U1 snRNP Inhibits pre-mRNA Polyadenylation Through a Direct Interaction Between U1 70K and poly(A) Polymerase

Mol Cell. 1998 Jan;1(2):255-64. doi: 10.1016/s1097-2765(00)80026-x.


It has previously been shown in vivo that bovine papillomavirus represses its late gene expression via a 5' splice site sequence located upstream of the late polyadenylation signal. Here, the mechanism of repression is determined by in vitro analysis. U1 snRNP binding to the 5' splice site results in inhibition of polyadenylation via a direct interaction with poly(A) polymerase (PAP). Although the inhibitory mechanism is similar to that used in U1A autoregulation, U1A within the U1 snRNP does not contribute to PAP inhibition. Instead the U1 70K protein, when bound to U1 snRNA, both interacts with and inhibits PAP. Conservation of the U1 70K inhibitory domains suggests that polyadenylation regulation via PAP inhibition may be more widespread than previously thought.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / metabolism
  • Amino Acid Sequence
  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cattle
  • Cell Nucleus / chemistry
  • Cell Nucleus / enzymology
  • Enzyme Activation / physiology
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Enzymologic*
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Polynucleotide Adenylyltransferase*
  • RNA Precursors / genetics
  • RNA Precursors / metabolism*
  • RNA Splicing / physiology
  • Ribonuclease H
  • Ribonucleoprotein, U1 Small Nuclear / genetics
  • Ribonucleoprotein, U1 Small Nuclear / metabolism*
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins*


  • Bacterial Proteins
  • Escherichia coli Proteins
  • RNA Precursors
  • Ribonucleoprotein, U1 Small Nuclear
  • SNP1 protein, S cerevisiae
  • SNRNP70 protein, human
  • Saccharomyces cerevisiae Proteins
  • Polynucleotide Adenylyltransferase
  • pcnB protein, E coli
  • Ribonuclease H
  • Adenine