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Dual requirement for yeast hnRNP Nab2p in mRNA poly(A) tail length control and nuclear export

Ronald E Hector1, Keith R Nykamp, Sonia Dheur

  • 1Department of Molecular Genetics and Microbiology, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL 32610-0266, USA.

The EMBO Journal
|April 3, 2002
PubMed

Insights

Nab2p is a nuclear protein crucial for controlling messenger RNA (mRNA) poly(A) tail length and export. Its absence causes abnormal tail growth and RNA buildup, highlighting its essential role in gene expression regulation.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • The link between mRNA 3'-end formation and nuclear export is increasingly evident.
  • Nuclear poly(A)-binding proteins play roles in mRNA processing and export.

Purpose of the Study:

  • To identify and characterize nuclear poly(A)-binding proteins involved in mRNA export.
  • To elucidate the function of Nab2p in poly(A) tail length control and mRNA nuclear export.

Main Methods:

  • Genetic analysis of yeast strains with altered NAB2 expression.
  • Biochemical assays to study polyadenylation and hyperadenylation in vitro.
  • Localization studies of poly(A)-binding proteins.

Main Results:

  • Nab2p is essential for poly(A) tail length control and nuclear mRNA export.
  • Loss of NAB2 leads to hyperadenylation and nuclear accumulation of poly(A)(+) RNA.
  • Nab2p's function in poly(A) tail length control is distinct from Pab1p and cannot be fully compensated by Pab1p overexpression.

Conclusions:

  • Nab2p is a key regulator of mRNA polyadenylation, activating polyadenylation while inhibiting hyperadenylation.
  • Nab2p acts as a crucial link between mRNA 3'-end formation and nuclear export.
  • The findings reveal Nab2p's essential role in maintaining mRNA homeostasis.

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