title: Immunological and biochemical characterisation of 7ap, a short protein translated from an alternative frame of ORF7 of PRRSV.
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.
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences , Budapest , Hungary.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Olasz
authors.affiliation: Veterinary Diagnostic Directorate, National Food Chain Safety Office , Budapest , Hungary.
authors.forename: Béla
authors.initials: B
authors.lastname: Dénes
authors.affiliation: Veterinary Diagnostic Directorate, National Food Chain Safety Office , Budapest , Hungary.
authors.forename: Ádám
authors.initials: Á
authors.lastname: Bálint
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences , Budapest , Hungary.
authors.forename: Tibor
authors.initials: T
authors.lastname: Magyar
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health (BVF), Swedish University of Agricultural Sciences (SLU) , Uppsala , Sweden.
authors.forename: Sándor
authors.initials: S
authors.lastname: Belák
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences , Budapest , Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Zádori
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000915:Antibody Affinity; D000918:Antibody Specificity; D002478:Cells, Cultured; D003168:Complement Fixation Tests; D004912:Erythrocytes / Q000378:metabolism; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008322:Mammals; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D007074:Immunoglobulin G; D014764:Viral Proteins
keywords: IgG binding; PRRSV; complement fixation inhibition; overlapping ORF; positive charged short peptide