Roles of Rad51 paralogs for promoting homologous recombination in Leishmania infantum.

Abstract

To achieve drug resistance Leishmania parasite alters gene copy number by using its repeated sequences widely distributed through the genome. Even though homologous recombination (HR) is ascribed to maintain genome stability, this eukaryote exploits this potent mechanism driven by the Rad51 recombinase to form beneficial extrachromosomal circular amplicons. Here, we provide insights on the formation of these circular amplicons by analyzing the functions of the Rad51 paralogs. We purified three Leishmania infantum Rad51 paralogs homologs (LiRad51-3, LiRad51-4 and LiRad51-6) all of which directly interact with LiRad51. LiRad51-3, LiRad51-4 and LiRad51-6 show differences in DNA binding and annealing capacities. Moreover, it is also noteworthy that LiRad51-3 and LiRad51-4 are able to stimulate Rad51-mediated D-loop formation. In addition, we succeed to inactivate the LiRad51-4 gene and report a decrease of circular amplicons in this mutant. The LiRad51-3 gene was found to be essential for cell viability. Thus, we propose that the LiRad51 paralogs play crucial functions in extrachromosomal circular DNA amplification to circumvent drug actions and preserve survival.

• Authors: Marie-Michelle Genois, Marie Plourde, Chantal Éthier, Gaétan Roy, Guy G Poirier, Marc Ouellette, Jean-Yves Masson
• Journal: Nucleic acids research (Nucleic Acids Res) Vol. 43 Issue 5 Pg. 2701-15 (Mar 11 2015) ISSN: 1362-4962 [Electronic] England
• PMID: 25712090 (Publication Type: Journal Article)
• Copyright: © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Chemical References

• DNA, Protozoan
• Protein Isoforms
• Protozoan Proteins
• Rad51 Recombinase

Topics

• Animals
• Blotting, Southern
• DNA, Protozoan (genetics, metabolism)
• Electrophoresis, Polyacrylamide Gel
• Homologous Recombination
• Leishmania infantum (genetics, metabolism)
• Mutation
• Polymerase Chain Reaction
• Protein Binding
• Protein Isoforms (genetics, metabolism)
• Protozoan Proteins (genetics, metabolism)
• Rad51 Recombinase (genetics, metabolism)
• Sf9 Cells
• Spodoptera