title: Sequence analysis of open reading frames (ORFs) 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus.
abstract: The sequence of ORFs 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus (PRRSV), ATCC VR2385, was determined by analysis of a cDNA lambda library. The cDNA clones containing PRRSV specific sequences were selected using a VR2385 ORF 4 specific PCR probe and sequenced. The ORFs 2, 3 and 4 overlapped each other and encoded polypeptides with predicted M(r) of 29.5 kDa (ORF 2), 28.7 kDa (ORF 3) and 19.5 kDa (ORF 4), respectively. No overlap was found between ORFs 4 and 5, and instead there was a 10 bp sequence which separated these two ORFs. The nucleic acid homology with corresponding ORFs of the European PRRSV isolate Lelystad virus (LV) was 65% for ORF 2, 64% for ORF 3 and 66% for ORF 4. Comparison of the ORF 4 sequences of VR2385 with that of another U.S. isolate MN-1b revealed only 86% amino acid sequence homology and the presence of deletions in the ORF 4 of MN-1b. Our results further strengthen the observation that there is sequence variation between US and European PRRSV isolates.
authors.affiliation: Veterinary Medical Research Institute, College of Veterinary Medicine, Iowa State University, Ames, USA.
authors.forename: I
authors.initials: I
authors.lastname: Morozov
authors.forename: X J
authors.initials: XJ
authors.lastname: Meng
authors.forename: P S
authors.initials: PS
authors.lastname: Paul
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018018:Arterivirus / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013552:Swine / Q000821:virology*; D014481:United States
chemical_list: D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral