Polyadenylation site choice in yeast is affected by competition between Npl3 and polyadenylation factor CFI
- 1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
- 2Department of Molecular Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
- 3Department of Structural Biology, Stanford University, Stanford, California 94305, USA
Abstract
Multiple steps in mRNA processing and transcription are coupled. Notably, the processing of mRNA 3′ ends is linked to transcription termination by RNA polymerase II. Previously, we found that the yeast hnRNP protein Npl3 can negatively regulate 3′ end mRNA formation and termination at the GAL1 gene. Here we show that overexpression of the Hrp1 or Rna14 subunits of the CF IA polyadenylation factor increases recognition of a weakened polyadenylation site. Genetic interactions of mutant alleles of NPL3 or HRP1 with RNA15 also indicate antagonism between these factors. Npl3 competes with Rna15 for binding to a polyadenylation precursor and inhibits cleavage and polyadenylation in vitro. These results suggest that an important function of hnRNP proteins is to ensure the fidelity of mRNA processing. Our results support a model in which balanced competition of Npl3 with mRNA processing factors may promote recognition of proper polyadenylation sites while suppressing cryptic sites.
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Footnotes
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↵4 Present address: National Cancer Institute, NIH, Bethesda, MD 20892.
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Reprint requests to: Stephen Buratowski, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA; e-mail: steveb{at}hms.harvard.edu; fax: (617) 738-0516.
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Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.607207.
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- Received April 26, 2007.
- Accepted June 25, 2007.
- Copyright © 2007 RNA Society
