Adding to Yersinia enterocolitica gene pool diversity: two cryptic plasmids from a biotype 1A isolate

Area of Science:

• Microbiology
• Genomics
• Molecular Biology

Background:

• Yersinia enterocolitica biotype 1A strains are typically non-adherent.
• The isolate 07-04449, however, exhibits adherence to eukaryotic cells.
• Understanding the genetic basis of these traits is crucial.

Purpose of the Study:

• To sequence and characterize two novel cryptic plasmids from an adherent Yersinia enterocolitica strain.
• To identify genes and genetic elements contributing to the strain's unique phenotype.
• To investigate horizontal gene transfer and genomic diversity within Yersinia.

Main Methods:

• Nucleotide sequencing of two cryptic plasmids (pYe4449-1 and pYe4449-2).
• Open reading frame (ORF) identification and sequence similarity analysis.
• Analysis of guanine-cytosine (C+G) content.
• Epitope-tagging for protein expression analysis.

Main Results:

• Plasmid pYe4449-1 contains five ORFs, including a novel Yersinia CcdA/CcdB-like toxin-antitoxin system, replication initiation protein, and mobilization factors.
• Plasmid pYe4449-2 contains 14 ORFs, including a TnpR-like resolvase, phage replication protein, DNA primase TraC, and two ORFs (ORF3 and ORF7) encoding potential secretable proteins.
• ORF5 on pYe4449-1 has a distinct C+G content, suggesting a different origin.
• Protein expression analysis indicated ORF3 is expressed at low temperatures, suggesting adaptation to environments outside swine.

Conclusions:

• The sequenced plasmids contribute to the genetic diversity of Yersinia enterocolitica.
• The presence of novel genes and systems highlights the role of horizontal gene transfer.
• The findings provide insights into the adaptability and evolution of Yersinia strains.