CryoEM structure of Saccharomyces cerevisiae U1 snRNP offers insight into alternative splicing

Nat Commun. 2017 Oct 19;8(1):1035. doi: 10.1038/s41467-017-01241-9.


U1 snRNP plays a critical role in 5'-splice site recognition and is a frequent target of alternative splicing factors. These factors transiently associate with human U1 snRNP and are not amenable for structural studies, while their Saccharomyces cerevisiae (yeast) homologs are stable components of U1 snRNP. Here, we report the cryoEM structure of yeast U1 snRNP at 3.6 Å resolution with atomic models for ten core proteins, nearly all essential domains of its RNA, and five stably associated auxiliary proteins. The foot-shaped yeast U1 snRNP contains a core in the "ball-and-toes" region architecturally similar to the human U1 snRNP. All auxiliary proteins are in the "arch-and-heel" region and connected to the core through the Prp42/Prp39 paralogs. Our demonstration that homodimeric human PrpF39 directly interacts with U1C-CTD, mirroring yeast Prp42/Prp39, supports yeast U1 snRNP as a model for understanding how transiently associated auxiliary proteins recruit human U1 snRNP in alternative splicing.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Alternative Splicing*
  • Cryoelectron Microscopy
  • Humans
  • RNA Precursors / genetics
  • RNA Precursors / metabolism
  • RNA Splice Sites
  • RNA, Fungal / genetics*
  • RNA, Fungal / metabolism
  • Ribonucleoprotein, U1 Small Nuclear / genetics*
  • Ribonucleoprotein, U1 Small Nuclear / metabolism*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism


  • RNA Precursors
  • RNA Splice Sites
  • RNA, Fungal
  • Ribonucleoprotein, U1 Small Nuclear
  • Saccharomyces cerevisiae Proteins