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

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

Congreso; MOLECULAR PARASITOLOGY MEETING XXXI; 2020

Genetics Society of America

Trypanosoma cruzi,the causative agent of Chagas disease, is characterized by regulating its geneexpression mainly at post-transcriptionallevel. RNA regulons consist ofribonucleoprotein complexes having mRNAs whose protein products act cooperativelyin a particular biologicalpathway. These clusters are regulatedby one or more RNA-bindingproteins (RBPs), thereby enabling quick changes of the protein cellular profilein response to internal or external stimuli. Previousresults demonstrated that the smalltrypanosome-exclusive protein U-rich RBP 1 (TcUBP1) is involved inmetacyclogenesis and exerts its function throughthe interaction with numerous mRNAs encoding cell-surface glycoproteins preferentially expressed in the trypomastigote infective stage,including members of the transialidaseand trans-sialidase-like (TcS) multigenic family. The aim of this studywas to evaluate if mRNA localization is a mechanism for stage-specific gene regulation. Using RNA FISH with a specific Cy3-oligo probe for TcStranscripts, we observed thatover-expression of TcUBP1-GFP in epimastigotes resulted in changes in the localization ofthese mRNAs from the posterior region to the peri-nuclear region of the cell, as is typicallyobserved in trypomastigotes. Toget a deep insight into thisresult we used the wild-type T. cruziCL-Brener strain and performeda trypomastigote-to-epimastigotedifferentiation in vitro. In thiscase we observed the relocalization of the transcripts from peri-nuclear region to the posterior region, andthe same change was observed for transcripts of anothercell-surface protein familynamed TASV, highly expressed in trypomastigotes. Indirect immunofluorescencelabeling of epimastigote cells with an anti-TcCruzipain polyclonal serum detected bothmRNAs families in asubcellular region that matches to reservosomes, an organelle absent ininfective stages. The resultsobtained suggest that RNA mobilization appears to operate in the regulation ofstage-specific gene expression, where the reservosomecould play a role in storing and protecting mRNAs during theepimastigote replicative stage. Finally, applying bioinformatic tools, wefocused on putative cis-acting RNA regulatory elements located in both TcSand TASV3?UTRs and identified novel interacting candidatesinvolved in this mRNA translocation