title: A novel gene required for natural competence in Aggregatibacter actinomycetemcomitans.
abstract: OBJECTIVE
  Natural competence is the ability of bacteria to take up extracellular DNA and incorporate it into their genomes. Some strains of Aggregatibacter actinomycetemcomitans, a critical periodontal pathogen, are naturally competent for transformation. However, information on natural competence genes is limited for this species. The aim of this study was to confirm the involvement of a novel gene identified near the fimbriae gene cluster in natural competence.
  
  
  METHODS
  The functions of putative open reading frames (ORFs), designated AA00863-AA00865, in the Oralgen project database for A. actinomycetemcomitans strain HK1651, have not been determined. Using naturally transformable A. actinomycetemcomitans strains D7S-1 and ATCC29523, we created deletion mutants of homologous genes of these ORFs. Natural competence in the study strains was determined using an agar-based transformation frequency assay.
  
  
  RESULTS
  Mutation of the AA00865 homolog, which we named urpA in A. actinomycetemcomitans strain D7S-1, resulted in the loss of natural competence, whereas mutations of the AA00864 and AA00863 homologs, located downstream of urpA gene, did not. Similar results were also observed in the mutants of A. actinomycetemcomitans ATCC29523. Complementation of the deleted sequence in the urpA mutant restored natural competence.
  
  
  CONCLUSIONS
  The urpA gene is a novel gene required for natural competence in A. actinomycetemcomitans and does not exhibit significant homology with any natural competence genes previously identified in other bacterial species.
authors: Section of Periodontology, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.
authors: A
authors: A
authors: Tanaka
authors: O
authors: O
authors: Fujise
authors: C
authors: C
authors: Chen
authors: M
authors: M
authors: Miura
authors: T
authors: T
authors: Hamachi
authors: K
authors: K
authors: Maeda
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D061269:DNA Transformation Competence / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D036781:Fimbriae Proteins / Q000235:genetics; D010861:Fimbriae, Bacterial / Q000235:genetics; D017353:Gene Deletion; D005798:Genes, Bacterial / Q000235:genetics*; D006801:Humans; D005810:Multigene Family / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C113731:Flp protein, bacteria; D036781:Fimbriae Proteins