Amino Acid Sequence Animals Cell Fractionation Cloning, Molecular Conserved Sequence Eukaryota Gene Expression Gene Silencing Mammalia Models, Molecular Molecular Sequence Data Protein Interaction Mapping Protein Structure, Tertiary Protozoan Proteins RNA Splicing RNA splicing RNA-Binding Proteins Sequence Homology, Amino Acid Trans-splicing Trypanosoma brucei Trypanosoma brucei brucei Trypanosoma cruzi Trypanosomatidae Two-Hybrid System Techniques U2 auxiliary factor article cell fractionation controlled study molecular cloning nonhuman