Scanning from an independently specified branch point defines the 3' splice site of mammalian introns

Nature. 1989 Nov 16;342(6247):243-7. doi: 10.1038/342243a0.


During pre-messenger RNA splicing the lariat branch point in mammalian introns is specified independently of the 3' splice site by the sequence surrounding the branch point and by an adjacent downstream polypyrimidine tract. The 3' splice site is dispensable for spliceosome assembly and cleavage at the 5' splice site, and is itself determined by a scanning process that recognizes the first AG located 3' of the branch point/polypyrimidine tract, irrespective of distance or sequence environment.

Publication types

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

MeSH terms

  • Animals
  • Base Sequence
  • Introns*
  • Molecular Sequence Data
  • Pyrimidines
  • RNA Splicing*
  • RNA, Messenger / genetics*
  • Rats
  • Structure-Activity Relationship
  • Tropomyosin / genetics*


  • Pyrimidines
  • RNA, Messenger
  • Tropomyosin