Degradation of Premature-miR-181b by the Translin/Trax RNase Increases Vascular Smooth Muscle Cell Stiffness.
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ABSTRACT:
SUBMITTER: Tuday E
PROVIDER: S-EPMC8363557 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Long-lasting forms of synaptic plasticity and memory require de novo protein synthesis. Yet, how learning triggers this process to form memory is unclear. Translin/trax is a candidate to drive this learning-induced memory mechanism by suppressing microRNA-mediated translational silencing at activated synapses. We find that mice lacking translin/trax display defects in synaptic tagging, which requires protein synthesis at activated synapses, and long-term memory. Hippocampal samples harvested from these mice following learning show increases in several disease-related microRNAs targeting the activin A receptor type 1C (ACVR1C), a component of the transforming growth factor-β receptor superfamily. Furthermore, the absence of translin/trax abolishes synaptic upregulation of ACVR1C protein after learning. Finally, synaptic tagging and long-term memory deficits in mice lacking translin/trax are mimicked by ACVR1C inhibition. Thus, we define a new memory mechanism by which learning reverses microRNA-mediated silencing of the novel plasticity protein ACVR1C via translin/trax.
| S-EPMC5606845 | biostudies-literature
Project description:The vertebrate RNA and ssDNA-binding protein Translin has been suggested to function in a variety of cellular processes, including DNA damage response, RNA transport, and translational control. The Translin-associated factor X (Trax) interacts with Translin, and Trax protein stability depends on the presence of Translin. To determine the function of the Drosophila Translin and Trax, we generated a translin null mutant and isolated a trax nonsense mutation. translin and trax single and double mutants are viable, fertile, and phenotypically normal. Meiotic recombination rates and chromosome segregation are also not affected in translin and trax mutants. In addition, we found no evidence for an increased sensitivity for DNA double-strand damage in embryos and developing larvae. Together with the lack of evidence for their involvement in DNA double-strand break checkpoints, this argues against a critical role for Translin and Trax in sensing or repairing such DNA damage. However, Drosophila translin is essential for stabilizing the Translin interaction partner Trax, a function that is surprisingly conserved throughout evolution. Conversely, trax is not essential for Translin stability as trax mutants exhibit normal levels of Translin protein.
| S-EPMC1667053 | biostudies-literature
Project description:Translin and Trax proteins are highly conserved nucleic acid binding proteins that have been implicated in RNA regulation in a range of biological processes including tRNA processing, RNA interference, microRNA degradation during oncogenesis, spermatogenesis and neuronal regulation. Here, we explore the function of this paralogue pair of proteins in the fission yeast. Using transcript analysis we demonstrate a reciprocal mechanism for control of telomere-associated transcripts. Mutation of tfx1+ (Trax) elevates transcript levels from silenced sub-telomeric regions of the genome, but not other silenced regions, such as the peri-centromeric heterochromatin. In the case of some sub-telomeric transcripts, but not all, this elevation is dependent on the Trax paralogue, Tsn1 (Translin). In a reciprocal fashion, Tsn1 (Translin) serves to repress levels of transcripts (TERRAs) from the telomeric repeats, whereas Tfx1 serves to maintain these elevated levels. This reveals a novel mechanism for the regulation of telomeric transcripts. We extend this to demonstrate that human Translin and Trax also control telomere-associated transcript levels in human cells in a telomere-specific fashion.
| S-EPMC5085120 | biostudies-literature
Project description:Conserved translin-TRAX complexes, also known as C3POs, have been implicated in many biological processes, but how they function remains unclear. Recently, C3PO was shown to be an endoRNase that promotes RNA interference (RNAi) in animal cells. Here, we show that C3PO does not play a significant role in RNAi in the filamentous fungus Neurospora crassa. Instead, the Neurospora C3PO functions as an RNase that removes the 5' pre-tRNA fragments after the processing of pre-tRNAs by RNase P. In addition, translin and trax mutants have elevated levels of tRNA and protein translation and are more resistant to a cell death-inducing agent. Finally, we show that C3PO is also involved in tRNA processing in mouse embryonic fibroblast cells. This study identifies the endogenous RNA substrates of C3PO and provides a potential explanation for its roles in apparently diverse biological processes.
| S-EPMC3414638 | biostudies-literature
Project description:Trax-translin heteromers, also known as C3PO, have been proposed to activate the RNA-induced silencing complex (RISC) by facilitating endonucleolytic cleavage of the siRNA passenger strand. We report on the crystal structure of hexameric Drosophila C3PO formed by truncated translin and Trax, along with electron microscopic and mass spectrometric studies on octameric C3PO formed by full-length translin and Trax. Our studies establish that Trax adopts the translin fold, possesses catalytic centers essential for C3PO's endoRNase activity and interacts extensively with translin to form an octameric assembly. The catalytic pockets of Trax subunits are located within the interior chamber of the octameric scaffold. Truncated C3PO, like full-length C3PO, shows endoRNase activity that leaves 3'-hydroxyl-cleaved ends. We have measured the catalytic activity of C3PO and shown it to cleave almost stoichiometric amounts of substrate per second.
| S-EPMC3109869 | biostudies-literature
Project description:ObjectiveDeletion of Translin (Tsn) from mice induces an unusual metabolic profile characterized by robust adiposity, normal body weight and glucose tolerance. Translin (TN) protein and its partner, trax (TX), form the TN/TX microRNA-degrading enzyme. Since the microRNA system plays a prominent role in regulating metabolism, we reasoned that the metabolic profile displayed by Tsn KO mice might reflect dysregulation of microRNA signaling.MethodsTo test this hypothesis, we inserted a mutation, E126A, in Tsnax, the gene encoding TX, that abolishes the microRNA-degrading enzymatic activity of the TN/TX complex. In addition, to help define the cell types that drive the adiposity phenotype, we have also generated mice with floxed alleles of Tsn or Tsnax.ResultsIntroduction of the E126A mutation in Tsnax does not impair expression of TN or TX proteins or their co-precipitation. Furthermore, these mice display selective increases in microRNAs that match those induced by Tsn deletion, confirming that this mutation in Tsnax inactivates the microRNA-degrading activity of the TN/TX complex. Mice homozygous for the Tsnax (E126A) mutation display a metabolic profile that closely mimics that of Tsn KO mice. Selective deletion of Tsn or Tsnax from either adipocytes or hepatocytes, two candidate cell types, does not phenocopy the elevated adiposity displayed by mice with constitutive Tsn deletion or the Tsnax (E126A) mutation. Furthermore, global, conditional deletion of Tsn in adulthood does not elicit increased adiposity.ConclusionTaken together, these findings indicate that inactivation of the TN/TX microRNA-degrading enzyme during development is necessary to drive the robust adiposity displayed by Tsn KO mice.
| S-EPMC7305343 | biostudies-literature
Project description:Translin is a human octameric protein that specifically binds the single-stranded microsatellite repeats d(GT)n and the corresponding transcripts (GU)n. It also binds, with lesser affinities, other single-stranded G-rich DNA and RNA sequences. TRAX is a human protein that bears a homology to Translin and interacts with it. Translin and TRAX have been proposed to be involved in DNA recombination, chromosomal translocation and mRNA transport and translation. Both proteins are highly conserved in eukaryotes, including the fission yeast Schizosaccharomyces pombe, which is amenable to genetic analysis. Here, we report the first study of the S.pombe Translin and TRAX homologs. We have deleted the genes encoding Translin and TRAX in S.pombe and found that the proliferation of the mutant cells was slightly stimulated, suggesting that these genes are not essential for the fission yeast. We have also shown that the S.pombe Translin and TRAX interact. Biochemical analysis of the S.pombe Translin, which was cloned and expressed in Escherichia coli, revealed that it is octameric and that it selectively binds d(GT)n and d(GTT)n microsatellite repeats. However, unlike the human protein, it has much higher affinities for the homologous RNA sequences (GU)n and (GUU)n. These data suggest that the S.pombe Translin is primarily involved in functions related to RNA metabolism.
| S-EPMC1180670 | biostudies-literature
Project description:Translin and TRAX proteins play roles in very important cellular processes such as DNA recombination, spatial and temporal expression of mRNA, and in siRNA processing. Translin forms a homomeric nucleic acid binding complex and binds to ssDNA and RNA. However, a mutant translin construct that forms homomeric complex lacking nucleic acid binding activity is able to form fully active heteromeric translin-TRAX complex when co-expressed with TRAX. A substantial progress has been made in identifying translin sites that mediate its binding activity, while TRAX was thought not to bind DNA or RNA on its own. We here for the first time demonstrate nucleic acid binding to TRAX by crosslinking radiolabeled ssDNA to heteromeric translin-TRAX complex using UV-laser. The TRAX and translin, photochemically crosslinked with ssDNA, were individually detected on SDS-PAGE. We mutated two motifs in TRAX and translin, designated B2 and B3, to help define the nucleic acid binding sites in the TRAX sequence. The most pronounced effect was observed in the mutants of B3 motif that impaired nucleic acid binding activity of the heteromeric complexes. We suggest that both translin and TRAX are binding competent and contribute to the nucleic acid binding activity.
| S-EPMC3299731 | biostudies-literature
Project description:The endogenous RNA substrates of Translin-TRAX complexes (also known as C3POs) and how they regulate diverse biological processes remain unknown. Here we show that Translin and TRAX do not play a significant role in RNAi in the filamentous fungus Neurospora crassa. Instead, the Neurospora C3PO complex functions as a ribonuclease that removes the 5’ pre-tRNA fragments after the processing of pre-tRNAs by RNase P. In translin and trax mutants, 5’ pre-tRNA fragments accumulate to very high levels that can be degraded specifically by both recombinant and endogenous Neurospora C3PO and recombinant Drosophila C3PO. In addition, the mutants have elevated tRNA levels and increased levels of protein translation and are more resistant to a programmed cell-death inducing agent. Together, this study identified the endogenous RNA substrates of C3PO and provides a potential explanation for its roles in seemingly diverse biological processes.
2012-07-30 | GSE38334 | GEO
Project description:BackgroundEndothelial dysfunction and arterial stiffening play major roles in cardiovascular diseases. The critical role for the miR-181 family in vascular inflammation has been documented. Here we tested whether the miR-181 family can influence the pathogenesis of hypertension and vascular stiffening.Methods and resultsqPCR data showed a significant decrease in miR-181b expression in the aorta of the older mice. Eight miR-181a1/b1-/- mice and wild types (C57BL6J:WT) were followed weekly for pulse wave velocity (PWV) and blood pressure measurements. After 20 weeks, the mice were tested for endothelial function and aortic modulus. There was a progressive increase in PWV and higher systolic blood pressure in miR-181a1/b1-/- mice compared with WTs. At 21 weeks, aortic modulus was significantly greater in the miR-181a1/b1-/- group, and serum TGF-β was found to be elevated at this time. A luciferase reporter assay confirmed miR-181b targets TGF-βi (TGF-β induced) in the aortic VSMCs. In contrast, wire myography revealed unaltered endothelial function along with higher nitric oxide production in the miR-181a1/b1-/- group. Cultured VECs and VSMCs from the mouse aorta showed more secreted TGF-β in VSMCs of the miR-181a1/b1-/- group; whereas, no change was observed from VECs. Circulating levels of angiotensin II were similar in both groups. Treatment with losartan (0.6 g/L) prevented the increase in PWV, blood pressure, and vascular stiffness in miR-181a1/b1-/- mice. Immunohistochemistry and western blot for p-SMAD2/3 validated the inhibitory effect of losartan on TGF-β signaling in miR-181a1/b1-/- mice.ConclusionsDecreased miR-181b with aging plays a critical role in ECM remodeling by removing the brake on the TGF-β, pSMAD2/3 pathway.
| S-EPMC5360327 | biostudies-literature