RSR-2, the Caenorhabditis elegans ortholog of human spliceosomal component SRm300/SRRM2, regulates development by influencing the transcriptional machinery

PLoS Genet. 2013 Jun;9(6):e1003543. doi: 10.1371/journal.pgen.1003543. Epub 2013 Jun 6.

Abstract

Protein components of the spliceosome are highly conserved in eukaryotes and can influence several steps of the gene expression process. RSR-2, the Caenorhabditis elegans ortholog of the human spliceosomal protein SRm300/SRRM2, is essential for viability, in contrast to the yeast ortholog Cwc21p. We took advantage of mutants and RNA interference (RNAi) to study rsr-2 functions in C. elegans, and through genetic epistasis analysis found that rsr-2 is within the germline sex determination pathway. Intriguingly, transcriptome analyses of rsr-2(RNAi) animals did not reveal appreciable splicing defects but instead a slight global decrease in transcript levels. We further investigated this effect in transcription and observed that RSR-2 colocalizes with DNA in germline nuclei and coprecipitates with chromatin, displaying a ChIP-Seq profile similar to that obtained for the RNA Polymerase II (RNAPII). Consistent with a novel transcription function we demonstrate that the recruitment of RSR-2 to chromatin is splicing-independent and that RSR-2 interacts with RNAPII and affects RNAPII phosphorylation states. Proteomic analyses identified proteins associated with RSR-2 that are involved in different gene expression steps, including RNA metabolism and transcription with PRP-8 and PRP-19 being the strongest interacting partners. PRP-8 is a core component of the spliceosome and PRP-19 is the core component of the PRP19 complex, which interacts with RNAPII and is necessary for full transcriptional activity. Taken together, our study proposes that RSR-2 is a multifunctional protein whose role in transcription influences C. elegans development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans Proteins / genetics*
  • Chromatin / genetics*
  • DNA-Binding Proteins / genetics*
  • Germ Cells
  • Humans
  • Phosphorylation
  • RNA Polymerase II
  • RNA Splicing / genetics
  • RNA-Binding Proteins / genetics
  • Sequence Homology, Amino Acid
  • Spliceosomes / genetics*
  • Spliceosomes / metabolism
  • Transcription, Genetic*

Substances

  • Caenorhabditis elegans Proteins
  • Chromatin
  • DNA-Binding Proteins
  • RNA-Binding Proteins
  • RSR-2 protein, C elegans
  • SRRM2 protein, human
  • RNA Polymerase II

Grants and funding

This work was funded by the European Commision (Marie Curie International Reintegration Grant: MIRG-CT-2007-206584), the Carlos III Institute (FIS: PS09/02145, PI12/01554), and the Marató of TV3 (Ref. 100910). Laura Fontrodona was supported by an AGAUR predoctoral fellowship. Julián Cerón is a Miguel Servet Junior Investigator. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.