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Mattoo S, Gupta A, Chauhan M, Agrawal A, Pore SK. Prospects and challenges of noncoding-RNA-mediated inhibition of heat shock protein 90 for cancer therapy. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195006. [PMID: 38218528 DOI: 10.1016/j.bbagrm.2024.195006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 01/15/2024]
Abstract
Heat Shock Protein 90 (HSP90) is a potential drug target for cancer therapy as it is often dysregulated in several cancers, including lung, breast, pancreatic, and prostate cancers. In cancer, HSP90 fails to maintain the structural and functional integrity of its several client proteins which are involved in the hallmarks of cancer such as cell proliferation, invasion, migration, angiogenesis, and apoptosis. Several small molecule inhibitors of HSP90 have been shown to exhibit anticancer effects in vitro and in vivo animal models. However, a few of them are currently under clinical studies. The status and potential limitations of these inhibitors are discussed here. Studies demonstrate that several noncoding RNAs (ncRNAs) such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) regulate HSP90 and its client proteins to modulate cellular processes to exhibit oncogenic or tumor suppressing properties. Over the last decade, miRNAs and lncRNAs have drawn significant interest from the scientific community as therapeutic agents or targets for clinical applications. Here, we discuss the detailed mechanistic regulation of HSP90 and its client proteins by ncRNAs. Moreover, we highlight the significance of these ncRNAs as potential therapeutic agents/targets, and the challenges associated with ncRNA-based therapies. This article aims to provide a holistic view on HSP90-regulating ncRNAs for the development of novel therapeutic strategies to combat cancer.
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Affiliation(s)
- Shria Mattoo
- Amity Institute of Molecular Medicine & Stem Cell Research, Amity University Uttar Pradesh, Noida 201311, India
| | - Abha Gupta
- Amity Institute of Molecular Medicine & Stem Cell Research, Amity University Uttar Pradesh, Noida 201311, India
| | - Manvee Chauhan
- Amity Institute of Molecular Medicine & Stem Cell Research, Amity University Uttar Pradesh, Noida 201311, India
| | - Akshi Agrawal
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida 201311, India
| | - Subrata Kumar Pore
- Amity Institute of Molecular Medicine & Stem Cell Research, Amity University Uttar Pradesh, Noida 201311, India.
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Rotavirus Induces Formation of Remodeled Stress Granules and P Bodies and Their Sequestration in Viroplasms To Promote Progeny Virus Production. J Virol 2018; 92:JVI.01363-18. [PMID: 30258011 DOI: 10.1128/jvi.01363-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/20/2018] [Indexed: 02/06/2023] Open
Abstract
Rotavirus replicates in unique virus-induced cytoplasmic inclusion bodies called viroplasms (VMs), the composition and structure of which have yet to be understood. Based on the analysis of a few proteins, earlier studies reported that rotavirus infection inhibits stress granule (SG) formation and disrupts P bodies (PBs). However, the recent demonstration that rotavirus infection induces cytoplasmic relocalization and colocalization with VMs of several nuclear hnRNPs and AU-rich element-binding proteins (ARE-BPs), which are known components of SGs and PBs, suggested the possibility of rotavirus-induced remodeling of SGs and PBs, prompting us to analyze a large number of the SG and PB components to understand the status of SGs and PBs in rotavirus-infected cells. Here we demonstrate that rotavirus infection induces molecular triage by selective exclusion of a few proteins of SGs (G3BP1 and ZBP1) and PBs (DDX6, EDC4, and Pan3) and sequestration of the remodeled/atypical cellular organelles, containing the majority of their components, in the VM. The punctate SG and PB structures are seen at about 4 h postinfection (hpi), coinciding with the appearance of small VMs, many of which fuse to form mature large VMs with progression of infection. By use of small interfering RNA (siRNA)-mediated knockdown and/or ectopic overexpression, the majority of the SG and PB components, except for ADAR1, were observed to inhibit viral protein expression and virus growth. In conclusion, this study demonstrates that VMs are highly complex supramolecular structures and that rotavirus employs a novel strategy of sequestration in the VM and harnessing of the remodeled cellular RNA recycling bins to promote its growth.IMPORTANCE Rotavirus is known to replicate in specialized virus-induced cytoplasmic inclusion bodies called viroplasms (VMs), but the composition and structure of VMs are not yet understood. Here we demonstrate that rotavirus interferes with normal SG and PB assembly but promotes formation of atypical SG-PB structures by selective exclusion of a few components and employs a novel strategy of sequestration of the remodeled SG-PB granules in the VMs to promote virus growth by modulating their negative influence on virus infection. Rotavirus VMs appear to be complex supramolecular structures formed by the union of the triad of viral replication complexes and remodeled SGs and PBs, as well as other host factors, and designed to promote productive virus infection. These observations have implications for the planning of future research with the aim of understanding the structure of the VM, the mechanism of morphogenesis of the virus, and the detailed roles of host proteins in rotavirus biology.
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Chen CYA, Zhang Y, Xiang Y, Han L, Chang JT, Shyu AB. Antagonistic actions of two human Pan3 isoforms on global mRNA turnover. RNA (NEW YORK, N.Y.) 2017; 23:1404-1418. [PMID: 28559491 PMCID: PMC5558910 DOI: 10.1261/rna.061556.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/25/2017] [Indexed: 05/03/2023]
Abstract
Deadenylation is a fundamental process that regulates eukaryotic gene expression. Mammalian deadenylation exhibits biphasic kinetics, with the Pan2-Pan3 and Ccr4-Caf1 deadenylase complexes mediating the first and second phase, respectively; however, the significance of the biphasic nature of deadenylation in mRNA turnover remains unclear. In this study, we discovered that two distinct isoforms of human Pan3 display opposing properties necessary for coordinating the two phases of deadenylation. The shorter isoform (Pan3S) interacts more strongly with PABP than the longer isoform (Pan3L) does. Pan2 deadenylase activity is enhanced by Pan3S but suppressed by Pan3L. Knocking down individual Pan3 isoforms has opposing effects on the global poly(A) tail length profile, P-body formation, and different mRNA decay pathways. Transcriptome-wide analysis of Pan3 knockdown effects on mRNA turnover shows that depleting either Pan3 isoform causes profound and extensive changes in mRNA stability globally. These results reveal a new fundamental step governing mammalian mRNA metabolism. We propose that the first phase of deadenylation, coordinated through the interplay among the two Pan3 isoforms, Pan2, and PABP, represents a cytoplasmic mRNA maturation step important for proper mRNA turnover.
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Affiliation(s)
- Chyi-Ying A Chen
- Department of Biochemistry and Molecular Biology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Yueqiang Zhang
- Department of Biochemistry and Molecular Biology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Yu Xiang
- Department of Biochemistry and Molecular Biology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Leng Han
- Department of Biochemistry and Molecular Biology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Jeffrey T Chang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
- School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Ann-Bin Shyu
- Department of Biochemistry and Molecular Biology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
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Patel PH, Barbee SA, Blankenship JT. GW-Bodies and P-Bodies Constitute Two Separate Pools of Sequestered Non-Translating RNAs. PLoS One 2016; 11:e0150291. [PMID: 26930655 PMCID: PMC4773245 DOI: 10.1371/journal.pone.0150291] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/11/2016] [Indexed: 01/05/2023] Open
Abstract
Non-translating RNAs that have undergone active translational repression are culled from the cytoplasm into P-bodies for decapping-dependent decay or for sequestration. Organisms that use microRNA-mediated RNA silencing have an additional pathway to remove RNAs from active translation. Consequently, proteins that govern microRNA-mediated silencing, such as GW182/Gw and AGO1, are often associated with the P-bodies of higher eukaryotic organisms. Due to the presence of Gw, these structures have been referred to as GW-bodies. However, several reports have indicated that GW-bodies have different dynamics to P-bodies. Here, we use live imaging to examine GW-body and P-body dynamics in the early Drosophila melanogaster embryo. While P-bodies are present throughout early embryonic development, cytoplasmic GW-bodies only form in significant numbers at the midblastula transition. Unlike P-bodies, which are predominantly cytoplasmic, GW-bodies are present in both nuclei and the cytoplasm. RNA decapping factors such as DCP1, Me31B, and Hpat are not associated with GW-bodies, indicating that P-bodies and GW-bodies are distinct structures. Furthermore, known Gw interactors such as AGO1 and the CCR4-NOT deadenylation complex, which have been shown to be important for Gw function, are also not present in GW-bodies. Use of translational inhibitors puromycin and cycloheximide, which respectively increase or decrease cellular pools of non-translating RNAs, alter GW-body size, underscoring that GW-bodies are composed of non-translating RNAs. Taken together, these data indicate that active translational silencing most likely does not occur in GW-bodies. Instead GW-bodies most likely function as repositories for translationally silenced RNAs. Finally, inhibition of zygotic gene transcription is unable to block the formation of either P-bodies or GW-bodies in the early embryo, suggesting that these structures are composed of maternal RNAs.
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Affiliation(s)
- Prajal H. Patel
- Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver, Denver, Colorado, United States of America
| | - Scott A. Barbee
- Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver, Denver, Colorado, United States of America
- Molecular and Cellular Biophysics Program, University of Denver, Denver, Colorado, United States of America
- * E-mail: (JTB); (SAB)
| | - J. Todd Blankenship
- Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver, Denver, Colorado, United States of America
- Molecular and Cellular Biophysics Program, University of Denver, Denver, Colorado, United States of America
- * E-mail: (JTB); (SAB)
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5
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mRNA destabilization is the dominant effect of mammalian microRNAs by the time substantial repression ensues. Mol Cell 2014; 56:104-15. [PMID: 25263593 DOI: 10.1016/j.molcel.2014.08.028] [Citation(s) in RCA: 361] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 08/21/2014] [Accepted: 08/22/2014] [Indexed: 01/01/2023]
Abstract
MicroRNAs (miRNAs) regulate target mRNAs through a combination of translational repression and mRNA destabilization, with mRNA destabilization dominating at steady state in the few contexts examined globally. Here, we extend the global steady-state measurements to additional mammalian contexts and find that regardless of the miRNA, cell type, growth condition, or translational state, mRNA destabilization explains most (66%->90%) miRNA-mediated repression. We also determine the relative dynamics of translational repression and mRNA destabilization for endogenous mRNAs as a miRNA is induced. Although translational repression occurs rapidly, its effect is relatively weak, such that by the time consequential repression ensues, the effect of mRNA destabilization dominates. These results imply that consequential miRNA-mediated repression is largely irreversible and provide other insights into the nature of miRNA-mediated regulation. They also simplify future studies, dramatically extending the known contexts and time points for which monitoring mRNA changes captures most of the direct miRNA effects.
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6
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Rajgor D, Mellad JA, Soong D, Rattner JB, Fritzler MJ, Shanahan CM. Mammalian microtubule P-body dynamics are mediated by nesprin-1. ACTA ACUST UNITED AC 2014; 205:457-75. [PMID: 24862572 PMCID: PMC4033771 DOI: 10.1083/jcb.201306076] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nesprins are a multi-isomeric family of spectrin-repeat (SR) proteins, predominantly known as nuclear envelope scaffolds. However, isoforms that function beyond the nuclear envelope remain poorly examined. Here, we characterize p50(Nesp1), a 50-kD isoform that localizes to processing bodies (PBs), where it acts as a microtubule-associated protein capable of linking mRNP complexes to microtubules. Overexpression of dominant-negative p50(Nesp1) caused Rck/p54, but not GW182, displacement from microtubules, resulting in reduced PB movement and cross talk with stress granules (SGs). These cells disassembled canonical SGs induced by sodium arsenite, but not those induced by hydrogen peroxide, leading to cell death and revealing PB-microtubule attachment is required for hydrogen peroxide-induced SG anti-apoptotic functions. Furthermore, p50(Nesp1) was required for miRNA-mediated silencing and interacted with core miRISC silencers Ago2 and Rck/p54 in an RNA-dependent manner and with GW182 in a microtubule-dependent manner. These data identify p50(Nesp1) as a multi-functional PB component and microtubule scaffold necessary for RNA granule dynamics and provides evidence for PB and SG micro-heterogeneity.
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Affiliation(s)
- Dipen Rajgor
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
| | - Jason A Mellad
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
| | - Daniel Soong
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
| | - Jerome B Rattner
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary T2N 4N1, Alberta, Canada
| | - Marvin J Fritzler
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary T2N 4N1, Alberta, Canada
| | - Catherine M Shanahan
- Cardiovascular Division, BHF Centre of Excellence, James Black Centre, King's College London, London SE5 9NU, England, UK
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Abstract
RNA granules have been observed in different organisms, cell types and under different conditions, and their formation is crucial for the mRNA life cycle. However, very little is known about the molecular mechanisms governing their assembly and disassembly. The aggregation-prone LSCRs (low-sequence-complexity regions), and in particular, the polyQ/N-rich regions, have been extensively studied under pathological conditions due to their role in neurodegenerative diseases. In the present review, we discuss recent in vitro, in vivo and computational data that, globally, suggest a role for polyQ/N regions in RNA granule assembly.
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Bhaskaran M, Mohan M. MicroRNAs: history, biogenesis, and their evolving role in animal development and disease. Vet Pathol 2014; 51:759-74. [PMID: 24045890 PMCID: PMC4013251 DOI: 10.1177/0300985813502820] [Citation(s) in RCA: 393] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The discovery of microRNAs (miRNAs) in 1993 followed by developments and discoveries in small RNA biology have redefined the biological landscape by significantly altering the longstanding dogmas that defined gene regulation. These small RNAs play a significant role in modulation of an array of physiological and pathological processes ranging from embryonic development to neoplastic progression. Unique miRNA signatures of various inherited, metabolic, infectious, and neoplastic diseases have added a new dimension to the studies that look at their pathogenesis and highlight their potential to be reliable biomarkers. Also, altering miRNA functionality and the development of novel in vivo delivery systems to achieve targeted modulation of specific miRNA function are being actively pursued as novel approaches for therapeutic intervention in many diseases. Here we review the current body of knowledge on the role of miRNAs in development and disease and discuss future implications.
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Affiliation(s)
- M Bhaskaran
- Infectious Disease Aerobiology, Division of Microbiology, Tulane National Primate Research Center, Covington, LA, USA
| | - M Mohan
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA, USA
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Thomas MG, Pascual ML, Maschi D, Luchelli L, Boccaccio GL. Synaptic control of local translation: the plot thickens with new characters. Cell Mol Life Sci 2014; 71:2219-39. [PMID: 24212248 PMCID: PMC11113725 DOI: 10.1007/s00018-013-1506-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 10/11/2013] [Accepted: 10/21/2013] [Indexed: 12/18/2022]
Abstract
The production of proteins from mRNAs localized at the synapse ultimately controls the strength of synaptic transmission, thereby affecting behavior and cognitive functions. The regulated transcription, processing, and transport of mRNAs provide dynamic control of the dendritic transcriptome, which includes thousands of messengers encoding multiple cellular functions. Translation is locally modulated by synaptic activity through a complex network of RNA-binding proteins (RBPs) and various types of non-coding RNAs (ncRNAs) including BC-RNAs, microRNAs, piwi-interacting RNAs, and small interference RNAs. The RBPs FMRP and CPEB play a well-established role in synaptic translation, and additional regulatory factors are emerging. The mRNA repressors Smaug, Nanos, and Pumilio define a novel pathway for local translational control that affects dendritic branching and spines in both flies and mammals. Recent findings support a role for processing bodies and related synaptic mRNA-silencing foci (SyAS-foci) in the modulation of synaptic plasticity and memory formation. The SyAS-foci respond to different stimuli with changes in their integrity thus enabling regulated mRNA release followed by translation. CPEB, Pumilio, TDP-43, and FUS/TLS form multimers through low-complexity regions related to prion domains or polyQ expansions. The oligomerization of these repressor RBPs is mechanistically linked to the aggregation of abnormal proteins commonly associated with neurodegeneration. Here, we summarize the current knowledge on how specificity in mRNA translation is achieved through the concerted action of multiple pathways that involve regulatory ncRNAs and RBPs, the modification of translation factors, and mRNA-silencing foci dynamics.
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Affiliation(s)
- María Gabriela Thomas
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
| | - Malena Lucía Pascual
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
| | - Darío Maschi
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- Present Address: Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO USA
| | - Luciana Luchelli
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
| | - Graciela Lidia Boccaccio
- Instituto Leloir, Av. Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
- IIBBA-CONICET, C1405BWE Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
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Meikar O, Vagin VV, Chalmel F, Sõstar K, Lardenois A, Hammell M, Jin Y, Da Ros M, Wasik KA, Toppari J, Hannon GJ, Kotaja N. An atlas of chromatoid body components. RNA (NEW YORK, N.Y.) 2014; 20:483-95. [PMID: 24554440 PMCID: PMC3964910 DOI: 10.1261/rna.043729.113] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 01/10/2014] [Indexed: 05/10/2023]
Abstract
The genome of male germ cells is actively transcribed during spermatogenesis to produce phase-specific protein-coding mRNAs and a considerable amount of different noncoding RNAs. Ribonucleoprotein (RNP) granule-mediated RNA regulation provides a powerful means to secure the quality and correct expression of the requisite transcripts. Haploid spermatids are characterized by a unique, unusually large cytoplasmic granule, the chromatoid body (CB), which emerges during the switch between the meiotic and post-meiotic phases of spermatogenesis. To better understand the role of the CB in male germ cell differentiation, we isolated CBs from mouse testes and revealed its full RNA and protein composition. We showed that the CB is mainly composed of RNA-binding proteins and other proteins involved RNA regulation. The CB was loaded with RNA, including pachytene piRNAs, a diverse set of mRNAs, and a number of uncharacterized long noncoding transcripts. The CB was demonstrated to accumulate nascent RNA during all the steps of round spermatid differentiation. Our results revealed the CB as a large germ cell-specific RNP platform that is involved in the control of the highly complex transcriptome of haploid male germ cells.
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Affiliation(s)
- Oliver Meikar
- Institute of Biomedicine, Department of Physiology, University of Turku, Turku FI-20520, Finland
| | - Vasily V. Vagin
- Watson School of Biological Sciences, Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Frédéric Chalmel
- Inserm Unité 1085-Irset, Université de Rennes 1, IFR140, Rennes F-35042, France
| | - Karin Sõstar
- Institute of Biomedicine, Department of Physiology, University of Turku, Turku FI-20520, Finland
| | - Aurélie Lardenois
- INRA, UMR703 PAnTher, F-44307 Nantes, France
- LUNAM Université, Oniris, École national vétérinaire, agro-alimentaire et de l'alimentation Nantes-Atlantique, F-44307 Nantes, France
| | - Molly Hammell
- Watson School of Biological Sciences, Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ying Jin
- Watson School of Biological Sciences, Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Matteo Da Ros
- Institute of Biomedicine, Department of Physiology, University of Turku, Turku FI-20520, Finland
| | - Kaja A. Wasik
- Watson School of Biological Sciences, Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Jorma Toppari
- Institute of Biomedicine, Department of Physiology, University of Turku, Turku FI-20520, Finland
- Department of Pediatrics, University of Turku, Turku FI-20520, Finland
| | - Gregory J. Hannon
- Watson School of Biological Sciences, Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Noora Kotaja
- Institute of Biomedicine, Department of Physiology, University of Turku, Turku FI-20520, Finland
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Smibert P, Yang JS, Azzam G, Liu JL, Lai EC. Homeostatic control of Argonaute stability by microRNA availability. Nat Struct Mol Biol 2013; 20:789-95. [PMID: 23708604 PMCID: PMC3702675 DOI: 10.1038/nsmb.2606] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 05/10/2013] [Indexed: 12/18/2022]
Abstract
Homeostatic mechanisms regulate the abundance of several components in small-RNA pathways. We used Drosophila and mammalian systems to demonstrate a conserved homeostatic system in which the status of miRNA biogenesis controls Argonaute protein stability. Clonal analyses of multiple mutants of core Drosophila miRNA factors revealed that stability of the miRNA effector AGO1 is dependent on miRNA biogenesis. Reciprocally, ectopic transcription of miRNAs within in vivo clones induced accumulation of AGO1, as did genetic interference with the ubiquitin-proteasome system. In mouse cells, we found that the stability of Ago2 declined in Dicer-knockout cells and was rescued by proteasome blockade or introduction of either Dicer plasmid or Dicer-independent miRNA constructs. Notably, Dicer-dependent miRNA constructs generated pre-miRNAs that bound Ago2 but did not rescue Ago2 stability. We conclude that Argonaute levels are finely tuned by cellular availability of mature miRNAs and the ubiquitin-proteasome system.
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Affiliation(s)
- Peter Smibert
- Department of Developmental Biology, Sloan-Kettering Institute, New York, New York, USA
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12
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Weil D, Hollien J. Cytoplasmic organelles on the road to mRNA decay. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:725-31. [PMID: 23337852 DOI: 10.1016/j.bbagrm.2013.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 01/02/2013] [Accepted: 01/03/2013] [Indexed: 11/27/2022]
Abstract
Localization of both mRNAs and mRNA decay factors to internal membranes of eukaryotic cells provides a means of coordinately regulating mRNAs with common functions as well as coupling organelle function to mRNA turnover. The classic mechanism of mRNA localization to membranes is the signal sequence-dependent targeting of mRNAs encoding membrane and secreted proteins to the cytoplasmic surface of the endoplasmic reticulum. More recently, however, mRNAs encoding proteins with cytosolic or nuclear functions have been found associated with various organelles, in many cases through unknown mechanisms. Furthermore, there are several types of RNA granules, many of which are sites of mRNA degradation; these are frequently found associated with membrane-bound organelles such as endosomes and mitochondria. In this review we summarize recent findings that link organelle function and mRNA localization to mRNA decay. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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13
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Short B. GW220 seals the fate of mRNAs. J Biophys Biochem Cytol 2012. [PMCID: PMC3514022 DOI: 10.1083/jcb.1984iti2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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