Genetically engineered frameshifted YopN-TyeA chimeras influence type III secretion system function in Yersinia...

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Molecular Biology

Background:

• Type III secretion systems (T3SS) are crucial virulence factors for Gram-negative bacteria like Yersinia spp.
• The YopN-TyeA heterodimer regulates T3SS substrate secretion and translocation into host cells.
• Yersinia pseudotuberculosis, like Yersinia pestis, produces a YopN-TyeA hybrid protein due to a ribosomal frameshift.

Purpose of the Study:

• To investigate the biological role of the naturally occurring YopN-TyeA hybrid protein in Y. pseudotuberculosis T3SS.
• To assess the impact of engineered YopN-TyeA hybrids on T3SS control and virulence.

Main Methods:

• Site-directed mutagenesis was used to engineer Y. pseudotuberculosis strains producing either predominantly YopN-TyeA hybrids or only singular YopN and TyeA.
• Engineered strains were analyzed for hybrid protein production, stability, secretion, and T3SS needle structure integrity.
• In vitro and in vivo assays, including competitive survival in mice, were performed to evaluate virulence.

Main Results:

• Engineered YopN-TyeA hybrids were produced, stable, and secreted efficiently in vitro, maintaining T3SS needle structures.
• Bacteria with highly altered YopN-TyeA hybrids exhibited diminished control of Yop translocation upon host cell contact.
• These strains showed attenuated virulence in competitive mouse infection assays.

Conclusions:

• The naturally occurring YopN-TyeA hybrid protein in Y. pseudotuberculosis likely influences T3SS control and activity during host cell interaction.
• The hybrid protein plays a role in regulating Yop translocation, impacting bacterial virulence.
• Understanding the hybrid's function provides insights into Yersinia pathogenesis.