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Identification of a nuclear export receptor for tRNA
G J Arts1, M Fornerod, I W Mattaj
1European Molecular Biology Laboratory, Heidelberg, Germany.
Current Biology : CB
|March 25, 1998
Summary
Researchers identified a novel human protein, Exportin (tRNA), that facilitates the export of transfer RNA (tRNA) from the cell nucleus. This discovery clarifies the mechanism of nuclear export for tRNA molecules.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Nuclear transport of macromolecules is regulated by importin-beta family receptors.
- Ran GTPase controls the assembly and disassembly of transport complexes.
- Yeast Los1p, a member of the importin-beta family, has an unclear role in tRNA production.
Purpose of the Study:
- To characterize a human homolog of yeast Los1p involved in nuclear transport.
- To elucidate the function of this protein in tRNA processing and export.
Main Methods:
- Characterization of a novel human importin-beta family member.
- Studying protein localization and interaction with tRNA in a RanGTP-dependent manner.
- Xenopus oocyte nuclear injection assays to assess tRNA export dynamics.
Main Results:
- The human protein shuttles between the nucleus and cytoplasm.
- It interacts with tRNA in a RanGTP-dependent manner.
- The protein specifically stimulates nuclear tRNA export and alleviates competitive inhibition.
Conclusions:
- The characterized human protein functions as a nuclear export receptor for tRNA.
- The protein is named Exportin (tRNA) based on its function.