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The spliceosomal PRP19 complex of trypanosomes.
Daniela L Ambrósio1, Nitika Badjatia, Arthur Günzl
1Department of Genetics and Genome Sciences, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT, 06030-6403, USA.
Molecular Microbiology
|December 20, 2014
Summary
Researchers identified the PRP19 complex in Trypanosoma brucei, revealing its role in spliceosome activation. Silencing SPF27 disrupted spliced leader trans-splicing, highlighting its importance in mRNA processing.
Area of Science:
- Molecular Biology
- Parasitology
- RNA Biology
Background:
- Trypanosomes utilize spliced leader (SL) trans-splicing for mRNA processing, a mechanism involving the spliceosome.
- Identifying trypanosome splicing factors is challenging due to evolutionary divergence from eukaryotic orthologs.
- Most characterized splicing factors are snRNP proteins; intact spliceosomes remain difficult to purify.
Purpose of the Study:
- To characterize the non-snRNP PRP19 complex in Trypanosoma brucei.
- To investigate the role of the PRP19 complex in spliceosome function and mRNA processing.
Main Methods:
- Proteomic analysis to identify components of the PRP19 complex.
- RNA interference (RNAi) to silence specific genes (e.g., SPF27).
- Analysis of SL RNA accumulation and cap methylation status.
Main Results:
- The PRP19 complex comprises core subunits PRP19, CDC5, PRL1, SPF27, and additional proteins PRP17, SKIP, and PPIL1.
- Three novel proteins were identified within this complex.
- SPF27 silencing inhibited the first step of splicing and caused accumulation of hypomethylated SL RNA.
- The observed defect mimicked that of CRK9 depletion, suggesting a functional link.
Conclusions:
- The identified PRP19 complex is a key component of the activated spliceosome in trypanosomes.
- SPF27 and potentially CRK9 play critical roles in spliceosome activation.
- This study advances the understanding of mRNA processing machinery in a unique eukaryotic system.
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