The dynamic translatome of retinal ganglion cell axons during assembly and maintenance of the mouse visual system
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE79352 | GEO | 2016/06/16
SECONDARY ACCESSION(S): PRJNA315830
REPOSITORIES: GEO
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Project description:Local mRNA translation mediates the adaptive responses of axons to extrinsic signals but direct evidence that it occurs in mammalian CNS axons in vivo is scant. We developed an axon-TRAP-RiboTag approach in mouse that allows deep-sequencing analysis of ribosome-bound mRNAs in the retinal ganglion cell axons of the developing and adult retinotectal projection in vivo. The embryonic-to-postnatal axonal translatome comprises an evolving subset of enriched genes with axon-specific roles suggesting distinct steps in axon wiring, such as elongation, pruning and synaptogenesis. Adult axons, remarkably, have a complex translatome with strong links to axon survival, neurotransmission and neurodegenerative disease. Translationally co-regulated mRNA subsets share common upstream regulators, and novel sequence elements generated by alternative splicing that promote axonal mRNA translation. Our results indicate that intricate regulation of compartment-specific mRNA translation in mammalian CNS axons supports the formation and maintenance of neural circuits in vivo. The profiling of ribosome-bound mRNAs in mouse retinal ganglion cell axons at 4 different developmental stages
2016-06-16 | E-GEOD-79352 | biostudies-arrayexpress
Project description:Localized mRNA translation regulates synapse function and axon maintenance, but how compartment-specific mRNA repertoires are regulated is largely unknown. We developed an axonal transcriptome capture method that allows deep sequencing of metabolically-labeled mRNAs from retinal ganglion cell axon terminals in mouse. Comparing axonal-to-somal transcriptomes and axonal translatome-to-transcriptome enables genome-wide visualization of mRNA transport and translation and unveils potential regulators tuned to each process. FMRP and TDP-43 stand out as key regulators of transport, and experiments in Fmr1 knock-out mice validate FMRP’s role in the axonal transportation of synapse-related mRNAs. Pulse-and-chase experiments enable genome-wide assessment of mRNA stability in axons and reveal a strong coupling between mRNA translation and decay. Measuring the absolute mRNA abundance per axon terminal shows that the axonal transcriptome is stably maintained in adulthood by persistent transport. Our datasets provide a rich resource for unique insights into RNA-based mechanisms in maintaining presynaptic structure and function in vivo.
2022-12-06 | GSE220187 | GEO
Project description:Ribosome assembly occurs mainly in the nucleolus yet recent studies have revealed robust enrichment and translation of mRNAs encoding many ribosomal proteins (RPs) in axons, far away from neuronal cell bodies. Here, we report a physical and functional interaction between locally synthesized RPs and ribosomes in the axon. We show that axonal RP translation is regulated through a novel sequence motif, CUIC, that forms an RNA-loop structure in the region immediately upstream of the initiation codon. Using imaging and subcellular proteomics techniques, we show that RPs synthesized in axons join axonal ribosomes in a nucleolus-independent fashion. Inhibition of axonal CUIC-regulated RP translation causes a significant decline in local translation activity and markedly reduces axon branching in the brain, revealing the physiological relevance of axonal RP synthesis in vivo. These results suggest that axonal translation supplies cytoplasmic RPs to maintain/modify local ribosomal function far from the nucleolus in neurons.
2019-12-11 | GSE135502 | GEO
Project description:Ribosome assembly occurs mainly in the nucleolus yet recent studies have revealed robust enrichment and translation of mRNAs encoding many ribosomal proteins (RPs) in axons, far away from neuronal cell bodies. Here, we report a physical and functional interaction between locally synthesized RPs and ribosomes in the axon. We show that axonal RP translation is regulated through a novel sequence motif, CUIC, that forms an RNA-loop structure in the region immediately upstream of the initiation codon. Using imaging and subcellular proteomics techniques, we show that RPs synthesized in axons join axonal ribosomes in a nucleolus-independent fashion. Inhibition of axonal CUIC-regulated RP translation causes a significant decline in local translation activity and markedly reduces axon branching in the brain, revealing the physiological relevance of axonal RP synthesis in vivo. These results suggest that axonal translation supplies cytoplasmic RPs to maintain/modify local ribosomal function far from the nucleolus in neurons.
2019-12-09 | PXD015574 | Pride
Project description:The subcellular localization of specific mRNAs is an evolutionary conserved mechanism that underlies the establishment of cellular polarity and specialized cell functions. In neurons, mRNA trafficking and local protein translation in dendrites provides an important mechanism that mediates synaptic development and plasticity. The significance of mRNA targeting and protein synthesis in axons, however, is still unclear. Only a small number of transcripts have been identified in axons to date, and their contribution to axon growth and neuronal survival remains largely unknown. Here, we report the results of a novel screen that allowed the separate identification of mRNAs localized in cell bodies and in axons of developing neurons. Using compartmentalized cultures of sympathetic neurons and Sequential Analysis of Gene Expression (SAGE), the screen identified more than 200 axonal mRNAs, including ones that encode cytoskeletal proteins and proteins that function in neural development and signal transduction. Importantly, several classes of transcripts were selectively enriched in axons, indicating that an active process drives the targeting of specific mRNAs from the cell bodies to the axons. This study is the first comprehensive and unbiased analysis of mRNA localization in subcellular domains of any neuronal cell type. We used compartmentalized chambers to culture neonatal rat sympathetic neurons (Campenot, 1977). In these cultures, the cell bodies are separated from the distal axons by a 1 mm wide Teflon divider, which maintains the cell bodies and axon terminals in separate fluid compartments. Primary rat sympathetic neurons are especially suitable for compartmentalized culture because they can be grown as a highly homogeneous population without glial cells. Neurons were seeded in the central compartment with nerve growth factor (NGF), and after a few days, the NGF was lowered in this compartment and supplied only to the peripheral compartment to stimulate axon growth. The anti-mitotic agent cytosine arabinoside C (Ara-C) was added to both compartments to remove non-neuronal cells. mRNA was then isolated after 12 days in culture (DIV) from cell body or axon compartments. As the initial mRNA content in axons was not sufficient to perform the SAGE analysis, both axon and cell body mRNAs were subjected to two rounds of linear amplification to obtain antisense RNA (aRNA). The amplified aRNA was then reverse transcribed and second strand synthesis was performed to proceed with the SAGE assay using the LongSAGE kit (Invitrogen) according to the manufacturer’s protocol.
2010-01-30 | E-GEOD-13788 | biostudies-arrayexpress
Project description:Spinal motor axons traverse large distances to innervate target muscle, and thus require local control of cellular events for proper functioning of the distal axon. To interrogate axon-specific processes we developed Axon-seq, a refined method incorporating microfluidic devices and stringent bioinformatic quality controls. Axon-seq demonstrates improved sensitivity and accuracy in whole-transcriptome sequencing of axons compared to previously published studies. Importantly, we show that axon transcriptomes are distinct from those of somas, displaying fewer detected genes and no contaminating astrocytic markers. We identified >5,000 transcripts in stem cell-derived spinal motor axons required for local oxidative energy production and ribosome generation. Axons contained unique transcription factor mRNAs, e.g. Ybx1, with implications for local axonal functions. Cross-comparison with existing mouse motor axon datasets, as well as our own human motor axon data identified a common axon transcriptome. As motor axons degenerate in amyotrophic lateral sclerosis (ALS), we investigated their response to the disease-causing SOD1G93A mutation, identifying 121 ALS-dysregulated transcripts. Several of these are implicated in axonal and dendritic outgrowth, including Nrp1, Dbn1, and Nek1, a known ALS-causing gene. In conclusion, Axon-seq proves a robust and improved method for RNA-seq of axons, furthers our understanding of peripheral axon biology, and identifies novel therapeutic targets to maintain neural connectivity in disease.
2018-12-11 | GSE121069 | GEO
Project description:During brain wiring, mRNAs are trafficked into axons and growth cones where they are differentially translated in response to extrinsic signals. Differential control of local protein synthesis mediates neuronal compartment-specific behaviors that aid axon guidance. Yet little is understood about how specific mRNAs are selected for translation. Here we have investigated the local role of microRNAs (miRNAs) in mRNA-specific translation during axon pathfinding of Xenopus laevis retinal ganglion cell (RGC) axons. Profiling experiments revealed a rich repertoire of axonal miRNAs in developing RGC axons and identified miR-182 as one of the most abundant. Loss of miR182 impairs Slit2-induced growth cone repulsion and causes RGC axon targeting defects in vivo. To aid miRNA target prediction, we also profiled mRNA expression in RGC axons. Our results show that miR-182 targets cofilin1 mRNA in RGC growth cones and modulates its local translation in response to Slit2.
2017-01-23 | GSE86883 | GEO
Project description:Local mRNA translation in axons is critical for the spatial and temporal regulation of the axonal proteome. A wide variety of mRNAs are localized and translated in axons, however how protein synthesis is regulated at specific subcellular sites in axons remains unclear. Here, we establish that the axonal endoplasmic reticulum (ER) supports axonal translation in developing neurons. Axonal ER tubule disruption impairs local translation and ribosome distribution. Using nanoscale resolution imaging, we find that ribosomes make frequent contacts with axonal ER tubules in a translation-dependent manner and are influenced by specific extrinsic cues. We identify P180/RRBP1 as an axonally distributed ribosome receptor that regulates local translation and binds to mRNAs enriched for axonal membrane proteins. Importantly, the impairment of axonal ER – ribosome interactions causes defects in axon morphology. Our results establish an important role for the axonal ER in dynamically localizing mRNA translation which is important for proper neuron development.
2024-04-29 | GSE262262 | GEO
Project description:The subcellular localization of specific mRNAs is an evolutionary conserved mechanism that underlies the establishment of cellular polarity and specialized cell functions. In neurons, mRNA trafficking and local protein translation in dendrites provides an important mechanism that mediates synaptic development and plasticity. The significance of mRNA targeting and protein synthesis in axons, however, is still unclear. Only a small number of transcripts have been identified in axons to date, and their contribution to axon growth and neuronal survival remains largely unknown. Here, we report the results of a novel screen that allowed the separate identification of mRNAs localized in cell bodies and in axons of developing neurons. Using compartmentalized cultures of sympathetic neurons and Sequential Analysis of Gene Expression (SAGE), the screen identified more than 200 axonal mRNAs, including ones that encode cytoskeletal proteins and proteins that function in neural development and signal transduction. Importantly, several classes of transcripts were selectively enriched in axons, indicating that an active process drives the targeting of specific mRNAs from the cell bodies to the axons. This study is the first comprehensive and unbiased analysis of mRNA localization in subcellular domains of any neuronal cell type.
2010-01-31 | GSE13788 | GEO
Project description:Ongoing neuronal activity during development and plasticity acts to refine synaptic connections and contributes to the induction of plasticity and ultimately long term memory storage. Activity-dependent post-transcriptional control of mRNAs occurs through transport to axonal and dendritic compartments, local translation, and mRNA stability. We have identified a mechanism that contributes to activity-dependent regulation of mRNA stability during synaptic plasticity. In this study we demonstrate rapid, post-transtriptional control over process-enriched mRNAs by neuronal activity. Systematic analysis of the 3'-UTRs of destablized transcripts, identifies enrichment in sequence motifs corresponding to miRNA binding sites. The miRNAs that were identified, miR-326-3p/miR-330-5p, miR-485-5p, miR-666-3p, and miR-761 are predicted to regulate networks of genes important in plasticity and development. We find that these miRNAs are developmentally regulated in the hippocampus, many increasing by postnatal day 14. We further show that miR-485-5p controls NGF-induced neurite outgrowth in PC12 cells, tau expression, and axonal development in hippocampal neurons. miRNAs can function at the synapse to rapidly control and affect short- and long-term changes at the synapse. These processes likely occur during refinement of synaptic connections and contribute to the induction of plasticity and learning and memory. 4 samples analysed, 3 coverslips pooled per sample. Mouse DRG neuron cell bodies and axons were separated in multicompartment cell cultures allowing electrical stimulation of axons, growing under a high-resistance partition between compartments, through platinum electrodes in the lid of the culture dish (Reference: http://www.ncbi.nlm.nih.gov/pubmed/9295372)
2014-03-12 | E-GEOD-55779 | biostudies-arrayexpress