Project description:Here, we report the genome-wide analysis of snRNAs that are bound to Gemin5 upon protein synthesis inhibition. Upon protein synthesis inhibition, the SMN complex that has a crucial role in the biogenesis of snRNPs dissociates into its subunits, leaving Gemin5 alone. The existence of these subunits was confirmed using a proteomics approach. As Gemin5 has been previously reported to be the RNA-binding protein of the SMN complex, we obtained the sequence of all Gemin5 immunoprecipitated snRNAs. We found that snRNAs that were accumulated on Gemin5 contained extra genomic sequences at the 3'-end. We were thus able to identify novel precursors of all the snRNAs that have not been identified previously. This study also provides a detailed method for the characterization of in vivo captured RNPs using a ribo-proteomics approach. Investigation of snRNAs specifically associated with Gemin5 upon protein synthesis inhibition
Project description:Here, we report the genome-wide analysis of snRNAs that are bound to Gemin5 upon protein synthesis inhibition. Upon protein synthesis inhibition, the SMN complex that has a crucial role in the biogenesis of snRNPs dissociates into its subunits, leaving Gemin5 alone. The existence of these subunits was confirmed using a proteomics approach. As Gemin5 has been previously reported to be the RNA-binding protein of the SMN complex, we obtained the sequence of all Gemin5 immunoprecipitated snRNAs. We found that snRNAs that were accumulated on Gemin5 contained extra genomic sequences at the 3'-end. We were thus able to identify novel precursors of all the snRNAs that have not been identified previously. This study also provides a detailed method for the characterization of in vivo captured RNPs using a ribo-proteomics approach.
Project description:We report the CLIP-seq data of the non-canonical RNA-binding site of Gemin5. This region consists of two domains, RBS1 and RBS2, differing in their RNA-interaction features. Interestingly, the most abundant RNA target of the RBS1 polypeptide was the Gemin5 mRNA. Biochemical and functional characterization of this target demonstrated that RBS1 domain physically interacts with a stem-loop upregulating mRNA translation by counteracting the negative effect of Gemin5 protein on global protein synthesis. We propose that the RBS1 domain of Gemin5 performs a dual role on translation control, which depends on the target RNA, allowing fine-tune the availability of Gemin5 to play its multiple roles in gene expression control
Project description:Translation is a tightly regulated and is predominantly controlled at the level of its initiation. Initiation occurs in a cap-dependent manner. Under stress conditions when cap-dependent translation is hampered, internal ribosome entry sites (IRESes) allow for cap-independent translation of certain mRNAs. IRES-dependent translation is commonly regulated by RNA-interacting proteins, known as IRES trans-acting factors (ITAFs). In the present study, we searched for new IRESes by identifying 5’ untranslated regions (UTRs) bound by the ITAF hnRNPA1. Using a PAR-iCLIP approach, we found the mRNA of thioredoxin interacting protein (TXNIP) bound by hnRNPA1. Upon verification of an IRES element within the 5’UTR of TXNIP, we determined additional interacting proteins, which predominantly appeared to interact with the IRES-regulatory second half of the 5’UTR. Amongst these PTB, FBP3, and GEMIN5 emerged as functional ITAFs. Finally, we found that the TXNIP IRES-inhibitory effect of PTB was dominant over the activating effect of FBP3, while it succumbed to the stimulatory function of GEMIN5. In summary, we identified and characterized a novel IRES within the 5’UTR of TXNIP, which is regulated by the ITAFs PTB, FBP3, and GEMIN5.
Project description:Here we report the identification at a genome-wide scale of the mRNAs associated to polysomes in Gemin5-depleted cells relative to control cells. Among the polysomal Gemin5-enhanced mRNAs, we identified numerous transcripts belonging to two distinct families, which encode ribosomal proteins and histones.
Project description:GEMIN5 is a critical component of snRNP assembly complex. Patients carrying novel autosomal recessive variants in the GEMIN5 gene showed symptoms of developmental delay, central hypotonia, and cerebellar ataxia which are distinct than classical spinal muscular atrophy. We performed RNA-seq analysis in iPSC-derived differentiated neurons with biallelic GEMIN5-H913R mutation to identify global alterations in various genes and pathways mediated by GEMIN5 mutations in patients.
Project description:The mammalian target of rapamycin (mTOR) is a pivotal kinase responsible for transducing cellular energy signals to regulate a host of metabolic processes including protein synthesis, which in turn regulate cell growth and proliferation. All aspects of mRNA life cycle are controlled by protein/RNA interactions and although several effectors of mTOR signalling have been identified to date, how mTOR re-sculptures the mRNA interactome is unknown. Here we characterise mTOR regulated RNA-binding proteins, identifying LARP1, whose binding to RNA increases upon mTOR inhibition. We identified over 3800 LARP1 bound mRNAs, which can be broken down into two groups, those constantly bound by LARP1, or mRNAs that increase their interaction following mTOR inhibition. LARP1 has been implicated in the control of TOP mRNA translation and importantly we observe a large number of TOP mRNAs increasing association with LARP1 upon mTOR inhibition. Regarding the regulation of LARP1, we show that LARP1 and PABP show coordinated differential mRNA binding after mTOR inhibition. Importantly we find that LARP1-PABP interaction is important for LARP1 mRNA binding and mutations in the DM15 domain of LARP1 do not perturb its RNA interaction. Lastly we show that mRNAs bound by LARP1 and PABP are translationally repressed, including mRNAs encoding proteins critical for cell growth and survival.
Project description:Pancreatic ductal adenocarcinoma (PDAC) relies on hyper-activated protein synthesis. Consistently, human and mouse PDAC lose expression of the translational repressor and mTOR target 4E-BP1. Using genome-wide polysome-profiling, we here explore mRNAs whose translational efficiencies depend on the mTOR/4E-BP1 axis in Miapaca-2 cells. This was performed by isolating cytoplasmic and efficiently translated (heavy polysome-associated) mRNAs from MiaPaca-2 cells upon PP242-mediated mTOR inhibition