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Portugal RS, Bauer A, Keil GM. Selection of differently temporally regulated African swine fever virus promoters with variable expression activities and their application for transient and recombinant virus mediated gene expression. Virology 2017; 508:70-80. [PMID: 28502836 DOI: 10.1016/j.virol.2017.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 01/09/2023]
Abstract
African swine fever virus threatens pig production worldwide due to the lack of vaccines, for which generation of both deletion and insertion mutants is considered. For development of the latter, operational ASFV promoters of different temporal regulation and strengths are desirable. We therefore compared the capacities of putative promoter sequences from p72, CD2v, p30, viral DNA polymerase and U104L genes to mediate expression of luciferase from transfected plasmids after activation in trans, or p30-, DNA polymerase- and U104L promoters in cis, using respective ASFV recombinants. We identified sequences with promoter activities upstream the viral ORFs, and showed that they differ in both their expression intensity regulating properties and in their temporal regulation. In summary, p30 and DNA polymerase promoters are recommended for high level early regulated transgene expression. For late expression, the p72, CD2v and U104L promoter are suitable. The latter however, only if low level transgene expression is aimed.
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Affiliation(s)
- Raquel S Portugal
- Institut für molekulare Virologie und Zellbiologie, Friedrich-Loeffler-Institut, Südufer 10, Greifswald, Insel Riems 17493, Germany.
| | - Anja Bauer
- Institut für molekulare Virologie und Zellbiologie, Friedrich-Loeffler-Institut, Südufer 10, Greifswald, Insel Riems 17493, Germany
| | - Guenther M Keil
- Institut für molekulare Virologie und Zellbiologie, Friedrich-Loeffler-Institut, Südufer 10, Greifswald, Insel Riems 17493, Germany
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Basto AP, Nix RJ, Boinas F, Mendes S, Silva MJ, Cartaxeiro C, Portugal RS, Leitão A, Dixon LK, Martins C. Kinetics of African swine fever virus infection in Ornithodoros erraticus ticks. J Gen Virol 2006; 87:1863-1871. [PMID: 16760388 DOI: 10.1099/vir.0.81765-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The kinetics of African swine fever virus (ASFV) infection in Ornithodoros erraticus ticks were investigated in specimens collected in the field at different times following an outbreak of the disease in Portugal in 1999 and in ticks infected experimentally with a virus isolated from a tick collected during this outbreak. In ticks collected from the field, initial screening for ASFV was carried out by PCR, followed by attempts to isolate the virus in macrophage cultures. Considering total numbers of ticks tested independently of developmental stages, ASFV DNA was detected in 42.3, 26.4 and 22.4% of specimens collected at weeks 0, 32 and 63 following the outbreak, respectively. Although virus was not isolated from most of these ticks, the proportion of isolations from large nymphs and adults increased between weeks 0 and 32 from 2 to 9 % and from 5 to 11.5%, respectively. These results, together with the higher virus titres at week 32, suggest that virus replication occurred. In contrast, virus isolations from small nymphs decreased over this period, from 5 to 1.3%. At week 63, infection rates decreased for all stages. Experimental infections showed the occurrence of virus replication within 4 weeks post-feeding and maintenance of high titres in almost 100% of ticks until 20 weeks post-infection. At weeks 41 and 61, a drop in virus titres and infection rates was observed. Relevant to the understanding of African swine fever epidemiology, our results show that ASFV replicates and persists in O. erraticus, but a viral clearance occurs at later times in both natural and experimental infections.
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Affiliation(s)
- Afonso P Basto
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Rebecca J Nix
- Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | - Fernando Boinas
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Susana Mendes
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Maria J Silva
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Clara Cartaxeiro
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Raquel S Portugal
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Alexandre Leitão
- Instituto de Investigação Científica Tropical, CVZ, CIISA, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Linda K Dixon
- Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | - Carlos Martins
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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Basto AP, Portugal RS, Nix RJ, Cartaxeiro C, Boinas F, Dixon LK, Leitão A, Martins C. Development of a nested PCR and its internal control for the detection of African swine fever virus (ASFV) in Ornithodoros erraticus. Arch Virol 2005; 151:819-26. [PMID: 16328146 DOI: 10.1007/s00705-005-0654-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 08/31/2005] [Indexed: 10/25/2022]
Abstract
A nested PCR assay, with an internal control, was developed to detect African swine fever virus (ASFV) DNA in Ornithodoros erraticus. The assay revealed a better analytical sensitivity than virus isolation and the OIE PCR protocol. All ticks collected from the field, which were positive by virus isolation, were also positive by PCR. Viral DNA was detected in a further 19 out of 60 ticks from which no virus was isolated. Our results show that this assay is reliable and can easily be used to screen large tick populations collected in the field for the presence of ASFV.
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Affiliation(s)
- A P Basto
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Lisboa, Portugal
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