Mex67p, a novel factor for nuclear mRNA export, binds to both poly(A)+ RNA and nuclear pores

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Analysis of mRNA Nuclear Export Kinetics in Mammalian Cells by Microinjection
11:32

Analysis of mRNA Nuclear Export Kinetics in Mammalian Cells by Microinjection

Published on: December 4, 2010

A Segref1, K Sharma, V Doye

  • 1University of Heidelberg, BZH, Germany.

The EMBO Journal
|June 2, 1997
PubMed

Insights

Mex67p is a crucial protein for messenger RNA (mRNA) export from the nucleus. This study identifies Mex67p

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Nuclear mRNA export is a fundamental cellular process.
  • Mex67p is a newly identified cellular factor involved in this process.
  • Homologs of Mex67p exist in humans and C. elegans.

Purpose of the Study:

  • To investigate the function of Mex67p in nuclear mRNA export.
  • To elucidate the mechanism by which Mex67p facilitates mRNA transport.
  • To identify interacting partners of Mex67p.

Main Methods:

  • Genetic interaction studies with nucleoporin Nup85p.
  • Analysis of poly(A)+ RNA localization in a thermosensitive mex67-5 mutant.
  • In vivo localization of Mex67p tagged with green fluorescent protein (GFP).
  • Biochemical crosslinking of Mex67p to mRNA.
  • Two-hybrid screening to identify interacting proteins.

Main Results:

  • The mex67-5 mutant shows poly(A)+ RNA accumulation in intranuclear foci at restrictive temperatures.
  • Nuclear protein import remains unaffected in the mutant.
  • Mex67p localizes to nuclear pores in vivo, while the mutant form accumulates in the cytoplasm.
  • Mex67p, but not Nup85p or Nup57p, directly crosslinks to mRNA.
  • A putative RNA-binding protein interacts with Mex67p.

Conclusions:

  • Mex67p plays an essential role in nuclear mRNA export.
  • Mex67p directly participates in the transport of mRNA from the nucleus to the cytoplasm.
  • Mex67p likely functions by binding to mRNA and facilitating its translocation through nuclear pores.

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