Functionally related transcripts have common RNA motifs for specific RNA-binding proteins in trypanosomes

Area of Science:

• Molecular Biology
• Genetics
• Parasitology

Background:

• Trypanosomes regulate gene expression primarily through post-transcriptional mechanisms, including mRNA stability and translation.
• RNA-binding proteins (RBPs) are crucial for these processes, forming messenger ribonucleoprotein (mRNP) complexes with transcripts.

Purpose of the Study:

• To identify mRNA targets for Trypanosoma cruzi U-rich RBP 1 (TcUBP1) and T. cruzi RBP 3 (TcRBP3).
• To characterize the RNA motifs and cis-elements recognized by these RBPs.
• To understand the role of these RBPs in coordinating gene expression.

Main Methods:

• Co-immunoprecipitation of RBP-associated RNAs from mRNP complexes.
• Validation of RBP-RNA interactions using independent experimental assays.
• Sequence analysis to identify RNA motifs and cis-elements in target transcripts.
• Functional analysis of RNA elements by insertion and substitution experiments.

Main Results:

• TcUBP1 and TcRBP3 bind to specific mRNA targets, with distinct RNA motifs identified for each protein.
• RBP binding sites (cis-elements) are stem-loop structures (30-35 bases) predominantly in the 3'-untranslated region (UTR) of mRNAs.
• Experimental manipulation of these RNA elements confirmed their role in RBP binding specificity and competition.

Conclusions:

• TcUBP1 targets are enriched in metabolic genes, while TcRBP3 targets include ribosomal protein-encoding transcripts.
• These findings suggest that specific RBPs coordinate the post-transcriptional regulation of functionally related mRNA subsets in Trypanosomes.