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1.
Trends Biochem Sci ; 47(6): 477-491, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35246374

RESUMO

In addition to their central functions in translation, ribosomes can adopt inactive structures that are fully assembled yet devoid of mRNA. We describe how the abundance of idle eukaryotic ribosomes is influenced by a broad range of biological conditions spanning viral infection, nutrient deprivation, and developmental cues. Vacant ribosomes may provide a means to exclude ribosomes from translation while also shielding them from degradation, and the variable identity of factors that occlude ribosomes may impart distinct functionality. We propose that regulated changes in the balance of idle and active ribosomes provides a means to fine-tune translation. We provide an overview of idle ribosomes, describe what is known regarding their function, and highlight questions that may clarify their biological roles.


Assuntos
Proteínas Ribossômicas , Ribossomos , Polirribossomos/metabolismo , Biossíntese de Proteínas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Ribossômicas/metabolismo , Ribossomos/metabolismo
2.
J Neurosci ; 43(16): 2921-2933, 2023 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-36894318

RESUMO

RNA stability is meticulously controlled. Here, we sought to determine whether an essential post-transcriptional regulatory mechanism plays a role in pain. Nonsense-mediated decay (NMD) safeguards against translation of mRNAs that harbor premature termination codons and controls the stability of ∼10% of typical protein-coding mRNAs. It hinges on the activity of the conserved kinase SMG1. Both SMG1 and its target, UPF1, are expressed in murine DRG sensory neurons. SMG1 protein is present in both the DRG and sciatic nerve. Using high-throughput sequencing, we examined changes in mRNA abundance following inhibition of SMG1. We confirmed multiple NMD stability targets in sensory neurons, including ATF4. ATF4 is preferentially translated during the integrated stress response (ISR). This led us to ask whether suspension of NMD induces the ISR. Inhibition of NMD increased eIF2-α phosphorylation and reduced the abundance of the eIF2-α phosphatase constitutive repressor of eIF2-α phosphorylation. Finally, we examined the effects of SMG1 inhibition on pain-associated behaviors. Peripheral inhibition of SMG1 results in mechanical hypersensitivity in males and females that persists for several days and priming to a subthreshold dose of PGE2. Priming was fully rescued by a small-molecule inhibitor of the ISR. Collectively, our results indicate that suspension of NMD promotes pain through stimulation of the ISR.SIGNIFICANCE STATEMENT Nociceptors undergo long-lived changes in their plasticity which may contribute to chronic pain. Translational regulation has emerged as a dominant mechanism in pain. Here, we investigate the role of a major pathway of RNA surveillance called nonsense-mediated decay (NMD). Modulation of NMD is potentially beneficial for a broad array of diseases caused by frameshift or nonsense mutations. Our results suggest that inhibition of the rate-limiting step of NMD drives behaviors associated with pain through activation of the ISR. This work reveals complex interconnectivity between RNA stability and translational regulation and suggests an important consideration in harnessing the salubrious benefits of NMD disruption.


Assuntos
Fator de Iniciação 2 em Eucariotos , Nociceptividade , Masculino , Feminino , Humanos , Camundongos , Animais , Fator de Iniciação 2 em Eucariotos/genética , Degradação do RNAm Mediada por Códon sem Sentido , Fosforilação , Dor , RNA Helicases/genética , RNA Helicases/metabolismo , Transativadores/genética
3.
Nucleic Acids Res ; 50(1): 536-548, 2022 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-34908132

RESUMO

In C. elegans, PUF proteins promote germline stem cell self-renewal. Their functions hinge on partnerships with two proteins that are redundantly required for stem cell maintenance. Here we focus on understanding how the essential partner protein, LST-1, modulates mRNA regulation by the PUF protein, FBF-2. LST-1 contains two nonidentical sites of interaction with FBF-2, LST-1 A and B. Our crystal structures of complexes of FBF-2, LST-1 A, and RNA visualize how FBF-2 associates with LST-1 A versus LST-1 B. One commonality is that FBF-2 contacts the conserved lysine and leucine side chains in the KxxL motifs in LST-1 A and B. A key difference is that FBF-2 forms unique contacts with regions N- and C-terminal to the KxxL motif. Consequently, LST-1 A does not modulate the RNA-binding affinity of FBF-2, whereas LST-1 B decreases RNA-binding affinity of FBF-2. The N-terminal region of LST-1 B, which binds near the 5' end of RNA elements, is essential to modulate FBF-2 RNA-binding affinity, while the C-terminal residues of LST-1 B contribute strong binding affinity to FBF-2. We conclude that LST-1 has the potential to impact which mRNAs are regulated depending on the precise nature of engagement through its functionally distinct FBF binding sites.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Ligação Proteica , RNA Mensageiro/metabolismo
4.
J Neurosci ; 42(49): 9129-9141, 2022 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-36270801

RESUMO

HuR is an RNA-binding protein implicated in RNA processing, stability, and translation. Previously, we examined protein synthesis in dorsal root ganglion (DRG) neurons treated with inflammatory mediators using ribosome profiling. We found that the HuR consensus binding element was enriched in transcripts with elevated translation. HuR is expressed in the soma of nociceptors and their axons. Pharmacologic inhibition of HuR with the small molecule CMLD-2 reduced the activity of mouse and human sensory neurons. Peripheral administration of CMLD-2 in the paw or genetic elimination of HuR from sensory neurons diminished behavioral responses associated with NGF- and IL-6-induced allodynia in male and female mice. Genetic disruption of HuR altered the proximity of mRNA decay factors near a key neurotrophic factor (TrkA). Collectively, the data suggest that HuR is required for local control of mRNA stability and reveals a new biological function for a broadly conserved post-transcriptional regulatory factor.SIGNIFICANCE STATEMENT Nociceptors undergo long-lived changes in excitability, which may contribute to chronic pain. Noxious cues that promote pain lead to rapid induction of protein synthesis. The underlying mechanisms that confer specificity to mRNA control in nociceptors are unclear. Here, we identify a conserved RNA-binding protein called HuR as a key regulatory factor in sensory neurons. Using a combination of genetics and pharmacology, we demonstrate that HuR is required for signaling in nociceptors. In doing so, we report an important mechanism of mRNA control in sensory neurons that ensures appropriate nociceptive responses to inflammatory mediators.


Assuntos
Proteína Semelhante a ELAV 1 , Nociceptores , Animais , Feminino , Humanos , Masculino , Camundongos , Dor Crônica/metabolismo , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Hiperalgesia/metabolismo , Nociceptores/metabolismo , Células Receptoras Sensoriais/metabolismo , Transdução de Sinais
5.
FASEB J ; 36(7): e22422, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35747924

RESUMO

Nociceptors are a type of sensory neuron that are integral to most forms of pain. Targeted disruption of nociceptor sensitization affords unique opportunities to prevent pain. An emerging model for nociceptors are sensory neurons derived from human stem cells. Here, we subjected five groups to high-throughput sequencing: human induced pluripotent stem cells (hiPSCs) prior to differentiation, mature hiPSC-derived sensory neurons, mature co-cultures containing hiPSC-derived astrocytes and sensory neurons, mouse dorsal root ganglion (DRG) tissues, and mouse DRG cultures. Co-culture of nociceptors and astrocytes promotes expression of transcripts enriched in DRG tissues. Comparisons of the hiPSC models to tissue samples reveal that many key transcripts linked to pain are present. Markers indicative of a range of neuronal subtypes present in the DRG were detected in mature hiPSCs. Intriguingly, translation factors were maintained at consistently high expression levels across species and culture systems. As a proof of concept for the utility of this resource, we validated expression of eukaryotic initiation factor 5A (eIF5A) in DRG tissues and hiPSC samples. eIF5A is subject to a unique posttranslational hypusine modification required for its activity. Inhibition of hypusine biosynthesis prevented hyperalgesic priming by inflammatory mediators in vivo and diminished hiPSC activity in vitro. Collectively, our results illuminate the transcriptomes of hiPSC sensory neuron models. We provide a demonstration for this resource through our investigation of eIF5A. Our findings reveal hypusine as a potential target for inflammation associated pain in males.


Assuntos
Células-Tronco Pluripotentes Induzidas , Animais , Humanos , Masculino , Camundongos , Nociceptores , Dor/genética , RNA Mensageiro , Transcriptoma
7.
J Neurosci ; 41(37): 7712-7726, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34326146

RESUMO

Injury responses require communication between different cell types in the skin. Sensory neurons contribute to inflammation and can secrete signaling molecules that affect non-neuronal cells. Despite the pervasive role of translational regulation in nociception, the contribution of activity-dependent protein synthesis to inflammation is not well understood. To address this problem, we examined the landscape of nascent translation in murine dorsal root ganglion (DRG) neurons treated with inflammatory mediators using ribosome profiling. We identified the activity-dependent gene, Arc, as a target of translation in vitro and in vivo Inflammatory cues promote local translation of Arc in the skin. Arc-deficient male mice display exaggerated paw temperatures and vasodilation in response to an inflammatory challenge. Since Arc has recently been shown to be released from neurons in extracellular vesicles (EVs), we hypothesized that intercellular Arc signaling regulates the inflammatory response in skin. We found that the excessive thermal responses and vasodilation observed in Arc defective mice are rescued by injection of Arc-containing EVs into the skin. Our findings suggest that activity-dependent production of Arc in afferent fibers regulates neurogenic inflammation potentially through intercellular signaling.SIGNIFICANCE STATEMENT Nociceptors play prominent roles in pain and inflammation. We examined rapid changes in the landscape of nascent translation in cultured dorsal root ganglia (DRGs) treated with a combination of inflammatory mediators using ribosome profiling. We identified several hundred transcripts subject to rapid preferential translation. Among them is the immediate early gene (IEG) Arc. We provide evidence that Arc is translated in afferent fibers in the skin. Arc-deficient mice display several signs of exaggerated inflammation which is normalized on injection of Arc containing extracellular vesicles (EVs). Our work suggests that noxious cues can trigger Arc production by nociceptors which in turn constrains neurogenic inflammation in the skin.


Assuntos
Proteínas do Citoesqueleto/metabolismo , Gânglios Espinais/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Transdução de Sinais/fisiologia , Vasodilatação/fisiologia , Animais , Proteínas do Citoesqueleto/genética , Inflamação/genética , Inflamação/metabolismo , Inflamação/fisiopatologia , Masculino , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Nociceptividade/fisiologia , Nociceptores/fisiologia , Doenças do Sistema Nervoso Periférico/genética , Doenças do Sistema Nervoso Periférico/metabolismo , Doenças do Sistema Nervoso Periférico/fisiopatologia
8.
RNA ; 26(11): 1680-1703, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32753408

RESUMO

The human PUF-family proteins, PUM1 and PUM2, posttranscriptionally regulate gene expression by binding to a PUM recognition element (PRE) in the 3'-UTR of target mRNAs. Hundreds of PUM1/2 targets have been identified from changes in steady-state RNA levels; however, prior studies could not differentiate between the contributions of changes in transcription and RNA decay rates. We applied metabolic labeling to measure changes in RNA turnover in response to depletion of PUM1/2, showing that human PUM proteins regulate expression almost exclusively by changing RNA stability. We also applied an in vitro selection workflow to precisely identify the binding preferences of PUM1 and PUM2. By integrating our results with prior knowledge, we developed a "rulebook" of key contextual features that differentiate functional versus nonfunctional PREs, allowing us to train machine learning models that accurately predict the functional regulation of RNA targets by the human PUM proteins.


Assuntos
RNA Mensageiro/química , RNA Mensageiro/genética , Proteínas de Ligação a RNA/metabolismo , Regiões 3' não Traduzidas , Regulação da Expressão Gênica , Células HEK293 , Humanos , Aprendizado de Máquina , Processamento Pós-Transcricional do RNA , Estabilidade de RNA , Sequenciamento Completo do Genoma
9.
J Neurosci ; 40(18): 3517-3532, 2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-32245829

RESUMO

One of the first signs of viral infection is body-wide aches and pain. Although this type of pain usually subsides, at the extreme, viral infections can induce painful neuropathies that can last for decades. Neither of these types of pain sensitization is well understood. A key part of the response to viral infection is production of interferons (IFNs), which then activate their specific receptors (IFNRs) resulting in downstream activation of cellular signaling and a variety of physiological responses. We sought to understand how type I IFNs (IFN-α and IFN-ß) might act directly on nociceptors in the dorsal root ganglion (DRG) to cause pain sensitization. We demonstrate that type I IFNRs are expressed in small/medium DRG neurons and that their activation produces neuronal hyper-excitability and mechanical pain in mice. Type I IFNs stimulate JAK/STAT signaling in DRG neurons but this does not apparently result in PKR-eIF2α activation that normally induces an anti-viral response by limiting mRNA translation. Rather, type I IFNs stimulate MNK-mediated eIF4E phosphorylation in DRG neurons to promote pain hypersensitivity. Endogenous release of type I IFNs with the double-stranded RNA mimetic poly(I:C) likewise produces pain hypersensitivity that is blunted in mice lacking MNK-eIF4E signaling. Our findings reveal mechanisms through which type I IFNs cause nociceptor sensitization with implications for understanding how viral infections promote pain and can lead to neuropathies.SIGNIFICANCE STATEMENT It is increasingly understood that pathogens interact with nociceptors to alert organisms to infection as well as to mount early host defenses. Although specific mechanisms have been discovered for diverse bacterial and fungal pathogens, mechanisms engaged by viruses have remained elusive. Here we show that type I interferons, one of the first mediators produced by viral infection, act directly on nociceptors to produce pain sensitization. Type I interferons act via a specific signaling pathway (MNK-eIF4E signaling), which is known to produce nociceptor sensitization in inflammatory and neuropathic pain conditions. Our work reveals a mechanism through which viral infections cause heightened pain sensitivity.


Assuntos
Viroses do Sistema Nervoso Central/metabolismo , Interferon Tipo I/toxicidade , Nociceptores/metabolismo , Limiar da Dor/fisiologia , Dor/metabolismo , Doenças do Sistema Nervoso Periférico/metabolismo , Animais , Células Cultivadas , Viroses do Sistema Nervoso Central/induzido quimicamente , Viroses do Sistema Nervoso Central/patologia , Feminino , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Gânglios Espinais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Nociceptores/efeitos dos fármacos , Nociceptores/patologia , Dor/induzido quimicamente , Dor/patologia , Limiar da Dor/efeitos dos fármacos , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Doenças do Sistema Nervoso Periférico/patologia
10.
Soft Matter ; 17(4): 785-809, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33410841

RESUMO

Stimuli-responsive materials are able to undergo controllable changes in materials properties in response to external cues. Increasing efforts have been directed towards building materials that mimic the responsive nature of biological systems. Nevertheless, limitations remain surrounding the way these synthetic materials interact and respond to their environment. In particular, it is difficult to synthesize synthetic materials that respond with specificity to poorly differentiated (bio)chemical and weak physical stimuli. The emerging area of engineered living materials (ELMs) includes composites that combine living cells and synthetic materials. ELMs have yielded promising advances in the creation of stimuli-responsive materials that respond with diverse outputs in response to a broad array of biochemical and physical stimuli. This review describes advances made in the genetic engineering of the living component and the processing-property relationships of stimuli-responsive ELMs. Finally, the implementation of stimuli-responsive ELMs as environmental sensors, biomedical sensors, drug delivery vehicles, and soft robots is discussed.


Assuntos
Polímeros Responsivos a Estímulos
11.
J Neurosci ; 39(35): 6829-6847, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253755

RESUMO

Nociceptors located in the trigeminal ganglion (TG) and DRG are the primary sensors of damaging or potentially damaging stimuli for the head and body, respectively, and are key drivers of chronic pain states. While nociceptors in these two tissues show a high degree of functional similarity, there are important differences in their development lineages, their functional connections to the CNS, and recent genome-wide analyses of gene expression suggest that they possess some unique genomic signatures. Here, we used translating ribosome affinity purification to comprehensively characterize and compare mRNA translation in Scn10a-positive nociceptors in the TG and DRG of male and female mice. This unbiased method independently confirms several findings of differences between TG and DRG nociceptors described in the literature but also suggests preferential utilization of key signaling pathways. Most prominently, we provide evidence that translational efficiency in mechanistic target of rapamycin (mTOR)-related genes is higher in the TG compared with DRG, whereas several genes associated with the negative regulator of mTOR, AMP-activated protein kinase, have higher translational efficiency in DRG nociceptors. Using capsaicin as a sensitizing stimulus, we show that behavioral responses are greater in the TG region and this effect is completely reversible with mTOR inhibition. These findings have implications for the relative capacity of these nociceptors to be sensitized upon injury. Together, our data provide a comprehensive, comparative view of transcriptome and translatome activity in TG and DRG nociceptors that enhances our understanding of nociceptor biology.SIGNIFICANCE STATEMENT The DRG and trigeminal ganglion (TG) provide sensory information from the body and head, respectively. Nociceptors in these tissues are critical first neurons in the pain pathway. Injury to peripheral neurons in these tissues can cause chronic pain. Interestingly, clinical and preclinical findings support the conclusion that injury to TG neurons is more likely to cause chronic pain and chronic pain in the TG area is more intense and more difficult to treat. We used translating ribosome affinity purification technology to gain new insight into potential differences in the translatomes of DRG and TG neurons. Our findings demonstrate previously unrecognized differences between TG and DRG nociceptors that provide new insight into how injury may differentially drive plasticity states in nociceptors in these two tissues.


Assuntos
Gânglios Espinais/metabolismo , Nociceptores/metabolismo , Transcriptoma , Gânglio Trigeminal/metabolismo , Animais , Feminino , Perfilação da Expressão Gênica , Masculino , Camundongos , Neurônios/metabolismo , Transdução de Sinais
12.
J Neurosci ; 39(3): 393-411, 2019 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-30459229

RESUMO

Nociceptors, sensory neurons in the DRG that detect damaging or potentially damaging stimuli, are key drivers of neuropathic pain. Injury to these neurons causes activation of translation regulation signaling, including the mechanistic target of rapamycin complex 1 (mTORC1) and mitogen-activated protein kinase interacting kinase (MNK) eukaryotic initiation factor (eIF) 4E pathways. This is a mechanism driving changes in excitability of nociceptors that is critical for the generation of chronic pain states; however, the mRNAs that are translated to lead to this plasticity have not been elucidated. To address this gap in knowledge, we used translating ribosome affinity purification in male and female mice to comprehensively characterize mRNA translation in Scn10a-positive nociceptors in chemotherapy-induced neuropathic pain (CIPN) caused by paclitaxel treatment. This unbiased method creates a new resource for the field, confirms many findings in the CIPN literature and also find extensive evidence for new target mechanisms that may cause CIPN. We provide evidence that an underlying mechanism of CIPN is sustained mTORC1 activation driven by MNK1-eIF4E signaling. RagA, a GTPase controlling mTORC1 activity, is identified as a novel target of MNK1-eIF4E signaling. This demonstrates a novel translation regulation signaling circuit wherein MNK1-eIF4E activity drives mTORC1 via control of RagA translation. CIPN and RagA translation are strongly attenuated by genetic ablation of eIF4E phosphorylation, MNK1 elimination or treatment with the MNK inhibitor eFT508. We identify a novel translational circuit for the genesis of neuropathic pain caused by chemotherapy with important implications for therapeutics.SIGNIFICANCE STATEMENT Neuropathic pain affects up to 10% of the population, but its underlying mechanisms are incompletely understood, leading to poor treatment outcomes. We used translating ribosome affinity purification technology to create a comprehensive translational profile of DRG nociceptors in naive mice and at the peak of neuropathic pain induced by paclitaxel treatment. We reveal new insight into how mechanistic target of rapamycin complex 1 is activated in neuropathic pain pointing to a key role of MNK1-eIF4E-mediated translation of a complex of mRNAs that control mechanistic target of rapamycin complex 1 signaling at the surface of the lysosome. We validate this finding using genetic and pharmacological techniques. Our work strongly suggests that MNK1-eIF4E signaling drives CIPN and that a drug in human clinical trials, eFT508, may be a new therapeutic for neuropathic pain.


Assuntos
Perfilação da Expressão Gênica , Camundongos Knockout/genética , Proteínas Monoméricas de Ligação ao GTP/genética , Neuralgia/genética , Nociceptores , Animais , Antineoplásicos Fitogênicos , Fator de Iniciação 4E em Eucariotos/genética , Feminino , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Camundongos , Camundongos Transgênicos , Canal de Sódio Disparado por Voltagem NAV1.8/genética , Neuralgia/induzido quimicamente , Neuralgia/psicologia , Paclitaxel , Medição da Dor , Proteínas Serina-Treonina Quinases/genética , Ribossomos/química , Transdução de Sinais/genética
13.
RNA Biol ; 17(4): 417-424, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31957541

RESUMO

mRNA function is controlled by RNA-binding proteins. The specificity of RNA-binding factors for their targets is critical in that it enables all subsequent regulation. Despite widespread recognition of the pervasive role RNA-binding proteins play in development and disease, they remain challenging to target with small molecules. A renaissance in RNA therapeutics has led to the identification of modifications that substantially increase RNA stability. When combined with information regarding specificity, a new class of oligonucleotide mimics has emerged as a means to competitively disrupt the regulation of endogenous substrates. These decoys have been used to inhibit RNA-binding proteins in living animals. Decoys will likely provide new insights into the expansive roles of RNA-binding proteins in biology and disease. Here, we describe examples where they have been used and discuss how they could be applied to new targets.


Assuntos
Oligonucleotídeos/farmacologia , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Humanos , Mimetismo Molecular , Ligação Proteica/efeitos dos fármacos , Estabilidade de RNA , RNA Mensageiro/química
14.
Trends Biochem Sci ; 40(3): 157-64, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25636997

RESUMO

RNA-protein interactions are pervasive. The specificity of these interactions dictates which RNAs are controlled by what protein. Here we describe a class of revolutionary new methods that enable global views of RNA-binding specificity in vitro, for both single proteins and multiprotein complexes. These methods provide insight into central issues in RNA regulation in living cells, including understanding the balance between free and bound components, the basis for exclusion of binding sites, detection of binding events in the absence of discernible regulatory elements, and new approaches to targeting endogenous transcripts by design. Comparisons of in vitro and in vivo binding provide a foundation for comprehensive understanding of the biochemistry of protein-mediated RNA regulatory networks.


Assuntos
Redes Reguladoras de Genes , Genômica/métodos , Proteínas de Ligação a RNA/metabolismo , RNA/metabolismo , Animais , Sítios de Ligação , Humanos , RNA/genética , Proteínas de Ligação a RNA/genética , Sequências Reguladoras de Ácido Nucleico
15.
RNA ; 23(11): 1636-1647, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28768715

RESUMO

A single protein can bind and regulate many mRNAs. Multiple proteins with similar specificities often bind and control overlapping sets of mRNAs. Yet little is known about the architecture or dynamics of overlapped networks. We focused on three proteins with similar structures and related RNA-binding specificities-Puf3p, Puf4p, and Puf5p of S. cerevisiae Using RNA Tagging, we identified a "super-network" comprised of four subnetworks: Puf3p, Puf4p, and Puf5p subnetworks, and one controlled by both Puf4p and Puf5p. The architecture of individual subnetworks, and thus the super-network, is determined by competition among particular PUF proteins to bind mRNAs, their affinities for binding elements, and the abundances of the proteins. The super-network responds dramatically: The remaining network can either expand or contract. These strikingly opposite outcomes are determined by an interplay between the relative abundance of the RNAs and proteins, and their affinities for one another. The diverse interplay between overlapping RNA-protein networks provides versatile opportunities for regulation and evolution.


Assuntos
Redes Reguladoras de Genes , RNA Fúngico/genética , RNA Fúngico/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Sítios de Ligação/genética , Modelos Moleculares , Nucleotidiltransferases/metabolismo , Ligação Proteica , RNA Fúngico/química , RNA Mensageiro/química , Proteínas de Ligação a RNA/química , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química
16.
J Neurophysiol ; 120(3): 1374-1385, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29947589

RESUMO

Following inflammation or injury, sensory neurons located in the dorsal root ganglia (DRG) may exhibit increased spontaneous and/or stimulus-evoked activity, contributing to chronic pain. Current treatment options for peripherally mediated chronic pain are highly limited, driving the development of cell- or tissue-based phenotypic (function-based) screening assays for peripheral analgesic and mechanistic lead discovery. Extant assays are often limited by throughput, content, use of tumorigenic cell lines, or tissue sources from immature developmental stages (i.e., embryonic or postnatal). Here, we describe a protocol for culturing adult mouse DRG neurons on substrate-integrated multiwell microelectrode arrays (MEAs). This approach enables multiplexed measurements of spontaneous as well as stimulus-evoked extracellular action potentials from large populations of cells. The DRG cultures exhibit stable spontaneous activity from 9 to 21 days in vitro. Activity is readily evoked by known chemical and physical agonists of sensory neuron activity such as capsaicin, bradykinin, PGE2, heat, and electrical field stimulation. Most importantly, we demonstrate that both spontaneous and stimulus-evoked activity may be potentiated by incubation with the inflammatory cytokine interleukin-6 (IL-6). Acute responsiveness to IL-6 is inhibited by treatment with a MAPK-interacting kinase 1/2 inhibitor, cercosporamide. In total, these findings suggest that adult mouse DRG neurons on multiwell MEAs are applicable to ongoing efforts to discover peripheral analgesic and their mechanisms of action. NEW & NOTEWORTHY This work describes methodologies for culturing spontaneously active adult mouse dorsal root ganglia (DRG) sensory neurons on microelectrode arrays. We characterize spontaneous and stimulus-evoked adult DRG activity over durations consistent with pharmacological interventions. Furthermore, persistent hyperexcitability could be induced by incubation with inflammatory cytokine IL-6 and attenuated with cercosporamide, an inhibitor of the IL-6 sensitization pathway. This constitutes a more physiologically relevant, moderate-throughput in vitro model for peripheral analgesic screening as well as mechanistic lead discovery.


Assuntos
Potenciais de Ação , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Gânglios Espinais/fisiologia , Interleucina-6/farmacologia , Células Receptoras Sensoriais/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Bradicinina/farmacologia , Capsaicina/farmacologia , Células Cultivadas , Dinoprostona/farmacologia , Estimulação Elétrica , Gânglios Espinais/efeitos dos fármacos , Temperatura Alta , Inflamação/fisiopatologia , Mediadores da Inflamação/farmacologia , Masculino , Camundongos , Microeletrodos , Nociceptores/efeitos dos fármacos , Nociceptores/fisiologia , Células Receptoras Sensoriais/efeitos dos fármacos
17.
Methods ; 118-119: 171-181, 2017 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-27729296

RESUMO

RNA-binding proteins (RBPs) collaborate to control virtually every aspect of RNA function. Tremendous progress has been made in the area of global assessment of RBP specificity using next-generation sequencing approaches both in vivo and in vitro. Understanding how protein-protein interactions enable precise combinatorial regulation of RNA remains a significant problem. Addressing this challenge requires tools that can quantitatively determine the specificities of both individual proteins and multimeric complexes in an unbiased and comprehensive way. One approach utilizes in vitro selection, high-throughput sequencing, and sequence-specificity landscapes (SEQRS). We outline a SEQRS experiment focused on obtaining the specificity of a multi-protein complex between Drosophila RBPs Pumilio (Pum) and Nanos (Nos). We discuss the necessary controls in this type of experiment and examine how the resulting data can be complemented with structural and cell-based reporter assays. Additionally, SEQRS data can be integrated with functional genomics data to uncover biological function. Finally, we propose extensions of the technique that will enhance our understanding of multi-protein regulatory complexes assembled onto RNA.


Assuntos
Proteínas de Drosophila/genética , Proteínas de Ligação a RNA/genética , RNA/química , Técnica de Seleção de Aptâmeros , Análise de Sequência de RNA/métodos , Animais , Sequência de Bases , Sítios de Ligação , Primers do DNA/química , Primers do DNA/metabolismo , RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Ligação Proteica , RNA/genética , RNA/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo
18.
Proc Natl Acad Sci U S A ; 109(16): 6054-9, 2012 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-22467831

RESUMO

mRNA control hinges on the specificity and affinity of proteins for their RNA binding sites. Regulatory proteins must bind their own sites and reject even closely related noncognate sites. In the PUF [Pumilio and fem-3 binding factor (FBF)] family of RNA binding proteins, individual proteins discriminate differences in the length and sequence of binding sites, allowing each PUF to bind a distinct battery of mRNAs. Here, we show that despite these differences, the pattern of RNA interactions is conserved among PUF proteins: the two ends of the PUF protein make critical contacts with the two ends of the RNA sites. Despite this conserved "two-handed" pattern of recognition, the RNA sequence is flexible. Among the binding sites of yeast Puf4p, RNA sequence dictates the pattern in which RNA bases are flipped away from the binding surface of the protein. Small differences in RNA sequence allow new modes of control, recruiting Puf5p in addition to Puf4p to a single site. This embedded information adds a new layer of biological meaning to the connections between RNA targets and PUF proteins.


Assuntos
Mapeamento de Interação de Proteínas/métodos , Estrutura Terciária de Proteína , Proteínas de Ligação a RNA/química , RNA/química , Regiões 3' não Traduzidas/genética , Animais , Sequência de Bases , Proteínas de Caenorhabditis elegans/química , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Cristalografia por Raios X , Modelos Moleculares , Mutação , Ligação Proteica , RNA/genética , RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Homologia de Sequência do Ácido Nucleico , Técnicas do Sistema de Duplo-Híbrido
19.
J Biol Chem ; 288(4): 2532-45, 2013 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-23195953

RESUMO

The Staufen family consists of proteins that possess double-stranded RNA-binding domains (dsRBDs). Staufen proteins of Drosophila and mammals regulate mRNA localization, translation, and decay. We report analysis of Staufen in Caenorhabditis elegans, which we have designated STAU-1. We focus on its biochemical properties, mRNA targets, and possible role in RNAi. We show that STAU-1 is expressed as mRNA and protein at all stages of C. elegans development. The wild-type, full-length protein, purified from bacteria, binds duplex RNA with high affinity in vitro. Purified, mutant proteins lacking single dsRBDs still bind RNA efficiently, demonstrating that no single domain is required for binding to duplex RNA (although dsRBD2 could not be tested). STAU-1 mRNA targets were identified via immunoprecipitation with specific anti-STAU-1 antibodies, followed by microarray analysis (RIP-Chip). These studies define a set of 418 likely STAU-1 mRNA targets. Finally, we demonstrate that stau-1 mutants enhance exogenous RNAi and that stau-1;eri-1 double mutants exhibit sterility and synthetic germ line defects.


Assuntos
Proteínas de Caenorhabditis elegans/química , Proteínas de Ligação a RNA/química , Regiões 3' não Traduzidas , Animais , Bioquímica/métodos , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/fisiologia , DNA Complementar/metabolismo , Modelos Biológicos , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Ligação Proteica , Interferência de RNA , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/fisiologia , Transgenes , Técnicas do Sistema de Duplo-Híbrido
20.
Wiley Interdiscip Rev RNA ; 15(2): e1843, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38576117

RESUMO

RNAs are meticulously controlled by proteins. Through direct and indirect associations, every facet in the brief life of an mRNA is subject to regulation. RNA-binding proteins (RBPs) permeate biology. Here, we focus on their roles in pain. Chronic pain is among the largest challenges facing medicine and requires new strategies. Mounting pharmacologic and genetic evidence obtained in pre-clinical models suggests fundamental roles for a broad array of RBPs. We describe their diverse roles that span RNA modification, splicing, stability, translation, and decay. Finally, we highlight opportunities to expand our understanding of regulatory interactions that contribute to pain signaling. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Regulation RNA in Disease and Development > RNA in Disease.


Assuntos
Splicing de RNA , Proteínas de Ligação a RNA , Humanos , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Dor/genética
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