Translational control of polyamine metabolism by CNBP is required for Drosophila locomotor function

ABSTRACTMicrosatellite expansions of CCTG repeats in the CNBP gene leads to accumulation of toxic RNA and have been associated to DM2. However, it is still unclear whether the dystrophic phenotype is also linked to CNBP decrease, a conserved CCHC-type zinc finger RNA binding protein that regulates translation and is required for mammalian development.Here we show that depletion of Drosophila CNBP in muscles causes age-dependent locomotor defects that are correlated with impaired polyamine metabolism. We demonstrate that the levels of ornithine decarboxylase (ODC) and polyamines are significantly reduced upon dCNBP depletion. Of note, we show a reduction of the CNBP-polyamine axis in muscle from DM2 patients. Mechanistically, we provide evidence that dCNBP controls polyamine metabolism through binding dOdc mRNA and regulating its translation. Remarkably, the locomotor defect of dCNBP-deficient flies is rescued by either polyamine supplementation or dOdc1 overexpression. We suggest that this dCNBP function is evolutionarily conserved in vertebrates with relevant implications for CNBP-related pathophysiological conditions.GRAPHICAL ABSTRACTCNBP controls muscle function by regulating the polyamine metabolismLack of dCNBP impairs locomotor function through ODC-polyamine downregulationdCNBP binds dOdc mRNA and regulates its translationPolyamine supplementation or dOdc1 reconstitution rescues locomotor defectsCNBP-ODC-polyamine levels are reduced in muscle of DM2 patients

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Translational control of polyamine metabolism by CNBP is required for Drosophila locomotor function

eLife ◽

10.7554/elife.69269 ◽

2021 ◽

Vol 10 ◽

Author(s):

Sonia Coni ◽

Federica A Falconio ◽

Marta Marzullo ◽

Marzia Munafò ◽

Benedetta Zuliani ◽

...

Keyword(s):

Translational Control ◽

Rna Binding ◽

Binding Protein ◽

Polyamine Metabolism ◽

Nucleic Acid Binding ◽

Mammalian Development ◽

Myotonic Dystrophy Type 2 ◽

Evolutionarily Conserved ◽

Toxic Rna

Microsatellite expansions of CCTG repeats in the cellular nucleic acid-binding protein (CNBP) gene leads to accumulation of toxic RNA and have been associated with myotonic dystrophy type 2 (DM2). However, it is still unclear whether the dystrophic phenotype is also linked to CNBP decrease, a conserved CCHC-type zinc finger RNA-binding protein that regulates translation and is required for mammalian development. Here, we show that depletion of Drosophila CNBP in muscles causes ageing-dependent locomotor defects that are correlated with impaired polyamine metabolism. We demonstrate that the levels of ornithine decarboxylase (ODC) and polyamines are significantly reduced upon dCNBP depletion. Of note, we show a reduction of the CNBP-polyamine axis in muscles from DM2 patients. Mechanistically, we provide evidence that dCNBP controls polyamine metabolism through binding dOdc mRNA and regulating its translation. Remarkably, the locomotor defect of dCNBP-deficient flies is rescued by either polyamine supplementation or dOdc1 overexpression. We suggest that this dCNBP function is evolutionarily conserved in vertebrates with relevant implications for CNBP-related pathophysiological conditions.

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Function and regulation of the mammalian Musashi mRNA translational regulator

Biochemical Society Transactions ◽

10.1042/bst0360528 ◽

2008 ◽

Vol 36 (3) ◽

pp. 528-530 ◽

Cited By ~ 27

Author(s):

Angus M. MacNicol ◽

Anna Wilczynska ◽

Melanie C. MacNicol

Keyword(s):

Stem Cell ◽

Translational Control ◽

Cell Biology ◽

Cell Cycle Progression ◽

Rna Binding ◽

Cell Populations ◽

Cycle Progression ◽

Evolutionarily Conserved ◽

Maternal Mrnas ◽

Stem Cell Populations

The evolutionarily conserved RNA-binding protein, Musashi, regulates neural stem cell self-renewal. Musashi expression is also indicative of stem cell populations in breast and intestinal tissues and is linked to cell overproliferation in cancers of these tissues. Musashi has been primarily implicated as a repressor of target mRNAs in stem cell populations. However, little is known about the mechanism by which Musashi exerts mRNA translational control or how Musashi function is regulated. Recent findings in oocytes of the frog, Xenopus, indicate an unexpected role for Musashi as an activator of a number of maternal mRNAs during meiotic cell cycle progression. Given the importance of Musashi function in stem cell biology and the implications of aberrant Musashi expression in cancer, it is critical that we understand the molecular processes that regulate Musashi function.

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A Toxic RNA Catalyzes the Cellular Synthesis of Its Own Inhibitor, Shunting It to Endogenous Decay Pathways

10.1101/741926 ◽

2019 ◽

Cited By ~ 1

Author(s):

Raphael I. Benhamou ◽

Alicia J. Angelbello ◽

Eric T. Wang ◽

Matthew D. Disney

Keyword(s):

Small Molecules ◽

Rna Binding ◽

Rna Binding Proteins ◽

Intron Retention ◽

Protein A ◽

List Type ◽

Nucleic Acid Binding ◽

Myotonic Dystrophy Type 2 ◽

Intron 1 ◽

Toxic Rna

SUMMARYMyotonic dystrophy type 2 (DM2) is a genetically defined muscular dystrophy caused by a toxic expanded repeat of r(CCUG) [heretofore (CCUG)exp], harbored in intron 1 of CHC-Type Zinc Finger Nucleic Acid Binding Protein (CNBP) pre-mRNA. This r(CCUG)exp causes DM2 via a gain-of-function mechanism that results in three hallmarks of its pathology: (i) binding to RNA-binding proteins (RBPs) that aggregate into nuclear foci; (ii) sequestration of muscleblind-like-1 (MBNL1) protein, a regulator of alternative pre-mRNA splicing, leading to splicing defects; and (iii) retention of intron 1 in the CNBP mRNA. Here, we find that CNBP intron retention is caused by the r(CCUG)exp-MBNL1 complex and can be rescued by small molecules. We studied two types of small molecules with different modes of action, ones that simply bind and ones that can be synthesized by a r(CCUG)exp-templated reaction in cells, that is the RNA synthesizes its own drug. Indeed, our studies completed in DM2 patient-derived fibroblasts show that the compounds disrupt the r(CCUG)exp-MBNL1 complex, reduce intron retention, subjecting the liberated intronic r(CCUG)exp to native decay pathways, and rescue other DM2-associated cellular defects. Collectively, this study shows that small molecules can affect RNA biology by shunting toxic transcripts towards native decay pathways.HIGHLIGHTSIntron retention in RNA repeat expansions can be due to repeats binding to proteinsSmall molecules that bind RNA repeats and inhibit protein binding can trigger decayA toxic RNA repeat can catalyze the synthesis of its own inhibitor on-siteOn-site drug synthesis most potently affects disease biologyeTOC BLURBThe most common way to target RNA is to use antisense oligonucleotides to target unstructured RNAs for destruction. Here, we show for the first time that small molecules targeting structured, disease-causing RNAs can shunt them towards native decay pathways by affecting their processing.

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The evolutionarily conserved RNA binding protein SMOOTH is essential for maintaining normal muscle function

Fly ◽

10.4161/fly.9517 ◽

2009 ◽

Vol 3 (4) ◽

pp. 235-246 ◽

Cited By ~ 8

Author(s):

Isabelle Draper ◽

Meg E. Tabaka ◽

F. Rob Jackson ◽

Robert N. Salomon ◽

Alan Kopin

Keyword(s):

Muscle Function ◽

Rna Binding ◽

Binding Protein ◽

Rna Binding Protein ◽

Normal Muscle ◽

Evolutionarily Conserved

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Core components of endosomal mRNA transport are evolutionarily conserved in fungi

10.1101/467787 ◽

2018 ◽

Author(s):

Jessica Müller ◽

Thomas Pohlmann ◽

Michael Feldbrügge

Keyword(s):

Rna Binding ◽

Fungal Species ◽

Active Movement ◽

List Type ◽

Mrna Transport ◽

Spatiotemporal Expression ◽

Evolutionarily Conserved ◽

Core Components ◽

Mode Of Transport ◽

Dependent Transport

AbstractActive movement of mRNAs by sophisticated transport machineries determines precise spatiotemporal expression of encoded proteins. A prominent example discovered in fungi is microtubule-dependent transport via endosomes. This mode of transport was thought to be only operational in the basidiomycete Ustilago maydis. Here, we report that distinct core components are evolutionarily conserved in fungal species of distantly related phyla like Mucoromycota. Interestingly, orthologues of the key RNA-binding protein Rrm4 from the higher basidiomycete Coprinopsis cinerea and the mucoromycete Rhizophagus irregularis shuttle on endosomes in hyphae of U. maydis. Thus, endosomal mRNA transport appears to be more wide-spread than initially anticipated.Highlights‐Core transport components Upa1 and Rrm4 are conserved in different fungal phyla‐Components of the Rrm4 machinery were most likely secondarily lost in ascomycetes‐Upa1 from Microbotryum lychnidis-dioicae is functional in U. maydis‐Rrm4 orthologues from Basidio- and Mucoromycota shuttle in hyphae of U. maydis

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Respiratory muscle function in the newborn: a narrative review

Pediatric Research ◽

10.1038/s41390-021-01529-z ◽

2021 ◽

Author(s):

Theodore Dassios ◽

Aggeliki Vervenioti ◽

Gabriel Dimitriou

Keyword(s):

Congenital Anomalies ◽

Muscle Function ◽

Respiratory Muscle ◽

Work Of Breathing ◽

Respiratory Muscles ◽

Current Evidence ◽

Muscle Fibres ◽

List Type ◽

Respiratory Muscle Function ◽

Neurally Adjusted Ventilator Assist

Abstract Our aim was to summarise the current evidence and methods used to assess respiratory muscle function in the newborn, focusing on current and future potential clinical applications. The respiratory muscles undertake the work of breathing and consist mainly of the diaphragm, which in the newborn is prone to dysfunction due to lower muscle mass, flattened shape and decreased content of fatigue-resistant muscle fibres. Premature infants are prone to diaphragmatic dysfunction due to limited reserves and limited capacity to generate force and avoid fatigue. Methods to assess the respiratory muscles in the newborn include electromyography, maximal respiratory pressures, assessment for thoraco-abdominal asynchrony and composite indices, such as the pressure–time product and the tension time index. Recently, there has been significant interest and a growing body of research in assessing respiratory muscle function using bedside ultrasonography. Neurally adjusted ventilator assist is a novel ventilation mode, where the level of the respiratory support is determined by the diaphragmatic electrical activity. Prolonged mechanical ventilation, hypercapnia and hypoxia, congenital anomalies and systemic or respiratory infection can negatively impact respiratory muscle function in the newborn, while caffeine and synchronised or volume-targeted ventilation have a positive effect on respiratory muscle function compared to conventional, non-triggered or pressure-limited ventilation, respectively. Impact Respiratory muscle function is impaired in prematurely born neonates and infants with congenital anomalies, such as congenital diaphragmatic hernia. Respiratory muscle function is negatively affected by prolonged ventilation and infection and positively affected by caffeine and synchronised compared to non-synchronised ventilation modes. Point-of-care diaphragmatic ultrasound and neurally adjusted ventilator assist are recent diagnostic and therapeutic technological developments with significant clinical applicability.

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The landscape of alternative polyadenylation in single cells of the developing mouse embryo

Nature Communications ◽

10.1038/s41467-021-25388-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Vikram Agarwal ◽

Sereno Lopez-Darwin ◽

David R. Kelley ◽

Jay Shendure

Keyword(s):

Rna Binding ◽

Developmental Stages ◽

Single Cells ◽

Neuronal Cell ◽

Alternative Polyadenylation ◽

Cell Types ◽

Untranslated Regions ◽

Mammalian Development ◽

Translation Rate ◽

Dynamic Landscape

Abstract3′ untranslated regions (3′ UTRs) post-transcriptionally regulate mRNA stability, localization, and translation rate. While 3′-UTR isoforms have been globally quantified in limited cell types using bulk measurements, their differential usage among cell types during mammalian development remains poorly characterized. In this study, we examine a dataset comprising ~2 million nuclei spanning E9.5–E13.5 of mouse embryonic development to quantify transcriptome-wide changes in alternative polyadenylation (APA). We observe a global lengthening of 3′ UTRs across embryonic stages in all cell types, although we detect shorter 3′ UTRs in hematopoietic lineages and longer 3′ UTRs in neuronal cell types within each stage. An analysis of RNA-binding protein (RBP) dynamics identifies ELAV-like family members, which are concomitantly induced in neuronal lineages and developmental stages experiencing 3′-UTR lengthening, as putative regulators of APA. By measuring 3′-UTR isoforms in an expansive single cell dataset, our work provides a transcriptome-wide and organism-wide map of the dynamic landscape of alternative polyadenylation during mammalian organogenesis.

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The Role of Translation Initiation Regulation in Haematopoiesis

Comparative and Functional Genomics ◽

10.1155/2012/576540 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Godfrey Grech ◽

Marieke von Lindern

Keyword(s):

Gene Expression ◽

Translation Initiation ◽

Translational Control ◽

Molecular Mechanisms ◽

Rna Binding ◽

Regulation Of Gene Expression ◽

Mrna Translation ◽

Translation Control ◽

Haematological Disorders

Organisation of RNAs into functional subgroups that are translated in response to extrinsic and intrinsic factors underlines a relatively unexplored gene expression modulation that drives cell fate in the same manner as regulation of the transcriptome by transcription factors. Recent studies on the molecular mechanisms of inflammatory responses and haematological disorders indicate clearly that the regulation of mRNA translation at the level of translation initiation, mRNA stability, and protein isoform synthesis is implicated in the tight regulation of gene expression. This paper outlines how these posttranscriptional control mechanisms, including control at the level of translation initiation factors and the role of RNA binding proteins, affect hematopoiesis. The clinical relevance of these mechanisms in haematological disorders indicates clearly the potential therapeutic implications and the need of molecular tools that allow measurement at the level of translational control. Although the importance of miRNAs in translation control is well recognised and studied extensively, this paper will exclude detailed account of this level of control.

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TAP (NXF1) Belongs to a Multigene Family of Putative RNA Export Factors with a Conserved Modular Architecture

Molecular and Cellular Biology ◽

10.1128/mcb.20.23.8996-9008.2000 ◽

2000 ◽

Vol 20 (23) ◽

pp. 8996-9008 ◽

Cited By ~ 139

Author(s):

Andrea Herold ◽

Mikita Suyama ◽

João P. Rodrigues ◽

Isabelle C. Braun ◽

Ulrike Kutay ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Rna Binding ◽

Mrna Export ◽

Modular Architecture ◽

Export Activity ◽

Evolutionarily Conserved ◽

Rna Export ◽

Higher Eukaryotes ◽

Leucine Rich Repeats ◽

Rna Export Factors

ABSTRACT Vertebrate TAP (also called NXF1) and its yeast orthologue, Mex67p, have been implicated in the export of mRNAs from the nucleus. The TAP protein includes a noncanonical RNP-type RNA binding domain, four leucine-rich repeats, an NTF2-like domain that allows heterodimerization with p15 (also called NXT1), and a ubiquitin-associated domain that mediates the interaction with nucleoporins. Here we show that TAP belongs to an evolutionarily conserved family of proteins that has more than one member in higher eukaryotes. Not only the overall domain organization but also residues important for p15 and nucleoporin interaction are conserved in most family members. We characterize two of four human TAP homologues and show that one of them, NXF2, binds RNA, localizes to the nuclear envelope, and exhibits RNA export activity. NXF3, which does not bind RNA or localize to the nuclear rim, has no RNA export activity. Database searches revealed that although only one p15(nxt) gene is present in the Drosophila melanogaster and Caenorhabditis elegans genomes, there is at least one additional p15 homologue (p15-2 [also called NXT2]) encoded by the human genome. Both human p15 homologues bind TAP, NXF2, and NXF3. Together, our results indicate that the TAP-p15 mRNA export pathway has diversified in higher eukaryotes compared to yeast, perhaps reflecting a greater substrate complexity.

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RNA Is a Double-Edged Sword in ALS Pathogenesis

Frontiers in Cellular Neuroscience ◽

10.3389/fncel.2021.708181 ◽

2021 ◽

Vol 15 ◽

Author(s):

Benjamin L. Zaepfel ◽

Jeffrey D. Rothstein

Keyword(s):

Motor Neurons ◽

Cortical Neurons ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Rna Metabolism ◽

Small Subset ◽

Toxic Rna ◽

Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease that affects upper and lower motor neurons. Familial ALS accounts for a small subset of cases (<10–15%) and is caused by dominant mutations in one of more than 10 known genes. Multiple genes have been causally or pathologically linked to both ALS and frontotemporal dementia (FTD). Many of these genes encode RNA-binding proteins, so the role of dysregulated RNA metabolism in neurodegeneration is being actively investigated. In addition to defects in RNA metabolism, recent studies provide emerging evidence into how RNA itself can contribute to the degeneration of both motor and cortical neurons. In this review, we discuss the roles of altered RNA metabolism and RNA-mediated toxicity in the context of TARDBP, FUS, and C9ORF72 mutations. Specifically, we focus on recent studies that describe toxic RNA as the potential initiator of disease, disease-associated defects in specific RNA metabolism pathways, as well as how RNA-based approaches can be used as potential therapies. Altogether, we highlight the importance of RNA-based investigations into the molecular progression of ALS, as well as the need for RNA-dependent structural studies of disease-linked RNA-binding proteins to identify clear therapeutic targets.

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