Two splicing factors carrying serine-arginine motifs, TSR1 and TSR1IP, regulate splicing, mRNA stability, and rRNA processing in Trypanosoma brucei

RNA Biol. 2014;11(6):715-31. doi: 10.4161/rna.29143. Epub 2014 May 13.


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. Mass-spectrometry 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.

Keywords: SR proteins; mRNA stability; proteomics of splicing complexes; rRNA processing; trans-splicing; trypanosomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Cell Nucleus / metabolism
  • Cluster Analysis
  • Gene Expression Profiling
  • Gene Order
  • Gene Silencing
  • Genetic Loci
  • Mass Spectrometry
  • Protein Interaction Domains and Motifs*
  • Protein Transport
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / metabolism*
  • RNA 3' Polyadenylation Signals
  • RNA Splicing*
  • RNA Stability*
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • RNA, Ribosomal / genetics*
  • RNA, Ribosomal / metabolism
  • RNA, Spliced Leader / genetics
  • RNA, Spliced Leader / metabolism
  • RNA-Binding Proteins / chemistry
  • RNA-Binding Proteins / metabolism*
  • Trans-Splicing
  • Transcription, Genetic
  • Transcriptome
  • Trypanosoma brucei brucei / genetics*
  • Trypanosoma brucei brucei / metabolism*


  • Protozoan Proteins
  • RNA, Messenger
  • RNA, Ribosomal
  • RNA, Spliced Leader
  • RNA-Binding Proteins
  • TSR1 interacting protein, trypanosoma