title: [Construction and virulence evaluation of the virB1-89K gene knockout mutant of type IV-like secretion system of Streptococcus suis serotype 2].
abstract: OBJECTIVE
  To construct the virB1-89K gene knockout mutant and its complementary strain of Streptococcus suis serotype 2 (SS2) highly virulent strain 05ZYH33 and evaluate the role of virB1-89K in the pathogenesis of SS2.
  
  
  METHODS
  The virB1-89K gene was knocked out by homologous recombination, then multiple-PCR and sequence analysis were used to identify the knockout strain deltavirB1-89K. The virB1-89K gene and its upstream promoter were cloned into the E. coli-S. suis shuttle vector pSET1, and the recombinant plasmid was electrotransformed into the deltavirB1-89K mutant to generate the complementary strain CvirB1-89K. The effects of virB1-89K deletion on the basic biological characteristics and virulence of SS2 were then determined in this study.
  
  
  RESULTS
  The isogenic mutant deltavirB1-89K and its complementary strain CvirB1-89K were successfully constructed. No significant differences in biological characteristics were found among the three strains. However, the virulence of the deltavirB1-89K mutant was reduced to 30% of the wild-type level and functional complementation of virB1-89K restored its pathogenicity.
  
  
  CONCLUSIONS
  The virB1-89K gene plays an important role in the pathogenesis of S. suis 2 infection.
authors.affiliation: Department of Microbiology, Third Military Medical University, Chongqing 400038, China. cinderellaqiu@163.com
authors.forename: Qiu
authors.initials: Q
authors.lastname: Zhong
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Tian
authors.initials: T
authors.lastname: Chen
authors.forename: Supeng
authors.initials: S
authors.lastname: Yin
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Xiancai
authors.initials: X
authors.lastname: Rao
authors.forename: Yinling
authors.initials: Y
authors.lastname: Tan
authors.forename: Fuquan
authors.initials: F
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic; D017384:Sequence Deletion; D013290:Streptococcal Infections / Q000382:microbiology*; D017011:Streptococcus suis / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D016019:Survival Analysis; D014774:Virulence
chemical_list: D001426:Bacterial Proteins