mRNA localization: a possible role in the regulation of stage-specific gene expression during Trypanosoma cruzi development

SABALETTE, KARINA B; CAMPO VANINA A; DE GAUDENZI JAVIER G

Congreso; MOLECULAR PARASITOLOGY MEETING XXXI; 2020

Trypanosoma cruzi, the causative agent of Chagas disease, is characterized by regulating its gene expression mainly at post-transcriptionallevel. RNA regulons consist of ribonucleoprotein complexes having mRNAs whose protein products act cooperatively in a particularbiological pathway. These clusters are regulated by one or more RNA-binding proteins (RBPs), thereby enabling quick changes of theprotein cellular profile in response to internal or external stimuli. Previous results demonstrated that the small trypanosome-exclusive proteinU-rich RBP 1 (TcUBP1) is involved in metacyclogenesis and exerts its function through the interaction with numerous mRNAs encoding cellsurfaceglycoproteins preferentially expressed in the trypomastigote infective stage, including members of the transialidase and transsialidase-like (TcS) multigenic family. The aim of this study was to evaluate if mRNA localization is a mechanism for stage-specific generegulation. Using RNA FISH with a specific Cy3-oligo probe for TcS transcripts, we observed that over-expression of TcUBP1-GFP inepimastigotes resulted in changes in the localization of these mRNAs from the posterior region to the peri-nuclear region of the cell, as istypically observed in trypomastigotes. To get a deep insight into this result we used the wild-type T. cruzi CL-Brener strain and performed atrypomastigote-to-epimastigote differentiation in vitro. In this case we observed the relocalization of the transcripts from peri-nuclear region tothe posterior region, and the same change was observed for transcripts of another cell-surface protein family named TASV, highly expressedin trypomastigotes. Indirect immunofluorescence labeling of epimastigote cells with an anti-TcCruzipain polyclonal serum detected bothmRNAs families in a subcellular region that matches to reservosomes, an organelle absent in infective stages. The results obtained suggestthat RNA mobilization appears to operate in the regulation of stage-specific gene expression, where the reservosome could play a role instoring and protecting mRNAs during the epimastigote replicative stage. Finally, applying bioinformatic tools, we focused on putative cisactingRNA regulatory elements located in both TcS and TASV 3?UTRs and identified novel interacting candidates involved in this mRNAtranslocation