Open AccessLocalization of FMRP‐associated mRNA granules and requirement of microtubules for activity‐dependent trafficking in hippocampal neurons
Author(s) -
Antar L. N.,
Dictenberg J. B.,
Plociniak M.,
Afroz R.,
Bassell G. J.
Publication year - 2005
Publication title -
genes, brain and behavior
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.315
H-Index - 91
eISSN - 1601-183X
pISSN - 1601-1848
DOI - 10.1111/j.1601-183x.2005.00128.x
Subject(s) - microbiology and biotechnology , hippocampal formation , dendritic spine , microtubule , biology , fluorescence recovery after photobleaching , fmr1 , stress granule , filopodia , messenger rna , dendritic filopodia , actin , chemistry , translation (biology) , neuroscience , biochemistry , fragile x , gene , membrane
Fragile X syndrome is caused by the absence of the fragile X mental‐retardation protein (FMRP), an mRNA‐binding protein, which may play important roles in the regulation of dendritic mRNA localization and/or synaptic protein synthesis. We have recently applied high‐resolution fluorescence imaging methods to document the presence, motility and activity‐dependent regulation of FMRP granule trafficking in dendrites and spines of cultured hippocampal neurons. In this study, we show that FMRP granules distribute to F‐actin‐rich compartments, including filopodia, spines and growth cones during the staged development of hippocampal neurons in culture. Fragile X mental‐retardation protein granules were shown to colocalize with ribosomes, ribosomal RNA and MAP1B mRNA, a known FMRP target, which encodes a protein important for microtubule and actin stabilization. The levels of FMRP within dendrites were reduced by disruption of microtubule dynamics, but not by disruption of F‐actin. Direct measurements of FMRP transport kinetics using fluorescence recovery after photobleaching in living neurons showed that microtubules were required to induce the mGluR‐dependent translocation into dendrites. This study provides further characterization of the composition and regulated trafficking of FMRP granules in dendrites of hippocampal neurons.