title: [Virulence comparison of genetic engineering virus containing different length poly(C) tract of foot-and-mouth disease virus].
abstract: OBJECTIVE
  Study the association of the length of poly(C) tract with virulence of foot-and-mouth disease virus.
  
  
  METHODS
  The recombinant plasmids pGEM-XJ/AKT/69 containing the full-length cDNA of FMDV were linearized by Nhe I /Not I and transcribed by T7 RNA polymerase. The in vitro transcripts were transfected into BHK-21 cells using Lipofectamine 2000 reagent. Then, the genetic engineering virus was rescued from BHK-21 cells. The poly(C) tracts were sequenced at different passages of rescued virus, and the pathogenicities were evaluated with 3-day-old mice and BHK-21 cells by detection of LD50 and TCID50.
  
  
  RESULTS
  After six passages in BHK-21 cells, cytopathic effect was observed by microscopy. The rescued virus was rejuvenated once in unweaned mice, and then came back to cell passage. We found that the poly(C) tract of rescued virus was shortened when the virus was passaged twice in BHK-21 cells. Although the data of LD50 in mice and TCID50 in BHK-21 cells showed that the virulence and infectivity of genetic engineering viruses were lower than its parental virus, no significant difference was observed between the genetic engineering viruses with the different length poly(C) tract.
  
  
  CONCLUSIONS
  The length of poly(C) tract ranged from 12 to 17 nucleotides did not cause significant influence on the virulence and infectivity of genetic engineering virus.
authors.affiliation: Lanzhou Vet Research Inst of Chinese Academy of Agricultural Sciences, State Key Lab of Vet Etiological Biology, National Foot-and-Mouth Disease Ref Lab, Key Lab of Animal Virology of Ministry of Agriculture, Lanzhou 730046, China. baixingwen@163.com
authors.forename: Xingwen
authors.initials: X
authors.lastname: Bai
authors.forename: Pinghua
authors.initials: P
authors.lastname: Li
authors.forename: Pu
authors.initials: P
authors.lastname: Sun
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Li
authors.forename: Huifang
authors.initials: H
authors.lastname: Bao
authors.forename: Zengjun
authors.initials: Z
authors.lastname: Lu
authors.forename: Yimei
authors.initials: Y
authors.lastname: Cao
authors.forename: Jianhong
authors.initials: J
authors.lastname: Guo
authors.forename: Zaixin
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D005818:Genetic Engineering; D051379:Mice; D011066:Poly C / Q000737:chemistry / Q000235:genetics*; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D014407:Tumor Cells, Cultured; D014774:Virulence / Q000235:genetics*; D014776:Virus Cultivation; D014779:Virus Replication / Q000502:physiology
chemical_list: D012367:RNA, Viral; D011066:Poly C