scholarly journals Selective Degradation of AU-Rich mRNAs Promoted by the p37 AUF1 Protein Isoform

2003 ◽  
Vol 23 (18) ◽  
pp. 6685-6693 ◽  
Author(s):  
Bedabrata Sarkar ◽  
Qiaoran Xi ◽  
Cheng He ◽  
Robert J. Schneider
Keyword(s):  
Untranslated Region ◽  
Mrna Decay ◽  
Limiting Factors ◽  
Rapid Decay ◽  
Selective Degradation ◽  
Protein Isoform ◽  
Mrna Destabilization ◽  
Reporter Mrna ◽  
Cytokine Mrnas

ABSTRACT An AU-rich element (ARE) consisting of repeated canonical AUUUA motifs confers rapid degradation to many cytokine mRNAs when present in the 3′ untranslated region. Destabilization of mRNAs with AREs (ARE-mRNAs) is consistent with the interaction of ARE-binding proteins such as tristetraprolin and the four AUF1 isoforms. However, the association of the AUF1-mRNA interaction with decreased ARE-mRNA stability is correlative and has not been directly tested. We therefore determined whether overexpression of AUF1 isoforms promotes ARE-mRNA destabilization and whether AUF1 isoforms are limiting components for ARE-mRNA decay. We show that the p37 AUF1 isoform and, to a lesser extent, the p40 isoform possess ARE-mRNA-destabilizing activity when overexpressed. Surprisingly, overexpressed p37 AUF1 also destabilized reporter mRNAs containing a noncanonical but AU-rich 3′ untranslated region. Since overexpressed p37 AUF1 could interact in vivo with the AU-rich reporter mRNA, AUF1 may be involved in rapid turnover of mRNAs that lack canonical AREs. Moreover, overexpression of p37 AUF1 restored the ability of cells to rapidly degrade ARE-mRNAs when that ability was saturated and inhibited by overexpression of ARE-mRNAs. Finally, activation of ARE-mRNA decay often involves a translation-dependent step, which was eliminated by overexpression of p37 AUF1. These data indicate that the p37 AUF1 isoform and, to some extent, the p40 isoform are limiting factors that facilitate rapid decay of AU-rich mRNAs.

scholarly journals A Yeast Homologue of Hsp70, Ssa1p, Regulates Turnover of the MFA2 Transcript through Its AU-Rich 3′ Untranslated Region

2003 ◽  
Vol 23 (8) ◽  
pp. 2623-2632 ◽  
Author(s):  
Radharani Duttagupta ◽  
Shobha Vasudevan ◽  
Carol J. Wilusz ◽  
Stuart W. Peltz
Keyword(s):  
Untranslated Region ◽  
Mrna Decay ◽  
Critical Role ◽  
Temperature Sensitive ◽  
Rich Region ◽  
Rapid Decay ◽  
Chaperone Protein ◽  
Eukaryotic Mrnas ◽  
Necessary And Sufficient ◽  
Dependent Mechanism

ABSTRACT Many eukaryotic mRNAs exhibit regulated decay in response to cellular signals. AU-rich elements (AREs) identified in the 3′ untranslated region (3′-UTR) of several such mRNAs play a critical role in controlling the half-lives of these transcripts. The yeast ARE-containing mRNA, MFA2, has been studied extensively and is degraded by a deadenylation-dependent mechanism. However, the trans-acting factors that promote the rapid decay of MFA2 have not been identified. Our results suggest that the chaperone protein Hsp70, encoded by the SSA family of genes, is involved in modulating MFA2 mRNA decay. MFA2 is specifically stabilized in a strain bearing a temperature-sensitive mutation in the SSA1 gene. Furthermore, an AU-rich region within the 3′-UTR of the message is both necessary and sufficient to confer this regulation. Stabilization occurs as a result of slower deadenylation in the ssa1ts strain, suggesting that Hsp70 is required for activation of the turnover pathway.

scholarly journals AU-Rich Elements Regulate Drosophila Gene Expression

2009 ◽  
Vol 29 (10) ◽  
pp. 2636-2643 ◽  
Author(s):  
Fatima Cairrao ◽  
Anason S. Halees ◽  
Khalid S. A. Khabar ◽  
Dominique Morello ◽  
Nathalie Vanzo
Keyword(s):  
Gene Expression ◽  
Mrna Decay ◽  
Cultured Cells ◽  
Species Conservation ◽  
Untranslated Regions ◽  
Temporal Gene Expression ◽  
Response To Stress ◽  
Novel Model ◽  
Reporter Mrna

ABSTRACT In mammals, AU-rich elements (AREs) are critical regulators of mRNA turnover. They recruit ARE-binding proteins that inhibit or stimulate rapid mRNA degradation in response to stress or developmental cues. Using a bioinformatics approach, we have identified AREs in Drosophila melanogaster 3′ untranslated regions and validated their cross-species conservation in distant Drosophila genomes. We have generated a Drosophila ARE database (D-ARED) and established that about 16% of D. melanogaster genes contain the mammalian ARE signature, an AUUUA pentamer in an A/U-rich context. Using candidate ARE genes, we show that Drosophila AREs stimulate reporter mRNA decay in cultured cells and in the physiological context of the immune response in D. melanogaster. In addition, we found that the conserved ARE-binding protein Tis11 regulates temporal gene expression through ARE-mediated decay (AMD) in D. melanogaster. Our work reveals that AREs are conserved and functional cis regulators of mRNA decay in Drosophila and highlights this organism as a novel model system to unravel in vivo the contribution of AMD to various processes.

scholarly journals C. elegans germ granules require both assembly and localized regulators for mRNA repression

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Scott Takeo Aoki ◽  
Tina R. Lynch ◽  
Sarah L. Crittenden ◽  
Craig A. Bingman ◽  
Marvin Wickens ◽  
...  
Keyword(s):  
Liquid Droplet ◽  
Scaffolding Protein ◽  
P Granules ◽  
C Elegans ◽  
Cytoplasmic Rna ◽  
And Function ◽  
Rnp Granules ◽  
Key Residues ◽  
Reporter Mrna

AbstractCytoplasmic RNA–protein (RNP) granules have diverse biophysical properties, from liquid to solid, and play enigmatic roles in RNA metabolism. Nematode P granules are paradigmatic liquid droplet granules and central to germ cell development. Here we analyze a key P granule scaffolding protein, PGL-1, to investigate the functional relationship between P granule assembly and function. Using a protein–RNA tethering assay, we find that reporter mRNA expression is repressed when recruited to PGL-1. We determine the crystal structure of the PGL-1 N-terminal region to 1.5 Å, discover its dimerization, and identify key residues at the dimer interface. Mutations of those interface residues prevent P granule assembly in vivo, de-repress PGL-1 tethered mRNA, and reduce fertility. Therefore, PGL-1 dimerization lies at the heart of both P granule assembly and function. Finally, we identify the P granule-associated Argonaute WAGO-1 as crucial for repression of PGL-1 tethered mRNA. We conclude that P granule function requires both assembly and localized regulators.

scholarly journals Humanin is an endogenous activator of chaperone-mediated autophagy

2017 ◽  
Vol 217 (2) ◽  
pp. 635-647 ◽  
Author(s):  
Zhenwei Gong ◽  
Inmaculada Tasset ◽  
Antonio Diaz ◽  
Jaime Anguiano ◽  
Emir Tas ◽  
...  
Keyword(s):  
Quality Control ◽  
Cell Death ◽  
Heat Shock Protein 90 ◽  
Protective Effects ◽  
Neuroprotective Effects ◽  
Selective Degradation ◽  
Cytosolic Side ◽  
Chaperone Mediated Autophagy

Chaperone-mediated autophagy (CMA) serves as quality control during stress conditions through selective degradation of cytosolic proteins in lysosomes. Humanin (HN) is a mitochondria-associated peptide that offers cytoprotective, cardioprotective, and neuroprotective effects in vivo and in vitro. In this study, we demonstrate that HN directly activates CMA by increasing substrate binding and translocation into lysosomes. The potent HN analogue HNG protects from stressor-induced cell death in fibroblasts, cardiomyoblasts, neuronal cells, and primary cardiomyocytes. The protective effects are lost in CMA-deficient cells, suggesting that they are mediated through the activation of CMA. We identified that a fraction of endogenous HN is present at the cytosolic side of the lysosomal membrane, where it interacts with heat shock protein 90 (HSP90) and stabilizes binding of this chaperone to CMA substrates as they bind to the membrane. Inhibition of HSP90 blocks the effect of HNG on substrate translocation and abolishes the cytoprotective effects. Our study provides a novel mechanism by which HN exerts its cardioprotective and neuroprotective effects.

IMMU-53. STING-ING GLIOBLASTOMA WITH SPHERICAL NUCLEIC ACIDS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi104-vi105
Author(s):  
Akanksha Mahajan ◽  
Lisa Hurley ◽  
Serena Tommasini-Ghelfi ◽  
Corey Dussold ◽  
Alexander Stegh ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
High Surface ◽  
Biological Properties ◽  
Innate Immune ◽  
Limiting Factors ◽  
Nucleic Acid Delivery ◽  
Sting Pathway ◽  
Spherical Nucleic Acids

Abstract The Stimulator of Interferon Genes (STING) pathway represents a major innate immune sensing mechanism for tumor-derived DNA. Modified cyclic dinucleotides (CDNs) that mimic the endogenous STING ligand cGAMP are currently being explored in patients with solid tumors that are amenable to intratumoral delivery. Inadequate bioavailability and insufficient lipophilicity are limiting factors for clinical CDN development, in particular when consideration is given to systemic administration approaches. We have shown that the formulation of oligonucleotides into Spherical Nucleic Acid (SNA) nanostructures, i.e.,the presentation of oligonucleotides at high density on the surface of nanoparticle cores, lead to biochemical and biological properties that are radically different from those of linear oligonucleotides. First-generation brain-penetrant siRNA-based SNAs (NCT03020017, recurrent GBM) have recently completed early clinical trials. Here, we report the development of a STING-agonistic immunotherapy by targeting cGAS, the sensor of cytosolic dsDNA upstream of STING, with SNAs presenting dsDNA at high surface density. The strategy of using SNAs exploits the ability of cGAS to raise STING responses by delivering dsDNA and inducing the catalytic production of endogenous CDNs. SNA nanostructures carrying a 45bp IFN-simulating dsDNA oligonucleotide, the most commonly used and widely characterized cGAS activator, potently activated the cGAS-STING pathway in vitro and in vivo. In a poorly immunogenic and highly aggressive syngeneic mouse glioma model, in which tumours were well-established, only one dose of intranasal treatment with STING-SNAs decelerated tumour growth, improved survival and importantly, was well-tolerated. Our use of SNAs addresses the challenges of nucleic acid delivery to intracranial tumor sites via intranasal route, exploits the binding of dsDNA molecules on the SNA surface to enhance the formation of a dimeric cGAS:DNA complex and establishes cGAS-agonistic SNAs as a novel class of immune-stimulatory modalities for triggering innate immune responses against tumor.

scholarly journals Conserved mRNA-granule component Scd6 targets Dhh1 to repress translation initiation and activates Dcp2-mediated mRNA decay in vivo

PLoS Genetics ◽  
2018 ◽  
Vol 14 (12) ◽  
pp. e1007806 ◽  
Author(s):  
Quira Zeidan ◽  
Feng He ◽  
Fan Zhang ◽  
Hongen Zhang ◽  
Allan Jacobson ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Mrna Decay

scholarly journals The 5' untranslated region of mRNA for ribosomal protein S19 is involved in its translational regulation during Xenopus development.

1990 ◽  
Vol 10 (2) ◽  
pp. 816-822 ◽  
Author(s):  
P Mariottini ◽  
F Amaldi
Keyword(s):  
Ribosomal Protein ◽  
Untranslated Region ◽  
Ribosomal Proteins ◽  
Translational Regulation ◽  
Xenopus Development ◽  
Untranslated Sequence ◽  
Gene Coding ◽  
Ribosomal Protein S19 ◽  
Fused Gene

During Xenopus development, the synthesis of ribosomal proteins is regulated at the translational level. To identify the region of the ribosomal protein mRNAs responsible for their typical translational behavior, we constructed a fused gene in which the upstream sequences (promoter) and the 5' untranslated sequence (first exon) of the gene coding for Xenopus ribosomal protein S19 were joined to the coding portion of the procaryotic chloramphenicol acetyltransferase (CAT) gene deleted of its own 5' untranslated region. This fused gene was introduced in vivo by microinjection into Xenopus fertilized eggs, and its activity was monitored during embryogenesis. By analyzing the pattern of appearance of CAT activity and the distribution of the S19-CAT mRNA between polysomes and messenger ribonucleoproteins, it was concluded that the 35-nucleotide-long 5' untranslated region of the S19 mRNA is able to confer to the fused S19-CAT mRNA the translational behavior typical of ribosomal proteins during Xenopus embryo development.

mRNA degradation by processive 3′-5′ exoribonucleases in Vitro and the implications for prokaryotic mRNA decay in Vivo

1991 ◽  
Vol 221 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Robert S. McLaren ◽  
Sarah F. Newbury ◽  
Geoffrey S.C. Dance ◽  
Helen C. Causton ◽  
Christopher F. Higgins
Keyword(s):  
Mrna Decay ◽  
Mrna Degradation

scholarly journals Noninvasive Optical, Electrical, and Acoustic Methods of Total Hemoglobin Determination

2008 ◽  
Vol 54 (2) ◽  
pp. 264-272 ◽  
Author(s):  
John W McMurdy ◽  
Gregory D Jay ◽  
Selim Suner ◽  
Gregory Crawford
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Oxygen Deficiency ◽  
Standard Of Care ◽  
Limiting Factors ◽  
Health Concern ◽  
Current Standard ◽  
Total Hemoglobin ◽  
Admittance Plethysmography ◽  
Significant Public Health

Abstract Background: Anemia is an underdiagnosed, significant public health concern afflicting >2 billion people worldwide. The detrimental effects of tissue oxygen deficiency on the cardiovascular system and concurrent appearance of anemia with numerous high-risk disorders highlight the importance of clinical screening. Currently there is no universally accepted, clinically applicable, noninvasive hemoglobin/hematocrit screening tool. The need for such a device has prompted an investigation into a breadth of techniques. Methods: A synopsis of the literature and current directions of research in noninvasive total hemoglobin measurement was collected. Contributions highlighted in this review are limited to those studies conducted with a clinical aspect, and most include in vivo patient studies. Results: The review of potential techniques presented here includes optoacoustic spectroscopy, spectrophotometric imaging, diffuse reflectance spectroscopy, transcutaneous illumination, electrical admittance plethysmography, and photoplethysmography. The technological performance, relative benefits of each approach, potential instrumentation design considerations, and future directions are discussed in each subcategory. Conclusions: Many techniques reviewed here have shown excellent accuracy, sensitivity, and specificity in measuring hemoglobin/hematocrit, thus in the near future a new clinically viable tool for noninvasive hemoglobin/hematocrit monitoring will likely be widely used for patient care. Limiting factors in clinical adoption will likely involve technology integration into the current standard of care in each field routinely dealing with anemia.

scholarly journals Preparation, characterization and evaluation of the in vivo trypanocidal activity of ursolic acid-loaded solid dispersion with poloxamer 407 and sodium caprate

2015 ◽  
Vol 51 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Josimar Oliveira Eloy ◽  
Juliana Saraiva ◽  
Sérgio de Albuquerque ◽  
Juliana Maldonado Marchetti
Keyword(s):  
Ursolic Acid ◽  
Solid Dispersion ◽  
Oral Absorption ◽  
Solid Dispersions ◽  
Poloxamer 407 ◽  
Drug Dissolution ◽  
Limiting Factors ◽  
Sodium Caprate ◽  
Trypanocidal Activity

Ursolic acid is a promising candidate for treatment of Chagas disease; however it has low aqueous solubility and intestinal absorption, which are both limiting factors for bioavailability. Among the strategies to enhance the solubility and dissolution of lipophilic drugs, solid dispersions are growing in popularity. In this study, we employed a mixture of the surfactants poloxamer 407 with sodium caprate to produce a solid dispersion containing ursolic acid aimed at enhancing both drug dissolution and in vivo trypanocidal activity. Compared to the physical mixture, the solid dispersion presented higher bulk density and smaller particle size. Fourier Transform Infrared Spectroscopy results showed hydrogen bonding intermolecular interactions between drug and poloxamer 407. X-ray diffractometry experiments revealed the conversion of the drug from its crystalline form to a more soluble amorphous structure. Consequently, the solubility of ursolic acid in the solid dispersion was increased and the drug dissolved in a fast and complete manner. Taken together with the oral absorption-enhancing property of sodium caprate, these results explained the increase of the in vivo trypanocidal activity of ursolic acid in solid dispersion, which also proved to be safe by cytotoxicity evaluation using the LLC-MK2 cell line.

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