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Trypanosoma cruzi elongation factor 1-α: Nuclear localization in parasites undergoing apoptosis

Abstract:

The cloning and sequencing of the gene coding for Trypanosoma cruzi elongation factor 1α (TcEF-1α) was performed by screening a T. cruzi genomic library with a probe obtained through the polymerase chain reaction (PCR) amplification of T. cruzi DNA using two oligonucleotides deduced from the sequence of T. brucei EF-1α. Southern blot analysis of T. cruzi digested genomic DNA and Northern blot hybridized with the labeled probe revealed that one copy of TcEF-1α exist in the genome of the parasite. Indirect immunofluorescence technique using anti-EF-1α antibodies and epimastigotes harvested after different days of in vitro culture showed that EF-1α is localised in the cytoplasm of the parasites from the exponential growth phase. Surprisingly, during the stationary phase (ageing parasites), EF-1α was found in the nucleus. Furthermore, treatment of parasites with the antibiotic drug geneticin (G418) which induces the death of epimastigotes by apoptosis showed selective localization of EF-1α in the nucleus of dying parasites. This observation supports the notion already reported in the case of mammalian cells that EF-1α could participate in the transcription processes and possibly in the case of T. cruzi, in the expression regulation of genes involved in the control of cell death. The possible transfection and genomic manipulation of T. cruzi may provide a model to study the role of TcEF-1α in this phenomenon.