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 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 The Ubiquitin Carboxyl Hydrolase BAP1 Forms a Ternary Complex with YY1 and HCF-1 and Is a Critical Regulator of Gene Expression

2010 ◽  
Vol 30 (21) ◽  
pp. 5071-5085 ◽  
Author(s):  
Helen Yu ◽  
Nazar Mashtalir ◽  
Salima Daou ◽  
Ian Hammond-Martel ◽  
Julie Ross ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ternary Complex ◽  
Transcriptional Control ◽  
Molecular Mechanisms ◽  
Mitochondrial Protein ◽  
Coiled Coil ◽  
Dependent Manner ◽  
Cellular Processes ◽  
Rich Domain

ABSTRACT The candidate tumor suppressor BAP1 is a deubiquitinating enzyme (DUB) involved in the regulation of cell proliferation, although the molecular mechanisms governing its function remain poorly defined. BAP1 was recently shown to interact with and deubiquitinate the transcriptional regulator host cell factor 1 (HCF-1). Here we show that BAP1 assembles multiprotein complexes containing numerous transcription factors and cofactors, including HCF-1 and the transcription factor Yin Yang 1 (YY1). Through its coiled-coil motif, BAP1 directly interacts with the zinc fingers of YY1. Moreover, HCF-1 interacts with the middle region of YY1 encompassing the glycine-lysine-rich domain and is essential for the formation of a ternary complex with YY1 and BAP1 in vivo. BAP1 activates transcription in an enzymatic-activity-dependent manner and regulates the expression of a variety of genes involved in numerous cellular processes. We further show that BAP1 and HCF-1 are recruited by YY1 to the promoter of the cox7c gene, which encodes a mitochondrial protein used here as a model of BAP1-activated gene expression. Our findings (i) establish a direct link between BAP1 and the transcriptional control of genes regulating cell growth and proliferation and (ii) shed light on a novel mechanism of transcription regulation involving ubiquitin signaling.

scholarly journals Identification of a functional hypoxia-responsive element that regulates the expression of the egl nine homologue 3 (egln3/phd3) gene

2005 ◽  
Vol 390 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Nuria Pescador ◽  
Yolanda Cuevas ◽  
Salvador Naranjo ◽  
Marisa Alcaide ◽  
Diego Villar ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Initiation ◽  
Initiation Site ◽  
Egg Laying ◽  
Dependent Manner ◽  
Low Oxygen ◽  
Consensus Sequences ◽  
Homologous Protein ◽  
Responsive Element

Low oxygen levels induce an adaptive response in cells through the activation of HIFs (hypoxia-inducible factors). These transcription factors are mainly regulated by a group of proline hydroxylases that, in the presence of oxygen, target HIF for degradation. The expression of two such enzymes, EGLN1 [EGL nine homologous protein 1, where EGL stands for egg laying defective (Caenorhabditis elegans gene)] and EGLN3, is induced by hypoxia through a negative feedback loop, and we have demonstrated recently that hypoxic induction of EGLN expression is HIF-dependent. In the present study, we have identified an HRE (hypoxia response element) in the region of the EGLN3 gene using a combination of bioinformatics and biological approaches. Initially, we isolated a number of HRE consensus sequences in a region of 40 kb around the human EGLN3 gene and studied their evolutionary conservation. Subsequently, we examined the functionality of the conserved HRE sequences in reporter and chromatin precipitation assays. One of the HREs, located within a conserved region of the first intron of the EGLN3 gene 12 kb downstream of the transcription initiation site, bound HIF in vivo. Furthermore, this sequence was able to drive reporter gene expression under conditions of hypoxia in an HRE-dependent manner. Indeed, we were able to demonstrate that HIF was necessary and sufficient to induce gene expression from this enhancer sequence.

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 The Tumor-sensitive Calmodulin-like Protein Is a Specific Light Chain of Human Unconventional Myosin X

2001 ◽  
Vol 276 (15) ◽  
pp. 12182-12189 ◽  
Author(s):  
Michael S. Rogers ◽  
Emanuel E. Strehler
Keyword(s):  
Light Chain ◽  
Membrane Trafficking ◽  
Cell Periphery ◽  
Dependent Manner ◽  
Unconventional Myosin ◽  
Iq Motif ◽  
Cellular Processes ◽  
Cell Growth And Differentiation ◽  
Myosin X

Human calmodulin-like protein (CLP) is an epithelial-specific Ca2+-binding protein whose expression is strongly down-regulated in cancers. Like calmodulin, CLP is thought to regulate cellular processes via Ca2+-dependent interactions with specific target proteins. Using gel overlays, we identified a ∼210-kDa protein binding specifically and in a Ca2+-dependent manner to CLP, but not to calmodulin. Yeast two-hybrid screening yielded a CLP-interacting clone encoding the three light chain binding IQ motifs of human “unconventional” myosin X. Pull-down experiments showed CLP binding to the IQ domain to be direct and Ca2+-dependent. CLP interacted strongly with IQ motif 3 (Kd∼0.5 nm) as determined by surface plasmon resonance. Epitope-tagged myosin X was localized preferentially at the cell periphery in MCF-7 cells, and CLP colocalized with myosin X in these cells. Myosin X was able to coprecipitate CLP and, to a lesser extent, calmodulin from transfected COS-1 cells, indicating that CLP is a specific light chain of myosin Xin vivo. Because unconventional myosins participate in cellular processes ranging from membrane trafficking to signaling and cell motility, myosin X is an attractive CLP target. Altered myosin X regulation in (tumor) cells lacking CLP may have as yet unknown consequences for cell growth and differentiation.

scholarly journals Increased extracellular signal regulated kinases phosphorylation in the adrenal gland in response to chronic ACTH treatment

2007 ◽  
Vol 192 (3) ◽  
pp. 647-658 ◽  
Author(s):  
Jorge G Ferreira ◽  
Célia D Cruz ◽  
Delminda Neves ◽  
Duarte Pignatelli
Keyword(s):  
Cell Proliferation ◽  
Mek Inhibitor ◽  
Nuclear Antigen ◽  
Dependent Manner ◽  
Cellular Processes ◽  
Extracellular Signal ◽  
Extracellular Stimuli ◽  
Corticosterone Release

ACTH released from the pituitary acts through activation of cAMP/PKA in adrenocortical cells stimulating steroidogenesis. Although ACTH was originally thought to have anti-proliferative effects on the adrenal, recently it has been described that it could also have proliferative effects acting through other signalling cascades. This is also relevant in humans given the increased levels of ACTH occurring together with adrenal cortex hyperplasia observed in Cushing’s disease and possibly in other situations such as chronic stress. One of the signalling pathways regulating cell proliferation is the extracellular signal regulated kinase (ERKs) pathway. ERKs are members of the MAPK family of cascades. They are activated by extracellular stimuli such as growth factors and mitogens, become phosphorylated through MEK1/2 and regulate a diversity of cellular processes such as proliferation and differentiation. Until now, no study addressed the effects of chronic ACTH administration on the activation of ERKs in vivo. Using rats submitted to different ACTH dosages as well as variable durations, we determined if ACTH induced ERKs activation and by establishing a parallelism with proliferating cell nuclear antigen (PCNA) expression, we aimed to demonstrate a role of ACTH-induced ERKs activation in cell proliferation. Blood was collected for hormonal analysis and the role of ACTH-induced ERKs activation in the stimulation of steroidogenesis was also studied. We confirmed that ACTH increased adrenal weight and corticosterone levels when compared with control or dexamethasone-treated animals. We also demonstrated that ACTH increases ERKs activation and PCNA expression in a time- and dose-dependent manner. When ERKs activation was blocked by the use of a specific MEK inhibitor (PD98059), there was a decrease in ACTH-induced corticosterone release and PCNA expression. We conclude that chronic ACTH induces ERKs activation and that this plays an important role in the induction of cell proliferation as well as steroidogenesis.

scholarly journals MEK/mTOR-dependent D1 dopamine receptor activation induces local protein synthesis via eEF2 dephosphorylation in neurons

2018 ◽  
Author(s):  
Orit David ◽  
Iliana Barrera ◽  
Bella Koltun ◽  
Sivan Ironi ◽  
Shunit Gal-Ben-Ari ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Dopamine Receptor ◽  
Elongation Factor ◽  
Mrna Translation ◽  
Receptor Activation ◽  
D1 Receptor ◽  
Dependent Manner ◽  
Primary Neuronal Culture ◽  
Local Protein Synthesis

AbstractNeuromodulators in general, and dopamine in particular, define brain and neuronal states in different ways including regulation of global and local mRNA translation. Yet, the signaling pathways underlying the effects of dopamine on mRNA translation are not clear. Here, using genetic, pharmacologic, biochemical, and imaging methods, we tested the hypothesis that dopamine regulates phosphorylation of the eukaryotic elongation factor 2 (eEF2). We found that activation of dopamine receptor D1 but not D2 leads to rapid dephosphorylation of eEF2 at Thr56 in cortical primary neuronal culture and in vivo in a time-dependent manner. Additionally, NMDA receptor, mTOR, and ERK pathways are upstream to the D1 receptor-dependent eEF2 dephosphorylation and essential for it. Furthermore, D1 receptor activation resulted in a major reduction in dendritic eEF2 phosphorylation levels together with a correlative increase in local mRNA translation. These results reveal the role of eEF2 in dopamine regulation of local mRNA translation in neurons.One-sentence summaryD1 receptor activation increases protein synthesis in dendrites by inactivating eEF2K in an ERK2/mTOR-dependent manner.

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