Human Fip1 is a subunit of CPSF that binds to U-rich RNA elements and stimulates poly(A) polymerase

EMBO J. 2004 Feb 11;23(3):616-26. doi: 10.1038/sj.emboj.7600070. Epub 2004 Jan 29.

Abstract

In mammals, polyadenylation of mRNA precursors (pre-mRNAs) by poly(A) polymerase (PAP) depends on cleavage and polyadenylation specificity factor (CPSF). CPSF is a multisubunit complex that binds to the canonical AAUAAA hexamer and to U-rich upstream sequence elements on the pre-mRNA, thereby stimulating the otherwise weakly active and nonspecific polymerase to elongate efficiently RNAs containing a poly(A) signal. Based on sequence similarity to the Saccharomyces cerevisiae polyadenylation factor Fip1p, we have identified human Fip1 (hFip1) and found that the protein is an integral subunit of CPSF. hFip1 interacts with PAP and has an arginine-rich RNA-binding motif that preferentially binds to U-rich sequence elements on the pre-mRNA. Recombinant hFip1 is sufficient to stimulate the in vitro polyadenylation activity of PAP in a U-rich element-dependent manner. hFip1, CPSF160 and PAP form a ternary complex in vitro, suggesting that hFip1 and CPSF160 act together in poly(A) site recognition and in cooperative recruitment of PAP to the RNA. These results show that hFip1 significantly contributes to CPSF-mediated stimulation of PAP activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs / genetics
  • Amino Acid Motifs / physiology
  • Amino Acid Sequence
  • Cloning, Molecular
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / metabolism
  • Poly A / genetics
  • Poly A / metabolism*
  • Polynucleotide Adenylyltransferase / metabolism*
  • Protein Binding / genetics
  • Protein Binding / physiology
  • RNA 3' Polyadenylation Signals / physiology*
  • RNA Precursors / genetics
  • RNA Precursors / metabolism*
  • mRNA Cleavage and Polyadenylation Factors / genetics
  • mRNA Cleavage and Polyadenylation Factors / metabolism*

Substances

  • FIP1L1 protein, human
  • Multiprotein Complexes
  • RNA Precursors
  • mRNA Cleavage and Polyadenylation Factors
  • Poly A
  • Polynucleotide Adenylyltransferase