Published online
doi:10.1083/jcb.200706164
The Journal of Cell Biology, Vol. 181, No. 4, 579-586
The Rockefeller University Press, 0021-9525 $30.00
© White et al.
Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2–dependent RNA granules
Robin White1,
Constantin Gonsior1,
Eva-Maria Krämer-Albers1,
Nadine Stöhr2,
Stefan Hüttelmaier2, and
Jacqueline Trotter1
1 Molecular Cell Biology, Department of Biology, Johannes Gutenberg University of Mainz, 55128 Mainz, Germany
2 NBL3 Research Group, Zentrum für Angewandte Medizinische und Human-biologische Forschung, Department of Medicine, Martin-Luther-University, 06120 Halle, Germany
Correspondence to J. Trotter: trotter{at}uni-mainz.de
Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that active Fyn phosphorylates hnRNP A2 and stimulates translation of an MBP A2RE–containing reporter construct. Neuronal adhesion molecule L1 binding to oligodendrocytes results in Fyn activation, which leads to an increase in hnRNP A2 phosphorylation. These results suggest that Fyn kinase activation results in the localized translation of MBP mRNA at sites of axon–glia contact and myelin deposition.
Abbreviations used in this paper: A2RE, A2 response element; CNS, central nervous system; ELISA, enzyme-linked immunosorbent assay; hnRNP, heterogeneous nuclear ribonucleoprotein; MBP, myelin basic protein; qRT-PCR, quantitative RT-PCR; UTR, untranslated region.
© 2008 White et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

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