Human pre-mRNA Cleavage Factor Im Is Related to Spliceosomal SR Proteins and Can Be Reconstituted in Vitro From Recombinant Subunits

Mol Cell. 1998 Jan;1(2):243-53. doi: 10.1016/s1097-2765(00)80025-8.


Four polypeptides of 25, 59, 68, and 72 kDa copurify with the activity of human cleavage factor Im (CF Im) involved in pre-mRNA 3' end processing. We report here the cloning of the 25 and 68 kDa subunits and the reconstitution of functional CF Im25/68 from these two polypeptides. Several lines of evidence indicate that CF Im exists in at least two different forms. The 68 kDa polypeptide has a domain organization reminiscent of spliceosomal SR proteins. Analysis of the kinetics of the cleavage reaction indicates that interaction of CF Im with the RNA is one of the earliest steps in the assembly of the 3' end processing complex and facilitates the recruitment of other processing factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal
  • Cell Fractionation
  • Chromatography
  • Cloning, Molecular
  • DNA, Complementary
  • Epitopes / analysis
  • Escherichia coli / genetics
  • Humans
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • RNA Precursors / genetics
  • RNA Precursors / metabolism*
  • RNA Precursors / pharmacology
  • RNA Splicing / physiology*
  • RNA-Binding Proteins / chemistry*
  • RNA-Binding Proteins / genetics*
  • RNA-Binding Proteins / immunology
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • mRNA Cleavage and Polyadenylation Factors


  • Antibodies, Monoclonal
  • DNA, Complementary
  • Epitopes
  • RNA Precursors
  • RNA-Binding Proteins
  • Recombinant Proteins
  • mRNA Cleavage and Polyadenylation Factors

Associated data

  • GENBANK/AJ001810
  • GENBANK/X67337