PMID- 21763365
OWN - NLM
STAT- MEDLINE
DCOM- 20111216
LR  - 20110829
IS  - 1872-7492 (Electronic)
IS  - 0168-1702 (Linking)
VI  - 160
IP  - 1-2
DP  - 2011 Sep
TI  - Establishment of a DNA-launched infectious clone for a highly pneumovirulent 
      strain of type 2 porcine reproductive and respiratory syndrome virus: 
      identification and in vitro and in vivo characterization of a large spontaneous 
      deletion in the nsp2 region.
PG  - 264-73
LID - 10.1016/j.virusres.2011.06.027 [doi]
AB  - A highly pneumovirulent strain of porcine reproductive and respiratory syndrome 
      virus (PRRSV), ATCC VR2385, was isolated from a pig exhibiting typical PRRS in 
      the early 90s. While passaging the virus in monkey kidney cells, we identified a 
      large spontaneous deletion of a 435-bp in the nsp2 gene. To assess the biological 
      significance of this spontaneous deletion, we first determined the full-length 
      genomic sequence of this virus and established a DNA-launched infectious clone of 
      the passage 14 virus containing the 435-bp nsp2 deletion (designated as 
      pIR-VR2385-CA). The full-length viral genome engineered with two ribozyme 
      elements at both ends was placed under the control of the eukaryotic CMV 
      promoter. The infectious virus was successfully rescued from pIR-VR2385-CA 
      DNA-transfected BHK-21 cells. To characterize the biological and pathological 
      significance of this large nsp2 deletion, we subsequently constructed another 
      DNA-launched infectious clone, pIR-VR2385-R, in which we restored the deleted 
      435-bp nsp2 sequence back to the pIR-VR2385-CA backbone. The growth 
      characteristics of the two rescued viruses (VR2385-CA and VR2385-R) were 
      compared, and the results showed that the VR2385-CA virus with the nsp2 deletion 
      replicated more efficiently in vitro (1.0-1.5 log titer higher) than the VR2385-R 
      virus with the restored nsp2 sequence but the VR2385-CA virus exhibited a 
      significantly reduced serum viral RNA load in vivo. A comparative pathogenicity 
      study in pigs (n=10) revealed that the nsp2 deletion had no effect on virus 
      virulence, and the restored nsp2 sequence in the VR2385-R virus remains stable 
      during virus replication in pigs. The results from this study indicates that the 
      spontaneous nsp2 deletion plays a role for enhanced PRRSV replication in vitro 
      but has no effect on the pathogenicity of the virus.
CI  - Copyright (c) 2011 Elsevier B.V. All rights reserved.
FAU - Ni, Yan-Yan
AU  - Ni YY
AD  - Center for Molecular Medicine and Infectious Diseases, Department of Biomedical 
      Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, 
      Blacksburg, VA 24061-0913 , USA.
FAU - Huang, Yao-Wei
AU  - Huang YW
FAU - Cao, Dianjun
AU  - Cao D
FAU - Opriessnig, Tanja
AU  - Opriessnig T
FAU - Meng, Xiang-Jin
AU  - Meng XJ
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20110707
PL  - Netherlands
TA  - Virus Res
JT  - Virus research
JID - 8410979
RN  - 0 (Viral Nonstructural Proteins)
SB  - IM
MH  - Animals
MH  - Cell Line
MH  - Cricetinae
MH  - Haplorhini
MH  - Porcine Reproductive and Respiratory Syndrome/*pathology/virology
MH  - Porcine respiratory and reproductive syndrome virus/*genetics/growth & 
      development/isolation & purification/*pathogenicity
MH  - *Sequence Deletion
MH  - Serial Passage
MH  - Swine
MH  - Viral Nonstructural Proteins/*genetics
MH  - Virulence
MH  - Virus Replication
EDAT- 2011/07/19 06:00
MHDA- 2011/12/17 06:00
CRDT- 2011/07/19 06:00
PHST- 2011/04/15 00:00 [received]
PHST- 2011/06/22 00:00 [revised]
PHST- 2011/06/30 00:00 [accepted]
PHST- 2011/07/19 06:00 [entrez]
PHST- 2011/07/19 06:00 [pubmed]
PHST- 2011/12/17 06:00 [medline]
AID - S0168-1702(11)00251-6 [pii]
AID - 10.1016/j.virusres.2011.06.027 [doi]
PST - ppublish
SO  - Virus Res. 2011 Sep;160(1-2):264-73. doi: 10.1016/j.virusres.2011.06.027. Epub 
      2011 Jul 7.