Long terminal repeat sequences from virulent and attenuated equine infectious anemia virus demonstrate distinct promoter activities.
Abstract: In the early 1970s, the Chinese Equine Infectious Anemia Virus (EIAV) vaccine, EIAV(DLA), was developed through successive passages of a wild-type virulent virus (EIAV(L)) in donkeys in vivo and then in donkey macrophages in vitro. EIAV attenuation and cell tropism adaptation are associated with changes in both envelope and long terminal repeat (LTR). However, specific LTR changes during Chinese EIAV attenuation have not been demonstrated. In this study, we compared LTR sequences from both virulent and attenuated EIAV strains and documented the diversities of LTR sequence from in vivo and in vitro infections. We found that EIAV LTRs of virulent strains were homologous, while EIAV vaccine have variable LTRs. Interestingly, experimental inoculation of EIAV(DLA) into a horse resulted in a restriction of the LTR variation. Furthermore, LTRs from EIAV(DLA) showed higher Tat transactivated activity than LTRs from virulent strains. By using chimeric clones of wild-type LTR and vaccine LTR, the main difference of activity was mapped to the changes of R region, rather than U3 region.
Publication Date: 2007-05-11 PubMed ID: 17499380DOI: 10.1016/j.virusres.2007.04.005Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research investigates the differences in long terminal repeat (LTR) sequences between virulent and attenuated strains of the Equine Infectious Anemia Virus (EIAV), finding that the LTRs of vaccinated strains show greater activity than those of virulent strains, with key differences found in the R region.
Background
- The research uses the Chinese EIAV vaccine, EIAV(DLA), as a basis for investigation. This vaccine was developed in the early 1970s through repeated passages of a virulent virus in donkeys and then in their macrophages in a lab setting.
- EIAV’s ability to weaken and adapt to different cell interactions is connected to changes in both its envelope and LTR. However, no information has been provided on explicit LTR changes during EIAV attenuation in the Chinese strain.
Research Method and Findings
- The authors compared LTR sequences from both virulent and attenuated EIAV strains. They also detailed the variety in sequence from infections happening in vivo and in vitro.
- The research discovered that virulent strains had homologous LTR sequences, while vaccinated strains had variable LTRs. Additionally, when the EIAV(DLA) vaccine was introduced into a horse, the variation of LTRs got restricted.
- Most strikingly, the LTRs from the EIAV(DLA) vaccine demonstrated more transactivated activity than those from the virulent strains.
- The primary distinction in activity was traced to changes in the R region, not the typically examined U3 region, using chimeric clones of wild-type LTR and vaccine LTR. This indicates specific areas of investigation for future study.
Significance
- The results of the study expand understanding on how EIAV attenuates and might adapt to different cells, with the LTRs playing a key role.
- It suggests changes in the LTR – especially the R region – could influence how effective a vaccine strain might be, due to the high transactivated activity in the LTRs of the vaccine strain EIAV(DLA).
- It also suggests potential specific areas for future investigation into the workings of EIAV and potentially other viruses.
Cite This Article
APA
Zhou T, Yuan XF, Hou SH, Tu YB, Peng JM, Wen JX, Qiu HJ, Wu DL, Chen HC, Wang XJ, Tong GZ.
(2007).
Long terminal repeat sequences from virulent and attenuated equine infectious anemia virus demonstrate distinct promoter activities.
Virus Res, 128(1-2), 58-64.
https://doi.org/10.1016/j.virusres.2007.04.005 Publication
Researcher Affiliations
- Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, PR China.
MeSH Terms
- Animals
- Base Sequence
- Cells, Cultured
- Equidae
- Equine Infectious Anemia / physiopathology
- Equine Infectious Anemia / virology
- Gene Expression Regulation, Viral
- Genes, tat
- Genetic Variation
- Horse Diseases / physiopathology
- Horse Diseases / virology
- Horses / virology
- Infectious Anemia Virus, Equine / genetics
- Infectious Anemia Virus, Equine / metabolism
- Infectious Anemia Virus, Equine / pathogenicity
- Macrophages / virology
- Molecular Sequence Data
- Monocytes / virology
- Phylogeny
- Promoter Regions, Genetic
- Sequence Analysis, DNA
- Terminal Repeat Sequences / genetics
- Terminal Repeat Sequences / physiology
- Transcriptional Activation
- Viral Vaccines
Citations
This article has been cited 4 times.- Wang HN, Rao D, Fu XQ, Hu MM, Dong JG. Equine infectious anemia virus in China. Oncotarget 2018 Jan 2;9(1):1356-1364.
- Wang XF, Liu Q, Wang YH, Wang S, Chen J, Lin YZ, Ma J, Zhou JH, Wang X. Characterization of Equine Infectious Anemia Virus Long Terminal Repeat Quasispecies In Vitro and In Vivo. J Virol 2018 Apr 15;92(8).
- Qi X, Wang X, Wang S, Lin Y, Jiang C, Ma J, Zhao L, Lv X, Shen R, Wang F, Kong X, Su Z, Zhou J. Genomic analysis of an effective lentiviral vaccine-attenuated equine infectious anemia virus vaccine EIAV FDDV13. Virus Genes 2010 Aug;41(1):86-98.
- Wei L, Fan X, Lu X, Zhao L, Xiang W, Zhang X, Xue F, Shao Y, Shen R, Wang X. Genetic variation in the long terminal repeat associated with the transition of Chinese equine infectious anemia virus from virulence to avirulence. Virus Genes 2009 Apr;38(2):285-8.
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