TRYPANOSOMA-CRUZI ELONGATION-FACTOR 1-ALPHA - NUCLEAR-LOCALIZATION INPARASITES UNDERGOING APOPTOSIS

The cloning and sequencing of the gene coding for Trypanosoma cruzi el ongation factor 1 alpha (TcEF-1 alpha) was performed by screening a T. cruzi genomic library with a probe obtained through the polymerase ch ain reaction (PCR) amplification of T. cruzi DNA using two oligonucleo tides deduced from the sequence of T. brucei EF-1 alpha. Southern blot analysis of T. cruzi digested genomic DNA and Northern blot hybridize d with the labeled probe revealed that one copy of TcEF-1 alpha exist in the genome of the parasite. Indirect immunofluorescence technique u sing anti-EF-1 alpha antibodies and epimastigotes harvested after diff erent days of in vitro culture showed that EF-1 alpha is localised in the cytoplasm of the parasites from the exponential growth phase. Surp risingly, during the stationary phase (ageing parasites), EF-1 alpha w as found in the nucleus. Furthermore, treatment of parasites with the antibiotic drug geneticin (G418) which induces the death of epimastigo tes by apoptosis showed selective localization of EF-1 alpha in the nu cleus of dying parasites. This observation supports the notion already reported in the case of mammalian cells that EF-1 alpha could partici pate in the transcription processes and possibly in the case of T. cru zi, in the expression regulation of genes involved in the control of c ell death. The possible transfection and genomic manipulation of T. cr uzi may provide a model to study the role of TcEF-1 alpha in this phen omenon.