QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 19, Issue 7, 3008-3019, July 2008

This Article Full Text Full Text (PDF) Supplemental Materials All Versions of this Article: E07-10-1083v1 19/7/3008    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Raju, C. S. Articles by Percipalle, P. PubMed PubMed Citation Articles by Raju, C. S. Articles by Percipalle, P.

In Cultured Oligodendrocytes the A/B-type hnRNP CBF-A Accompanies MBP mRNA Bound to mRNA Trafficking Sequences

Chandrasekhar S. Raju^*, Christian Göritz^*, Ylva Nord^*, Ola Hermanson, Carmen López-Iglesias, Neus Visa, Goncalo Castelo-Branco, and Piergiorgio Percipalle^*

*Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, Stockholm SE-171 77, Sweden; Department of Neuroscience, Karolinska Institute, Stockholm SE-171 77, Sweden; Serveis Cientificotècnics, Universitat de Barcelona, E-08028 Barcelona, Spain; and Department of Molecular Biology and Functional Genomics, Stockholm University, Stockholm, SE-10691, Sweden

Submitted October 26, 2007; Revised April 8, 2008; Accepted May 6, 2008
Monitoring Editor: A. Gregory Matera

Heterogeneous ribonucleoproteins (hnRNPs) have key roles in RNA biogenesis, including pre-mRNP assembly, transport and cytoplasmic localization. Here we show by biochemical fractionation of nuclear extracts and protein–protein interaction assays that the A/B-type hnRNP CBF-A is in a multiprotein complex with hnRNP A2 and A3 and hnRNP U. Using RNA affinity chromatography and gel retardation assays, CBF-A was found to bind directly to RNA trafficking sequences in the 3'-UTR of the myelin basic protein (MBP) mRNA. In primary oligodendrocytes, astrocytes, neurons, and mouse forebrain sections, CBF-A revealed a characteristic granular cytoplasmic distribution. In mouse forebrain CBF-A–positive granules were preferentially found in regions with loosely bundled myelin fibers. In cultured oligodendrocytes, CBF-A was found to be specifically associated with endogenous MBP mRNA and CBF-A gene silencing resulted in the retention of MBP granules in the cell body. Finally, immunoelectron microscopy in differentiating oligodendrocytes showed that CBF-A is located in cytoplasmic granules that are often associated with the cytoskeleton. The results suggest that CBF-A is a novel transacting factor required for cytoplasmic mRNA transport and localization.

Address correspondence to: Piergiorgio Percipalle (piergiorgio.percipalle{at}ki.se)