In trypanosomes, mRNAs are processed by trans-splicing; in this process, a common exon, the spliced leader, is added to all mRNAs from a small RNA donor, the spliced leader RNA (SL RNA). However, little is known regarding how this process is regulated. In this study we investigated the function of two serine-arginine-rich proteins, TSR1 and TSR1IP, implicated in trans-splicing in Trypanosoma brucei. Depletion of these factors by RNAi suggested their role in both cis- and trans-splicing. Microarray was used to examine the transcriptome of the silenced cells. The level of hundreds of mRNAs was changed, suggesting that these proteins have a role in regulating only a subset of T. brucei mRNAs. Massspectrometry analyses of complexes associated with these proteins suggest that these factors function in mRNA stability, translation, and rRNA processing. We further demonstrate changes in the stability of mRNA as a result of depletion of the two TSR proteins. In addition, rRNA defects were observed under the depletion of U2AF35, TSR1, and TSR1IP, but not SF1, suggesting involvement of SR proteins in rRNA processing.
Bibliographical noteFunding Information:
The work was supported by the Deutsche Forcshungsgemeinschaft (DFG) via DIP and the Israel Science Foundation. Michaeli S holds the David and Inez Myers Chair in RNA silencing of diseases. Carmi S thanks the Human Frontier Science Program for financial support. We thank Dr Mark Katzenellenbogen for his initial analysis of the microarray data.
- Proteomics of splicing complexes
- RRNA processing
- SR proteins
- mRNA stability