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Pml39, a novel protein of the nuclear periphery required for nuclear retention of improper messenger

Benoît Palancade1, Michela Zuccolo, Sophie Loeillet

  • 1Pores Nucléaires et Transport Nucléocytoplasmique, Unité Mixte de Recherche 144 Centre National de la Recherche Scientifique, Paris Cedex, France. palancad@curie.fr

Molecular Biology of the Cell
|September 16, 2005
PubMed

Insights

We discovered PML39, a protein that interacts with nuclear pore complexes in yeast. PML39 retains improperly assembled messenger ribonucleoparticles (mRNPs) in the nucleus, preventing their export.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • The nuclear pore complex (NPC) regulates transport between the nucleus and cytoplasm.
  • Messenger ribonucleoparticles (mRNPs) must be properly assembled for efficient nuclear export.
  • Proteins interacting with NPCs and mRNPs are crucial for nuclear export control.

Purpose of the Study:

  • To characterize a novel Saccharomyces cerevisiae protein, PML39, and its role in nuclear export.
  • To elucidate the interaction of PML39 with nucleoporins and its function in mRNP retention.

Main Methods:

  • Genetic screening in Saccharomyces cerevisiae.
  • Localization studies using Pml39-green fluorescent protein (GFP) fusions.
  • Yeast two-hybrid assays.
  • Analysis of mutant phenotypes (e.g., nup60delta, pml39delta).

Main Results:

  • PML39 interacts with nucleoporins Mlp1 and Mlp2 at specific nuclear pore complexes.
  • Deletion of PML39 causes leakage of unspliced mRNAs.
  • Overexpression of PML39 traps intron-containing mRNAs and Nab2 in nuclear domains.
  • PML39 deletion partially rescues thermosensitive mRNP assembly mutants.

Conclusions:

  • PML39 acts as an upstream effector of Mlp1 and Mlp2.
  • PML39 is involved in retaining improperly assembled mRNPs in the nucleus.
  • PML39 plays a critical role in nuclear export quality control.

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