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

SABALETTE, KB; CAMPO, VA; DE GAUDENZI, JG

Mar del Plata

Congreso; Reunión Conjunta de Sociedades de Biociencias 2019; 2019

SAP

RNA regulons, ribonucleoprotein complexes composed by functionally related mRNAs together with RNA-binding proteins (RBPs), play an important role in the post-transcriptional regulation of gene expression in trypanosomes. The RNA-binding protein U-rich RBP 1 (TcUBP1) targets numerous mRNAs encoding cell-surface glycoproteins preferentially expressed in infective trypomastigotes of Trypanosoma cruzi, the agent of Chagas disease. All these mRNA targets have common 3´-UTRs with a 50-nt linear sequence motif proximately upstream of the signature RNA element for TcUBP1. Overexpression of TcUBP1-GFP in replicative epimastigotes resulted in changes in the subcellular localization of these transcripts from the posterior region to the perinuclear region of the cell, as is typically observed in infective trypomastigotes. We hypothesize that mRNA localization is a mechanism for stage-specific gene regulation in trypanosomes. To test this possibility, we used the wild-type T. cruzi CL-Brener strain and performed a trypomastigote-to-epimastigote differentiation in vitro, incubating the parasites in BHT media supplemented with BFS 10%. During this differentiation process the expression and localization of cell-surface associated glycoprotein transcripts was followed by RNA FISH, with an specific Cy3-oligo probe, at different time points during 42 days. After incubation and washing, the RNA signal changed from being uniformly distributed in the cytosol (in the trypomastigote form, day 1) to be preferentially restricted to the posterior region of the cell (in the epimastigote form, day 42). Indirect immunoflourescence labelling of cells with an anti-TcCruzipain polyclonal serum detected these mRNAs in a subcellular region that match to reservosomes, suggesting that RNA localization mechanisms triggered by TcUBP1 might be involved in the regulation of stage-specific protein expression.