Characterization of putative toxin/antitoxin systems in Vibrio parahaemolyticus.
OBJECTIVE
To obtain more information about the toxin/antitoxin (TA) systems in the Vibrio genus and also to examine their involvement in the induction of a viable but nonculturable (VBNC) state, we searched homologues of the Escherichia coli TA systems in the Vibrio parahaemolyticus genome.


RESULTS
We found that a gene cluster, vp1842/vp1843, in the V. parahaemolyticus genome database has homology to that encoding the E. coli TA proteins, DinJ/YafQ. Expression of the putative toxin gene vp1843 in E. coli cells strongly inhibited the cell growth, while coexpression with the putative antitoxin gene vp1842 neutralized this effect. Mutational analysis identified Lys37 and Pro45 in the gene product VP1843 of vp1843 as crucial residues for the growth retardation of E. coli cells. VP1843, unlike the E. coli toxin YafQ, has no protein synthesis inhibitory activity, and that instead the expression of vp1843 in E. coli caused morphological change of the cells.


CONCLUSIONS
The gene cluster vp1842/vp1843 encodes the V. parahaemolyticus TA system; VP1843 inhibits cell growth, whereas VP1842 serves as an antitoxin by forming a stable complex with VP1843.


CONCLUSIONS
The putative toxin, VP1843, may be involved in the induction of the VBNC state in V. parahaemolyticus by inhibiting cell division.
Department of Health and Nutrition Sciences, Faculty of Health and Nutrition, Nishikyushu University, Kanzaki-shi, Saga, Japan.
M
M
Hino
J
J
Zhang
H
H
Takagi
T
T
Miyoshi
T
T
Uchiumi
T
T
Nakashima
Y
Y
Kakuta
M
M
Kimura
D000595:Amino Acid Sequence; D000992:Antitoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004768:Enterotoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016680:Genome, Bacterial; D008958:Models, Molecular; D008969:Molecular Sequence Data; D005810:Multigene Family; D017386:Sequence Homology, Amino Acid; D014736:Vibrio parahaemolyticus / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity
D000992:Antitoxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; C523349:DinJ protein, E coli; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C523350:YafQ protein, E coli; C048616:enterotoxin, Vibrio parahaemolyticus
Vibrio parahaemolyticus; enteropathogen; stress response; toxin/antitoxin; viable but nonculturable state