and cancer. To investigate the relationship between its distribution and avian retrovirus replication, in the present study, a monoclonal antibody (mAb) against chicken TRIM62 was generated. The open reading frame of chicken TRIM62 was amplified by polymerase chain reaction (PCR) and inserted into the expression vector pET-28a. The recombinant expression vectors were transformed into Escherichia coli BL21 (DE3)...
June 2018: Monoclonal Antibodies in Immunodiagnosis and Immunotherapy
Wei Meng, Defang Zhou, Chengui Li, Guihua Wang, Libo Huang, Ziqiang Cheng
Avian leukosis virus subgroup J (ALV-J), an oncogenic retrovirus, induces myelocytomas and other various tumors, leading to great economical losses in poultry industry. It is a great challenge to develop effective preventive methods for ALV-J control due to its antigenic variations in the variable regions of envelope. In present study, we generated a mouse polyclonal antibody targeting the first extracellular loop (ECL1) of chicken Na+ /H+ exchanger isoform 1 (chNHE1), the receptor of ALV-J, to block ALV-J infection in vitro and in vivo...
June 2018: Research in Veterinary Science
T Murakami, Y Sassa
Avian leucosis virus (ALV) is an oncogenic retrovirus that induces tumours including lymphoid leucosis and myeloid leucosis. Pleomorphic malignant mesothelioma and myelocytoma, which were thought to be induced by ALV subgroup J (ALV-J) infection, were identified in a 432-day-old broiler breeder. The bird showed no clinical signs; however, at necropsy examination there were multiple nodules in the alimentary tract. Microscopical analysis showed that these consisted of pleomorphic cells and myelocyte-like cells...
April 2018: Journal of Comparative Pathology
Chaoqi Ren, Mengmeng Yu, Yao Zhang, Minghui Fan, Fangfang Chang, Lixiao Xing, Yongzhen Liu, Yongqiang Wang, Xiaole Qi, Changjun Liu, Yanping Zhang, Hongyu Cui, Kai Li, Li Gao, Qing Pan, Xiaomei Wang, Yulong Gao
Avian leukosis virus subgroup J (ALV-J), a highly oncogenic retrovirus, causes leukemia-like proliferative diseases in chickens. microRNAs post-transcriptionally suppress targets and are involved in the development of various tumors. We previously showed that miR-221 is upregulated in ALV-J-induced tumors. In this study, we analyzed the possible function of miR-221 in ALV-J tumorigenesis. The target validation system showed that CDKN1B is a target of miR-221 and is downregulated in ALV-J infection. As CDKN1B arrests the cell cycle and regulates its progression, we analyzed the proliferation of ALV-J-infected DF-1 cells...
June 2018: Virology
Marike Visser, Heather Walz, Stephanie Shrader, Jey Koehler, Jamie Bellah
An adult bald eagle ( Haliaeetus leucocephalus) presented for nystagmus and an inability to fly. On physical examination, the eagle was open-mouth breathing and tachycardic at 200 beats per minute, had a wrinkled cere and sunken eyes, and was an estimated 10% dehydrated. Additionally, the eagle was extremely weak, with neurologic abnormalities including bilateral proprioceptive deficits, nystagmus, and no pupillary light reflex in the left eye. Despite aggressive treatment, the eagle continued to decline rapidly and subsequently died...
March 2018: Journal of Avian Medicine and Surgery
Gilles Darcis, Atze T Das, Ben Berkhout
Jan Svoboda studied aspects of viral latency, in particular with respect to disease induction by avian RNA tumor viruses, which were later renamed as part of the extended retrovirus family. The course of retroviral pathogenesis is intrinsically linked to their unique property of integrating the DNA copy of the retroviral genome into that of the host cell, thus forming the provirus. Retroviral latency has recently become of major clinical interest to allow a better understanding of why we can effectively block the human immunodeficiency virus type 1 (HIV-1) in infected individuals with antiviral drugs, yet never reach a cure...
March 29, 2018: Viruses
Dalibor Miklík, Filip Šenigl, Jiří Hejnar
Individual groups of retroviruses and retroviral vectors differ in their integration site preference and interaction with the host genome. Hence, immediately after infection genome-wide distribution of integrated proviruses is non-random. During long-term in vitro or persistent in vivo infection, the genomic position and chromatin environment of the provirus affects its transcriptional activity. Thus, a selection of long-term stably expressed proviruses and elimination of proviruses, which have been gradually silenced by epigenetic mechanisms, helps in the identification of genomic compartments permissive for proviral transcription...
March 8, 2018: Viruses
Gary Lam, Karen Beemon
Avian leukosis virus (ALV) is a simple retrovirus that can induce B-cell lymphoma in chicken(s) and other birds by insertional mutagenesis. The promoter region of telomerase reverse transcriptase (TERT) has been identified as an important integration site for tumorigenesis. Tumors with TERT promoter integrations are associated with increased TERT expression. The mechanism of this activation is still under investigation. We asked whether insertion of proviral DNA perturbs the epigenome of the integration site and, subsequently, impacts the regulation of neighboring genes...
February 10, 2018: Viruses
Wei Wang, Bingning Dong, Feng Yang
The RCAS (replication-competent avian sarcoma leukosis virus long-terminal repeat with splice acceptor)-TVA (tumor virus A) gene delivery system has been successfully used in modeling human cancers. Based on this, we have recently developed a novel RCI-Oncogene (RCAS-Cre-IRES-Oncogene) gene delivery system that can be used to efficiently manipulate gene expression in spontaneous tumors in vivo. We used this system for tumor gene knockout (TuKO) and demonstrated a crucial role of FGFR1 in driving mammary tumor metastasis...
January 16, 2018: Current Protocols in Molecular Biology
Katherine E Gadek, Hong Wang, Monica N Hall, Mitchell Sungello, Andrew Libby, Drew MacLaskey, Robert H Eckel, Bradley B Olwin
Excessive circulating triglycerides due to reduction or loss of lipoprotein lipase activity contribute to hypertriglyceridemia and increased risk for pancreatitis. The only gene therapy treatment for lipoprotein lipase deficiency decreases pancreatitis but minimally reduces hypertriglyceridemia. Synthesized in multiple tissues including striated muscle and adipose tissue, lipoprotein lipase is trafficked to blood vessel endothelial cells where it is anchored at the plasma membrane and hydrolyzes triglycerides into free fatty acids...
2018: PloS One
Filip Šenigl, Dalibor Miklík, Miroslav Auxt, Jirí Hejnar
Most retroviruses preferentially integrate into certain genomic locations and, as a result, their genome-wide integration patterns are non-random. We investigate the epigenetic landscape of integrated retroviral vectors and correlate it with the long-term stability of proviral transcription. Retroviral vectors derived from the avian sarcoma/leukosis virus expressing the GFP reporter were used to transduce the human myeloid lymphoblastoma cell line K562. Because of efficient silencing of avian retrovirus in mammalian cells, only ∼3% of established clones displayed stable proviral expression...
December 15, 2017: Nucleic Acids Research
Alexander Suh, Linnéa Smeds, Hans Ellegren
Transposable elements (TEs) are genomic parasites capable of inserting virtually anywhere in the host genome, with manifold consequences for gene expression, DNA methylation and genomic stability. Notably, they can contribute to phenotypic variation and hence be associated with, for example, local adaptation and speciation. However, some organisms such as birds have been widely noted for the low densities of TEs in their genomes and this has been attributed to a potential dearth in transposition during their evolution...
January 2018: Molecular Ecology
George Zhang, Yudan Chi, Yi-Chieh Nancy Du
Metastatic cancer accounts for 90% of deaths in patients with solid tumors. There is an urgent need to better understand the drivers of cancer metastasis and to identify novel therapeutic targets. To investigate molecular events that drive the progression from primary cancer to metastasis, we have developed a bitransgenic mouse model, RIP-Tag; RIP-tva. In this mouse model, the rat insulin promoter (RIP) drives the expression of the SV40 T antigen (Tag) and the receptor for subgroup A avian leukosis virus (tva) in pancreatic β cells...
October 16, 2017: Journal of Visualized Experiments: JoVE
Majken Lindholm Olesen, Lotte Leick Jørgensen, Merete Blixenkrone-Møller, Eva Sandberg, Peer Lyng Frandsen, Erik Østergaard, Eva Rauhe Bækdahl, Helena Fridholm, Anders Fomsgaard, Maiken Worsøe Rosenstierne
The absence of extraneous agents (EA) in the raw material used for production and in finished products is one of the principal safety elements related to all medicinal products of biological origin, such as live-attenuated vaccines. The aim of this study was to investigate the applicability of the Lawrence Livermore Microbial detection array version 2 (LLMDAv2) combined with whole genome amplification and sequencing for screening for viral EAs in live-attenuated vaccines and specific pathogen-free (SPF) eggs...
January 2018: Biologicals: Journal of the International Association of Biological Standardization
Sanandan Malhotra, Shelby Winans, Gary Lam, James Justice, Robin Morgan, Karen Beemon
Avian leukosis virus (ALV) is a simple retrovirus that causes a wide range of tumors in chickens, the most common of which are B-cell lymphomas. The viral genome integrates into the host genome and uses its strong promoter and enhancer sequences to alter the expression of nearby genes, frequently inducing tumors. In this study, we compare the preferences for ALV integration sites in cultured cells and in tumors, by analysis of over 87,000 unique integration sites. In tissue culture we observed integration was relatively random with slight preferences for genes, transcription start sites and CpG islands...
November 2017: PLoS Pathogens
Xiaolu Guan, Yao Zhang, Mengmeng Yu, Chaoqi Ren, Yanni Gao, Bingling Yun, Yongzhen Liu, Yongqiang Wang, Xiaole Qi, Changjun Liu, Hongyu Cui, Yanping Zhang, Li Gao, Kai Li, Qing Pan, Baoshan Zhang, Xiaomei Wang, Yulong Gao
Chicken Na+ /H+ exchanger type I (chNHE1), a multispan transmembrane protein, is a cellular receptor of the subgroup J avian leukosis virus (ALV-J). To identify the functional determinants of chNHE1 responsible for the ALV-J receptor activity, a series of chimeric receptors was created by exchanging the extracellular loops (ECL) of human NHE1 (huNHE1) and chNHE1 and by ECL replacement with a hemagglutinin (HA) tag. These chimeric receptors then were used in binding and entry assays to map the minimal ALV-J gp85-binding domain of chNHE1...
January 1, 2018: Journal of Virology
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