TRANSLATIONAL CONTROL IN T. CRUZI

CAMARA MARIA DE LOS MILAGROS; SANTIAGO BERTOTTI; JUAN D ALFONZO; CARLOS A BUSCAGLIA

Santa Fe

Congreso; XXVIII Reunión Anual de la Sociedad Argentina de Protozoología y Enfermedades Parasitarias; 2016

Sociedad Argentina de Protozologia

The protozoan T. cruzi is the etiological agent ofChagas disease, a major public health issue inLatin America. Due to its predominant clonalproliferation, this species is composed by multiple?discrete typing units? displaying considerablegenetic diversity. Comparative analysis led to theidentification of quantitative/qualitative differenceson the expression of multiple molecules includingwell-established virulence factors such as transsialidasesand mucins. It has been explored thatcontrol of gene expression in T. cruzi is essentiallyconcerted by post-transcriptional mechanismswhich would be reinforced by epigenetic factorsand/or translational control. TcSMUG is anhomogeneous multiple member family of Thr-richmucins genes. Along their transit to the parasitesurface, the hydroxyl groups of some of the Thrresidues are further elaborated with short O-linkedoligosaccharide chains that are thought to conferprotective, adhesive and functional properties tothe mature TcSMUG products. TcSMUG iscomposed of two groups of genes, named L andS, organized in independent tandem arrays anddiffering in the structure of their genomic loci. Bothgroups are co-expressed in the epimastigotesstage, and share structural homologies, butpresent different functions and post-transcriptionalmodifications. One notable feature is thatTcSMUGL products in contrast to TcSMUGS showsubstantial differences in their expression levelsamong parasites stocks. In the present work weexplore the molecular basis which controlsTcSMUG L inter-stock differential expressionvariability which would be relying in a translationalmechanism operating on TcSMUGL mRNAs whichwould depend on stock specific codon usage anddifferences in the overall ?tRNA signature? (tRNAsgene transcription, tRNA maduration and tRNAediting).