scholarly journals Identification of 3’ UTR motifs required for mRNA localization to myelin sheaths in vivo

2019 ◽  
Author(s):  
Katie M. Yergert ◽  
Rebecca O’Rouke ◽  
Jacob H. Hines ◽  
Bruce Appel
Keyword(s):  
Mrna Localization ◽  
Global Regulator ◽  
Local Protein Synthesis ◽  
Consensus Sequences ◽  
Cellular Processes ◽  
Zebrafish Larvae ◽  
Myelin Sheaths ◽  
Growth Zones ◽  
Local Protein

ABSTRACTMyelin is a specialized membrane produced by oligodendrocytes that insulates and supports axons. Oligodendrocytes extend numerous cellular processes, as projections of the plasma membrane, and simultaneously wrap multiple layers of myelin membrane around target axons. Notably, myelin sheaths originating from the same oligodendrocyte are variable in size, suggesting local mechanisms regulate myelin sheath growth. Purified myelin contains ribosomes and hundreds of mRNAs, supporting a model that mRNA localization and local protein synthesis regulate sheath growth and maturation. However, the mechanisms by which mRNAs are selectively enriched in myelin sheaths are unclear. To investigate how mRNAs are targeted to myelin sheaths, we tested the hypothesis that transcripts are selected for myelin enrichment through consensus sequences in the 3’ untranslated region (3’ UTR). Using methods to visualize mRNA in living zebrafish larvae, we identified candidate 3’ UTRs that were sufficient to localize mRNA to sheaths and enriched near growth zones of nascent membrane. We bioinformatically identified motifs common in 3’ UTRs from three myelin-enriched transcripts and determined that these motifs are required for mRNA transport to myelin sheaths. Finally, we show that one motif is highly enriched in the myelin transcriptome, suggesting that this sequence is a global regulator of mRNA localization during developmental myelination.

scholarly journals Identification of 3′ UTR motifs required for mRNA localization to myelin sheaths in vivo

PLoS Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. e3001053
Author(s):  
Katie M. Yergert ◽  
Caleb A. Doll ◽  
Rebecca O’Rouke ◽  
Jacob H. Hines ◽  
Bruce Appel
Keyword(s):  
Mrna Localization ◽  
Dependent Manner ◽  
Global Regulator ◽  
Local Protein Synthesis ◽  
Consensus Sequences ◽  
Cellular Processes ◽  
Myelin Sheaths ◽  
Growth Zones ◽  
Local Protein

Myelin is a specialized membrane produced by oligodendrocytes that insulates and supports axons. Oligodendrocytes extend numerous cellular processes, as projections of the plasma membrane, and simultaneously wrap multiple layers of myelin membrane around target axons. Notably, myelin sheaths originating from the same oligodendrocyte are variable in size, suggesting local mechanisms regulate myelin sheath growth. Purified myelin contains ribosomes and hundreds of mRNAs, supporting a model that mRNA localization and local protein synthesis regulate sheath growth and maturation. However, the mechanisms by which mRNAs are selectively enriched in myelin sheaths are unclear. To investigate how mRNAs are targeted to myelin sheaths, we tested the hypothesis that transcripts are selected for myelin enrichment through consensus sequences in the 3′ untranslated region (3′ UTR). Using methods to visualize mRNA in living zebrafish larvae, we identified candidate 3′ UTRs that were sufficient to localize mRNA to sheaths and enriched near growth zones of nascent membrane. We bioinformatically identified motifs common in 3′ UTRs from 3 myelin-enriched transcripts and determined that these motifs are required and sufficient in a context-dependent manner for mRNA transport to myelin sheaths. Finally, we show that 1 motif is highly enriched in the myelin transcriptome, suggesting that this sequence is a global regulator of mRNA localization during developmental myelination.

scholarly journals The Coding And Small-Non-Coding Hippocampal Synaptic RNAome

2020 ◽  
Author(s):  
Robert Epple ◽  
Dennis Krüger ◽  
Tea Berulava ◽  
Gerrit Brehm ◽  
Rezaul Islam ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Microfluidic System ◽  
Messenger Rnas ◽  
Local Protein Synthesis ◽  
Neuronal Dendrites ◽  
Novel Approach ◽  
Microfluidic Chamber ◽  
Microfluidic Chambers ◽  
Local Protein

AbstractNeurons are highly compartmentalized cells that depend on local protein synthesis. Thus, messenger RNAs (mRNAs) have been detected in neuronal dendrites and more recently also at the pre- and postsynaptic compartment. Other RNA species, such as microRNAs, have also been described at synapses where they are believed to control mRNA availability for local translation. Nevertheless, a combined dataset analyzing the synaptic coding and non-coding RNAome via next-generation sequencing approaches is missing. Here we isolate synaptosomes from the hippocampus of young wild type mice and provide the coding and non-coding synaptic RNAome. These data are complemented by a novel approach to analyze the synaptic RNAome from primary hippocampal neurons grown in microfluidic chambers. Our data show that synaptic microRNAs control almost the entire synaptic mRNAome and we identified several hub microRNAs. By combining the in vivo synaptosomal data with our novel microfluidic chamber system, we also provide evidence to support the hypothesis that part of the synaptic microRNAome may be supplied to neurons via astrocytes. Moreover, the microfluidic system is suitable to study the dynamics of the synaptic RNAome in response to stimulation. In conclusion, our data provide a valuable resource and hint to several important targets for future experiments.

scholarly journals Presynaptic FMRP and local protein synthesis support structural and functional plasticity of glutamatergic axon terminals

2021 ◽  
Author(s):  
Hannah R Monday ◽  
Shivani C Kharod ◽  
Young J Yoon ◽  
Robert H Singer ◽  
Pablo E Castillo
Keyword(s):  
Protein Synthesis ◽  
Rna Binding ◽  
Mossy Fiber ◽  
Fragile X ◽  
Long Term Potentiation ◽  
Local Protein Synthesis ◽  
Axon Terminals ◽  
Local Protein

Learning and memory critically rely on long-lasting, synapse-specific modifications. While postsynaptic forms of plasticity typically require local protein synthesis, whether and how local protein synthesis contributes to presynaptic changes remains unclear. Here, we examined the hippocampal mossy fiber (MF)-CA3 synapse which expresses both structural and functional presynaptic plasticity. We report that MF boutons synthesize protein locally and contain ribosomes. Long-term potentiation of MF-CA3 synaptic transmission (MF-LTP) was associated with translation-dependent enlargement of MF boutons. Moreover, increasing in vitro and in vivo MF activity enhanced protein synthesis in MFs. Remarkably, deletion of presynaptic Fragile X mental retardation protein (FMRP), an RNA-binding protein expressed in MF boutons and previously implicated in local postsynaptic protein synthesis-dependent plasticity, blocked structural and functional MF-LTP, suggesting that FMRP is a critical regulator of presynaptic function. Thus, presynaptic FMRP and protein synthesis dynamically control presynaptic structure and function in the mature brain.

scholarly journals Single Molecule Translation Imaging of Local Protein Synthesis and RNA Docking Reveals the Regulation of Site Specific Axon Remodeling In Vivo

2018 ◽  
Vol 114 (3) ◽  
pp. 153a
Author(s):  
Clemens F. Kaminski ◽  
Hovy Ho-Wai Wong ◽  
Florian Strohl ◽  
Julie Quiaojin Lin ◽  
Christine E. Holt
Keyword(s):  
Protein Synthesis ◽  
Single Molecule ◽  
Site Specific ◽  
Local Protein Synthesis ◽  
Local Protein

scholarly journals ESCRT-II controls retinal axon growth by regulating DCC receptor levels and local protein synthesis

Open Biology ◽  
2016 ◽  
Vol 6 (4) ◽  
pp. 150218 ◽  
Author(s):  
Filip A. Konopacki ◽  
Hovy Ho-Wai Wong ◽  
Asha Dwivedy ◽  
Anaïs Bellon ◽  
Michael D. Blower ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Axon Growth ◽  
Endocytic Pathway ◽  
Loss Of Function ◽  
Gradient Sensing ◽  
Deleted In Colorectal Cancer ◽  
Local Protein Synthesis ◽  
Local Protein

Endocytosis and local protein synthesis (LPS) act coordinately to mediate the chemotropic responses of axons, but the link between these two processes is poorly understood. The endosomal sorting complex required for transport (ESCRT) is a key regulator of cargo sorting in the endocytic pathway, and here we have investigated the role of ESCRT-II, a critical ESCRT component, in Xenopus retinal ganglion cell (RGC) axons. We show that ESCRT-II is present in RGC axonal growth cones (GCs) where it co-localizes with endocytic vesicle GTPases and, unexpectedly, with the Netrin-1 receptor, deleted in colorectal cancer (DCC). ESCRT-II knockdown (KD) decreases endocytosis and, strikingly, reduces DCC in GCs and leads to axon growth and guidance defects. ESCRT-II-depleted axons fail to turn in response to a Netrin-1 gradient in vitro and many axons fail to exit the eye in vivo . These defects, similar to Netrin-1/DCC loss-of-function phenotypes, can be rescued in whole ( in vitro ) or in part ( in vivo ) by expressing DCC. In addition, ESCRT-II KD impairs LPS in GCs and live imaging reveals that ESCRT-II transports mRNAs in axons. Collectively, our results show that the ESCRT-II-mediated endocytic pathway regulates both DCC and LPS in the axonal compartment and suggest that ESCRT-II aids gradient sensing in GCs by coupling endocytosis to LPS.

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