A key presynaptic role in transformation for a widespread bacterial protein: DprA conveys incoming ssDNA to RecA.
Fiche publication
Date publication
septembre 2007
Journal
Cell
Auteurs
Membres identifiés du Cancéropôle Est :
Dr PIETREMENT Olivier
Tous les auteurs :
Mortier-Barrière I, Velten M, Dupaigne P, Mirouze N, Piétrement O, McGovern S, Fichant G, Martin B, Noirot P, Le Cam E, Polard P, Claverys JP
Lien Pubmed
Résumé
Natural transformation is a mechanism for genetic exchange in many bacterial genera. It proceeds through the uptake of exogenous DNA and subsequent homology-dependent integration into the genome. In Streptococcus pneumoniae, this integration requires the ubiquitous recombinase, RecA, and DprA, a protein of unknown function widely conserved in bacteria. To unravel the role of DprA, we have studied the properties of the purified S. pneumoniae protein and its Bacillus subtilis ortholog (Smf). We report that DprA and Smf bind cooperatively to single-stranded DNA (ssDNA) and that these proteins both self-interact and interact with RecA. We demonstrate that DprA-RecA-ssDNA filaments are produced and that these filaments catalyze the homology-dependent formation of joint molecules. Finally, we show that while the Escherichia coli ssDNA-binding protein SSB limits access of RecA to ssDNA, DprA lowers this barrier. We propose that DprA is a new member of the recombination-mediator protein family, dedicated to natural bacterial transformation.
Mots clés
Bacillus subtilis, enzymology, Bacterial Proteins, genetics, Cell Nucleus, enzymology, DNA, Bacterial, metabolism, DNA, Circular, metabolism, DNA, Single-Stranded, metabolism, DNA, Superhelical, metabolism, DNA-Binding Proteins, genetics, Escherichia coli, enzymology, Escherichia coli Proteins, genetics, Evolution, Molecular, Exodeoxyribonucleases, metabolism, Genomic Instability, Membrane Proteins, genetics, Nucleic Acid Conformation, Protein Binding, Rec A Recombinases, genetics, Recombinant Proteins, metabolism, Recombination, Genetic, Streptococcus pneumoniae, enzymology, Transformation, Bacterial
Référence
Cell. 2007 Sep;130(5):824-36