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Iron availability regulates DNA recombination in Neisseria gonorrhoeae
1Department of Microbiology-Immunology, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611, USA.
Molecular Microbiology
|September 6, 2000
Summary
Neisseria gonorrhoeae uses pilus variation to evade immunity. Low iron conditions increase pilus variation by boosting DNA recombination and repair, aiding gonococcal adaptation during infection.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Neisseria gonorrhoeae uses pili for host cell attachment and disease establishment.
- Pilus antigenic variation is crucial for gonococcal immune evasion and adaptation.
- Understanding factors influencing pilus variation is key to controlling gonorrhea.
Purpose of the Study:
- To investigate the impact of environmental conditions on pilus antigenic variation in N. gonorrhoeae.
- To determine the mechanisms underlying iron-mediated changes in pilus variation.
Main Methods:
- Development of a competitive reverse transcriptase (RT)-PCR assay to quantify pilin antigenic variation.
- Testing the effect of various in vitro environmental conditions on variation frequency.
- Investigating the link between pilus variation, DNA recombination, and repair in iron-starved cultures.
Main Results:
- Limited iron significantly increased the frequency of pilus antigenic variation in N. gonorrhoeae.
- Increased pilus variation correlated with elevated DNA recombination and repair processes under iron limitation.
- This low iron-induced increase in variation was independent of RecA expression and occurred in Fur mutant strains.
Conclusions:
- Iron limitation acts as a signal for increased recombinational events in N. gonorrhoeae.
- These iron-modulated recombinational events likely contribute to gonococcal pathogenesis.
- Understanding the role of iron in pilus variation offers potential therapeutic targets.