Protein 61K, encoded by a gene (PRPF31) linked to autosomal dominant retinitis pigmentosa, is required for U4/U6*U5 tri-snRNP formation and pre-mRNA splicing

EMBO J. 2002 Mar 1;21(5):1148-57. doi: 10.1093/emboj/21.5.1148.


In each round of nuclear pre-mRNA splicing, the U4/U6*U5 tri-snRNP must be assembled from U4/U6 and U5 snRNPs, a reaction that is at present poorly understood. We have characterized a 61 kDa protein (61K) found in human U4/U6*U5 tri-snRNPs, which is homologous to yeast Prp31p, and show that it is required for this step. Immunodepletion of protein 61K from HeLa nuclear extracts inhibits tri-snRNP formation and subsequent spliceosome assembly and pre-mRNA splicing. Significantly, complementation with recombinant 61K protein restores each of these steps. Protein 61K is operationally defined as U4/U6 snRNP-specific as it remains bound to this particle at salt concentrations where the tri-snRNP dissociates. However, as shown by two-hybrid analysis and biochemical assays, protein 61K also interacts specifically with the U5 snRNP-associated 102K protein, indicating that it physically tethers U4/U6 to the U5 snRNP to yield the tri-snRNP. Interestingly, protein 61K is encoded by a gene (PRPF31) that has been shown to be linked to autosomal dominant retinitis pigmentosa. Thus, our studies suggest that disruptions in tri-snRNP formation and function resulting from mutations in the 61K protein may contribute to the manifestation of this disease.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Mutational Analysis
  • Eye Proteins / genetics
  • Eye Proteins / physiology*
  • Fungal Proteins*
  • Genes, Dominant
  • Genetic Complementation Test
  • HeLa Cells
  • Humans
  • Macromolecular Substances
  • Protein Interaction Mapping
  • RNA Precursors / metabolism*
  • RNA Splicing / physiology*
  • Recombinant Fusion Proteins / metabolism
  • Recombinant Fusion Proteins / physiology
  • Retinitis Pigmentosa / genetics*
  • Ribonucleoprotein, U4-U6 Small Nuclear / metabolism*
  • Ribonucleoprotein, U5 Small Nuclear / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Spliceosomes / metabolism*
  • Two-Hybrid System Techniques


  • Eye Proteins
  • Fungal Proteins
  • Macromolecular Substances
  • PRP31 protein, S cerevisiae
  • PRPF31 protein, human
  • RNA Precursors
  • Recombinant Fusion Proteins
  • Ribonucleoprotein, U4-U6 Small Nuclear
  • Ribonucleoprotein, U5 Small Nuclear
  • Saccharomyces cerevisiae Proteins