RNase-mediated reprogramming of Yersinia virulence

Area of Science:

• Bacteriology
• Molecular Biology
• Genetics

Background:

• RNA degradation is crucial for bacterial gene regulation and virulence.
• The specific roles of individual RNases in controlling bacterial virulence factors are largely unknown.

Purpose of the Study:

• To investigate the influence of 11 RNases on the expression of the type III secretion system (T3SS) and Yops in Yersinia pseudotuberculosis.
• To elucidate the mechanisms by which specific RNases regulate T3SS/Yop expression.

Main Methods:

• Genetic manipulation of RNase genes in Yersinia pseudotuberculosis.
• Analysis of T3SS and Yop gene expression.
• Transcriptomic profiling.
• Investigation of RNA-protein interactions affecting mRNA stability and translation.

Main Results:

• Exoribonuclease PNPase and endoribonuclease RNase III were found to inhibit T3SS and Yop gene transcription by repressing the master activator LcrF.
• PNPase accelerates lcrF mRNA degradation via YopD.
• RNase III downregulates CsrB/CsrC RNAs, increasing CsrA activity for enhanced lcrF mRNA translation and stability.
• Transcriptomic analysis revealed global gene expression reprogramming driven by T3SS/Yop secretion.

Conclusions:

• RNases PNPase and RNase III play critical, distinct roles in regulating Yersinia virulence gene expression at multiple levels.
• This RNase-mediated control system fine-tunes the T3SS/Yop machinery to antagonize host immune responses.
• Understanding these mechanisms offers insights into bacterial pathogenesis and potential therapeutic targets.