The ZnuABC operon is important for Yersinia ruckeri infections of rainbow trout, Oncorhynchus mykiss (Walbaum).
Signature-tagged mutagenesis was used to identify genes essential for survival of Yersinia ruckeri in its natural host, rainbow trout, Oncorhynchus mykiss. A mini-Tn5-Km2 signature-tagged mutant, C6-1, was missing from rainbow trout kidney at 7 days after an immersion challenge. The transposon insertion in C6-1 was in a homologue of the znuA gene of Escherichia coli that encodes ZnuA, a zinc-binding periplasmic protein of the high-affinity zinc transporter ZnuABC. Further sequencing of the C6-1 locus in Y. ruckeri identified homologues of two other genes: znuB, encoding a putative inner membrane permease, and znuC, encoding a putative ATPase. When present on a low-copy plasmid, the znuABC locus of Y. ruckeri fully restored growth of a zinc transport-deficient DeltaznuABC mutant of E. coli. Unlike DeltaznuABC mutants of E. coli and Salmonella typhimurium, the DeltaznuABC mutant of Y. ruckeri did not demonstrate significantly slower growth in zinc-deficient M9 minimal medium or in Luria-Bertani (LB) medium supplemented with the metal chelators EDTA and tetrakis-(2-pyridylmethyl)-ethylenediamine (TPEN). In LB medium, the znuA::lacZ and znuCB::lacZ transcriptional fusions of Y. ruckeri were derepressed by addition of EDTA and TPEN and were repressed by addition of zinc and manganese. In a competitive challenge by immersion, the DeltaznuABC mutant was unable to compete with the parental strain and survived poorly in rainbow trout kidney, indicating that the ZnuABC transporter has a role in establishing and maintaining a rainbow trout infection by Y. ruckeri.
Dahiya
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Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, Guelph N1G 2W1, ON, Canada.
Stevenson
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RM
D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000235:genetics; D005816:Genetic Complementation Test; D007668:Kidney / Q000382:microbiology; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D017686:Oncorhynchus mykiss; D016019:Survival Analysis; D015009:Yersinia Infections / Q000382:microbiology / Q000662:veterinary*; D044124:Yersinia ruckeri / Q000235:genetics* / Q000254:growth & development
D018528:ATP-Binding Cassette Transporters