Identification of a nuclear putative glutaredoxin in Trypanosoma cruzi

GARAVAGLIA, PA; GARCIA, GA; ESTEVA, MI; RUIZ, AM

Iguazu, Misiones, Argentina

Congreso; XL Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2004

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Glutaredoxins (Grxs) are thiol-redox enzymes, which contain an active site  with the sequence motif CXXC. Grxs are responsible for the reduction of intracellular disulfides in vivo and moreover, they contribute to a range of important cellular processes, as DNA synthesis, transcriptional control and cell growth and death control. We have cloned a novel gene codifying for an atypical Grx in the ethiological agent of Chagas’ Disease, Trypanosoma cruzi. With the aim  to identify the native protein in the parasite, a serum against the recombinant TcGrx was raised in mice. The anti-TcGrx serum recognized in western blot a protein with the expected molecular weight of 35 kDa in epimastigote, amastigote and tripomastigote stages. In epimastigotes, TcGrx was present in nucleus enriched fractions, but not in soluble fraction. The sub-cellular location of TcGrx was confirmed by immunogold electronic microscopy using the anti-TcGrx serum. Labelling localized mainly in nucleus, specifically in the nucleolus, and in a lesser extent in the kinetoplastid DNA. Since nuclear TcGrx is present in non-soluble fractions, we are currently trying different solubilization protocols in order to further carry out its biochemical characterization and define its function.