Delocalization of the multifunctional RNA splicing factor TLS/FUS in hippocampal neurones: exclusion from the nucleus and accumulation in dendritic granules and spine heads.
Long-term synaptic change in the cortex and the hippocampus is believed to require the highly localized delivery and translation of mRNAs in the dendritic shafts and spines. The molecular interactions that underlie local signalling between synapses and mRNAs are still largely undefined. After purification from total brain extracts, the NMDA receptor is known to be associated with numerous proteins, including the multifunctional RNA-binding factor TLS (also called FUS). In non-neural tissue, TLS is a vital nuclear protein with roles in DNA repair, homologous recombination, transcriptional regulation and pre-mRNA processing. We have examined the distribution of TLS in hippocampal neurones, both in the adult brain and in mature primary cultures, using subcellular fractionation and immunofluorescence techniques. TLS immunoreactivity is largely excluded from the neuronal nucleus and is found in the cytosol and in somatodendritic particles. In some of these particles, TLS colocalizes with Sam68, a nuclear RNA-binding protein that we previously showed is incorporated into dendritic RNA granules. Some of the TLS clusters also colocalize with NMDA receptor clusters. Finally, TLS clusters are occasionally seen within spine heads. The apparent removal of TLS from the nucleus might result in specific patterns of mRNA transcription or splicing in hippocampal neurones. TLS may also contribute to steering, anchoring or regulating mRNAs at synaptic sites.
Belly
Agnès
A
Laboratoire Neurodégénérescence et Plasticité, Université Joseph Fourier and INSERM EMI 0108, Pavillon de Neurologie, Centre Hospitalier Universitaire, F-38043 Grenoble cedex 9, France.
Moreau-Gachelin
Françoise
F
Sadoul
Rémy
R
Goldberg
Yves
Y
D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002458:Cell Fractionation / Q000379:methods; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D049229:Dendritic Spines / Q000378:metabolism*; D004622:Embryo, Mammalian; D005455:Fluorescent Antibody Technique / Q000379:methods; D006624:Hippocampus / Q000166:cytology*; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D034702:RNA-Binding Protein FUS / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C489559:KHDRBS1 protein, human; C489787:MAP2 protein, rat; D008869:Microtubule-Associated Proteins; C409466:NR1 NMDA receptor; D034702:RNA-Binding Protein FUS; D016601:RNA-Binding Proteins; D016194:Receptors, N-Methyl-D-Aspartate