Identification of bovine viral diarrhea virus nonstructural polypeptide NS4B/P38.
The bovine pestivirus polyprotein is processed into at least 11 mature polypeptides. Previous studies with polyprotein region-specific antiserum raised against beta-galactosidase fusion proteins or synthetic peptides allowed the assignment of viral non-structural proteins to specific segments of the BVDV genome. However, the gene product from the NS4B/P38 region of the viral genome remained to be demonstrated directly. BVDV cDNA fragments predicted to encode part of NS4B/P38 (from codon 2521 to 2838 of the BVDV open reading frame) and a portion of NS5A/P58 (from codon 3008 to 3340) were expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli. Polyclonal rabbit antibodies prepared against each of the purified fusion proteins, GST-2521-2838 and GST-3008-3340, were used to immunoprecipitate viral polypeptides present in BVDV-infected cell lysates. Rabbit antiserum to GST-2521-2838 bound a polypeptide of 38 kDa identified as the mature NS4B/P38 polypeptide; while anti GST-3008-3340 lacked this specificity and bound NS5A/P58. Moreover, both antisera recognized a 96 kDa polypeptide, previously identified as a NS4B-NS5A/PP96 precursor. The function of the newly identified and highly conserved NS4B/P38 protein in viral replication remains to be determined.
van Olphen
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Department of Veterinary and Biomedical Sciences, IANR, University of Nebraska-Lincoln 68583-0905, USA.
Donis
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D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D000918:Antibody Specificity; D000956:Antigens, Viral / Q000276:immunology*; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology*; D010455:Peptides / Q000276:immunology*; D011817:Rabbits; D017361:Viral Nonstructural Proteins / Q000276:immunology*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D010455:Peptides; D017361:Viral Nonstructural Proteins