title: [Construction of luxS gene knockout mutant of Enterococcus faecalis].
abstract: OBJECTIVE
  To construct quorum sensing luxS knockout mutants of Enterococcus faecalis through homologous recombination.
  
  
  METHODS
  The upstream and downstream flank DNA fragments of E. faecalis luxS gene (up, dn) and erythromycin resistance gene (erm) were amplified by PCR. In order to construct recombination plasmid Puemrd, these DNA fragments were inserted into the plasmid pUC18 by corresponding double digests. After allelic exchange, the luxS knockout mutants strains were selected on 30 μg/mL erythromycin plates.
  
  
  RESULTS
  With endonuclease reaction and DNA sequencing, it was proved that the objective plasmid, Puemrd, was constructed correctly. The luxS knockout mutants strains were confirmed by PCR.
  
  
  CONCLUSIONS
  Enterococcus faecalis luxS gene has been successfully disrupted with homologous recombination. This mutant strain sets a good foundation for further functional study.
authors.affiliation: Department of Endodontics,Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine; Shanghai Key Laboratory of Stomatology. Shanghai 200011, China.E-mail:zyhe23@126.com.
authors.forename: Zhi-yan
authors.initials: ZY
authors.lastname: He
authors.forename: Lan
authors.initials: L
authors.lastname: Cheng
authors.forename: Yu-xia
authors.initials: YX
authors.lastname: Wang
authors.forename: Zheng-wei
authors.initials: ZW
authors.lastname: Huang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D013437:Carbon-Sulfur Lyases / Q000235:genetics*; D013293:Enterococcus faecalis / Q000235:genetics*; D055786:Gene Knockout Techniques; D010957:Plasmids; D016133:Polymerase Chain Reaction; D053038:Quorum Sensing
chemical_list: D001426:Bacterial Proteins; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria