OmpA and OmpC are critical host factors for bacteriophage Sf6 entry in Shigella

Area of Science:

• Microbiology
• Virology
• Structural Biology

Background:

• Bacterial outer membrane proteins A and C co-purify with bacteriophage Sf6, suggesting they may act as host receptors.
• The precise molecular mechanisms of viral host recognition and genome transfer remain incompletely understood.

Purpose of the Study:

• To investigate the roles of bacterial outer membrane proteins A and C in bacteriophage Sf6 infection.
• To elucidate the molecular interactions during Sf6 phage entry into Shigella flexneri.

Main Methods:

• In vivo studies using Shigella flexneri omp null mutants, including plaque assays.
• Time-lapse fluorescence microscopy to observe single virion genome ejection.
• Cryo-electron tomography to visualize phage-host membrane interactions.
• In vitro studies to assess Sf6 genome release.

Main Results:

• Outer membrane proteins A and C were confirmed to mediate Sf6 infection, significantly increasing its rate and efficiency.
• Cryo-electron tomography revealed the phage tail needle contacting and indenting the bacterial outer membrane.
• In vitro studies demonstrated that both lipopolysaccharide and outer membrane proteins are necessary for Sf6 genome release.

Conclusions:

• Bacteriophage Sf6 utilizes either outer membrane protein A or C as its receptor for host cell entry.
• Outer membrane protein A is identified as the preferred receptor for Sf6 infection.
• The findings provide critical insights into the molecular basis of bacteriophage-host interactions.