Remodeling of an RNA regulon for a cell-surface associated Trypanosoma cruzi glycoprotein during parasite differentiation

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

Mar del Plata

Congreso; XXXI Reunión Anual de la Sociedad Argentina de Protozoología; 2019

RNA regulons, ribonucleoprotein complexes composed by functionallyrelated mRNAs together with RNA-binding proteins (RBPs), play an importantrole in the post-transcriptional regulation of gene expression in trypanosomes.The RNA-binding protein U-rich RBP 1 (TcUBP1) targets numerous mRNAs encodingcell-surface glycoproteins preferentially expressed in infectivetrypomastigotes of Trypanosoma cruzi, the agent of Chagas disease.All these mRNA targets have common 3´-UTRs with a 50-nt linear sequence motifproximately upstream of the signature RNA element for TcUBP1. Overexpression ofTcUBP1-GFP in replicative epimastigotes resulted in changes in the subcellularlocalization of these transcripts from the posterior region to the perinuclearregion of the cell, as is typically observed in infectivetrypomastigotes. We hypothesize that mRNA localization is a mechanism forstage-specific gene regulation in trypanosomes. To test this possibility,we used the wild-typeT. cruzi CL-Brener strain and performed atrypomastigote-to-epimastigote differentiation in vitro, incubatingthe parasites in BHT media supplemented with BFS 10%. During thisdifferentiation process, the expression and localization of cell-surfaceassociated glycoprotein transcripts were followed by RNA FISH, with a specificCy3-oligo probe, at different time-points ranging from 1 to 42 days. Afterincubation and washing, the RNA signal changed from being uniformly distributedin the cytosol (in the trypomastigote form, day 1) to be preferentiallyrestricted to the posterior region of the cell (in the epimastigote form, day42). Indirect immunofluorescence labeling of cells with an anti-TcCruzipainpolyclonal serum detected these mRNAs in a subcellular region that matches toreservosomes, suggesting that RNA localization mechanisms triggered by TcUBP1might be involved in the regulation of stage-specific protein expression.