HITS-CLIP analysis of FMRP mRNA binding sites from P11-P25 mouse brain polysomes
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE45148 | GEO | 2013/03/15
SECONDARY ACCESSION(S): PRJNA193166
REPOSITORIES: GEO
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Project description:FMRP loss-of-function causes Fragile X Syndrome (FXS) and autistic features. FMRP is a polyribosome-associated neuronal RNA-binding protein, suggesting that it plays a key role in regulating neuronal translation, but there has been little consensus regarding either its RNA targets or mechanism of action. Here we use high throughput sequencing of RNAs isolated by crosslinking immunoprecipitation (HITS-CLIP) to identify FMRP interactions with mouse brain polyribosomal mRNAs. FMRP interacts with the coding region of transcripts encoding pre- and postsynaptic proteins, and transcripts implicated in autism spectrum disorders Polyribosomes were prepared from UV254-crosslinked pooled littermate FVB mouse brains as described in detail in published paper PMID 21784246. Polyribosomes were dissociated under denaturing conditions using two different protocols to disrupt ribonucleoprotein complexes. In most experiments Fmr1-null littermates were used in parallel to confirm FMRP specificity. After mild RNAse treatment to reduce the size of RNA to 60-100 nucleotides, endogenous FMRP was immunoprecipitated with one of two antibody combinations, either mixed monoclonal antibodies 7G1-1 and 2F5, or polyclonal antibody ab17722 (Abcam). The ages of the mice were P11, P13, P14, P15, and P25. In addition, to assess a different neuronal polysome-associated protein, as another control, lysates prepared from two samples, the P11 and P13 mice, were split in half and one half IPed with a human anti-Hu antisera as the neuronal Hu proteins are polysome-associated in brain. In sum, 7 FMRP HITS-CLIP experiments were performed including (1) P14 mouse polysomes prepared by Protocol 1 and IPed with 7G1-1/2F5 (2) P14 mouse polysomes prepared by Protocol 1 and IPed with ab17722 (3) P15 mouse polysomes prepared by Protocol 1 and IPed with 7G1-1/2F5 (4) P25 mouse polysomes prepared by Protocol 1 and IPed with 7G1-1/2F5 (5) P25 mouse polysomes prepared by Protocol 1 and IPed with ab17722 (6) P11 mouse polysomes prepared by Protocol 2 and IPed with ab17722 and (7) P13 mouse polysomes prepared by Protocol 2 and IPed with ab17722. FMRP-bound or Hu-bound RNA tags were cloned and submitted for high throughput sequencing on the Life Science 454 platform (samples 1-5) or the Illumina platform (samples 6 and 7 and the 2 Hu samples processed in parallel with samples 6 and 7). Full details are given in PMID 21784246.
2013-03-15 | E-GEOD-45148 | biostudies-arrayexpress
Project description:Translation activation of local synaptic mRNA is critical to learning and memory. Despite extensive studies on how phosphorylations of ribosome units and translation factors enable fast response to exogenous stimuli, our knowledge on molecular pathways utilized by RNA binding proteins (RBPs) to control translation of specific mRNAs remains incomplete. We have previously found that YTHDF1 regulates depolarization-induced protein synthesis by promoting translation of N6-methyladenosine (m6A)-modified transcripts. Here we report an unexpected mechanism that the stimuli-induced neuronal translation is mediated by phosphorylation of a YTHDF1-binding protein FMRP. Phosphorylation of FMRP serine 499 induced by neuronal depolarization alters the condensing behavior of prion-like protein YTHDF1. Unphosphorylated FMRP sequesters YTHDF1 away from the translation initiation complex, whereas the stimulation-induced FMRP phosphorylation releases YTHDF1 to form translational active condensates with the ribosome to activate translation of YTHDF1 target transcripts. In fragile X syndrome (FXS) models characterized with low FMRP expression, we observed YTHDF1-mediated hyperactive translation, which notably impacts FXS pathophysiology. Developmental defects in an FXS forebrain organoid model could be reversed by a selective small-molecule inhibitor of YTHDF1 which acts by suppressing its condensation in neurons. We characterized transcriptome-wide translation alterations with the inhibitor treatment in organoids and identified targets that explain alleviated FXS pathology. Our study thus reveals FMRP and its phosphorylation as an important regulator of the activity-dependent translation during neuronal development and stimulation, and identifies YTHDF1 as a potential therapeutic target for FXS in which developmental defects caused by FMRP depletion could be reversed through YTHDF1 inhibition.
2023-10-31 | GSE214882 | GEO
Project description:Loss of the neuronal RNA binding protein FMRP causes Fragile X Syndrome (FXS), the most common cause of inherited intellectual disability, yet it is unknown which brain regions and cell types within them contribute to disease pathophysiology. We used conditional tagging of FMRP and CLIP (cTag FMRP CLIP) to examine FMRP targets specifically in CA1 hippocampal neurons, a critical cell type for learning and memory known to have altered synaptic function in FXS. Integrating this data with analysis of ribosome-bound transcripts from the same neuronal population revealed CA1-enriched binding of autism-relevant mRNAs, and unexpected CA1-specific regulation of transcripts encoding circadian proteins.
2020-01-07 | GSE127846 | GEO
Project description:Fragile X syndrome (FXS) is a rare disease but is the most common form of inherited intellectual disability and a leading cause of autism. FXS is due to the absence of the Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein mainly involved in translational control. Even if this molecular defect is known, no specific therapy is available for FXS. The first alteration observed in the brain of FXS patients and of Fmr1 KO mice, model for FXS, is represented by an abnormal dendritic morphology that is associated with an altered synaptic plasticity. These findings led to numerous studies focused on mature neurons. However, recently, an increasing body of evidence is pointing out the importance of FMRP in the early steps of brain development. Thus, with the purpose to decipher the earliest molecular events leading to FXS we developed a stem-cell-based disease model by knocking-down the expression of Fmr1 in mouse embryonic stem (ES) cells. To gain insights in the pathways that are affected when FMRP is repressed, we performed a gene expression profile analysis comparing total RNA from shFmr1 and shControl ES cells using whole genome mouse microarrays. Transcripts were clustered according to their Gene Ontology classification using the DAVID software. Surprisingly, the most altered functional category was Nervous system development and function, highlighting the role of FMRP also during the earliest steps of neural development. To study the precise role of FMRP in Embryonic stem (ES) cells, we used an RNAi-based loss-of-function strategy by transducing mouse ES cells with a lentivirus expressing GFP and a shRNA targeting the constitutive exon 1 of Fmr1 (shFmr1). A random shRNA (shCT) was used as a control sequence. Transduced cells were sorted by flow cytometry and established as non-clonal cell populations. RNA samples were harvested and profiling experiments were performed in â??dye-balanceâ?? as indicated for each replicate.
2016-07-04 | E-GEOD-71184 | biostudies-arrayexpress
Project description:Fragile X syndrome (FXS) is the most common inherited form of intellectual disability and a leading genetic cause of autism. FXS is caused by the loss of functional fragile X mental retardation protein (FMRP). FMRP is an RNA-binding protein forming a messenger ribonucleoprotein complex with polyribosomes in the regulation of protein synthesis at synapses. Three-dimensional (3D) aggregate culture of human-induced pluripotent stem cells (iPSCs) has evolved from embryoid body cultures, quite faithfully following human organogenesis, and provides a new platform to investigate human brain development in a dish, otherwise inaccessible to experimentation. To determine whether the loss of FMRP could alter the development of human brain organoids, we have generated forebrain organoids from three FXS male patients and three healthy male controls. We observed reduced proliferation of neural progenitor cells and premature neural differentiation as well as perturbed cell cycle progression in FXS forebrain organoids. There is also a deficit in the production of GABAergic neurons as well as an altered balance between the number of excitatory and inhibitory neurons in FXS organoids. Interestingly these deficits were not observed with FXS mouse model. To compare the differential gene expression caused by the loss of FMRP between human and mouse, we then performed RNA-seq to identify the differentially expressed genes using both mouse embryonic brain cortex and human forebrain organoids at the comparable developmental stages. We detected very few genes differentially expressed in the absence of Fmrp in mouse. However, we identified 200 genes downregulated and 126 genes up-regulated in human FXS organoids, indicating human-specific impact caused by the loss of FMRP. Our bulk RNA-seq analyses revealed a more pervasive gene expression alteration in human organoids. Thus, it is plausible to speculate that there could be important human-specific genes that might be related with FXS pathogenesis. To test this idea, we used human forebrain organoids and the mouse embryonic brains in parallel to perform enhanced crosslinking and FMRP immunoprecipitation followed by high-throughput sequencing and bioinformatics analysis (CLIP-seq). Our analyses identified more than 3,700 mRNA bound by FMRP in human organoids. Of the 3,700 mRNAs, ~1,600 overlapped with mouse mRNAs. Further, ~80% of the identified mouse mRNA species overlap with previously published results in mouse. To better understand the developmental, cellular and molecular changes and to gain insight beyond bulk gene expression analysis in forebrain organoids from FXS patients compared to control, we next performed single cell RNA-seq (scRNA-seq) to characterize distinct cell populations, specific cell types and cell states. We found that the population of specific neuron type were changed upon the loss of FMRP. Next, investigated if there were developmental differences in the transitioning from the early, primitive state to one of the more committed end states between control and FXS organoids, with many cells distributed along a “trajectory” between them. we found several bifurcation points of FXS cells from the general trajectory, and the cells of these subpopulations with altered neuronal states are strongly enriched for FXS. These results together suggest that the loss of FMRP could cause neurodevelopmental deficits specifically in human, and fragile X organoids could provide a unique platform to study the molecular pathogenesis of FXS and identify human-specific druggable targets for FXS and autism in general.
2021-06-19 | GSE146878 | GEO
Project description:Fragile X syndrome (FXS) is a rare disease but is the most common form of inherited intellectual disability and a leading cause of autism. FXS is due to the absence of the Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein mainly involved in translational control. Even if this molecular defect is known, no specific therapy is available for FXS. The first alteration observed in the brain of FXS patients and of Fmr1 KO mice, model for FXS, is represented by an abnormal dendritic morphology that is associated with an altered synaptic plasticity. These findings led to numerous studies focused on mature neurons. However, recently, an increasing body of evidence is pointing out the importance of FMRP in the early steps of brain development. Thus, with the purpose to decipher the earliest molecular events leading to FXS we developed a stem-cell-based disease model by knocking-down the expression of Fmr1 in mouse embryonic stem (ES) cells. To gain insights in the pathways that are affected when FMRP is repressed, we performed a gene expression profile analysis comparing total RNA from shFmr1 and shControl ES cells using whole genome mouse microarrays. Transcripts were clustered according to their Gene Ontology classification using the DAVID software. Surprisingly, the most altered functional category was Nervous system development and function, highlighting the role of FMRP also during the earliest steps of neural development.
2016-07-04 | GSE71184 | GEO
Project description:Loss of functional fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS) and is the leading monogenic cause of autism spectrum disorders and intellectual disability. FMRP is most notably a translational repressor and is thought to inhibit translation elongation by stalling ribosomes as FMRP-bound polyribosomes from brain tissue are resistant to puromycin and nuclease treatment. Here, we present data showing that the C-terminal non-canonical RNA-binding domain of FMRP is essential and sufficient to induce puromycin-resistant mRNA•ribosome complexes. Given that stalled ribosomes can stimulate ribosome collisions and no-go mRNA decay (NGD), we tested the ability of FMRP to drive NGD of its target transcripts in neuroblastoma cells. Indeed, FMRP and ribosomal proteins, but not PABPC1, were enriched in isolated nuclease-resistant disomes compared to controls. Using siRNA knockdown and RNA-seq, we identified 16 putative FMRP-mediated NGD substrates, many of which encode proteins involved in neuronal development and function. Increased mRNA stability of the putative substrates was also observed when either FMRP was depleted or NGD was prevented via RNAi. Taken together, these data support that FMRP stalls ribosomes and can stimulate NGD in cells, albeit on a small number of transcripts, revealing an unappreciated role of FMRP that would be misregulated in FXS when FMRP is lost.
2024-08-28 | GSE254586 | GEO
Project description:The Fragile X Mental Retardation Protein, FMRP, is thought to regulate the translation of a specific set of neuronal mRNAs on polyribosomes. Therefore, we prepared polyribosomes on sucrose gradients and purified mRNA specifically from these fractions, as well as the total mRNA levels, to determine whether a set of mRNAs might be changed in its % association with polyribosomes in the absence of FMRP in the KO mouse model. No significant differences were found, other than the Fmr1 transcript itself, in total mRNA levels or % polyribosome association that withstood multiple test correction, in P7 Fmr1 KO mouse cerebral cortex compared with WT littermates.. We prepared polyribosomes on sucrose gradients from 6 littermate pairs of Fmr1 KO and WT littermates (FVB background, P7 males, cerebral cortex) and purified RNA from both polyribosomal fractions and input to the gradient, reflecting total mRNA levels for comparison.
2011-07-20 | E-GEOD-26745 | biostudies-arrayexpress
Project description:Fragile X syndrome (FXS), the leading cause of inherited form of mental retardation and autism, is caused by the transcriptional silencing of fmr1 encoding the protein of FMRP. FMRP, acting as an RNA binding protein, FMRP is a wide expressed protein, but primarily in the brain and testis and can regulate approximately 4% of transcripts. Macroorchidism is one of the common symptoms observed both in the FXS people and mice. Thus, we analyzed the protein profiles of cerebral cortex, hippocampus and testis from both the fmr1-KO and WT mouse using a quantitative proteomics. Proteins (FMRP, RS8, RL23A and MPZ) identified by MS/MS were also verified by Western blot. Among the identified proteins, most of the significant changed proteins were downregulated in the FMRP absence. The Gene Ontology and pathway analysis revealed that the changed proteins were clustered in polyribosome and RNA binding proteins in both cerebral cortex and hippocampus, but not the same in testis. Our results provide detailed insights to the ribosome protein profiles of cerebral cortex, hippocampus and testis in the absence of FMRP. Our studies also give a better understanding of protein profile changes and underling dysregulated pathways arising from the fmr1 silencing in the FXS.
2022-02-28 | PXD005089 | Pride
Project description:The loss of fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS), the most common inherited intellectual disability. How the loss of FMRP alters protein expression and astroglial functions remains essentially unknown. Here we showed that selective loss of astroglial FMRP in vivo up-regulates a brain-enriched miRNA, miR-128-3p, in mouse and human FMRP-deficient astroglia, which suppresses developmental expression of astroglial metabotropic glutamate receptor 5 (mGluR5), a major receptor in mediating developmental astroglia to neuron communication. Selective in vivo inhibition of miR-128-3p in FMRP-deficient astroglia sufficiently rescues decreased mGluR5 function, while astroglial overexpression of miR-128-3p strongly and selectively diminishes developmental astroglial mGluR5 signaling. Subsequent transcriptome and proteome profiling further suggests that FMRP commonly and preferentially regulates protein expression through posttranscriptional, but not transcriptional, mechanisms in astroglia. Overall, our study defines an FMRP-dependent cell-autonomous miR pathway that selectively alters developmental astroglial mGluR5 signaling, unveiling astroglial molecular mechanisms involved in FXS pathogenesis.
2020-09-10 | GSE157724 | GEO