CONICET | Buscador de Institutos y Recursos Humanos

Little is known about chromatin structure and epigenetic regulation in trypanosomatids. T. cruzi chromatin is organized in nucleosomes and it condenses as fibbers during cell division. T. cruzi histones are among the most divergent known and their posttranslational modifications and their role in gene expression regulation, are poorly understanded. Bromodomain-containing proteins bind acetylated lysine residues and this motif is present in many transcriptional regulators, participating in chromatin structure remodelling and transcription control. Several chromatin remodelling factors and Histone Acetyl Transferase complexes contain at least one bromodomain motif. We are interested in studying bromodomain factors functions in T. cruzi. By using bioinformatic tools we found three sequences that codify for bromodomain proteins (BDF1 to 3) and two sequences with far similitude to bromodomain (BDF4 and 5). One of them, TcBDF2, was detected by WB in protein extracts of epimastigotes, tripomastigotes and amastigotes using specific antibodies raised against recombinant TcBDF2 and purified by affinity column. Cellular localization was studied by indirect immunofluorescence assay and it was detected at the nucleus, showing a granular staining pattern, in all parasites forms. Nuclear localization was confirmed by WB using nuclear protein extracts. In addition, parasites were treated with Zeocin, UV and Gamma radiation. Preliminary studies showed that TcBDF2 expression increased after UV treatment, upto a maximal value at 18 hour after treatment, and decreased to normal levels at 48 hours. However it is not observed with others treatments. It is known that protein-complexes containing bromodomain factors are taking part or DNA repair mechanisms and recombination in eukaryotes. Probably these mechanisms are also present in this parasite. More studies are underway to confirm these results.

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