A 43-nt U-rich element in the 3'untranslated region of a large number of Trypanosoma cruzi transcripts is important for mRNA abundance in intracellular amastigotes.

LI, Z.H.; DE GAUDENZI, J.G.; ALVAREZ, V.E.; MENDIONDO, N.; WANG, H.; KISSINGER, J.; FRASCH, A.C.; DOCAMPO, R.

JOURNAL OF BIOLOGICAL CHEMISTRY

AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Lugar: Bethesda, Maryland; Año: 2012

0021-9258

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 (3´UTR) 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 3´UTR 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 trypanosome-specific RNA-binding protein (RBP) TcUBP1, but not with other related RBPs. Co-immunoprecipitation experiments of TcUBP1-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 element, 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.