Evidence for trans splicing in trypanosomes

Cell. 1986 Nov 21;47(4):527-35. doi: 10.1016/0092-8674(86)90617-3.


The 5' ends of trypanosome mRNAs consist of an identical sequence of 35 nucleotides. This "mini-exon" sequence is derived from the 5' end of a 137 nucleotide RNA (medRNA). The remainder of each mRNA is derived from a protein-coding exon that is not linked to the mini-exon. We propose that medRNA is spliced in trans to de-novo-initiated transcripts of protein-coding genes. This trans splicing model predicts that the downstream portion of medRNA will be part of a branched structure and then be released as a free product (minRNA). We demonstrate that significant levels of minRNA exist in trypanosome RNA. Furthermore, minRNA can be released from high molecular weight RNA by a HeLa cell S100 "debranching" extract. We conclude that trans splicing is the physiological process by which mature mRNA molecules are synthesized in trypanosomes.

Publication types

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

MeSH terms

  • Animals
  • Base Sequence
  • Endonucleases
  • Exons
  • Nucleic Acid Precursors / genetics*
  • RNA Splicing*
  • RNA, Messenger / genetics*
  • Single-Strand Specific DNA and RNA Endonucleases
  • Trypanosoma / genetics*


  • Nucleic Acid Precursors
  • RNA, Messenger
  • Endonucleases
  • Single-Strand Specific DNA and RNA Endonucleases