title: Comparative sequence analysis of open reading frames 2 to 7 of the modified live vaccine virus and other North American isolates of the porcine reproductive and respiratory syndrome virus.
abstract: To elucidate changes associated with the attenuated virulence in a modified live porcine reproductive and respiratory syndrome (PRRS) vaccine (Boehringer Ingelheim Animal Health, St. Joseph, MO), derived from an American prototype ATCC virus VR-2332, nucleotide sequence of 3' genome covering open reading frames (ORFs) 2 to 7 coding regions from the vaccine virus was determined by RT-PCR with two overlapping fragments. Comparisons showed 98 base changes (94 substitutions, 3 deletions, and 1 addition) out of 3318 nucleotides between the vaccine virus and its parental virus. There were 15, 26, 17, 29, 9, and 6 base substitutions in ORFs 2, 3, 4, 5, 6, and 7, respectively, resulting in 5, 13, 8, 13, 2, and 3 amino acid (a.a.) substitutions in their deduced proteins, respectively. Most of these a.a. substitutions were also present in 17 known virulent/wild type PRRS virus isolates from North America. However, there were 1, 4, 1, and 1 unique a.a. substitutions in the vaccine virus ORFs 2, 3, 4, and 5 deduced proteins, respectively. These unique amino substitutions may be responsible for the attenuated virulence in the vaccine virus.
authors.affiliation: USDA, ARS, U.S. Meat Animal Research Center, Clay Center, Nebraska 68933, USA.
authors.forename: S X
authors.initials: SX
authors.lastname: Yang
authors.forename: J
authors.initials: J
authors.lastname: Kwang
authors.forename: W
authors.initials: W
authors.lastname: Laegreid
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004279:DNA, Viral; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009656:North America; D016366:Open Reading Frames; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics* / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D014613:Vaccines, Attenuated; D014765:Viral Vaccines / Q000235:genetics*
chemical_list: D004279:DNA, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines