The Medical Research Council Cancer Unit

Cambridge, United Kingdom

The Medical Research Council Cancer Unit

Cambridge, United Kingdom
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Wickramasinghe V.,The Medical Research Council Cancer Unit | Savill J.,The Medical Research Council Cancer Unit | Chavali S.,The Medical Research Council Laboratory of Molecular Biology | Jonsdottir A.,The Medical Research Council Cancer Unit | And 5 more authors.
Molecular Cell | Year: 2013

Messenger RNA (mRNA) export from the nucleus is essential for eukaryotic gene expression. Here we identify a transcript-selective nuclear export mechanism affecting certain human transcripts, enriched for functions in genome duplication and repair, controlled by inositol polyphosphate multikinase (IPMK), an enzyme catalyzing inositol polyphosphate and phosphoinositide turnover. We studied transcripts encoding RAD51, a protein essential for DNA repair by homologous recombination (HR), to characterize the mechanism underlying IPMK-regulated mRNA export. IPMK depletion or catalytic inactivation selectively decreases RAD51 protein abundance and the nuclear export of RAD51 mRNA, thereby impairing HR. Recognition of a sequence motif in the untranslated region of RAD51 transcripts by the mRNA export factor ALY requires IPMK. Phosphatidylinositol (3,4,5)-trisphosphate (PIP3), an IPMK product, restores ALY recognition in IPMK-depleted cell extracts, suggesting a mechanism underlying transcript selection. Our findings implicate IPMK in a transcript-selective mRNA export pathway controlled by phosphoinositide turnover that preserves genome integrity in humans. © 2013 Elsevier Inc.


PubMed | The Medical Research Council Cancer Unit
Type: Journal Article | Journal: Molecular cell | Year: 2013

Messenger RNA (mRNA) export from the nucleus is essential for eukaryotic gene expression. Here we identify a transcript-selective nuclear export mechanism affecting certain human transcripts, enriched for functions in genome duplication and repair, controlled by inositol polyphosphate multikinase (IPMK), an enzyme catalyzing inositol polyphosphate and phosphoinositide turnover. We studied transcripts encoding RAD51, a protein essential for DNA repair by homologous recombination (HR), to characterize the mechanism underlying IPMK-regulated mRNA export. IPMK depletion or catalytic inactivation selectively decreases RAD51 protein abundance and the nuclear export of RAD51 mRNA, thereby impairing HR. Recognition of a sequence motif in the untranslated region of RAD51 transcripts by the mRNA export factor ALY requires IPMK. Phosphatidylinositol (3,4,5)-trisphosphate (PIP3), an IPMK product, restores ALY recognition in IPMK-depleted cell extracts, suggesting a mechanism underlying transcript selection. Our findings implicate IPMK in a transcript-selective mRNA export pathway controlled by phosphoinositide turnover that preserves genome integrity in humans.

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