The human U1A snRNP protein regulates polyadenylation via a direct interaction with poly(A) polymerase

Samuel I. Gunderson, Katrin Beyer, Georges Martin, Water Keller, Wilbert C. Boelens, Iain W. Mattaj

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The human U1 snRNP-specific U1A protein autoregulates its production by binding its own pre-mRNA and inhibiting polyadenylation. The mechanism of this regulation has been elucidated by in vitro studies. U1A protein is shown not to prevent either binding of cleavage and polyadenylation specificity factor (CPSF) to its recognition sequence (AUUAAA) or to prevent cleavage of U1A pre-mRNA. Instead, U1A protein bound to U1A pre-mRNA inhibits both specific and nonspecific polyadenylation by mammalian, but not by yeast, poly(A) polymerase (PAP). Domains are identified in both proteins whose removal uncouples the polyadenylation activity of mammalian PAP from its inhibition via RNA-bound U1A protein. Finally, U1A protein is shown to specifically interact with mammalian PAP in vitro. The possibility that this interaction may reflect a broader role of the U1A protein in polyadenylation is discussed.

Original languageEnglish (US)
Pages (from-to)531-541
Number of pages11
Issue number3
StatePublished - Feb 11 1994
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)

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