Caracterização de aspectos epigenéticos em trypanosoma cruzi : interação entre histonas variantes h2az e h2bv

Abstract

Trypanosoma cruzi is a single-celled eukaryotic protozoan, known as the causative agent of Chagas disease. The differentiation between their different stages of life (epimastigotes, amastigotes, cellular and blood trypomastigotes) is also accompanied by structural changes in chromatin. Several studies indicate that trypanosome chromatin contains different types of epigenetic changes, including the deposition of variant histones, such as H2Bv and H2AZ. Dimers of H2Bv and H2AZ were found in other trypanosomatids (Trypanosoma brucei), possibly influencing the functions of transcriptional activation, gene silencing and heterochromatin formation in eukromatin regions. Considering this information, the present work aimed to identify possible interactions between the histone variants H2AZ and H2Bv in Trypanosoma cruzi. Initially, the H2AZ gene was cloned into the pJET1.2/blunt vector and a subcloning into the pMAL-p2x vector; insertion of the recombinant plasmid in Escherichia coli BL2 (DE3) expression bacteria, their expression and purification; the interaction test between H2AZ and H2Bv proteins. Finally, the purification of recombinant proteins by imobilized metal ion affinity chromatography with further analysis of the interaction assay. Purification of recombinant proteins was confirmed after analysis by SDSPAGE electrophoresis. The analysis of the interaction test revealed the presence of H2AZ and H2Bv, but also of other contaminants. As the protein purification was not standardized, it was not possible to identify the interaction between H2AZ and H2Bv during the present study. However, the hypothesis that these variant histones dimerize in T. cruzi and thus act in the regulation of the parasite's gene transcription must not be discarded.