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Skariah G, Albin RL. Repeat RNA Toxicity Drives Ribosomal RNA Processing Defects in SCA2. Mov Disord 2021; 36:2464-2467. [PMID: 34783387 DOI: 10.1002/mds.28795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 11/05/2022] Open
Affiliation(s)
- Geena Skariah
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Roger Lee Albin
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA.,Neurology Service and GRECC, VAAAHS, Ann Arbor, Michigan, USA
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2
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Nawaz A, Shilikbay T, Skariah G, Ceman S. Unwinding the roles of RNA helicase MOV10. Wiley Interdiscip Rev RNA 2021; 13:e1682. [PMID: 34327836 PMCID: PMC8799784 DOI: 10.1002/wrna.1682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/15/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022]
Abstract
MOV10 is an RNA helicase that associates with the RNA‐induced silencing complex component Argonaute (AGO), likely resolving RNA secondary structures. MOV10 also binds the Fragile X mental retardation protein to block AGO2 binding at some sites and associates with UPF1, a principal component of the nonsense‐mediated RNA decay pathway. MOV10 is widely expressed and has a key role in the cellular response to viral infection and in suppressing retrotransposition. Posttranslational modifications of MOV10 include ubiquitination, which leads to stimulation‐dependent degradation, and phosphorylation, which has an unknown function. MOV10 localizes to the nucleus and/or cytoplasm in a cell type‐specific and developmental stage‐specific manner. Knockout of Mov10 leads to embryonic lethality, underscoring an important role in development where it is required for the completion of gastrulation. MOV10 is expressed throughout the organism; however, most studies have focused on germline cells and neurons. In the testes, the knockdown of Mov10 disrupts proliferation of spermatogonial progenitor cells. In brain, MOV10 is significantly elevated postnatally and binds mRNAs encoding cytoskeleton and neuron projection proteins, suggesting an important role in neuronal architecture. Heterozygous Mov10 mutant mice are hyperactive and anxious and their cultured hippocampal neurons have reduced dendritic arborization. Zygotic knockdown of Mov10 in Xenopus laevis causes abnormal head and eye development and mislocalization of neuronal precursors in the brain. Thus, MOV10 plays a vital role during development, defense against viral infection and in neuronal development and function: its many roles and regulation are only beginning to be unraveled. This article is categorized under:RNA Interactions with Proteins and Other Molecules > RNA‐Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein‐RNA Interactions: Functional Implications
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Affiliation(s)
- Aatiqa Nawaz
- Department of Cell and Developmental Biology, University of Illinois-Urbana Champaign, Champaign, Illinois, USA
| | - Temirlan Shilikbay
- Department of Cell and Developmental Biology, University of Illinois-Urbana Champaign, Champaign, Illinois, USA
| | - Geena Skariah
- Neuroscience Program, University of Illinois-Urbana Champaign, Champaign, Illinois, USA.,Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephanie Ceman
- Department of Cell and Developmental Biology, Neuroscience Program, University of Illinois-Urbana Champaign, Champaign, Illinois, USA
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3
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Skariah G, Todd PK. Translational control in aging and neurodegeneration. Wiley Interdiscip Rev RNA 2020; 12:e1628. [PMID: 32954679 DOI: 10.1002/wrna.1628] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/19/2020] [Accepted: 09/07/2020] [Indexed: 12/13/2022]
Abstract
Protein metabolism plays central roles in age-related decline and neurodegeneration. While a large body of research has explored age-related changes in protein degradation, alterations in the efficiency and fidelity of protein synthesis with aging are less well understood. Age-associated changes occur in both the protein synthetic machinery (ribosomal proteins and rRNA) and within regulatory factors controlling translation. At the same time, many of the interventions that prolong lifespan do so in part by pre-emptively decreasing protein synthesis rates to allow better harmonization to age-related declines in protein catabolism. Here we review the roles of translation regulation in aging, with a specific focus on factors implicated in age-related neurodegeneration. We discuss how emerging technologies such as ribosome profiling and superior mass spectrometric approaches are illuminating age-dependent mRNA-specific changes in translation rates across tissues to reveal a critical interplay between catabolic and anabolic pathways that likely contribute to functional decline. These new findings point to nodes in posttranscriptional gene regulation that both contribute to aging and offer targets for therapy. This article is categorized under: Translation > Translation Regulation Translation > Ribosome Biogenesis Translation > Translation Mechanisms.
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Affiliation(s)
- Geena Skariah
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
- Ann Arbor VA Healthcare System, Department of Veterans Affairs, Ann Arbor, Michigan, USA
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4
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Kenny PJ, Kim M, Skariah G, Nielsen J, Lannom MC, Ceman S. The FMRP-MOV10 complex: a translational regulatory switch modulated by G-Quadruplexes. Nucleic Acids Res 2020; 48:862-878. [PMID: 31740951 PMCID: PMC7145700 DOI: 10.1093/nar/gkz1092] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 10/30/2019] [Accepted: 11/04/2019] [Indexed: 01/19/2023] Open
Abstract
The Fragile X Mental Retardation Protein (FMRP) is an RNA binding protein that regulates translation and is required for normal cognition. FMRP upregulates and downregulates the activity of microRNA (miRNA)-mediated silencing in the 3' UTR of a subset of mRNAs through its interaction with RNA helicase Moloney leukemia virus 10 (MOV10). This bi-functional role is modulated through RNA secondary structures known as G-Quadruplexes. We elucidated the mechanism of FMRP's role in suppressing Argonaute (AGO) family members' association with mRNAs by mapping the interacting domains of FMRP, MOV10 and AGO and then showed that the RGG box of FMRP protects a subset of co-bound mRNAs from AGO association. The N-terminus of MOV10 is required for this protection: its over-expression leads to increased levels of the endogenous proteins encoded by this co-bound subset of mRNAs. The N-terminus of MOV10 also leads to increased RGG box-dependent binding to the SC1 RNA G-Quadruplex and is required for outgrowth of neurites. Lastly, we showed that FMRP has a global role in miRNA-mediated translational regulation by recruiting AGO2 to a large subset of RNAs in mouse brain.
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Affiliation(s)
- Phillip J Kenny
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Miri Kim
- Neuroscience Program, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Geena Skariah
- Neuroscience Program, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Joshua Nielsen
- Integrative Biology, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Monica C Lannom
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Stephanie Ceman
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
- Neuroscience Program, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
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5
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Krans A, Skariah G, Zhang Y, Bayly B, Todd PK. Neuropathology of RAN translation proteins in fragile X-associated tremor/ataxia syndrome. Acta Neuropathol Commun 2019; 7:152. [PMID: 31665086 PMCID: PMC6821001 DOI: 10.1186/s40478-019-0782-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/30/2019] [Indexed: 11/10/2022] Open
Abstract
CGG repeat expansions in FMR1 cause the neurodegenerative disorder Fragile X-associated Tremor/Ataxia Syndrome (FXTAS). Ubiquitinated neuronal intranuclear inclusions (NIIs) are the neuropathological hallmark of FXTAS. Both sense strand derived CGG repeats and antisense strand derived CCG repeats support non-AUG initiated (RAN) translation of homopolymeric proteins in potentially 6 different reading frames. However, the relative abundance of these proteins in FXTAS brains and their co-localization with each other and NIIs is lacking. Here we describe rater-blinded assessment of immunohistochemical and immunofluorescence staining with newly generated antibodies to different CGG RAN translation products in FXTAS and control brains as well as co-staining with ubiquitin, p62/SQSTM1, and ubiquilin 2. We find that both FMRpolyG and a second CGG repeat derived RAN translation product, FMRpolyA, accumulate in aggregates in FXTAS brains. FMRpolyG is a near-obligate component of both ubiquitin-positive and p62-positive NIIs in FXTAS, with occurrence of aggregates in 20% of all hippocampal neurons and > 90% of all inclusions. A subset of these inclusions also stain positive for the ALS/FTD associated protein ubiquilin 2. Ubiquitinated inclusions and FMRpolyG+ aggregates are rarer in cortex and cerebellum. Intriguingly, FMRpolyG staining is also visible in control neuronal nuclei. In contrast to FMRpolyG, staining for FMRpolyA and CCG antisense derived RAN translation products were less abundant and less frequent components of ubiquitinated inclusions. In conclusion, RAN translated FMRpolyG is a common component of ubiquitin and p62 positive inclusions in FXTAS patient brains.
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Affiliation(s)
- Amy Krans
- University of Michigan Medical School, Ann Arbor, USA
- Ann Arbor VA Medical Center, Ann Arbor, MI, USA
| | - Geena Skariah
- University of Michigan Medical School, Ann Arbor, USA
| | - Yuan Zhang
- University of Michigan Medical School, Ann Arbor, USA
| | - Bryana Bayly
- University of Michigan Medical School, Ann Arbor, USA
| | - Peter K Todd
- University of Michigan Medical School, Ann Arbor, USA.
- Ann Arbor VA Medical Center, Ann Arbor, MI, USA.
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Haenfler JM, Skariah G, Rodriguez CM, Monteiro da Rocha A, Parent JM, Smith GD, Todd PK. Targeted Reactivation of FMR1 Transcription in Fragile X Syndrome Embryonic Stem Cells. Front Mol Neurosci 2018; 11:282. [PMID: 30158855 PMCID: PMC6104480 DOI: 10.3389/fnmol.2018.00282] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/25/2018] [Indexed: 12/15/2022] Open
Abstract
Fragile X Syndrome (FXS) is the most common inherited cause of intellectual disability and autism. It results from expansion of a CGG nucleotide repeat in the 5′ untranslated region (UTR) of FMR1. Large expansions elicit repeat and promoter hyper-methylation, heterochromatin formation, FMR1 transcriptional silencing and loss of the Fragile X protein, FMRP. Efforts aimed at correcting the sequelae resultant from FMRP loss have thus far proven insufficient, perhaps because of FMRP’s pleiotropic functions. As the repeats do not disrupt the FMRP coding sequence, reactivation of endogenous FMR1 gene expression could correct the proximal event in FXS pathogenesis. Here we utilize the Clustered Regularly Interspaced Palindromic Repeats/deficient CRISPR associated protein 9 (CRISPR/dCas9) system to selectively re-activate transcription from the silenced FMR1 locus. Fusion of the transcriptional activator VP192 to dCas9 robustly enhances FMR1 transcription and increases FMRP levels when targeted directly to the CGG repeat in human cells. Using a previously uncharacterized FXS human embryonic stem cell (hESC) line which acquires transcriptional silencing with serial passaging, we achieved locus-specific transcriptional re-activation of FMR1 messenger RNA (mRNA) expression despite promoter and repeat methylation. However, these changes at the transcript level were not coupled with a significant elevation in FMRP protein expression in FXS cells. These studies demonstrate that directing a transcriptional activator to CGG repeats is sufficient to selectively reactivate FMR1 mRNA expression in Fragile X patient stem cells.
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Affiliation(s)
- Jill M Haenfler
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Geena Skariah
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Caitlin M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Andre Monteiro da Rocha
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, United States
| | - Jack M Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
| | - Gary D Smith
- Departments of Obstetrics/Gynecology, Physiology, and Urology, University of Michigan, Ann Arbor, MI, United States
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
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7
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Skariah G, Perry KJ, Drnevich J, Henry JJ, Ceman S. RNA helicase Mov10 is essential for gastrulation and central nervous system development. Dev Dyn 2018; 247:660-671. [PMID: 29266590 DOI: 10.1002/dvdy.24615] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 11/21/2017] [Accepted: 12/18/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Mov10 is an RNA helicase that modulates access of Argonaute 2 to microRNA recognition elements in mRNAs. We examined the role of Mov10 in Xenopus laevis development and show a critical role for Mov10 in gastrulation and in the development of the central nervous system (CNS). RESULTS Knockdown of maternal Mov10 in Xenopus embryos using a translation blocking morpholino led to defects in gastrulation and the development of notochord and paraxial mesoderm, and a failure to neurulate. RNA sequencing of the Mov10 knockdown embryos showed significant upregulation of many mRNAs when compared with controls at stage 10.5 (including those related to the cytoskeleton, adhesion, and extracellular matrix, which are involved in those morphogenetic processes). Additionally, the degradation of the miR-427 target mRNA, cyclin A1, was delayed in the Mov10 knockdowns. These defects suggest that Mov10's role in miRNA-mediated regulation of the maternal to zygotic transition could lead to pleiotropic effects that cause the gastrulation defects. Additionally, the knockdown of zygotic Mov10 showed that it was necessary for normal head, eye, and brain development in Xenopus consistent with a recent study in the mouse. CONCLUSIONS Mov10 is essential for gastrulation and normal CNS development. Developmental Dynamics 247:660-671, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Geena Skariah
- Neuroscience Program, University of Illinois-Urbana Champaign, Urbana, Illinois
| | - Kimberly J Perry
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, Illinois
| | - Jenny Drnevich
- High-Performance Biological Computing, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, Illinois
| | - Jonathan J Henry
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, Illinois
| | - Stephanie Ceman
- Neuroscience Program, University of Illinois-Urbana Champaign, Urbana, Illinois.,Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, Illinois.,College of Medicine, University of Illinois-Urbana Champaign, Urbana, Illinois
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8
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Skariah G, Seimetz J, Norsworthy M, Lannom MC, Kenny PJ, Elrakhawy M, Forsthoefel C, Drnevich J, Kalsotra A, Ceman S. Mov10 suppresses retroelements and regulates neuronal development and function in the developing brain. BMC Biol 2017; 15:54. [PMID: 28662698 PMCID: PMC5492891 DOI: 10.1186/s12915-017-0387-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 05/26/2017] [Indexed: 12/20/2022] Open
Abstract
Background Moloney leukemia virus 10 (Mov10) is an RNA helicase that mediates access of the RNA-induced silencing complex to messenger RNAs (mRNAs). Until now, its role as an RNA helicase and as a regulator of retrotransposons has been characterized exclusively in cell lines. We investigated the role of Mov10 in the mouse brain by examining its expression over development and attempting to create a Mov10 knockout mouse. Loss of both Mov10 copies led to early embryonic lethality. Results Mov10 was significantly elevated in postnatal murine brain, where it bound retroelement RNAs and mRNAs. Mov10 suppressed retroelements in the nucleus by directly inhibiting complementary DNA synthesis, while cytosolic Mov10 regulated cytoskeletal mRNAs to influence neurite outgrowth. We verified this important function by observing reduced dendritic arborization in hippocampal neurons from the Mov10 heterozygote mouse and shortened neurites in the Mov10 knockout Neuro2A cells. Knockdown of Fmrp also resulted in shortened neurites. Mov10, Fmrp, and Ago2 bound a common set of mRNAs in the brain. Reduced Mov10 in murine brain resulted in anxiety and increased activity in a novel environment, supporting its important role in the development of normal brain circuitry. Conclusions Mov10 is essential for normal neuronal development and brain function. Mov10 preferentially binds RNAs involved in actin binding, neuronal projection, and cytoskeleton. This is a completely new and critically important function for Mov10 in neuronal development and establishes a precedent for Mov10 being an important candidate in neurological disorders that have underlying cytoarchitectural causes like autism and Alzheimer’s disease. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0387-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Geena Skariah
- Neuroscience Program, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Joseph Seimetz
- Biochemistry, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Miles Norsworthy
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Monica C Lannom
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Phillip J Kenny
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Mohamed Elrakhawy
- Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Craig Forsthoefel
- College of Medicine, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Jenny Drnevich
- High-Performance Biological Computing, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Auinash Kalsotra
- Biochemistry, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA.,College of Medicine, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA
| | - Stephanie Ceman
- Neuroscience Program, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA. .,Cell and Developmental Biology, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA. .,College of Medicine, University of Illinois-Urbana Champaign, Urbana, IL, 61801, USA.
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Kenny PJ, Zhou H, Kim M, Skariah G, Khetani RS, Drnevich J, Arcila ML, Kosik KS, Ceman S. MOV10 and FMRP regulate AGO2 association with microRNA recognition elements. Cell Rep 2014; 9:1729-1741. [PMID: 25464849 DOI: 10.1016/j.celrep.2014.10.054] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 10/09/2014] [Accepted: 10/18/2014] [Indexed: 10/24/2022] Open
Abstract
The fragile X mental retardation protein FMRP regulates translation of its bound mRNAs through incompletely defined mechanisms. FMRP has been linked to the microRNA pathway, and we show here that it associates with the RNA helicase MOV10, also associated with the microRNA pathway. FMRP associates with MOV10 directly and in an RNA-dependent manner and facilitates MOV10's association with RNAs in brain and cells, suggesting a cooperative interaction. We identified the RNAs recognized by MOV10 using RNA immunoprecipitation and iCLIP. Examination of the fate of MOV10 on RNAs revealed a dual function for MOV10 in regulating translation: it facilitates microRNA-mediated translation of some RNAs, but it also increases expression of other RNAs by preventing AGO2 function. The latter subset was also bound by FMRP in close proximity to the MOV10 binding site, suggesting that FMRP prevents MOV10-mediated microRNA suppression. We have identified a mechanism for FMRP-mediated translational regulation through its association with MOV10.
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Affiliation(s)
- Phillip J Kenny
- Cell and Developmental Biology, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Hongjun Zhou
- Neuroscience Research Institute and Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Miri Kim
- College of Medicine, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA; Neuroscience Program, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Geena Skariah
- Neuroscience Program, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Radhika S Khetani
- High-Performance Biological Computing, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Jenny Drnevich
- High-Performance Biological Computing, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA
| | - Mary Luz Arcila
- Neuroscience Research Institute and Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Kenneth S Kosik
- Neuroscience Research Institute and Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Stephanie Ceman
- Cell and Developmental Biology, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA; College of Medicine, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA; Neuroscience Program, Roy J. Carver Biotechnology Center, University of Illinois-Urbana Champaign, Urbana, IL 61801, USA.
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10
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Joardar A, Malliahgari SR, Skariah G, Gupta R. 2'-O-methylation of the wobble residue of elongator pre-tRNA(Met) in Haloferax volcanii is guided by a box C/D RNA containing unique features. RNA Biol 2011; 8:782-91. [PMID: 21654217 PMCID: PMC3256356 DOI: 10.4161/rna.8.5.16015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 02/16/2011] [Accepted: 03/29/2011] [Indexed: 11/19/2022] Open
Abstract
The wobble residue C34 of Haloferax volcanii elongator tRNA(Met) is 2'-O-methylated. Neither a protein enzyme nor a guide RNA for this modification has been described. In this study, we show that this methylation is guided by a box C/D RNA targeting the intron-containing precursor of the tRNA. This guide RNA is starkly different from its homologs. This unique RNA of approximately 75 bases, named sR-tMet, is encoded in the genomes of H. volcanii and several other haloarchaea. A unique feature of sR-tMet is that the mature RNA in H. volcanii is substantially larger than its predicted size, whereas those in other haloarchaea are as predicted. While the 5'-ends of all tested haloarchaeal sR-tMets are equivalent, H. volcanii sR-tMet possesses an additional 51-base extension at its 3' end. This extension is present in the precursor but not in the mature sR-tMet of Halobacterium sp., suggesting differential 3'-end processing of sR-tMet in these two closely related organisms. Archaeal box C/D RNAs mostly contain a K-loop at the C'/D' motif. Another unique feature of sR-tMet is that its C'/D' motif lacks either a conventional K-turn or a K-loop. Instead, it contains two tandem, sheared G•A base pairs and a pyrimidine-pyrimidine pair in the non-canonical stem; the latter may form an alternative K-turn. Gel shift assays indicate that the L7Ae protein can form a stable complex with this unusual C'/D' motif, suggesting a novel RNA structure for L7Ae interaction.
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Affiliation(s)
- Archi Joardar
- Department of Biochemistry and Molecular Biology, Southern Illinois University, Carbondale, IL, USA
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11
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Rai R, Varma SPMV, Shinde N, Ghosh S, Kumaran SP, Skariah G, Laloraya S. Small ubiquitin-related modifier ligase activity of Mms21 is required for maintenance of chromosome integrity during the unperturbed mitotic cell division cycle in Saccharomyces cerevisiae. J Biol Chem 2011; 286:14516-30. [PMID: 21324902 PMCID: PMC3077650 DOI: 10.1074/jbc.m110.157149] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The SUMO ligase activity of Mms21/Nse2, a conserved member of the Smc5/6 complex, is required for resisting extrinsically induced genotoxic stress. We report that the Mms21 SUMO ligase activity is also required during the unchallenged mitotic cell cycle in Saccharomyces cerevisiae. SUMO ligase-defective cells were slow growing and spontaneously incurred DNA damage. These cells required caffeine-sensitive Mec1 kinase-dependent checkpoint signaling for survival even in the absence of extrinsically induced genotoxic stress. SUMO ligase-defective cells were sensitive to replication stress and displayed synthetic growth defects with DNA damage checkpoint-defective mutants such as mec1, rad9, and rad24. MMS21 SUMO ligase and mediator of replication checkpoint 1 gene (MRC1) were epistatic with respect to hydroxyurea-induced replication stress or methyl methanesulfonate-induced DNA damage sensitivity. Subjecting Mms21 SUMO ligase-deficient cells to transient replication stress resulted in enhancement of cell cycle progression defects such as mitotic delay and accumulation of hyperploid cells. Consistent with the spontaneous activation of the DNA damage checkpoint pathway observed in the Mms21-mediated sumoylation-deficient cells, enhanced frequency of chromosome breakage and loss was detected in these mutant cells. A mutation in the conserved cysteine 221 that is engaged in coordination of the zinc ion in Loop 2 of the Mms21 SPL-RING E3 ligase catalytic domain resulted in strong replication stress sensitivity and also conferred slow growth and Mec1 dependence to unchallenged mitotically dividing cells. Our findings establish Mms21-mediated sumoylation as a determinant of cell cycle progression and maintenance of chromosome integrity during the unperturbed mitotic cell division cycle in budding yeast.
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Affiliation(s)
- Ragini Rai
- Department of Biochemistry, Indian Institute of Science, C. V. Raman Avenue, Bangalore, Karnataka 560012, India
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