Differential distribution of novel restriction-modification systems in clonal lineages of Neisseria meningitidis

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Neisseria meningitidis harbors diverse genetic elements that influence its evolution and pathogenicity.
• Restriction-modification (R-M) systems are crucial for bacterial genome defense and can impact horizontal gene transfer.

Purpose of the Study:

• To identify and characterize novel R-M systems in Neisseria meningitidis.
• To investigate the distribution and potential functional roles of these R-M systems in different meningococcal lineages.

Main Methods:

• Representational difference analysis (RDA) was employed to isolate novel R-M systems.
• The distribution of identified R-M systems was assessed across 103 meningococcal strains.
• Cocultivation experiments were performed to evaluate the functional impact of R-M systems on DNA transfer.

Main Results:

• Three novel R-M systems, NmeBI, NmeAI, and NmeDI, were identified in Neisseria meningitidis.
• NmeBI and NmeDI were found at conserved locations between the pheS and pheT genes, suggesting a hotspot for foreign DNA insertion.
• NmeBI demonstrated the ability to partially restrict DNA transfer from ET-37 complex to ET-5 complex meningococci.

Conclusions:

• The identified R-M systems (NmeBI, NmeAI, NmeDI) are prevalent in specific Neisseria meningitidis lineages.
• The location of NmeBI and NmeDI suggests their integration into a common insertion site within the meningococcal genome.
• NmeBI plays a role in regulating DNA transfer, potentially influencing the genetic diversity and adaptation of Neisseria meningitidis.