Adding to Yersinia enterocolitica gene pool diversity: two cryptic plasmids from a biotype 1A isolate.
We report the nucleotide sequence of two novel cryptic plasmids (4357 and 14 662 base pairs) carried by a Yersinia enterocolitica biotype 1A strain isolated from pork. As distinguished from most biotype 1A strains, this isolate, designated 07-04449, exhibited adherence to eukaryotic cells. The smaller plasmid pYe4449-1 carries five attributable open reading frames (ORFs) encoding the first CcdA/CcdB-like antitoxin/toxin system described for a Yersinia plasmid, a RepA-like replication initiation protein, and mobilizing factors MobA and MobC. The deduced amino acid sequences showed highest similarity to proteins described in Salmonella (CcdA/B), Klebsiella (RepA), and Plesiomonas (MobA/C) indicating genomic fluidity among members of the Enterobacteriaceae. One additional ORF with unknown function, termed ORF5, was identified with an ancestry distinct from the rest of the plasmid. While the C+G content of ORF5 is 38.3%, the rest of pYe4449-1 shows a C+G content of 55.7%. The C+G content of the larger plasmid pYe4449-2 (54.9%) was similar to that of pYe4449-1 (53.7%) and differed from that of the Y. enterocolitica genome (47.3%). Of the 14 ORFs identified on pYe4449-2, only six ORFs showed significant similarity to database entries. For three of these ORFs likely functions could be ascribed: a TnpR-like resolvase and a phage replication protein, localized each on a low C+G island, and DNA primase TraC. Two ORFs of pYe4449-2, ORF3 and ORF7, seem to encode secretable proteins. Epitope-tagging of ORF3 revealed protein expression at 4 degrees C but not at or above 27 degrees C suggesting adaptation to a habitat outside swine. The hypothetical protein encoded by ORF7 is the member of a novel repeat protein family sharing the DxxGN(x)(n)DxxGN motif. Our findings illustrate the exceptional gene pool diversity within the species Y. enterocolitica driven by horizontal gene transfer events.
Lepka
Daniela
D
Robert Koch Institute, Wernigerode Branch, Burgstrasse 37, 38855 Wernigerode, Germany.
Kerrinnes
Tobias
T
Skiebe
Evelyn
E
Hahn
Birgitt
B
Fruth
Angelika
A
Wilharm
Gottfried
G
D000595:Amino Acid Sequence; D000818:Animals; D020029:Base Pairing; D001483:Base Sequence; D002448:Cell Adhesion; D002460:Cell Line; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D000939:Epitopes; D004926:Escherichia coli / Q000235:genetics; D005788:Gene Pool; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D014644:Genetic Variation; D006367:HeLa Cells; D006801:Humans; D016366:Open Reading Frames; D010957:Plasmids / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013552:Swine; D013696:Temperature; D014169:Transformation, Bacterial; D015008:Yersinia enterocolitica / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D000939:Epitopes