Characterization of the Trypanosoma cruzi Rad51 gene and its role in recombination events associated with the parasite resistance to ionizing radiation

Carlos Gustavo Regis-da-Silva, Jorge Marcelo Freitas, Danielle Gomes Passos-Silva, Carolina Furtado, Luiz Augusto-Pinto, Márcio Tadeu Pereira, Wanderson Duarte DaRocha, Glória Regina Franco, Andréa Mara Macedo, Jean Sebastien Hoffmann, Christophe Cazaux, Sérgio Danilo Junho Pena, Santuza Maria Ribeiro Teixeira, Carlos Renato Machado

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

The Rad51 gene encodes a highly conserved enzyme involved in DNA double-strand break (DSB) repair and recombination processes. We cloned and characterized the Rad51 gene from Trypanosoma cruzi, the protozoan parasite that causes Chagas disease. This gene is expressed in all three forms of the parasite life cycle, with mRNA levels that are two-fold more abundant in the intracellular amastigote form. The recombinase activity of the TcRad51 gene product was verified by an increase in recombination events observed in transfected mammalian cells expressing TcRad51 and containing two inactive copies of the neomycin-resistant gene. As a component of the DSB repair machinery, we investigated the role of TcRad51 in the resistance to ionizing radiation and zeocin treatment presented by T. cruzi. When exposed to gamma irradiation, different strains of the parasite survive to dosages as high as 1 kGy. A role for TcRad51 in this process was evidenced by the increased expression of its mRNA after irradiation. Furthermore, transfected parasites over-expressing TcRad51 have a faster kinetics of recovery of the normal pattern of chromosomal bands after irradiation as well as a higher resistance to zeocin treatment than do wild-type cultures.

Original languageEnglish
Pages (from-to)191-200
Number of pages10
JournalMolecular and Biochemical Parasitology
Volume149
Issue number2
DOIs
StatePublished - Oct 2006
Externally publishedYes

Keywords

  • Ionizing radiation
  • RAD51
  • Recombination
  • Trypanosoma cruzi

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