An 43-nt AU-rich element in the 3´UTR of a large number of Trypanosoma cruzi mRNAs is important for mRNA stability in intracellular amastigotes

LI, ZH; DE GAUDENZI, JG; ALVAREZ, V; WANG, H; KISSINGER, J; FRASCH, AC; DOCAMPO, R

Woods Hole

Congreso; MPMXXII 2011 Molecular Parasitology Meeting XVII; 2011

MPM

Trypanosoma cruzi, the agent of Chagas disease, does not seem to control gene expression through regulation of transcription initiation, and makes use of post-transcriptional mechanisms. We report here a 43-nt U-rich RNA element located in the 3 untranslated region (3UTR) of a large number of T. cruzi mRNAs that is important for mRNA abundance in the intracellular amastigote stage of the parasite. Whole genome scan analysis, differential display RT-PCR, northern blot, and RT-PCR analyses were used to determine the transcript levels of more than 900 U-rich-containing mRNAs of large gene families as well as single and low copy number genes. Our results indicate that the 43-nt U-rich mRNA element is preferentially present in amastigotes. The cis-element of a protein kinase 3UTR but not its mutated version, promoted the expression of the green fluorescent protein (GFP) reporter gene in amastigotes. The regulatory cis-element, but not its mutated version, was also shown to interact with the trypanosomal-specific RNA-binding protein (RBP) TcUBP1, but not with other related RBPs. Co-immunoprecipitation experiments of UBP1-containing ribonucleoprotein complexes formed in vivo validated the interaction with representative endogenous RNAs having the element. These results suggest that this 43-nt U-rich motif, together with other yet unidentified sequences, might be involved in the modulation of abundance and/or translation of subsets of transcripts in the amastigote stage.