EvfG is a multi-function protein located in the Type VI secretion system for ExPEC

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Molecular Biology

Background:

• The Type VI secretion system (T6SS) is a critical bacterial nanoweapon involved in interbacterial competition and virulence.
• Research on T6SS in Extraintestinal pathogenic Escherichia coli (ExPEC) is limited, with key regulatory mechanisms underexplored.

Purpose of the Study:

• To identify and characterize novel genes regulating T6SS function in ExPEC.
• To elucidate the role of the uncharacterized gene evfG in ExPEC RS218 T6SS activity and bacterial traits.

Main Methods:

• Gene identification within the T6SS cluster.
• Experimental analysis of evfG's role in T6SS expression and activity.
• Investigation of evfG's interaction with c-di-GMP and sodA.
• Transcriptome analysis and additional assays to assess evfG-controlled traits.

Main Results:

• The gene evfG was identified and confirmed to be involved in T6SS expression in ExPEC RS218.
• EvfG modulates T6SS activity by competitively binding c-di-GMP, reducing its inhibitory effect.
• EvfG recruits sodA to mitigate oxidative stress.
• EvfG regulates multiple bacterial traits including adhesion, invasion, motility, drug resistance, and pathogenicity.

Conclusions:

• EvfG acts as a multifunctional regulator for the T6SS and associated bacterial activities in ExPEC.
• Understanding evfG's role advances T6SS research and opens opportunities for novel vaccine and therapeutic strategies against ExPEC infections.