Biochemical and Functional Characterization of the Cis-Spliceosomal U1 Small Nuclear RNP From Trypanosoma Brucei

Mol Biochem Parasitol. 2002 May;121(2):233-43. doi: 10.1016/s0166-6851(02)00044-0.


Recent studies in the trypanosome system have revealed that in addition to trans splicing of a short spliced leader (SL) exon, there is also cis splicing of internal introns. It has been suggested that cis splicing requires base-pairing of U1 small nuclear RNA (snRNA) and the 5' splice site. We have cloned the gene for U1 snRNA from Trypanosoma brucei and characterized the U1 snRNP. Based on immunoprecipitation and direct mass-spectrometric protein analysis the U1 snRNP contains the common Sm core found also in the known trans-spliceosomal snRNPs U2, U4/U6, and U5. The 5' end of U1 snRNA in the U1 snRNP is accessible for and functional in specific recognition of the 5' splice site of the poly(A) polymerase intron.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cloning, Molecular
  • Molecular Sequence Data
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism
  • RNA Splice Sites / physiology
  • RNA, Protozoan / metabolism
  • RNA, Small Nuclear* / chemistry
  • RNA, Small Nuclear* / genetics
  • RNA, Small Nuclear* / metabolism
  • Ribonuclease H / metabolism
  • Ribonucleoprotein, U1 Small Nuclear* / chemistry
  • Ribonucleoprotein, U1 Small Nuclear* / genetics
  • Ribonucleoprotein, U1 Small Nuclear* / metabolism
  • Sequence Analysis, DNA
  • Spliceosomes / metabolism*
  • Trypanosoma brucei brucei / genetics
  • Trypanosoma brucei brucei / metabolism*


  • Protozoan Proteins
  • RNA Splice Sites
  • RNA, Protozoan
  • RNA, Small Nuclear
  • Ribonucleoprotein, U1 Small Nuclear
  • U1 small nuclear RNA
  • Ribonuclease H