Cross-intron bridging interactions in the yeast commitment complex are conserved in mammals

Cell. 1997 May 2;89(3):403-12. doi: 10.1016/s0092-8674(00)80221-4.


The commitment complex is the first defined step in the yeast (S. cerevisiae) splicing pathway. It contains U1 snRNP as well as Mud2p, which resembles human U2AF65. In a genetic screen, we identified the yeast gene MSL-5, which is a novel commitment complex component. Genetic and biochemical criteria indicate a direct interaction between Msl5p and both Mud2p and the U1 snRNP protein Prp40p. This defines a bridge between the two ends of the intron. Msl5p (renamed BBP for branchpoint bridging protein) has a mammalian ortholog, the splicing factor SF1. Our results show that SF1 interacts strongly with human U2AF65, and that SF1 is a bona fide E complex component. This implies that aspects of these novel cross-intron protein-protein interactions are conserved between yeast and mammals.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Conserved Sequence*
  • DNA-Binding Proteins*
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Humans
  • Introns / genetics*
  • Mammals
  • Mutagenesis / physiology
  • RNA Splicing / genetics
  • RNA Splicing Factors
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Ribonucleoprotein, U1 Small Nuclear / genetics
  • Ribonucleoprotein, U1 Small Nuclear / metabolism
  • Ribonucleoproteins / genetics
  • Ribonucleoproteins / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Splicing Factor U2AF
  • Transcription Factors*


  • DNA-Binding Proteins
  • Fungal Proteins
  • MUD2 protein, S cerevisiae
  • RNA Splicing Factors
  • RNA-Binding Proteins
  • Recombinant Fusion Proteins
  • Ribonucleoprotein, U1 Small Nuclear
  • Ribonucleoproteins
  • SF1 protein, S cerevisiae
  • SF1 protein, human
  • Saccharomyces cerevisiae Proteins
  • Splicing Factor U2AF
  • Transcription Factors