FMRP association with and regulation of Fragile X granules exhibit circuit-dependent requirements for the KH2 RNA binding domain

2018 ◽  
Author(s):  
Ellen C. Gingrich ◽  
Katherine A. Shepard ◽  
Molly E. Mitchell ◽  
Kirsty Sawicka ◽  
Jennifer C. Darnell ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Fragile X ◽  
Brain Regions ◽  
Binding Domain ◽  
Cell Type ◽  
Related Disorder ◽  
Rna Granules ◽  
Rna Binding Domain

AbstractThe localization and translation of mRNAs is controlled by a diverse array of ribonucleoprotein particles (RNPs), multimolecular complexes containing mRNAs and RNA binding proteins. Fragile X granules (FXGs) are a family of RNPs that exemplify the diversity of RNA granules in the mammalian nervous system. FXGs are found in a conserved subset of neurons, where they localize exclusively to the axonal compartment. Notably, the specific RNA binding proteins and mRNAs found in FXGs depend on brain circuit and neuron type, with all forebrain FXGs containing Fragile X mental retardation protein (FMRP), the protein mutated in the human autism-related disorder Fragile X syndrome. FMRP negatively regulates FXG abundance but is not required for their association with ribosomes or mRNA. To better understand the circuit-dependent mechanisms whereby FMRP associates with and regulates FXGs, we asked how a disease-causing point mutation, I304N, in the KH2 RNA binding domain of FMRP affects these granules in two brain regions – cortex and hippocampus. We found that FMRPI304N had a reduced association with FXGs, as it was absent from approximately half of FXGs in cortex and nearly all FXGs in hippocampus. FXG abundance correlated with the number of FMRP-containing FXGs, suggesting that FMRP regulates FXG abundance by KH2-independent mechanisms that occur locally within the granules. Together, these findings illustrate that cell type-dependent mechanisms guide the assembly of similar RNA granules. Further, point mutations in RNA granule components may lead to cell type-dependent phenotypes that produce atypical forms of disorders that normally arise from more severe mutations.

RNA-Binding Proteins and Translation in Neurodegenerative Disease

2020 ◽  
Author(s):  
Kent E. Duncan
Keyword(s):  
Neurodegenerative Diseases ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Fragile X ◽  
Potential Contribution ◽  
Fused In Sarcoma ◽  
Specific Mrnas ◽  
Ataxia Syndrome ◽  
Research Frontiers

Both RNA-binding proteins (RBPs) and translation are increasingly implicated in several neurodegenerative diseases, but their specific roles in promoting disease are not yet fully defined. This chapter critically evaluates the evidence that altered translation of specific mRNAs mediated by RNA-binding proteins plays an important role in driving specific neurodegenerative diseases. First, diseases are discussed where a causal role for RNA-binding proteins in disease appears solid, but whether this involves altered translation is less clear. The main foci here are TAR DNA-binding protein (TDP-43) and fused in sarcoma (FUS) in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Subsequently, diseases are presented where altered translation is believed to contribute, but involvement of RNA-binding proteins is less clear. These include Huntington’s and other repeat expansion disorders such as fragile X tremor/ataxia syndrome (FXTAS), where repeat-induced non-AUG-initiated (RAN) translation is a focus. The potential contribution of both canonical and non-canonical RBPs to altered translation in Parkinson’s disease is discussed. The chapter closes by proposing key research frontiers for the field to explore and outlining methodological advances that could help to address them.

scholarly journals Two functionally distinct RNA-binding motifs in the regulatory domain of the protein kinase DAI.

1995 ◽  
Vol 15 (1) ◽  
pp. 358-364 ◽  
Author(s):  
S R Green ◽  
L Manche ◽  
M B Mathews
Keyword(s):  
Amino Acid ◽  
Protein Kinase ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Alpha Helix ◽  
Binding Domain ◽  
Single Amino Acid ◽  
Double Stranded Rna ◽  
C Terminus ◽  
Rna Binding Domain

The RNA-binding domain of the protein kinase DAI, the double-stranded RNA inhibitor of translation, contains two repeats of a motif that is also found in a number of other RNA-binding proteins. This motif consists of 67 amino acid residues and is predicted to contain a positively charged alpha helix at its C terminus. We have analyzed the effects of equivalent single amino acid changes in three conserved residues distributed over each copy of the motif. Mutants in the C-terminal portion of either repeat were severely defective, indicating that both copies of the motif are essential for RNA binding. Changes in the N-terminal and central parts of the motif were more debilitating if they were made in the first motif than in the second, suggesting that the first motif is the more important for RNA binding and that the second motif is structurally more flexible. When the second motif was replaced by a duplicate of the first motif, the ectopic copy retained its greater sensitivity to mutation, implying that the two motifs have distinct functions with respect to the process of RNA binding. Furthermore, the mutations have the same effect on the binding of double-stranded RNA and VA RNA, consistent with the existence of a single RNA-binding domain for both activating and inhibitory RNAs.

scholarly journals Lack of a Clear Behavioral Phenotype in an Inducible FXTAS Mouse Model Despite the Presence of Neuronal FMRpolyG-Positive Aggregates

2020 ◽  
Vol 7 ◽  
Author(s):  
Saif N. Haify ◽  
Ruchira S. D. Mankoe ◽  
Valerie Boumeester ◽  
Esmay C. van der Toorn ◽  
Rob F. M. Verhagen ◽  
...  
Keyword(s):  
Mouse Model ◽  
Rna Binding ◽  
Neurodegenerative Disorder ◽  
Rna Binding Proteins ◽  
Fragile X ◽  
Brain Regions ◽  
Intranuclear Inclusions ◽  
Behavioral Deficits ◽  
Cgg Repeat ◽  
Progressive Cerebellar Ataxia

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a rare neurodegenerative disorder caused by a 55–200 CGG repeat expansion in the 5′ untranslated region of the Fragile X Mental Retardation 1 (FMR1) gene. FXTAS is characterized by progressive cerebellar ataxia, Parkinsonism, intention tremors and cognitive decline. The main neuropathological hallmark of FXTAS is the presence of ubiquitin-positive intranuclear inclusions in neurons and astrocytes throughout the brain. The molecular pathology of FXTAS involves the presence of 2 to 8-fold elevated levels of FMR1 mRNA, and of a repeat-associated non-AUG (RAN) translated polyglycine peptide (FMRpolyG). Increased levels of FMR1 mRNA containing an expanded CGG repeat can result in cellular toxicity by an RNA gain-of-function mechanism. The increased levels of CGG repeat-expanded FMR1 transcripts may create RNA foci that sequester important cellular proteins, including RNA-binding proteins and FMRpolyG, in intranuclear inclusions. To date, it is unclear whether the FMRpolyG-positive intranuclear inclusions are a cause or a consequence of FXTAS disease pathology. In this report we studied the relation between the presence of neuronal intranuclear inclusions and behavioral deficits using an inducible mouse model for FXTAS. Neuronal intranuclear inclusions were observed 4 weeks after dox-induction. After 12 weeks, high numbers of FMRpolyG-positive intranuclear inclusions could be detected in the hippocampus and striatum, but no clear signs of behavioral deficits related to these specific brain regions were found. In conclusion, the observations in our inducible mouse model for FXTAS suggest a lack of correlation between the presence of intranuclear FMRpolyG-positive aggregates in brain regions and specific behavioral phenotypes.

scholarly journals Analyzing the Surface Structure of the Binding Domain on DNA and RNA Binding Proteins

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 30042-30049
Author(s):  
Wei Wang ◽  
Keliang Li ◽  
Hehe Lv ◽  
Hongjun Zhang ◽  
Shiguang Zhang ◽  
...  
Keyword(s):  
Surface Structure ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Domain ◽  
Dna And Rna ◽  
Dna And Rna Binding

scholarly journals Cataloguing and Selection of mRNAs Localized to Dendrites in Neurons and Regulated by RNA-Binding Proteins in RNA Granules

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 167 ◽  
Author(s):  
Ohashi ◽  
Shiina
Keyword(s):  
Synaptic Plasticity ◽  
Cell Fate ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Memory Formation ◽  
Long Term Memory ◽  
Local Translation ◽  
Rna Granules

Spatiotemporal translational regulation plays a key role in determining cell fate and function. Specifically, in neurons, local translation in dendrites is essential for synaptic plasticity and long-term memory formation. To achieve local translation, RNA-binding proteins in RNA granules regulate target mRNA stability, localization, and translation. To date, mRNAs localized to dendrites have been identified by comprehensive analyses. In addition, mRNAs associated with and regulated by RNA-binding proteins have been identified using various methods in many studies. However, the results obtained from these numerous studies have not been compiled together. In this review, we have catalogued mRNAs that are localized to dendrites and are associated with and regulated by the RNA-binding proteins fragile X mental retardation protein (FMRP), RNA granule protein 105 (RNG105, also known as Caprin1), Ras-GAP SH3 domain binding protein (G3BP), cytoplasmic polyadenylation element binding protein 1 (CPEB1), and staufen double-stranded RNA binding proteins 1 and 2 (Stau1 and Stau2) in RNA granules. This review provides comprehensive information on dendritic mRNAs, the neuronal functions of mRNA-encoded proteins, the association of dendritic mRNAs with RNA-binding proteins in RNA granules, and the effects of RNA-binding proteins on mRNA regulation. These findings provide insights into the mechanistic basis of protein-synthesis-dependent synaptic plasticity and memory formation and contribute to future efforts to understand the physiological implications of local regulation of dendritic mRNAs in neurons.

scholarly journals Axonal localization of the fragile X family of RNA binding proteins is conserved across mammals

2019 ◽  
Vol 528 (3) ◽  
pp. 502-519 ◽  
Author(s):  
Katherine A. Shepard ◽  
Lulu I T. Korsak ◽  
Danielle DeBartolo ◽  
Michael R. Akins
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Fragile X

scholarly journals Molecular dynamics of FMRP and other RNA-binding proteins in MEG-01 differentiation: the role of mRNP complexes in non-neuronal development

2016 ◽  
Vol 94 (6) ◽  
pp. 597-608 ◽  
Author(s):  
M. McCoy ◽  
D. Poliquin-Duchesneau ◽  
F. Corbin
Keyword(s):  
Protein Content ◽  
Binding Proteins ◽  
Rna Binding ◽  
De Novo ◽  
Rna Binding Proteins ◽  
Morphological Changes ◽  
Fragile X ◽  
Cellular Protein ◽  
The Body ◽  
Total Protein Content

Asymmetrically differentiating cells are formed with the aid of RNA-binding proteins (RBPs), which can bind, stabilize, regulate, and transport target mRNAs. The loss of RBPs in neurons may lead to severe neurodevelopmental diseases such as the Fragile X Syndrome with the absence of the Fragile X Mental Retardation Protein (FMRP). Because the latter is ubiquitous and shares many similarities with other RBPs involved in the development of peripheral cells, we suggest that FMRP would have a role in the differentiation of all tissues where it is expressed. A MEG-01 differentiation model was, therefore, established to study the global developmental functions of FMRP. PMA induction of MEG-01 cells causes important morphological changes driven by cytoskeletal dynamics. Cytoskeleton change and colocalization analyses were performed by confocal microscopy and sucrose gradient fractionation. Total cellular protein content and de novo synthesis were also analyzed. Microtubular transport mediates the displacement of FMRP and other RBP-containing mRNP complexes towards regions of the cell in development. De novo protein synthesis decreases significantly upon differentiation and total protein content composition is altered. Because those results are comparable with those obtained in neurons, the absence of FMRP would have significant consequences in cells everywhere in the body. The latter should be further investigated to give a better understanding of the systemic implications of imbalances of FMRP and other functionally similar RBPs.

scholarly journals FMRP promotes RNA localization to neuronal projections through interactions between its RGG domain and G-quadruplex RNA sequences

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Raeann Goering ◽  
Laura I Hudish ◽  
Bryan B Guzman ◽  
Nisha Raj ◽  
Gary J Bassell ◽  
...  
Keyword(s):  
Fragile X Syndrome ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Fragile X ◽  
Rna Localization ◽  
Null Mouse ◽  
Rna Sequences ◽  
Rna Molecules ◽  
G Quadruplex

The sorting of RNA molecules to subcellular locations facilitates the activity of spatially restricted processes. We have analyzed subcellular transcriptomes of FMRP-null mouse neuronal cells to identify transcripts that depend on FMRP for efficient transport to neurites. We found that these transcripts contain an enrichment of G-quadruplex sequences in their 3′ UTRs, suggesting that FMRP recognizes them to promote RNA localization. We observed similar results in neurons derived from Fragile X Syndrome patients. We identified the RGG domain of FMRP as important for binding G-quadruplexes and the transport of G-quadruplex-containing transcripts. Finally, we found that the translation and localization targets of FMRP were distinct and that an FMRP mutant that is unable to bind ribosomes still promoted localization of G-quadruplex-containing messages. This suggests that these two regulatory modes of FMRP may be functionally separated. These results provide a framework for the elucidation of similar mechanisms governed by other RNA-binding proteins.

At the Interface of Three Nucleic Acids: The Role of RNA-Binding Proteins and Poly(ADP-ribose) in DNA Repair

Acta Naturae ◽  
2017 ◽  
Vol 9 (2) ◽  
pp. 4-16 ◽  
Author(s):  
E. E. Alemasova ◽  
O. I. Lavrik
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Regulation Of Gene Expression ◽  
Rna Granules ◽  
Dna And Rna ◽  
Cytoplasmic Rna

RNA-binding proteins (RBPs) regulate RNA metabolism, from synthesis to decay. When bound to RNA, RBPs act as guardians of the genome integrity at different levels, from DNA damage prevention to the post-transcriptional regulation of gene expression. Recently, RBPs have been shown to participate in DNA repair. This fact is of special interest as DNA repair pathways do not generally involve RNA. DNA damage in higher organisms triggers the formation of the RNA-like polymer - poly(ADP-ribose) (PAR). Nucleic acid-like properties allow PAR to recruit DNA- and RNA-binding proteins to the site of DNA damage. It is suggested that poly(ADP-ribose) and RBPs not only modulate the activities of DNA repair factors, but that they also play an important role in the formation of transient repairosome complexes in the nucleus. Cytoplasmic biomolecules are subjected to similar sorting during the formation of RNA assemblages by functionally related mRNAs and promiscuous RBPs. The Y-box-binding protein 1 (YB-1) is the major component of cytoplasmic RNA granules. Although YB-1 is a classic RNA-binding protein, it is now regarded as a non-canonical factor of DNA repair.

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