Tracking the Fragile X Mental Retardation Protein in a Highly Ordered Neuronal RiboNucleoParticles Population: A Link between Stalled Polyribosomes and RNA Granules
| Autor: | Paul De Koninck, Alain Y. Dury, Sandra Tremblay, Rachid El Fatimy, Claude Robert, Xavier H. Jaglin, Laetitia Davidovic, Edouard W. Khandjian |
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| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
Cancer Research Gene Expression Video microscopy RNA-binding protein RNA-binding proteins Biochemistry Fragile X Mental Retardation Protein Mice Animal Cells Protein biosynthesis Genetics (clinical) Cytoskeleton Neurons education.field_of_study Neuronal Plasticity Messenger RNA Brain Gene Expression Regulation Developmental Cell biology Fragile X syndrome Nucleic acids medicine.anatomical_structure Dendritic Structure Cellular Structures and Organelles Cellular Types Research Article lcsh:QH426-470 Population Biology 03 medical and health sciences medicine Genetics Animals Humans RNA Messenger education Molecular Biology Ecology Evolution Behavior and Systematics RNA Biology and Life Sciences Proteins Cell Biology Neuronal Dendrites medicine.disease Molecular biology lcsh:Genetics 030104 developmental biology Fragile X Syndrome Polyribosomes Protein Biosynthesis Cellular Neuroscience Synapses Soma Protein Translation Ribosomes Neuroscience |
| Zdroj: | PLoS Genetics PLoS Genetics, Vol 12, Iss 7, p e1006192 (2016) |
| ISSN: | 1553-7404 |
| Popis: | Local translation at the synapse plays key roles in neuron development and activity-dependent synaptic plasticity. mRNAs are translocated from the neuronal soma to the distant synapses as compacted ribonucleoparticles referred to as RNA granules. These contain many RNA-binding proteins, including the Fragile X Mental Retardation Protein (FMRP), the absence of which results in Fragile X Syndrome, the most common inherited form of intellectual disability and the leading genetic cause of autism. Using FMRP as a tracer, we purified a specific population of RNA granules from mouse brain homogenates. Protein composition analyses revealed a strong relationship between polyribosomes and RNA granules. However, the latter have distinct architectural and structural properties, since they are detected as close compact structures as observed by electron microscopy, and converging evidence point to the possibility that these structures emerge from stalled polyribosomes. Time-lapse video microscopy indicated that single granules merge to form cargoes that are transported from the soma to distal locations. Transcriptomic analyses showed that a subset of mRNAs involved in cytoskeleton remodelling and neural development is selectively enriched in RNA granules. One third of the putative mRNA targets described for FMRP appear to be transported in granules and FMRP is more abundant in granules than in polyribosomes. This observation supports a primary role for FMRP in granules biology. Our findings open new avenues for the study of RNA granule dysfunctions in animal models of nervous system disorders, such as Fragile X syndrome. Author Summary Fragile X syndrome is the most common form of inherited mental retardation affecting approximately 1 female out of 7000 and 1 male out of 4000 worldwide. The syndrome is due to the silencing of a single gene, the Fragile Mental Retardation 1 (FMR1), that codes for the Fragile X mental retardation protein (FMRP). This protein is highly expressed in brain and controls local protein synthesis essential for neuronal development and maturation as well as the formation of neural circuits. Several studies suggest a role for FMRP in the regulation of mRNA transport along axons and dendrites to distant synaptic locations in structures called RNA granules. Here we report the isolation of a particular subpopulation of these structures and the analysis of their architecture and composition in terms of RNA and protein. Also, using time-lapse video microscopy, we monitored granule transport and fusion throughout neuronal processes. These findings open new avenues for the study of RNA transport dysfunctions in animal models of nervous system disorders. |
| Databáze: | OpenAIRE |
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