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ComE, a competence protein from Neisseria gonorrhoeae with DNA-binding activity
1Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York 10021. ichen@phri.nyu.edu
Journal of Bacteriology
|April 28, 2001
Summary
Researchers identified ComE, a novel DNA-binding protein essential for Neisseria gonorrhoeae genetic transformation. This protein facilitates exogenous DNA uptake, crucial for bacterial competence, without impacting pili function.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Neisseria gonorrhoeae possesses natural competence for genetic transformation, facilitated by type IV pili.
- DNA uptake is sequence-specific, but no known competence factors interact directly with incoming DNA.
Purpose of the Study:
- To identify and characterize novel DNA-binding proteins involved in Neisseria gonorrhoeae competence.
- To elucidate the role of ComE in the mechanism of genetic transformation.
Main Methods:
- Bioinformatic searches identified the comE gene based on homology to Bacillus subtilis ComEA.
- Genetic manipulation of N. gonorrhoeae strains to create comE deletion mutants.
- Analysis of transformation frequencies, DNA uptake ability, piliation, and twitching motility.
- Biochemical assays to determine DNA-binding activity of recombinant ComE.
Main Results:
- The comE gene exists in four identical copies in N. gonorrhoeae and N. meningitidis.
- Deletion of comE copies progressively reduced transformation frequencies, with complete deletion causing a 4x10^4-fold reduction.
- ComE-deficient mutants showed impaired exogenous DNA uptake but retained normal piliation and motility.
- Recombinant ComE protein demonstrated non-sequence-specific DNA binding activity.
Conclusions:
- ComE is a novel, multi-copy DNA-binding competence factor in Neisseria species.
- ComE is essential for efficient exogenous DNA uptake during genetic transformation.
- ComE functions independently of pilus biogenesis and motility mechanisms.