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Published on: June 25, 2013
RecX facilitates homologous recombination by modulating RecA activities
Paula P Cárdenas1, Begoña Carrasco, Clarisse Defeu Soufo
1Department of Microbial Biotechnology, Centro Nacional de Biotechnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Plos Genetics
|January 4, 2013
Summary
The Bacillus subtilis RecX protein modulates DNA repair and recombination. Its absence impairs natural transformation, highlighting its crucial role in genetic exchange and species recombination.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- The recX gene in Bacillus subtilis, previously known as yfhG, encodes a protein involved in DNA repair.
- RecX shares partial identity with Proteobacterial RecX proteins, suggesting conserved functions.
Purpose of the Study:
- To investigate the function of the Bacillus subtilis RecX protein in DNA recombination and repair.
- To elucidate RecX's role in natural transformation and its interaction with RecA.
Main Methods:
- Characterization of the recX342 mutant strain.
- RecX-YFP fusion protein localization studies in response to DNA damage and natural competence.
- Analysis of RecX's effect on RecA-mediated recombination and transformation frequencies.
Main Results:
- RecX modulates the SOS response and facilitates RecA-mediated recombinational repair.
- RecX forms foci on the nucleoid, co-localizing with RecA and RecF during DNA damage and competence.
- Absence of RecX severely impairs natural transformation and RecX suppresses negative effects of RecA during plasmid transformation.
Conclusions:
- RecX is a genuine recombination protein essential for Bacillus subtilis natural transformation.
- RecX modulates RecA filament dynamics, facilitating recombination initiation and interspecies recombination.
- RecX plays a critical role in preventing RecA mis-sensing and ensuring efficient DNA strand exchange.
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