Identification and characterization of the cell division protein MapZ from Streptococcus suis

Area of Science:

• Microbiology
• Bacterial genetics
• Cell biology

Background:

• Streptococcus suis is a significant zoonotic pathogen causing severe diseases in both pigs and humans.
• A previously identified conditionally essential gene (SSU0375) in S. suis requires functional characterization.
• Understanding S. suis pathogenesis is critical for developing effective treatments and control strategies.

Purpose of the Study:

• To elucidate the function of the SSU0375 gene product in Streptococcus suis.
• To investigate the role of this gene in bacterial growth and cell division.
• To determine if SSU0375 encodes a homolog of the MapZ protein involved in bacterial cytokinesis.

Main Methods:

• Bioinformatics analysis and homology modeling to predict protein function.
• Gene depletion experiments in S. suis strain 10 to assess growth phenotypes.
• Electron and light microscopy to analyze cell morphology and division septa.
• Genetic rescue experiments to confirm gene function.

Main Results:

• Bioinformatics analysis revealed homology between SSU0375 and Streptococcus pneumoniae MapZ.
• Depletion of the SSU0375 locus resulted in significant growth defects in S. suis.
• Mutant strains exhibited aberrant cell morphology, including irregular shapes and mispositioned septa.
• Genetic rescue restored the wild-type phenotype, confirming the gene's essential role.

Conclusions:

• The SSU0375 gene product in Streptococcus suis functions as a MapZ homolog.
• This MapZ homolog is essential for proper septum positioning and cell division.
• Findings contribute to understanding the cell division mechanisms in Streptococci and S. suis pathogenesis.