Sequences and proteins that influence mRNA processing in Trypanosoma brucei: Evolutionary conservation of SR-domain and PTB protein functions.

Background: Spliced leader trans splicing is the addition of a short, capped sequence to the 5' end of mRNAs. It is widespread in eukaryotic evolution, but factors that influence trans splicing acceptor site choice have been little investigated. In Kinetoplastids, all protein-coding mRNAs are 5' trans spliced.

Phosphorylation and interactions associated with the control of the Leishmania Poly-A Binding Protein 1 (PABP1) function during translation initiation.

The Poly-A Binding Protein (PABP) is a conserved eukaryotic polypeptide involved in many aspects of mRNA metabolism. During translation initiation, PABP interacts with the translation initiation complex eIF4F and enhances the translation of polyadenylated mRNAs. Schematically, most PABPs can be divided into an N-terminal RNA-binding region, a non-conserved linker segment and the C-terminal MLLE domain.

The unique Leishmania EIF4E4 N-terminus is a target for multiple phosphorylation events and participates in critical interactions required for translation initiation.

The eukaryotic initiation factor 4E (eIF4E) recognizes the mRNA cap structure and, together with eIF4G and eIF4A, form the eIF4F complex that regulates translation initiation in eukaryotes. In trypanosomatids, 2 eIF4E homologues (EIF4E3 and EIF4E4) have been shown to be part of eIF4F-like complexes with presumed roles in translation initiation. Both proteins possess unique N-terminal extensions, which can be targeted for phosphorylation.

The eIF4E subunits of two distinct trypanosomatid eIF4F complexes are subjected to differential post-translational modifications associated to distinct growth phases in culture.

The eukaryotic eIF4F complex, the cap binding complex, functions during translation initiation through interactions mediated by its three subunits (eIF4E, eIF4G and eIF4A), other initiation factors and the ribosome. In trypanosomatids, various eIF4E and eIF4G homologues were identified, with two eIF4F-like complexes confirmed (EIF4E4/EIF4G3/EIF4AI and EIF4E3/EIF4G4/EIF4AI). Here, the expression pattern of these complexes was investigated during Leishmania amazonensis and Trypanosoma brucei growth.

Molecular characterization of Aeromonas spp. and Vibrio cholerae O1 isolated during a diarrhea outbreak.

This work aimed to assess pathogenic potential and clonal relatedness of Aeromonas sp. and Vibrio cholerae isolates recovered during a diarrhea outbreak in Brazil. Clinical and environmental isolates were investigated for the presence of known pathogenic genes and clonal relatedness was assessed by intergenic spacer region (ISR) 16S-23S amplification.