The human homologue of Saccharomyces cerevisiae Gle1p is required for poly(A)+ RNA export.

Watkins JL, Murphy R, Emtage JL, Wente SR
Proc Natl Acad Sci U S A. 1998 95 (12): 6779-84

PMID: 9618489 · PMCID: PMC22633 · DOI:10.1073/pnas.95.12.6779

The mechanism of mRNA export is a complex issue central to cellular physiology. We characterized previously yeast Gle1p, a protein with a leucine-rich (LR) nuclear export sequence (NES) that is essential for poly(A)+ RNA export in Saccharomyces cerevisiae. To characterize elements of the vertebrate mRNA export pathway, we identified a human homologue of yeast Gle1p and analyzed its function in mammalian cells. hGLE1 encodes a predicted 75-kDa polypeptide with high sequence homology to yeast Gle1p, but hGle1p does not contain a sequence motif matching any of the previously characterized NESs. hGLE1 can complement a yeast gle1 temperature-sensitive export mutant only if a LR-NES is inserted into it. To determine whether hGle1p played a role in nuclear export, anti-hGle1p antibodies were microinjected into HeLa cells. In situ hybridization of injected cells showed that poly(A)+ RNA export was inhibited. In contrast, there was no effect on the nuclear import of a glucocorticoid receptor reporter. We conclude that hGle1p functions in poly(A)+ RNA export, and that human cells facilitate such export with a factor similar to yeast but without a recognizable LR-NES. With hGle1p localized at the nuclear pore complexes, hGle1p is positioned to act at a terminal step in the export of mature RNA messages to the cytoplasm.

MeSH Terms (18)

Amino Acid Sequence Biological Transport Carrier Proteins Cloning, Molecular Fungal Proteins Gene Expression Regulation Genes, Fungal HeLa Cells Humans In Situ Hybridization Molecular Sequence Data Nuclear Pore Complex Proteins Protein Biosynthesis RNA, Messenger Saccharomyces cerevisiae Saccharomyces cerevisiae Proteins Sequence Analysis Sequence Homology, Amino Acid

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