title: [Construction and characterization of Listeria monocytogenes deltaprfA mutant strains].
abstract: OBJECTIVE
  Listeria monocytogenes (Lm) is an important pathogen that can cause serious listeriosis in humans and animals. The pathogenicity of Lm has a close relationship with the PrfA protein regulating the expression of virulence genes. Therefore, we studied the regulation functions of PrfA and its role on Lm's virulence.
  
  
  METHODS
  The prfA genes of LM4, serotype 1/2a, and F4636, serotype 4b, were deleted by homologous recombination technology, and the biological characteristics of the mutants were further studied.
  
  
  RESULTS
  The prfA gene deleted strains LM4deltaprfA and F4636deltaprfA and their back mutation strains were successfully constructed. The results show that the hemolysis activity was lost in prfA deleted strains and was recovered in the reverse mutant strains. The prfA deleted strains lost phospholipase activity; their adhesion and invasion ability significantly decreased. Furthermore, their 50% lethal doses (LD50) were 5 logs higher comparing with wild type strains.
  
  
  CONCLUSIONS
  PrfA regulates hly, plcB and inl gene family and affects significantly Lm's virulence.
authors.affiliation: Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China. chgbai@163.com
authors.forename: Chunguang
authors.initials: C
authors.lastname: Bai
authors.forename: Yuelan
authors.initials: Y
authors.lastname: Yin
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Jia
authors.forename: Hong
authors.initials: H
authors.lastname: Fu
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Gao
authors.forename: Xin'an
authors.initials: X
authors.lastname: Jiao
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics*; D008089:Listeria monocytogenes / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation; D010454:Peptide Termination Factors / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D010454:Peptide Termination Factors; C545356:PrfA protein, Listeria monocytogenes