Comparison of the major virulence-related genes of Listeria monocytogenes in internalin A truncated strain 36-25-1 and a clinical wild-type strain.
BACKGROUND
Internalin A (InlA) facilitates the invasion of Listeria monocytogenes into a host cell. Some strains of Listeria monocytogenes express truncated forms of InlA, which reduces invasiveness. However, few virulence-related genes other than inlA have been analyzed in InlA-truncated strains. In the present study, we sequenced the draft genome of strain 36-25-1, an InlA-truncated strain, with pyrosequencing and compared 36 major virulence-related genes in this strain and a clinical wild-type strain.


RESULTS
Strain 36-25-1 possessed all of the virulence-related genes analyzed. Of the analyzed genes, only 4 genes (dltA, gtcA, iap, and inlA) differed when the nucleotide sequences of strain 36-25-1 and the clinical wild-type strain were compared. Analysis of the deduced amino acid sequences found no mutations that significantly influenced virulence in genes other than inlA.


CONCLUSIONS
The virulence-associated genes in strain 36-25-1 differ little from those of the clinical wild-type strain, indicating that a slight mutation in the nucleotide sequence determines the virulence of the InlA-truncated strain. In addition, the results suggest that, aside from InlA-mediated cell invasiveness, there is almost no difference between the virulence of strain 36-25-1 and that of the clinical wild-type strain.
Daisuke
D
Kyoui
Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan. hajime@kaiyodai.ac.jp.
Hajime
H
Takahashi
Satoko
S
Miya
Takashi
T
Kuda
Bon
B
Kimura
D001426:Bacterial Proteins / Q000235:genetics*; D016680:Genome, Bacterial; D006801:Humans; D008089:Listeria monocytogenes / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
D001426:Bacterial Proteins; D037521:Virulence Factors; C069761:internalin protein, Bacteria