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Jaimes-Dueñez J, Goyeneche-Ortiz E, Tique-Oviedo M, Ortiz-Pineda MC, Cardenas-Pinto L, Jimenez-Leaño AP, Ruiz-Saenz J. Molecular frequency of bovine leukemia virus in Creole cattle of Eastern Colombia. Vet Anim Sci 2024; 25:100372. [PMID: 39022766 PMCID: PMC11253674 DOI: 10.1016/j.vas.2024.100372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024] Open
Abstract
Enzootic Bovine Leukosis (EBL), caused by the bovine leukosis virus (BLV), is a global infectious disease affecting livestock. This study focuses on studying the frequency and genetic traits of BLV in three Creole breeds including Chino Santandereano (Chino), Casanareño (CAS), and Sanmartinero (SM) in Eastern Colombia. We implemented a cross-sectional survey between 2019 and 2020 across four departments (Arauca, Casanare, Santander and Meta) in Eastern Colombia to assess the molecular characteristics of BLV infection in these breeds. A total of 253 cattle were analyzed, of which 42.6 %, 28.8 %, and 28.4 % belonged to the Chino, CAS, and SM breeds, respectively. BLV provirus was detected using nested polymerase chain reaction (n-PCR) targeting the conserved region of the env viral gene. Subsequently, the obtained amplicons were sequenced and subjected to phylogenetic analyses. The overall BLV infection frequency was 26.48 % (95 % CI: 21.01 - 31.98 %), with Chino exhibiting the highest frequency (35.1 %) following by SAM and CAS, respectively (P < 0.05). Other epidemiological variables associated with the infection included age, department, and season (P < 0.05). BLV-positive animals exhibited elevated levels of total serum proteins (P < 0.05), while molecular characterization revealed the exclusive circulation of BLV genotype 1 within these breeds. This study provides an updated assessment of BLV infection in Creole breeds from the eastern of Colombia, underscoring their lower infection frequency compared to introduced breeds and their reduced susceptibility to developing clinical signs. The epidemiological and molecular characteristics observed should be considered in developing control programs aimed at improving genetic resistance to BLV in Colombian cattle.
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Affiliation(s)
- Jeiczon Jaimes-Dueñez
- Grupo de Investigación en Ciencias Animales - GRICA, Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia UCC, Bucaramanga, Colombia
| | - Eyner Goyeneche-Ortiz
- Grupo de Investigación en Ciencias Animales - GRICA, Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia UCC, Bucaramanga, Colombia
| | - Marisol Tique-Oviedo
- Grupo de Investigación en Ciencias Animales - GRICA, Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia UCC, Bucaramanga, Colombia
| | - Melissa C Ortiz-Pineda
- Grupo de Investigación en Ciencias Animales - GRICA, Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia UCC, Bucaramanga, Colombia
| | - Luis Cardenas-Pinto
- Grupo de Investigación en Ciencias Animales - GRICA, Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia UCC, Bucaramanga, Colombia
| | - Angela Patricia Jimenez-Leaño
- Grupo de Investigación en Ciencias Animales - GRICA, Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia UCC, Bucaramanga, Colombia
| | - Julian Ruiz-Saenz
- Grupo de Investigación en Ciencias Animales - GRICA, Facultad de Medicina Veterinaria y Zootecnia, Universidad Cooperativa de Colombia UCC, Bucaramanga, Colombia
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Duran-Yelken S, Alkan F. Molecular analysis of the env, LTR, and pX regions of bovine leukemia virus in dairy cattle of Türkiye. Virus Genes 2024:10.1007/s11262-024-02058-7. [PMID: 38355991 DOI: 10.1007/s11262-024-02058-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/28/2024] [Indexed: 02/16/2024]
Abstract
Bovine leukemia virus is a retrovirus that causes enzootic bovine leukosis and is associated with global economic losses in the livestock industry. The aim of this study was to investigate the genotype determination of BLVs from cattle housed in 6 different farms in Türkiye and the characterization of their LTR and pX (tax, rex, R3, and G4 gene) regions. For this purpose, blood samples from 48 cattle infected with BLV were used. The phylogenetic analysis based on the env gene sequences revealed that all BLVs were clustered in genotype 1 (G1), and the sequences of the LTR (n = 48) and the pX region (n = 33) of BLVs were obtained. Also, analysis of these nucleic acid and amino acid sequences allowed assessments similar to those reported in earlier studies to be relevant to transactivation and pathogenesis. This study reports the molecular analysis of the LTR and pX region of BLVs in Türkiye for the first time.
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Affiliation(s)
- Selda Duran-Yelken
- Department of Virology, Faculty of Veterinary Medicine, Kastamonu University, Kastamonu, Turkey.
| | - Feray Alkan
- Department of Virology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
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Pluta A, Taxis TM, van der Meer F, Shrestha S, Qualley D, Coussens P, Rola-Łuszczak M, Ryło A, Sakhawat A, Mamanova S, Kuźmak J. An immunoinformatics study reveals a new BoLA-DR-restricted CD4+ T cell epitopes on the Gag protein of bovine leukemia virus. Sci Rep 2023; 13:22356. [PMID: 38102157 PMCID: PMC10724172 DOI: 10.1038/s41598-023-48899-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leucosis (EBL), which has been reported worldwide. The expression of viral structural proteins: surface glycoprotein (gp51) and three core proteins - p15 (matrix), p24 (capsid), and p12 (nucleocapsid) induce a strong humoral and cellular immune response at first step of infection. CD4+ T-cell activation is generally induced by bovine leukocyte antigen (BoLA) region- positive antigen-presenting cells (APC) after processing of an exogenous viral antigen. Limited data are available on the BLV epitopes from the core proteins recognized by CD4+ T-cells. Thus, immunoinformatic analysis of Gag sequences obtained from 125 BLV isolates from Poland, Canada, Pakistan, Kazakhstan, Moldova and United States was performed to identify the presence of BoLA-DRB3 restricted CD4+ T-cell epitopes. The 379 15-mer overlapping peptides spanning the entire Gag sequence were run in BoLA-DRB3 allele-binding regions using a BoLA-DRB- peptide binding affinity prediction algorithm. The analysis identified 22 CD4+ T-cell peptide epitopes of variable length ranging from 17 to 22 amino acids. The predicted epitopes interacted with 73 different BoLA-DRB3 alleles found in BLV-infected cattle. Importantly, two epitopes were found to be linked with high proviral load in PBMC. A majority of dominant and subdominant epitopes showed high conservation across different viral strains, and therefore could be attractive targets for vaccine development.
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Affiliation(s)
- Aneta Pluta
- Department of Biochemistry, National Veterinary Research Institute, 24-100, Puławy, Poland.
| | - Tasia Marie Taxis
- Department of Animal Science, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, 48824, USA
| | - Frank van der Meer
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Sulav Shrestha
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Dominic Qualley
- Department of Chemistry and Biochemistry, and Center for One Health Studies, Berry College, Mt. Berry, GA, 30149, USA
| | - Paul Coussens
- Department of Animal Science, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, 48824, USA
| | - Marzena Rola-Łuszczak
- Department of Biochemistry, National Veterinary Research Institute, 24-100, Puławy, Poland
| | - Anna Ryło
- Department of Biochemistry, National Veterinary Research Institute, 24-100, Puławy, Poland
| | - Ali Sakhawat
- Animal Quarantine Department, Ministry of National Food Security and Research, Peshawar, 25000, Pakistan
| | - Saltanat Mamanova
- Laboratory of Virology, Kazakh Scientific Research Veterinary Institute, LLP, 223 Raiymbek Avenue, 050000, Almaty, Republic of Kazakhstan
| | - Jacek Kuźmak
- Department of Biochemistry, National Veterinary Research Institute, 24-100, Puławy, Poland
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Borjigin L, Yoneyama S, Saito S, Polat M, Inokuma M, Shinozaki Y, Tanaka N, Yamanaka R, Yasui A, Mimura M, Murakami H, Takeshima SN, Aida Y. A novel real time PCR assay for bovine leukemia virus detection using mixed probes and degenerate primers targeting novel BLV strains. J Virol Methods 2021; 297:114264. [PMID: 34411645 DOI: 10.1016/j.jviromet.2021.114264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/12/2021] [Accepted: 08/12/2021] [Indexed: 01/10/2023]
Abstract
The bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, the most common neoplastic disease in cattle. We previously developed the quantitative real-time PCR (qPCR) assay to measure the proviral loads of BLV using coordination of common motif (CoCoMo) degenerate primers. We here found four single mutations within the probe region of the original BLV-CoCoMo-qPCR assay, three of which have negative impact on its sensitivity in the probe sequences of the long terminal regions of the BLV-CoCoMo-qPCR-2 assay, using genomic DNA from 887 cows from 27 BLV-positive farms via a nationwide survey conducted in 2011 and 2017 in Japan. Therefore, the modified probes were designed to completely match the three BLV mutant strains identified here. Moreover, we examined the optimum ratio of the concentration to be mixed with the wild type and three new BLV TaqMan probes were designed here using genomic DNAs extracted from cattle naturally infected with the wild type BLV strain and three mutant strains. Finally, we successfully established an improved assay maintained the original sensitivity and reproducibility and can detect novel BLV strains.
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Affiliation(s)
- Liushiqi Borjigin
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, 351-0198, Japan
| | - Shuji Yoneyama
- Central Livestock Hygiene Service Center of Tochigi Prefecture, Utsunomiya, Tochigi, 321-0905, Japan
| | - Susumu Saito
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, 351-0198, Japan
| | - Meripet Polat
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, 351-0198, Japan
| | - Michihito Inokuma
- Chuo Livestock Hygiene Service Center of Chiba Prefecture, Chiba, Chiba, 262-0011, Japan
| | - Yasuo Shinozaki
- Nanbu Livestock Hygiene Service Center of Chiba Prefecture, Kamogawa, Chiba, 296-0033, Japan
| | - Naoko Tanaka
- Nanbu Livestock Hygiene Service Center of Chiba Prefecture, Kamogawa, Chiba, 296-0033, Japan
| | - Risa Yamanaka
- Kumagaya Livestock Hygiene Service Center of Saitama Prefecture, Kumagaya, Saitama, 360-0813, Japan
| | - Anna Yasui
- Kumagaya Livestock Hygiene Service Center of Saitama Prefecture, Kumagaya, Saitama, 360-0813, Japan
| | - Munehito Mimura
- Kumagaya Livestock Hygiene Service Center of Saitama Prefecture, Kumagaya, Saitama, 360-0813, Japan
| | - Hironobu Murakami
- Laboratory of Animal Health Ⅱ, School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, 252-5201, Japan
| | - Shin-Nosuke Takeshima
- Department of Food and Nutrition, Jumonji University, Niiza, Saitama, 352-8510, Japan
| | - Yoko Aida
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, 351-0198, Japan; Laboratory of Global Infectious Diseases Control Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.
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Qian M, Wang W, Zhang Y, Zhao Y, Quan H, Chen Y, Dai X, Guo Z. Identification and characteristic analysis of enhancers across 13 major cancer types. PRECISION CLINICAL MEDICINE 2021; 4:204-208. [PMID: 35693214 PMCID: PMC8982554 DOI: 10.1093/pcmedi/pbab019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/29/2021] [Accepted: 07/29/2021] [Indexed: 11/20/2022] Open
Abstract
Enhancers are often mutated and dysregulated in various diseases such as cancer. By integrating the function annotation of the mammalian genome (FANTOM) enhancers expression profiles and RNA-seq data from The Cancer Genome Atlas (TCGA) of 13 cancers and their corresponding para-cancerous tissues, we systematically identified a total of 4702 significantly differentially expressed (DE) enhancers. Furthermore, a total of 1036 DE genes regulated by DE enhancers were identified. It was found that in these 13 cancers, most (61.13%) enhancers were ubiquitously expressed, whereas DE enhancers were more likely to be tissue-specific expressed, and the DE genes regulated by DE enhancers were significantly enriched in cancer-related pathways. Finally, it was manifested that 74 single nucleotide polymorphisms (SNPs) were located in 37 DE enhancers, and these SNPs affected the gain and loss of functional transcription factor binding sites of 758 transcription factors, which were shown to be highly correlated with tumorigenesis and development.
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Affiliation(s)
- Mingming Qian
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Wenzhu Wang
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Yana Zhang
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Yi Zhao
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Huige Quan
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Yuting Chen
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Xinyue Dai
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Zhiyun Guo
- School of Life Sciences and Engineering, Southwest Jiaotong University, Chengdu 610031, China
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Blazhko N, Shatokhin K, Khripko Y, Ngirande C, Kochnev N. Mutational and phylogenetic status of west siberian strains of BLV. BIO WEB OF CONFERENCES 2021. [DOI: 10.1051/bioconf/20213606025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The study is devoted of full-genome BLV sequences circulating in cattle populations of the Novosibirsk region, Russia. The phylogenetic tree shows that the West Siberian isolates are quite closely related to such previously isolated strains as AF399704 (Brazil), AP018007, AP018016, AP018019, LC007988, LC007991 (Japan) and EF065638 (Belgium) we calculations show that the number of mutations that could independently occur in parallel evolving BLV strains significantly exceeds the expected number based on the probability of corresponding substitutions. It was also found that the studied isolates have some mutations, the presence of which, at first glance, is possible only with their divergent development in different independently evolving branches. However, calculations show that the probability of an independent origin of an identical mutation is extremely small, which indicates the possibility of exchanging RNA sites between isolates circulating in West Siberian cattle populations.
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Pluta A, Willems L, Douville RN, Kuźmak J. Effects of Naturally Occurring Mutations in Bovine Leukemia Virus 5'-LTR and Tax Gene on Viral Transcriptional Activity. Pathogens 2020; 9:pathogens9100836. [PMID: 33066207 PMCID: PMC7656303 DOI: 10.3390/pathogens9100836] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/05/2020] [Accepted: 10/09/2020] [Indexed: 01/28/2023] Open
Abstract
Bovine leukemia virus (BLV) is a deltaretrovirus infecting bovine B cells and causing enzootic bovine leucosis (EBL). The long terminal repeat (LTR) plays an indispensable role in viral gene expression. The BLV Tax protein acts as the main transactivator of LTR-driven transcription of BLV viral genes. The aim of this study was to analyze mutations in the BLV LTR region and tax gene to determine their association with transcriptional activity. LTRs were obtained from one hundred and six BLV isolates and analyzed for their genetic variability. Fifteen variants were selected and characterized based on mutations in LTR regulatory elements, and further used for in vitro transcription assays. Reporter vectors containing the luciferase gene under the control of each variant BLV promoter sequence, in addition to variant Tax expression vectors, were constructed. Both types of plasmids were used for cotransfection of HeLa cells and the level of luciferase activity was measured as a proxy of transcriptional activity. Marked differences in LTR promoter activity and Tax transactivation activity were observed amongst BLV variants. These results demonstrate that mutations in both the BLV LTR and tax gene can affect the promoter activity, which may have important consequences on proviral load, viral fitness, and transmissibility in BLV-infected cattle.
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Affiliation(s)
- Aneta Pluta
- Department of Biochemistry, National Veterinary Research Institute, 24-100 Puławy, Poland;
- Correspondence:
| | - Luc Willems
- Molecular and Cellular Epigenetics (Interdisciplinary Cluster for Applied Genoproteomics, GIGA) and Molecular Biology (TERRA), University of Liège (ULiège), 4000 Liege, Belgium;
| | - Renée N. Douville
- Department of Biology, The University of Winnipeg, Winnipeg, MB R3B 2E9, Canada;
- Department of Immunology, University of Manitoba, Winnipeg, MB R3E 0T5, Canada
| | - Jacek Kuźmak
- Department of Biochemistry, National Veterinary Research Institute, 24-100 Puławy, Poland;
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Regulation of Expression and Latency in BLV and HTLV. Viruses 2020; 12:v12101079. [PMID: 32992917 PMCID: PMC7601775 DOI: 10.3390/v12101079] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 12/14/2022] Open
Abstract
Human T-lymphotrophic virus type 1 (HTLV-1) and Bovine leukemia virus (BLV) belong to the Deltaretrovirus genus. HTLV-1 is the etiologic agent of the highly aggressive and currently incurable cancer adult T-cell leukemia (ATL) and a neurological disease HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). BLV causes neoplastic proliferation of B cells in cattle: enzootic bovine leucosis (EBL). Despite the severity of these conditions, infection by HTLV-1 and BLV appear in most cases clinically asymptomatic. These viruses can undergo latency in their hosts. The silencing of proviral gene expression and maintenance of latency are central for the establishment of persistent infection, as well as for pathogenesis in vivo. In this review, we will present the mechanisms that control proviral activation and retroviral latency in deltaretroviruses, in comparison with other exogenous retroviruses. The 5′ long terminal repeats (5′-LTRs) play a main role in controlling viral gene expression. While the regulation of transcription initiation is a major mechanism of silencing, we discuss topics that include (i) the epigenetic control of the provirus, (ii) the cis-elements present in the LTR, (iii) enhancers with cell-type specific regulatory functions, (iv) the role of virally-encoded transactivator proteins, (v) the role of repressors in transcription and silencing, (vi) the effect of hormonal signaling, (vii) implications of LTR variability on transcription and latency, and (viii) the regulatory role of non-coding RNAs. Finally, we discuss how a better understanding of these mechanisms may allow for the development of more effective treatments against Deltaretroviruses.
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Murakami H, Todaka H, Uchiyama J, Sato R, Sogawa K, Sakaguchi M, Tsukamoto K. A point mutation to the long terminal repeat of bovine leukemia virus related to viral productivity and transmissibility. Virology 2019; 537:45-52. [PMID: 31445323 DOI: 10.1016/j.virol.2019.08.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/21/2022]
Abstract
It is important to establish the molecular basis of the high transmissibility of bovine leukemia virus (BLV) to develop new methods of preventing viral transmission. Hence, the aim of this study was to determine whether some strains had transmission advantages. First, we determined the whole BLV genome sequences of all 34 BLV-infected cows from one farm. Phylogenetic analysis divided strains into 26 major and 8 minor strains. The major strains dominantly spread independent of host factor, bovine leucocyte antigen. Further analysis, with molecular clones, associated transmissibility with viral productivity in vitro. In addition, the two groups could be classified by group-specific mutations. The reverse genetic approach demonstrated that a spontaneous mutation at nucleotide 175 of the BLV genome, which is located in the viral promoter region, could alter viral productivity by changing viral transactivation, suggesting that BLV transmissibility is affected by a spontaneous mutation associated with viral productivity.
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Affiliation(s)
- Hironobu Murakami
- Laboratory of Animal Health Ⅱ, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan.
| | - Haruna Todaka
- Laboratory of Animal Health Ⅱ, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
| | - Jumpei Uchiyama
- Laboratory of Veterinary Microbiology Ⅰ, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
| | - Reiichiro Sato
- Laboratory of Clinical Veterinary Medicine for Large Animal, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
| | - Kazuyuki Sogawa
- Laboratory of Biochemistry, School of Life and Environmental Science, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
| | - Masahiro Sakaguchi
- Laboratory of Veterinary Microbiology Ⅰ, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
| | - Kenji Tsukamoto
- Laboratory of Animal Health Ⅱ, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa, 252-5201, Japan
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Transcriptional activation of long terminal repeat of bovine leukemia virus by bovine heat shock factor 1. Virus Res 2019; 269:197641. [PMID: 31228509 DOI: 10.1016/j.virusres.2019.197641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/17/2019] [Accepted: 06/18/2019] [Indexed: 11/21/2022]
Abstract
Bovine leukemia virus (BLV) causes enzootic bovine leukosis (EBL). The BLV genome encodes Tax protein, a transcriptional activator of viral gene expression that binds to the BLV long terminal repeat (LTR). Heat shock factor 1 (HSF1) is a known regulator of the heat shock response proteins, including heat shock proteins. In the present study, the BLV LTR was investigated for interaction of heat shock element (HSE) with HSF1 and the viral Tax protein. It could be confirmed that a functional HSE is well conserved in different BLV strains. The LTR transcriptional activity, as measured by luciferase reporter assay, was upregulated by bovine HSF1 - without Tax expression - in feline CC81 cells. The HSF1 activated LTR transcription by binding to the HSE. LTR-activation was lost upon HSE removal from the LTR and upon expression of a mutant HSF1 lacking the DNA-binding domain. We conclude that BLV LTR is activated to a basal level by host transcriptional factor HSF1, but without Tax protein involvement.
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