1. |
- Bálint, Adám, et al.
(author)
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Characterisation of the nucleic acid binding features of the PRRSV 7ap and its ability to induce antinuclear antibodies
- 2017
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In: Acta Veterinaria Hungarica. - : Akademiai Kiado Zrt.. - 0236-6290 .- 1588-2705. ; 65, s. 124-134
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Journal article (peer-reviewed)abstract
- A short alternative open reading frame named ORF7a has recently been discovered within the nucleocapsid gene of the porcine reproductive and respiratory syndrome virus (PRRSV) genome. Proteins (7ap) translated from the ORF7a of two divergent strains - a type I and a type II - are able to completely reduce the motility of nucleic acids at relatively high molar charge ratios in gel retardation assays indicating strong dsDNA-and ssRNA-binding capability. Conserved RNA-and DNA-binding properties suggest that nucleic acid binding is a functional property of the divergent 7aps, and not an arbitrary consequence of their net positive charge. Sera from Hu7ap-immunised pigs and mice did not react with Hu7ap or Hu7ap-GFP; however, antinuclear antibodies were detected in the sera of the immunised animals, suggesting an ability of Hu7ap to interact with or mimic autoantigenic macromolecules.
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2. |
- Bálint, Adám, et al.
(author)
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IMMUNOLOGICAL AND BIOCHEMICAL CHARACTERISATION OF 7ap, A SHORT PROTEIN TRANSLATED FROM AN ALTERNATIVE FRAME OF ORF7 OF PRRSV
- 2016
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In: Acta Veterinaria Hungarica. - : Akademiai Kiado Zrt.. - 0236-6290 .- 1588-2705. ; 64, s. 273-287
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Journal article (peer-reviewed)abstract
- Sequence analysis revealed a short alternative open reading frame (ORF) named ORF7a within the nucleocapsid gene of genetically divergent porcine reproductive and respiratory syndrome virus (PRRSV) genomes. Alignment of the corresponding protein sequences (named 7ap) revealed substantial heterogeneity among 7aps of different genotypes, though all of them are predicted to be positively charged. Green fluorescent protein and FLAG fusion constructs of ORF7a of the HU-14432/2011 PRRSV demonstrated that 7ap is expressed. 7ap of HU-14432/2011 (Hu7ap) was synthesised chemically, and ELISA experiments revealed that Hu7ap binds strongly to mammalian IgGs. Protein-protein gel retardation assays and complement fixation inhibition suggest that 7aps bind to the CH2 domain of the IgG(Fc) fragment. Cellular localisation and immunological characteristics of PRRSV 7ap may indicate multiple functions including nuclear and cytoplasmic over-tuning of normal cellular processes and immunosuppression.
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3. |
- Bálint, Adám, et al.
(author)
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Molecular Characterization of Feline Infectious Peritonitis Virus Strain DF-2 and Studies of the Role of ORF3abc in Viral Cell Tropism
- 2012
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In: Journal of Virology. - 0022-538X .- 1098-5514. ; 86, s. 6258-6267
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Journal article (peer-reviewed)abstract
- The full-length genome of the highly lethal feline infectious peritonitis virus (FIPV) strain DF-2 was sequenced and cloned into a bacterial artificial chromosome (BAC) to study the role of ORF3abc in the FIPV-feline enteric coronavirus (FECV) transition. The reverse genetic system allowed the replacement of the truncated ORF3abc of the original FIPV DF-2 genome with the intact ORF3abc of the canine coronavirus (CCoV) reference strain Elmo/02. The in vitro replication kinetics of these two viruses was studied in CrFK and FCWF-4 cell lines, as well as in feline peripheral blood monocytes. Both viruses showed similar replication kinetics in established cell lines. However, the strain with a full-length ORF3 showed markedly lower replication of more than 2 log(10) titers in feline peripheral blood monocytes. Our results suggest that the truncated ORF3abc plays an important role in the efficient macrophage/monocyte tropism of type II FIPV.
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4. |
- Belak, Sandor, et al.
(author)
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Cellular localisation of the proteins of region 3 of feline enteric coronavirus
- 2018
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In: Acta Veterinaria Hungarica. - : Akademiai Kiado Zrt.. - 0236-6290 .- 1588-2705. ; 66, s. 493-508
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Journal article (peer-reviewed)abstract
- Feline enteric coronaviruses have three open reading frames (ORFs) in region 3 (3a, 3b, and 3c). All three ORFs were expressed with C-terminal eGFP and 3xFLAG tags in different cell lines and their localisation was determined. ORF 3a is predicted to contain DNA-binding and transcription activator domains, and it is localised in the nucleus and in the cytoplasm. ORF 3b is also predicted to contain DNA-binding and activator domains, and was found to localise in the mitochondrion. Besides that, in some of the non-infected and FIPV-infected cells nucleolar, perinuclear or nuclear membrane accumulation of the eGFP-tagged 3b was observed. The exact compartmental localisation of ORF 3c is yet to be determined. However, based on our co-localisation studies 3c does not seem to be localised in the ER-Golgi network, ERGIC or peroxisomes. The expression of 3c-eGFP is clearly cell type dependent, it is more stable in MARC 145 cells than in Fcwf-4 or CrFK cells, which might reflect in vivo stability differences of 3c in natural target cells (enterocytes vs. monocytes/macrophages).
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