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A more recent version of this article appeared on January 1, 2005
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Submitted on June 24, 2004
Revised on September 29, 2004
Accepted on October 20, 2004
*Fundación Instituto Leloir - IIB Facultad de Ciencias Exactas y Naturales, University of Buenos Aires - IIBBA-CONICET, Buenos Aires, Argentina;
Instituto de Química y Fisicoquímica Biológica, Facultad de Farmacia y Bioquímica, University of Buenos Aires, CONICET, Buenos Aires, Argentina;
Department of Neurology, Instituto de Investigaciones Neurológicas Raul Carrea (FLENI), Buenos Aires, Argentina; ||Institute for Cell Biochemistry and Clinical Neurobiology, Center for Molecular Neurobiology, University Hospital Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany
Monitoring Editor: Peter Walter
Staufen is a conserved double-stranded RNA-binding protein required for mRNA localization in Drosophila oocytes and embryos. The mammalian homologues Staufen 1 and Staufen 2 have been implicated in dendritic RNA targeting in neurons. Here we show that in rodent oligodendrocytes, these two proteins are present in two independent sets of RNA granules located at the distal myelinating processes. A third kind of RNA granules lacks Staufen and contains major myelin mRNAs. Myelin Staufen granules associate with microfilaments and microtubules, and their subcellular distribution is affected by polysome-disrupting drugs. Under oxidative stress, both Staufen 1 and Staufen 2 are recruited into stress granules (SGs), which are stress-induced organelles containing transiently silenced messengers. Staufen SGs contain the Poly(A)-binding protein (PABP), the RNA-binding proteins HuR and TIAR, and small but not large ribosomal subunits. Staufen recruitment into perinuclear SGs is paralleled by a similar change in the overall localization of polyadenylated RNA. Under the same conditions, the distribution of recently transcribed and exported mRNAs is not affected. Our results indicate that Staufen 1 and Staufen 2 are novel and ubiquitous SG components and suggest that Staufen RNPs are involved in repositioning of most polysomal mRNAs, but not of recently synthesized transcripts, during the stress response.
These authors contributed equally to this work.
¶Corresponding author.
E-mail: gboccaccio{at}leloir.org.ar