1
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Ma T, Xiong ES, Lardelli RM, Lykke-Andersen J. Sm complex assembly and 5' cap trimethylation promote selective processing of snRNAs by the 3' exonuclease TOE1. Proc Natl Acad Sci U S A 2024; 121:e2315259121. [PMID: 38194449 PMCID: PMC10801842 DOI: 10.1073/pnas.2315259121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 12/06/2023] [Indexed: 01/11/2024] Open
Abstract
Competing exonucleases that promote 3' end maturation or degradation direct quality control of small non-coding RNAs, but how these enzymes distinguish normal from aberrant RNAs is poorly understood. The Pontocerebellar Hypoplasia 7 (PCH7)-associated 3' exonuclease TOE1 promotes maturation of canonical small nuclear RNAs (snRNAs). Here, we demonstrate that TOE1 achieves specificity toward canonical snRNAs through their Sm complex assembly and cap trimethylation, two features that distinguish snRNAs undergoing correct biogenesis from other small non-coding RNAs. Indeed, disruption of Sm complex assembly via snRNA mutations or protein depletions obstructs snRNA processing by TOE1, and in vitro snRNA processing by TOE1 is stimulated by a trimethylated cap. An unstable snRNA variant that normally fails to undergo maturation becomes fully processed by TOE1 when its degenerate Sm binding motif is converted into a canonical one. Our findings uncover the molecular basis for how TOE1 distinguishes snRNAs from other small non-coding RNAs and explain how TOE1 promotes maturation specifically of canonical snRNAs undergoing proper processing.
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Affiliation(s)
- Tiantai Ma
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
| | - Erica S. Xiong
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
| | - Rea M. Lardelli
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
| | - Jens Lykke-Andersen
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA92093
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2
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Li H, Ma T, Remsberg JR, Won SJ, DeMeester KE, Njomen E, Ogasawara D, Zhao KT, Huang TP, Lu B, Simon GM, Melillo B, Schreiber SL, Lykke-Andersen J, Liu DR, Cravatt BF. Assigning functionality to cysteines by base editing of cancer dependency genes. Nat Chem Biol 2023; 19:1320-1330. [PMID: 37783940 PMCID: PMC10698195 DOI: 10.1038/s41589-023-01428-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 08/24/2023] [Indexed: 10/04/2023]
Abstract
Covalent chemistry represents an attractive strategy for expanding the ligandability of the proteome, and chemical proteomics has revealed numerous electrophile-reactive cysteines on diverse human proteins. Determining which of these covalent binding events affect protein function, however, remains challenging. Here we describe a base-editing strategy to infer the functionality of cysteines by quantifying the impact of their missense mutation on cancer cell proliferation. The resulting atlas, which covers more than 13,800 cysteines on more than 1,750 cancer dependency proteins, confirms the essentiality of cysteines targeted by covalent drugs and, when integrated with chemical proteomic data, identifies essential, ligandable cysteines in more than 160 cancer dependency proteins. We further show that a stereoselective and site-specific ligand targeting an essential cysteine in TOE1 inhibits the nuclease activity of this protein through an apparent allosteric mechanism. Our findings thus describe a versatile method and valuable resource to prioritize the pursuit of small-molecule probes with high function-perturbing potential.
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Affiliation(s)
- Haoxin Li
- Department of Chemistry, Scripps Research, La Jolla, CA, USA.
| | - Tiantai Ma
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | | | - Sang Joon Won
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | | | - Evert Njomen
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | | | - Kevin T Zhao
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Cambridge, MA, USA
| | - Tony P Huang
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Cambridge, MA, USA
| | - Bingwen Lu
- Vividion Therapeutics, San Diego, CA, USA
| | | | - Bruno Melillo
- Department of Chemistry, Scripps Research, La Jolla, CA, USA
| | - Stuart L Schreiber
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Jens Lykke-Andersen
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Howard Hughes Medical Institute, Cambridge, MA, USA
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3
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Kalmykova AI, Sokolova OA. Retrotransposons and Telomeres. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1739-1753. [PMID: 38105195 DOI: 10.1134/s0006297923110068] [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: 06/19/2023] [Revised: 07/24/2023] [Accepted: 08/12/2023] [Indexed: 12/19/2023]
Abstract
Transposable elements (TEs) comprise a significant part of eukaryotic genomes being a major source of genome instability and mutagenesis. Cellular defense systems suppress the TE expansion at all stages of their life cycle. Piwi proteins and Piwi-interacting RNAs (piRNAs) are key elements of the anti-transposon defense system, which control TE activity in metazoan gonads preventing inheritable transpositions and developmental defects. In this review, we discuss various regulatory mechanisms by which small RNAs combat TE activity. However, active transposons persist, suggesting these powerful anti-transposon defense mechanisms have a limited capacity. A growing body of evidence suggests that increased TE activity coincides with genome reprogramming and telomere lengthening in different species. In the Drosophila fruit fly, whose telomeres consist only of retrotransposons, a piRNA-mediated mechanism is required for telomere maintenance and their length control. Therefore, the efficacy of protective mechanisms must be finely balanced in order not only to suppress the activity of transposons, but also to maintain the proper length and stability of telomeres. Structural and functional relationship between the telomere homeostasis and LINE1 retrotransposon in human cells indicates a close link between selfish TEs and the vital structure of the genome, telomere. This relationship, which permits the retention of active TEs in the genome, is reportedly a legacy of the retrotransposon origin of telomeres. The maintenance of telomeres and the execution of other crucial roles that TEs acquired during the process of their domestication in the genome serve as a type of payment for such a "service."
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Affiliation(s)
- Alla I Kalmykova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
| | - Olesya A Sokolova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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4
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Huynh TN, Parker R. The PARN, TOE1, and USB1 RNA deadenylases and their roles in non-coding RNA regulation. J Biol Chem 2023; 299:105139. [PMID: 37544646 PMCID: PMC10493513 DOI: 10.1016/j.jbc.2023.105139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/08/2023] Open
Abstract
The levels of non-coding RNAs (ncRNAs) are regulated by transcription, RNA processing, and RNA degradation pathways. One mechanism for the degradation of ncRNAs involves the addition of oligo(A) tails by non-canonical poly(A) polymerases, which then recruit processive sequence-independent 3' to 5' exonucleases for RNA degradation. This pathway of decay is also regulated by three 3' to 5' exoribonucleases, USB1, PARN, and TOE1, which remove oligo(A) tails and thereby can protect ncRNAs from decay in a manner analogous to the deubiquitination of proteins. Loss-of-function mutations in these genes lead to premature degradation of some ncRNAs and lead to specific human diseases such as Poikiloderma with Neutropenia (PN) for USB1, Dyskeratosis Congenita (DC) for PARN and Pontocerebellar Hypoplasia type 7 (PCH7) for TOE1. Herein, we review the biochemical properties of USB1, PARN, and TOE1, how they modulate ncRNA levels, and their roles in human diseases.
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Affiliation(s)
- Thao Ngoc Huynh
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.
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5
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Ma T, Xiong ES, Lardelli RM, Lykke-Andersen J. The 3' exonuclease TOE1 selectively processes snRNAs through recognition of Sm complex assembly and 5' cap trimethylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.15.553431. [PMID: 37645788 PMCID: PMC10462049 DOI: 10.1101/2023.08.15.553431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Competing exonucleases that promote 3' end maturation or degradation direct quality control of small non-coding RNAs, but how these enzymes distinguish normal from aberrant RNAs is poorly understood. The Pontocerebellar Hypoplasia 7 (PCH7)-associated 3' exonuclease TOE1 promotes maturation of canonical small nuclear RNAs (snRNAs). Here, we demonstrate that TOE1 achieves specificity towards canonical snRNAs by recognizing Sm complex assembly and cap trimethylation, two features that distinguish snRNAs undergoing correct biogenesis from other small non-coding RNAs. Indeed, disruption of Sm complex assembly via snRNA mutations or protein depletions obstructs snRNA processing by TOE1, and in vitro snRNA processing by TOE1 is stimulated by a trimethylated cap. An unstable snRNA variant that normally fails to undergo maturation becomes fully processed by TOE1 when its degenerate Sm binding motif is converted into a canonical one. Our findings uncover the molecular basis for how TOE1 distinguishes snRNAs from other small non-coding RNAs and explain how TOE1 promotes maturation specifically of canonical snRNAs undergoing proper processing.
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Affiliation(s)
- Tiantai Ma
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Erica S Xiong
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Rea M Lardelli
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Jens Lykke-Andersen
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
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6
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Wang H, Ming X, Zhang S, Chen J, Liu X, Wu X, Zhang S, Zhang Y, Cui W, Li W, Liu Y. Knockdown of Toe1 causes developmental arrest during the morula-to-blastocyst transition in mice. Theriogenology 2022; 194:154-161. [PMID: 36257135 DOI: 10.1016/j.theriogenology.2022.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/06/2022] [Accepted: 10/07/2022] [Indexed: 11/04/2022]
Abstract
The target of EGR1 protein 1 (TOE1) is evolutionarily conserved from Caenorhabditis elegans to mammals, which plays a critical role in the maturation of a variety of small nuclear RNAs. Mutation in human TOE1 has been reported to cause pontocerebellar hypoplasia type 7, a severe neurodegenerative syndrome. However, the role of TOE1 in early embryonic development remains unclear. Herein, we found that Toe1 mRNA and protein were expressed in mouse preimplantation embryos. Silencing Toe1 by siRNA led to morula-to-blastocyst transition failure. This developmental arrest can be rescued by Toe1 mRNA microinjection. EdU incorporation assay showed a defect in blastomere proliferation within developmentally arrested embryos. Further studies revealed that Toe1 knockdown caused increased signals for γH2AX and micronuclei, indicative of sustained DNA damage. Moreover, mRNA levels of cell cycle inhibitor p21 were significantly upregulated in Toe1 knockdown embryos before developmental arrest. Together, these results suggest that TOE1 is indispensable for mouse early embryo development potentially through maintaining genomic integrity. Our findings provide further insight into the role of TOE1 in mouse preimplantation embryonic development.
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Affiliation(s)
- Hongcheng Wang
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China; Linquan Modern Agricultural Technology Cooperation and Extension Service Center, The Anhui Agricultural University's Comprehensive Experimental Station in the Northwest of Anhui Province, Linquan, Anhui, 236400, China
| | - Xin Ming
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China
| | - Shengnan Zhang
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China
| | - Ji Chen
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China
| | - Xinli Liu
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China
| | - Xiaoqing Wu
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China
| | - Shangrong Zhang
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China
| | - Yunhai Zhang
- Linquan Modern Agricultural Technology Cooperation and Extension Service Center, The Anhui Agricultural University's Comprehensive Experimental Station in the Northwest of Anhui Province, Linquan, Anhui, 236400, China
| | - Wei Cui
- Department of Veterinary and Animal Sciences, Animal Models Core Facility, Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, 01002, USA
| | - Wenyong Li
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China.
| | - Yong Liu
- Anhui Province Key Laboratory of Embryo Development and Reproductive Regulation, Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Fuyang City, Anhui Province, 236037, China; Department of Veterinary and Animal Sciences, Animal Models Core Facility, Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, 01002, USA.
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7
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ANGEL2 phosphatase activity is required for non-canonical mitochondrial RNA processing. Nat Commun 2022; 13:5750. [PMID: 36180430 PMCID: PMC9525292 DOI: 10.1038/s41467-022-33368-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 09/14/2022] [Indexed: 11/18/2022] Open
Abstract
Canonical RNA processing in mammalian mitochondria is defined by tRNAs acting as recognition sites for nucleases to release flanking transcripts. The relevant factors, their structures, and mechanism are well described, but not all mitochondrial transcripts are punctuated by tRNAs, and their mode of processing has remained unsolved. Using Drosophila and mouse models, we demonstrate that non-canonical processing results in the formation of 3′ phosphates, and that phosphatase activity by the carbon catabolite repressor 4 domain-containing family member ANGEL2 is required for their hydrolysis. Furthermore, our data suggest that members of the FAST kinase domain-containing protein family are responsible for these 3′ phosphates. Our results therefore propose a mechanism for non-canonical RNA processing in metazoan mitochondria, by identifying the role of ANGEL2. A subset of mitochondrial transcripts is not flanked by tRNAs and thus does not conform to the canonical mode of processing. Here, Clemente et al. demonstrate that phosphatase activity of ANGEL2 is required for correct processing of these transcripts.
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8
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Loss of telomere silencing is accompanied by dysfunction of Polo kinase and centrosomes during Drosophila oogenesis and early development. PLoS One 2021; 16:e0258156. [PMID: 34624021 PMCID: PMC8500440 DOI: 10.1371/journal.pone.0258156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/18/2021] [Indexed: 12/03/2022] Open
Abstract
Telomeres are nucleoprotein complexes that protect the ends of eukaryotic linear chromosomes from degradation and fusions. Telomere dysfunction leads to cell growth arrest, oncogenesis, and premature aging. Telomeric RNAs have been found in all studied species; however, their functions and biogenesis are not clearly understood. We studied the mechanisms of development disorders observed upon overexpression of telomeric repeats in Drosophila. In somatic cells, overexpression of telomeric retrotransposon HeT-A is cytotoxic and leads to the accumulation of HeT-A Gag near centrosomes. We found that RNA and RNA-binding protein Gag encoded by the telomeric retrotransposon HeT-A interact with Polo and Cdk1 mitotic kinases, which are conserved regulators of centrosome biogenesis and cell cycle. The depletion of proteins Spindle E, Ccr4 or Ars2 resulting in HeT-A overexpression in the germline was accompanied by mislocalization of Polo as well as its abnormal stabilization during oogenesis and severe deregulation of centrosome biogenesis leading to maternal-effect embryonic lethality. These data suggest a mechanistic link between telomeric HeT-A ribonucleoproteins and cell cycle regulators that ensures the cell response to telomere dysfunction.
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9
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Norppa AJ, Frilander MJ. The integrity of the U12 snRNA 3' stem-loop is necessary for its overall stability. Nucleic Acids Res 2021; 49:2835-2847. [PMID: 33577674 PMCID: PMC7968993 DOI: 10.1093/nar/gkab048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 01/14/2021] [Accepted: 02/07/2021] [Indexed: 12/20/2022] Open
Abstract
Disruption of minor spliceosome functions underlies several genetic diseases with mutations in the minor spliceosome-specific small nuclear RNAs (snRNAs) and proteins. Here, we define the molecular outcome of the U12 snRNA mutation (84C>U) resulting in an early-onset form of cerebellar ataxia. To understand the molecular consequences of the U12 snRNA mutation, we created cell lines harboring the 84C>T mutation in the U12 snRNA gene (RNU12). We show that the 84C>U mutation leads to accelerated decay of the snRNA, resulting in significantly reduced steady-state U12 snRNA levels. Additionally, the mutation leads to accumulation of 3′-truncated forms of U12 snRNA, which have undergone the cytoplasmic steps of snRNP biogenesis. Our data suggests that the 84C>U-mutant snRNA is targeted for decay following reimport into the nucleus, and that the U12 snRNA fragments are decay intermediates that result from the stalling of a 3′-to-5′ exonuclease. Finally, we show that several other single-nucleotide variants in the 3′ stem-loop of U12 snRNA that are segregating in the human population are also highly destabilizing. This suggests that the 3′ stem-loop is important for the overall stability of the U12 snRNA and that additional disease-causing mutations are likely to exist in this region.
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Affiliation(s)
- Antto J Norppa
- Institute of Biotechnology, P.O. Box 56, Viikinkaari 5, University of Helsinki, FI-00014 Helsinki, Finland
| | - Mikko J Frilander
- Institute of Biotechnology, P.O. Box 56, Viikinkaari 5, University of Helsinki, FI-00014 Helsinki, Finland
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10
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Kawamoto T, Yoshimoto R, Taniguchi I, Kitabatake M, Ohno M. ISG20 and nuclear exosome promote destabilization of nascent transcripts for spliceosomal U snRNAs and U1 variants. Genes Cells 2020; 26:18-30. [PMID: 33147372 DOI: 10.1111/gtc.12817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/29/2020] [Accepted: 10/29/2020] [Indexed: 11/28/2022]
Abstract
Primary RNA transcripts are processed in a plethora of ways to become mature functional forms. In one example, human spliceosomal U snRNAs are matured at their 3'-end by an exonuclease termed TOE1. This process is important because mutations in TOE1 gene can cause a human genetic disease, pontocerebellar hypoplasia (PCH). Nevertheless, TOE1 may not be the only maturation exonuclease for U snRNAs in the cell. Here, we biochemically identify two exonucleolytic factors, Interferon-stimulated gene 20-kDa protein (ISG20) and the nuclear exosome as such candidates, using a newly developed in vitro system that recapitulates 3'-end maturation of U1 snRNA. However, extensive 3'-end sequencing of endogenous U1 snRNA of the knockdown (KD) cells revealed that these factors are not the maturation factors per se. Instead, the nascent transcripts of the spliceosomal U snRNAs as well as of unstable U1 variants were found to increase in quantity upon KD of the factors. These results indicated that ISG20 and the nuclear exosome promote the degradation of nascent spliceosomal U snRNAs and U1 variants, and therefore implied their role in the quality control of newly synthesized U snRNAs.
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Affiliation(s)
- Takahito Kawamoto
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Rei Yoshimoto
- Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Hirakata, Japan
| | - Ichiro Taniguchi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Makoto Kitabatake
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Mutsuhito Ohno
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
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11
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Lardelli RM, Lykke-Andersen J. Competition between maturation and degradation drives human snRNA 3' end quality control. Genes Dev 2020; 34:989-1001. [PMID: 32499401 PMCID: PMC7328512 DOI: 10.1101/gad.336891.120] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/29/2020] [Indexed: 12/11/2022]
Abstract
Polymerases and exonucleases act on 3' ends of nascent RNAs to promote their maturation or degradation but how the balance between these activities is controlled to dictate the fates of cellular RNAs remains poorly understood. Here, we identify a central role for the human DEDD deadenylase TOE1 in distinguishing the fates of small nuclear (sn)RNAs of the spliceosome from unstable genome-encoded snRNA variants. We found that TOE1 promotes maturation of all regular RNA polymerase II transcribed snRNAs of the major and minor spliceosomes by removing posttranscriptional oligo(A) tails, trimming 3' ends, and preventing nuclear exosome targeting. In contrast, TOE1 promotes little to no maturation of tested U1 variant snRNAs, which are instead targeted by the nuclear exosome. These observations suggest that TOE1 is positioned at the center of a 3' end quality control pathway that selectively promotes maturation and stability of regular snRNAs while leaving snRNA variants unprocessed and exposed to degradation in what could be a widespread mechanism of RNA quality control given the large number of noncoding RNAs processed by DEDD deadenylases.
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Affiliation(s)
- Rea M Lardelli
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - Jens Lykke-Andersen
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
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12
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Kordyukova M, Sokolova O, Morgunova V, Ryazansky S, Akulenko N, Glukhov S, Kalmykova A. Nuclear Ccr4-Not mediates the degradation of telomeric and transposon transcripts at chromatin in the Drosophila germline. Nucleic Acids Res 2020; 48:141-156. [PMID: 31724732 PMCID: PMC7145718 DOI: 10.1093/nar/gkz1072] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 10/28/2019] [Accepted: 10/30/2019] [Indexed: 01/05/2023] Open
Abstract
Ccr4-Not is a highly conserved complex involved in cotranscriptional RNA surveillance pathways in yeast. In Drosophila, Ccr4-Not is linked to the translational repression of miRNA targets and the posttranscriptional control of maternal mRNAs during oogenesis and embryonic development. Here, we describe a new role for the Ccr4-Not complex in nuclear RNA metabolism in the Drosophila germline. Ccr4 depletion results in the accumulation of transposable and telomeric repeat transcripts in the fraction of chromatin-associated RNA; however, it does not affect small RNA levels or the heterochromatin state of the target loci. Nuclear targets of Ccr4 mainly comprise active full-length transposable elements (TEs) and telomeric and subtelomeric repeats. Moreover, Ccr4-Not foci localize at telomeres in a Piwi-dependent manner, suggesting a functional relationship between these pathways. Indeed, we detected interactions between the components of the Ccr4-Not complex and piRNA machinery, which indicates that these pathways cooperate in the nucleus to recognize and degrade TE transcripts at transcription sites. These data reveal a new layer of transposon control in the germline, which is critical for the maintenance of genome integrity.
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Affiliation(s)
- Maria Kordyukova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Olesya Sokolova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Valeriya Morgunova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Sergei Ryazansky
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Natalia Akulenko
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Sergey Glukhov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Alla Kalmykova
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
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13
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Arvola RM, Chang CT, Buytendorp JP, Levdansky Y, Valkov E, Freddolino PL, Goldstrohm AC. Unique repression domains of Pumilio utilize deadenylation and decapping factors to accelerate destruction of target mRNAs. Nucleic Acids Res 2020; 48:1843-1871. [PMID: 31863588 PMCID: PMC7038932 DOI: 10.1093/nar/gkz1187] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/02/2019] [Accepted: 12/09/2019] [Indexed: 12/20/2022] Open
Abstract
Pumilio is an RNA-binding protein that represses a network of mRNAs to control embryogenesis, stem cell fate, fertility and neurological functions in Drosophila. We sought to identify the mechanism of Pumilio-mediated repression and find that it accelerates degradation of target mRNAs, mediated by three N-terminal Repression Domains (RDs), which are unique to Pumilio orthologs. We show that the repressive activities of the Pumilio RDs depend on specific subunits of the Ccr4-Not (CNOT) deadenylase complex. Depletion of Pop2, Not1, Not2, or Not3 subunits alleviates Pumilio RD-mediated repression of protein expression and mRNA decay, whereas depletion of other CNOT components had little or no effect. Moreover, the catalytic activity of Pop2 deadenylase is important for Pumilio RD activity. Further, we show that the Pumilio RDs directly bind to the CNOT complex. We also report that the decapping enzyme, Dcp2, participates in repression by the N-terminus of Pumilio. These results support a model wherein Pumilio utilizes CNOT deadenylase and decapping complexes to accelerate destruction of target mRNAs. Because the N-terminal RDs are conserved in mammalian Pumilio orthologs, the results of this work broadly enhance our understanding of Pumilio function and roles in diseases including cancer, neurodegeneration and epilepsy.
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Affiliation(s)
- René M Arvola
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Chung-Te Chang
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
| | - Joseph P Buytendorp
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yevgen Levdansky
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
| | - Eugene Valkov
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Aaron C Goldstrohm
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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14
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Son A, Park JE, Kim VN. PARN and TOE1 Constitute a 3' End Maturation Module for Nuclear Non-coding RNAs. Cell Rep 2019; 23:888-898. [PMID: 29669292 DOI: 10.1016/j.celrep.2018.03.089] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 12/27/2017] [Accepted: 03/20/2018] [Indexed: 10/17/2022] Open
Abstract
Poly(A)-specific ribonuclease (PARN) and target of EGR1 protein 1 (TOE1) are nuclear granule-associated deadenylases, whose mutations are linked to multiple human diseases. Here, we applied mTAIL-seq and RNA sequencing (RNA-seq) to systematically identify the substrates of PARN and TOE1 and elucidate their molecular functions. We found that PARN and TOE1 do not modulate the length of mRNA poly(A) tails. Rather, they promote the maturation of nuclear small non-coding RNAs (ncRNAs). PARN and TOE1 act redundantly on some ncRNAs, most prominently small Cajal body-specific RNAs (scaRNAs). scaRNAs are strongly downregulated when PARN and TOE1 are compromised together, leading to defects in small nuclear RNA (snRNA) pseudouridylation. They also function redundantly in the biogenesis of telomerase RNA component (TERC), which shares sequence motifs found in H/ACA box scaRNAs. Our findings extend the knowledge of nuclear ncRNA biogenesis, and they provide insights into the pathology of PARN/TOE1-associated genetic disorders whose therapeutic treatments are currently unavailable.
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Affiliation(s)
- Ahyeon Son
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Jong-Eun Park
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea; Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - V Narry Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea.
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15
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Deng T, Huang Y, Weng K, Lin S, Li Y, Shi G, Chen Y, Huang J, Liu D, Ma W, Songyang Z. TOE1 acts as a 3' exonuclease for telomerase RNA and regulates telomere maintenance. Nucleic Acids Res 2019; 47:391-405. [PMID: 30371886 PMCID: PMC6326811 DOI: 10.1093/nar/gky1019] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 10/14/2018] [Indexed: 12/14/2022] Open
Abstract
In human cells, telomeres are elongated by the telomerase complex that contains the reverse transcriptase hTERT and RNA template TERC/hTR. Poly(A)-specific ribonuclease (PARN) is known to trim hTR precursors by removing poly(A) tails. However, the precise mechanism of hTR 3′ maturation remains largely unknown. Target of Egr1 (TOE1) is an Asp-Glu-Asp-Asp (DEDD) domain containing deadenylase that is mutated in the human disease Pontocerebella Hypoplasia Type 7 (PCH7) and implicated in snRNA and hTR processing. We have previously found TOE1 to localize specifically in Cajal bodies, where telomerase RNP complex assembly takes place. In this study, we showed that TOE1 could interact with hTR and the telomerase complex. TOE1-deficient cells accumulated hTR precursors, including oligoadenylated and 3′-extended forms, which was accompanied by impaired telomerase activity and shortened telomeres. Telomerase activity in TOE1-deficient cells could be rescued by wild-type TOE1 but not the catalytically inactive mutant. Our results suggest that hTR 3′ end processing likely involves multiple exonucleases that work in parallel and/or sequentially, where TOE1 may function non-redundantly as a 3′-to-5′ exonuclease in conjunction with PARN. Our study highlights a mechanistic link between TOE1 mutation, improper hTR processing and telomere dysfunction in diseases such as PCH7.
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Affiliation(s)
- Tingting Deng
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Yan Huang
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Kai Weng
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou 510623, China
| | - Song Lin
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Yujing Li
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Guang Shi
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Yali Chen
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Junjiu Huang
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Dan Liu
- Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Wenbin Ma
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China
| | - Zhou Songyang
- State Key Laboratory of Oncology in South China, Cancer Center, Collaborative Innovation Center for Cancer Medicine, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.,Guangzhou Regenerative Medicine and Health-Guangdong Laboratory (GRMH-GDL), Institute of Healthy Aging Research, Sun Yat-sen University, Guangzhou 510006, China.,Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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16
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Hughes KL, Abshire ET, Goldstrohm AC. Regulatory roles of vertebrate Nocturnin: insights and remaining mysteries. RNA Biol 2018; 15:1255-1267. [PMID: 30257600 PMCID: PMC6284557 DOI: 10.1080/15476286.2018.1526541] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Post-transcriptional control of messenger RNA (mRNA) is an important layer of gene regulation that modulates mRNA decay, translation, and localization. Eukaryotic mRNA decay begins with the catalytic removal of the 3' poly-adenosine tail by deadenylase enzymes. Multiple deadenylases have been identified in vertebrates and are known to have distinct biological roles; among these proteins is Nocturnin, which has been linked to circadian biology, adipogenesis, osteogenesis, and obesity. Multiple studies have investigated Nocturnin's involvement in these processes; however, a full understanding of its molecular function remains elusive. Recent studies have provided new insights by identifying putative Nocturnin-regulated mRNAs in mice and by determining the structure and regulatory activities of human Nocturnin. This review seeks to integrate these new discoveries into our understanding of Nocturnin's regulatory functions and highlight the important remaining unanswered questions surrounding its regulation, biochemical activities, protein partners, and target mRNAs.
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Affiliation(s)
- Kelsey L Hughes
- a Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , Minneapolis , MN , USA
| | - Elizabeth T Abshire
- a Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , Minneapolis , MN , USA.,b Department of Biological Chemistry , University of Michigan , Ann Arbor , MI , USA
| | - Aaron C Goldstrohm
- a Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , Minneapolis , MN , USA
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17
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Comprehensive Identification of Nuclear and Cytoplasmic TNRC6A-Associating Proteins. J Mol Biol 2017; 429:3319-3333. [DOI: 10.1016/j.jmb.2017.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/18/2017] [Accepted: 04/24/2017] [Indexed: 11/20/2022]
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18
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Abstract
Poly(A) tails are found at the 3' end of almost every eukaryotic mRNA and are important for the stability of mRNAs and their translation into proteins. Thus, removal of the poly(A) tail, a process called deadenylation, is critical for regulation of gene expression. Most deadenylation enzymes are components of large multi-protein complexes. Here, we describe an in vitro deadenylation assay developed to study the exonucleolytic activities of the multi-protein Ccr4-Not and Pan2-Pan3 complexes. We discuss how this assay can be used with short synthetic RNAs, as well as longer RNA substrates generated using in vitro transcription. Importantly, quantitation of the reactions allows detailed analyses of deadenylation in the presence and absence of accessory factors, leading to new insights into targeted mRNA decay.
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19
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Scott EY, Penedo MCT, Murray JD, Finno CJ. Defining Trends in Global Gene Expression in Arabian Horses with Cerebellar Abiotrophy. CEREBELLUM (LONDON, ENGLAND) 2017; 16:462-472. [PMID: 27709457 PMCID: PMC5336519 DOI: 10.1007/s12311-016-0823-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Equine cerebellar abiotrophy (CA) is a hereditary neurodegenerative disease that affects the Purkinje neurons of the cerebellum and causes ataxia in Arabian foals. Signs of CA are typically first recognized either at birth to any time up to 6 months of age. CA is inherited as an autosomal recessive trait and is associated with a single nucleotide polymorphism (SNP) on equine chromosome 2 (13074277G>A), located in the fourth exon of TOE1 and in proximity to MUTYH on the antisense strand. We hypothesize that unraveling the functional consequences of the CA SNP using RNA-seq will elucidate the molecular pathways underlying the CA phenotype. RNA-seq (100 bp PE strand-specific) was performed in cerebellar tissue from four CA-affected and five age-matched unaffected horses. Three pipelines for differential gene expression (DE) analysis were used (Tophat2/Cuffdiff2, Kallisto/EdgeR, and Kallisto/Sleuth) with 151 significant DE genes identified by all three pipelines in CA-affected horses. TOE1 (Log2(foldchange) = 0.92, p = 0.66) and MUTYH (Log2(foldchange) = 1.13, p = 0.66) were not differentially expressed. Among the major pathways that were differentially expressed, genes associated with calcium homeostasis and specifically expressed in Purkinje neurons, CALB1 (Log2(foldchange) = -1.7, p < 0.01) and CA8 (Log2(foldchange) = -0.97, p < 0.01), were significantly down-regulated, confirming loss of Purkinje neurons. There was also a significant up-regulation of markers for microglial phagocytosis, TYROBP (Log2(foldchange) = 1.99, p < 0.01) and TREM2 (Log2(foldchange) = 2.02, p < 0.01). These findings reaffirm a loss of Purkinje neurons in CA-affected horses along with a potential secondary loss of granular neurons and activation of microglial cells.
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Affiliation(s)
- E Y Scott
- Department of Animal Science, University of California, Davis, USA
| | - M C T Penedo
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, USA
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, USA
| | - J D Murray
- Department of Animal Science, University of California, Davis, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, USA.
| | - C J Finno
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, USA.
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20
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Lardelli RM, Schaffer AE, Eggens VRC, Zaki MS, Grainger S, Sathe S, Van Nostrand EL, Schlachetzki Z, Rosti B, Akizu N, Scott E, Silhavy JL, Heckman LD, Rosti RO, Dikoglu E, Gregor A, Guemez-Gamboa A, Musaev D, Mande R, Widjaja A, Shaw TL, Markmiller S, Marin-Valencia I, Davies JH, de Meirleir L, Kayserili H, Altunoglu U, Freckmann ML, Warwick L, Chitayat D, Blaser S, Çağlayan AO, Bilguvar K, Per H, Fagerberg C, Christesen HT, Kibaek M, Aldinger KA, Manchester D, Matsumoto N, Muramatsu K, Saitsu H, Shiina M, Ogata K, Foulds N, Dobyns WB, Chi NC, Traver D, Spaccini L, Bova SM, Gabriel SB, Gunel M, Valente EM, Nassogne MC, Bennett EJ, Yeo GW, Baas F, Lykke-Andersen J, Gleeson JG. Biallelic mutations in the 3' exonuclease TOE1 cause pontocerebellar hypoplasia and uncover a role in snRNA processing. Nat Genet 2017; 49:457-464. [PMID: 28092684 PMCID: PMC5325768 DOI: 10.1038/ng.3762] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 12/07/2016] [Indexed: 02/08/2023]
Abstract
Deadenylases are best known for degrading the poly(A) tail during mRNA decay. The deadenylase family has expanded throughout evolution and, in mammals, consists of 12 Mg2+-dependent 3'-end RNases with substrate specificity that is mostly unknown. Pontocerebellar hypoplasia type 7 (PCH7) is a unique recessive syndrome characterized by neurodegeneration and ambiguous genitalia. We studied 12 human families with PCH7, uncovering biallelic, loss-of-function mutations in TOE1, which encodes an unconventional deadenylase. toe1-morphant zebrafish displayed midbrain and hindbrain degeneration, modeling PCH-like structural defects in vivo. Surprisingly, we found that TOE1 associated with small nuclear RNAs (snRNAs) incompletely processed spliceosomal. These pre-snRNAs contained 3' genome-encoded tails often followed by post-transcriptionally added adenosines. Human cells with reduced levels of TOE1 accumulated 3'-end-extended pre-snRNAs, and the immunoisolated TOE1 complex was sufficient for 3'-end maturation of snRNAs. Our findings identify the cause of a neurodegenerative syndrome linked to snRNA maturation and uncover a key factor involved in the processing of snRNA 3' ends.
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Affiliation(s)
- Rea M Lardelli
- University of California San Diego, La Jolla, California, USA
| | - Ashleigh E Schaffer
- University of California San Diego, La Jolla, California, USA.,Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA.,Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Veerle R C Eggens
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, the Netherlands
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Stephanie Grainger
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Shashank Sathe
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Eric L Van Nostrand
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Zinayida Schlachetzki
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Basak Rosti
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Naiara Akizu
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Eric Scott
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Jennifer L Silhavy
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Laura Dean Heckman
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Rasim Ozgur Rosti
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Esra Dikoglu
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Anne Gregor
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Alicia Guemez-Gamboa
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Damir Musaev
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Rohit Mande
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Ari Widjaja
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Tim L Shaw
- University of California San Diego, La Jolla, California, USA
| | - Sebastian Markmiller
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Isaac Marin-Valencia
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Justin H Davies
- Department of Paediatric Medicine, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Linda de Meirleir
- Pediatric Neurology and Metabolic Diseases, Universitair Ziekenhuis Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hulya Kayserili
- Medical Genetics Department, Koc University School of Medicine, Istanbul, Turkey
| | - Umut Altunoglu
- Medical Genetics Department, Istanbul Medical Faculty, Istanbul University, Istanbul Turkey
| | - Mary Louise Freckmann
- Department of Clinical Genetics, The Canberra Hospital, Woden, Australian Capital Territory, Australia
| | - Linda Warwick
- Australian Capital Territory Genetic Service, The Canberra Hospital, Canberra City, Australian Capital Territory, Australia
| | - David Chitayat
- Department of Pediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Susan Blaser
- Division of Neuroradiology, Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ahmet Okay Çağlayan
- Department of Medical Genetics, School of Medicine, Istanbul Bilim University, Istanbul, Turkey.,Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology and Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kaya Bilguvar
- Department of Genetics, Yale Center for Genome Analysis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Huseyin Per
- Division of Pediatric Neurology, Department of Pediatrics, Erciyes University School of Medicine, Kayseri, Turkey
| | - Christina Fagerberg
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Henrik T Christesen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
| | - Maria Kibaek
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
| | - Kimberly A Aldinger
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - David Manchester
- Department of Pediatrics, Clinical Genetics and Metabolism, University of Colorado School of Medicine, Children's Hospital Colorado, Aurora, Colorado, USA
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University, Graduate School of Medicine, Yokohama, Japan
| | - Kazuhiro Muramatsu
- Department of Pediatrics, Gunma University School of Medicine, Showa-machi, Maebashi City, Japan
| | - Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University, Graduate School of Medicine, Yokohama, Japan.,Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masaaki Shiina
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazuhiro Ogata
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Nicola Foulds
- Southampton University Hospitals Trust, Southampton, UK
| | - William B Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Neil C Chi
- UCSD Cardiology, University of California San Diego, La Jolla, California, USA
| | - David Traver
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Luigina Spaccini
- Clinical Genetics Unit, Department of Women, Mother and Neonates, "Vittore Buzzi" Children's Hospital, Istituti Clinici di Perfezionamento, Milan, Italy
| | - Stefania Maria Bova
- Child Neurology Unit, Department of Pediatrics, "Vittore Buzzi" Children Hospital, Istituti Clinici di Perfezionamento, Milan, Italy
| | - Stacey B Gabriel
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
| | - Murat Gunel
- Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology and Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Enza Maria Valente
- Section of Neurosciences, Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - Marie-Cecile Nassogne
- Pediatric Neurology, Université Catholique de Louvain, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Eric J Bennett
- University of California San Diego, La Jolla, California, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA.,Department of Physiology, National University of Singapore and Molecular Engineering Laboratory, A*STAR, Singapore
| | - Frank Baas
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, the Netherlands
| | | | - Joseph G Gleeson
- University of California San Diego, La Jolla, California, USA.,Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
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21
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Hebert MD, Poole AR. Towards an understanding of regulating Cajal body activity by protein modification. RNA Biol 2016; 14:761-778. [PMID: 27819531 DOI: 10.1080/15476286.2016.1243649] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The biogenesis of small nuclear ribonucleoproteins (snRNPs), small Cajal body-specific RNPs (scaRNPs), small nucleolar RNPs (snoRNPs) and the telomerase RNP involves Cajal bodies (CBs). Although many components enriched in the CB contain post-translational modifications (PTMs), little is known about how these modifications impact individual protein function within the CB and, in concert with other modified factors, collectively regulate CB activity. Since all components of the CB also reside in other cellular locations, it is also important that we understand how PTMs affect the subcellular localization of CB components. In this review, we explore the current knowledge of PTMs on the activity of proteins known to enrich in CBs in an effort to highlight current progress as well as illuminate paths for future investigation.
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Affiliation(s)
- Michael D Hebert
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Aaron R Poole
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
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22
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Łabno A, Tomecki R, Dziembowski A. Cytoplasmic RNA decay pathways - Enzymes and mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:3125-3147. [PMID: 27713097 DOI: 10.1016/j.bbamcr.2016.09.023] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 12/14/2022]
Abstract
RNA decay plays a crucial role in post-transcriptional regulation of gene expression. Work conducted over the last decades has defined the major mRNA decay pathways, as well as enzymes and their cofactors responsible for these processes. In contrast, our knowledge of the mechanisms of degradation of non-protein coding RNA species is more fragmentary. This review is focused on the cytoplasmic pathways of mRNA and ncRNA degradation in eukaryotes. The major 3' to 5' and 5' to 3' mRNA decay pathways are described with emphasis on the mechanisms of their activation by the deprotection of RNA ends. More recently discovered 3'-end modifications such as uridylation, and their relevance to cytoplasmic mRNA decay in various model organisms, are also discussed. Finally, we provide up-to-date findings concerning various pathways of non-coding RNA decay in the cytoplasm.
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Affiliation(s)
- Anna Łabno
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Rafał Tomecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland.
| | - Andrzej Dziembowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland.
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Kojima S, Gendreau KL, Sher-Chen EL, Gao P, Green CB. Changes in poly(A) tail length dynamics from the loss of the circadian deadenylase Nocturnin. Sci Rep 2015; 5:17059. [PMID: 26586468 PMCID: PMC4653638 DOI: 10.1038/srep17059] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 10/21/2015] [Indexed: 12/15/2022] Open
Abstract
mRNA poly(A) tails are important for mRNA stability and translation, and enzymes that regulate the poly(A) tail length significantly impact protein profiles. There are eleven putative deadenylases in mammals, and it is thought that each targets specific transcripts, although this has not been clearly demonstrated. Nocturnin (NOC) is a unique deadenylase with robustly rhythmic expression and loss of Noc in mice (Noc KO) results in resistance to diet-induced obesity. In an attempt to identify target transcripts of NOC, we performed “poly(A)denylome” analysis, a method that measures poly(A) tail length of transcripts in a global manner, and identified 213 transcripts that have extended poly(A) tails in Noc KO liver. These transcripts share unexpected characteristics: they are short in length, have long half-lives, are actively translated, and gene ontology analyses revealed that they are enriched in functions in ribosome and oxidative phosphorylation pathways. However, most of these transcripts do not exhibit rhythmicity in poly(A) tail length or steady-state mRNA level, despite Noc’s robust rhythmicity. Therefore, even though the poly(A) tail length dynamics seen between genotypes may not result from direct NOC deadenylase activity, these data suggest that NOC exerts strong effects on physiology through direct and indirect control of target mRNAs.
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Affiliation(s)
- Shihoko Kojima
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA, 75390-9111.,Department of Biological Sciences, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA, USA, 24061
| | - Kerry L Gendreau
- Department of Biological Sciences, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA, USA, 24061
| | - Elaine L Sher-Chen
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA, 75390-9111
| | - Peng Gao
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA, 75390-9111
| | - Carla B Green
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA, 75390-9111
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24
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Discovery of another anti-HIV protein in the search for the CD8+ cell anti-HIV Factor. Proc Natl Acad Sci U S A 2015; 112:7888-9. [PMID: 26085138 DOI: 10.1073/pnas.1509324112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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25
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TOE1 is an inhibitor of HIV-1 replication with cell-penetrating capability. Proc Natl Acad Sci U S A 2015; 112:E3392-401. [PMID: 26056259 DOI: 10.1073/pnas.1500857112] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Target of Egr1 (TOE1) is a nuclear protein localized primarily in nucleoli and Cajal bodies that was identified as a downstream target of the immediate early gene Egr1. TOE1 displays a functional deadenylation domain and has been shown to participate in spliceosome assembly. We report here that TOE1 can function as an inhibitor of HIV-1 replication and show evidence that supports a direct interaction of TOE1 with the viral specific transactivator response element as part of the inhibitory mechanism. In addition, we show that TOE1 can be secreted by activated CD8(+) T lymphocytes and can be cleaved by the serine protease granzyme B, one of the main components of cytotoxic granules. Both full-length and cleaved TOE1 can spontaneously cross the plasma membrane and penetrate cells in culture, retaining HIV-1 inhibitory activity. Antiviral potency of TOE1 and its cell-penetrating capability have been identified to lie within a 35-amino-acid region containing the nuclear localization sequence.
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Suzuki Y, Arae T, Green PJ, Yamaguchi J, Chiba Y. AtCCR4a and AtCCR4b are Involved in Determining the Poly(A) Length of Granule-bound starch synthase 1 Transcript and Modulating Sucrose and Starch Metabolism in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2015; 56:863-74. [PMID: 25630334 DOI: 10.1093/pcp/pcv012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 01/21/2015] [Indexed: 05/11/2023]
Abstract
Removing the poly(A) tail is the first and rate-limiting step of mRNA degradation and apparently an effective step not only for modulating mRNA stability but also for translation of many eukaryotic transcripts. Carbon catabolite repressor 4 (CCR4) has been identified as a major cytoplasmic deadenylase in Saccharomyces cerevisiae. The Arabidopsis thaliana homologs of the yeast CCR4, AtCCR4a and AtCCR4b, were identified by sequence-based analysis; however, their role and physiological significance in plants remain to be elucidated. In this study, we revealed that AtCCR4a and AtCCR4b are localized to cytoplasmic mRNA processing bodies, which are specific granules consisting of many enzymes involved in mRNA turnover. Double mutants of AtCCR4a and AtCCR4b exhibited tolerance to sucrose application but not to glucose. The levels of sucrose in the seedlings of the atccr4a/4b double mutants were reduced, whereas no difference was observed in glucose levels. Further, amylose levels were slightly but significantly increased in the atccr4a/4b double mutants. Consistent with this observation, we found that the transcript encoding granule-bound starch synthase 1 (GBSS1), which is responsible for amylose synthesis, is accumulated to a higher level in the atccr4a/4b double mutant plants than in the control plants. Moreover, we revealed that GBSS1 has a longer poly(A) tail in the double mutant than in the control plant, suggesting that AtCCR4a and AtCCR4b can influence the poly(A) length of transcripts related to starch metabolism. Our results collectively suggested that AtCCR4a and AtCCR4b are involved in sucrose and starch metabolism in A. thaliana.
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Affiliation(s)
- Yuya Suzuki
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Toshihiro Arae
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Pamela J Green
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Junji Yamaguchi
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Yukako Chiba
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan JST PRESTO, Kawaguchi, 332-0012 Japan
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Hrit J, Raynard N, Van Etten J, Sankar K, Petterson A, Goldstrohm AC. In vitro analysis of RNA degradation catalyzed by deadenylase enzymes. Methods Mol Biol 2014; 1125:325-39. [PMID: 24590800 DOI: 10.1007/978-1-62703-971-0_26] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this chapter, we describe a method for purification and analysis of the enzymatic activity of deadenylase enzymes. Nearly all eukaryotic messenger RNAs are modified at the 3' end by the addition of an adenosine polymer: the poly-adenosine tail. The poly(A) tail plays a central role in protein expression and mRNA fate. The poly(A) tail promotes translation of the mRNA. Shortening of the poly(A) tail, referred to as deadenylation, reduces protein synthesis and initiates destruction of the mRNA. A specialized class of exoribonucleases, called deadenylase enzymes, carries out this process. Deadenylases are found throughout eukarya, but their functions remain largely unexplored. We present a detailed protocol to analyze deadenylase activity in vitro. First, recombinant deadenylase enzyme is over-expressed and purified from bacteria. Next, labeled RNA substrate is prepared. Deadenylation reactions are performed, and reaction products are analyzed by denaturing gel electrophoresis. Reaction rates are then determined quantitatively. Crucial controls and experimental parameters are described along with practical tips that promote success.
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Affiliation(s)
- Joel Hrit
- Genetics Training Program, Department of Biological Chemistry, University of Michigan Medical School, 1150 West Medical Center Dr., Room 5301 MSRB3, SPC 5606, Ann Arbor, MI, 48109, USA
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28
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López-Rosas I, Marchat LA, Olvera BG, Guillen N, Weber C, Hernández de la Cruz O, Ruíz-García E, Astudillo-de la Vega H, López-Camarillo C. Proteomic analysis identifies endoribouclease EhL-PSP and EhRRP41 exosome protein as novel interactors of EhCAF1 deadenylase. J Proteomics 2014; 111:59-73. [PMID: 24998979 DOI: 10.1016/j.jprot.2014.06.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 05/31/2014] [Accepted: 06/20/2014] [Indexed: 01/17/2023]
Abstract
UNLABELLED In higher eukaryotic cells mRNA degradation initiates by poly(A) tail shortening catalyzed by deadenylases CAF1 and CCR4. In spite of the key role of mRNA turnover in gene expression regulation, the underlying mechanisms remain poorly understood in parasites. Here, we aimed to study the function of EhCAF1 and identify associated proteins in Entamoeba histolytica. By biochemical assays, we evidenced that EhCAF1 has both RNA binding and deadenylase activities in vitro. EhCAF1 was located in cytoplasmic P-bodies that increased in number and size after cellular stress induced by DNA damage, heat shock, and nitric oxide. Using pull-down assays and ESI-MS/MS mass spectrometry, we identified 15 potential EhCAF1-interacting proteins, including the endoribonuclease EhL-PSP. Remarkably, EhCAF1 colocalized with EhL-PSP in cytoplasmic P-bodies in trophozoites. Bioinformatic analysis of EhL-PSP network proteins predicts a potential interaction with EhRRP41 exosome protein. Consistently, we evidenced that EhL-PSP colocalizes and physically interacts with EhRRP41. Strikingly, EhRRP41 did not coimmunoprecipitate EhCAF1, suggesting the existence of two EhL-PSP-containing complexes. In conclusion, our results showed novel interactions between mRNA degradation proteins and evidenced for the first time that EhCAF1 is a functional deadenylase that interacts with EhL-PSP endoribonuclease in P-bodies, while EhL-PSP interacts with EhRRP41 exosome protein in this early-branched eukaryote. BIOLOGICAL SIGNIFICANCE This study provides evidences for the functional deadenylase activity of EhCAF1 and shows a link between different mRNA degradation proteins in E. histolytica. By proteomic tools and pull down assays, we evidenced that EhCAF1 interacts with the putative endoribonuclease EhL-PSP, which in turn interacts with exosome EhRRP41 protein. Our data suggest for the first time the presence of two complexes, one containing the endoribonuclease EhL-PSP and the deadenylase EhCAF1 in P-bodies; and another containing the endoribonuclease EhL-PSP and the exosome EhRRP41 exoribonuclease. Overall, these results provide novel data that may help to understand mRNA decay mechanisms in this parasite.
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Affiliation(s)
- Itzel López-Rosas
- Autonomous University of Mexico City, Genomics Sciences Program, Mexico City, Mexico; Biotechnology Program, National School of Medicine and Homeopathy, National Polytechnic Institute, Mexico City, Mexico
| | - Laurence A Marchat
- Biotechnology Program, National School of Medicine and Homeopathy, National Polytechnic Institute, Mexico City, Mexico; Institutional Program of Molecular Biomedicine, National School of Medicine and Homeopathy, National Polytechnic Institute, Mexico City, Mexico
| | - Beatriz Gallo Olvera
- Biotechnology Program, National School of Medicine and Homeopathy, National Polytechnic Institute, Mexico City, Mexico; Institutional Program of Molecular Biomedicine, National School of Medicine and Homeopathy, National Polytechnic Institute, Mexico City, Mexico
| | - Nancy Guillen
- Unit of Cell Biology for Parasitism, Pasteur Institute, Paris, France; INSERM U786, Paris, France
| | - Christian Weber
- Unit of Cell Biology for Parasitism, Pasteur Institute, Paris, France; INSERM U786, Paris, France
| | | | - Erika Ruíz-García
- Translational Medicine Laboratory, National Institute of Cancerology, Mexico City, Mexico
| | - Horacio Astudillo-de la Vega
- Laboratory of Translational Cancer Research and Cellular Therapy, Oncology Hospital, Medical Center Siglo XXI, Mexico City, Mexico
| | - César López-Camarillo
- Autonomous University of Mexico City, Genomics Sciences Program, Mexico City, Mexico.
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Temme C, Simonelig M, Wahle E. Deadenylation of mRNA by the CCR4-NOT complex in Drosophila: molecular and developmental aspects. Front Genet 2014; 5:143. [PMID: 24904643 PMCID: PMC4033318 DOI: 10.3389/fgene.2014.00143] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/02/2014] [Indexed: 11/13/2022] Open
Abstract
Controlled shortening of the poly(A) tail of mRNAs is the first step in eukaryotic mRNA decay and can also be used for translational inactivation of mRNAs. The CCR4-NOT complex is the most important among a small number of deadenylases, enzymes catalyzing poly(A) tail shortening. Rates of poly(A) shortening differ between mRNAs as the CCR4-NOT complex is recruited to specific mRNAs by means of either sequence-specific RNA binding proteins or miRNAs. This review summarizes our current knowledge concerning the subunit composition and deadenylation activity of the Drosophila CCR4-NOT complex and the mechanisms by which the complex is recruited to particular mRNAs. We discuss genetic data implicating the complex in the regulation of specific mRNAs, in particular in the context of development.
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Affiliation(s)
- Claudia Temme
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg Halle, Germany
| | - Martine Simonelig
- Genetics and Development, Institute of Human Genetics - CNRS UPR1142 Montpellier, France
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg Halle, Germany
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30
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Inada T, Makino S. Novel roles of the multi-functional CCR4-NOT complex in post-transcriptional regulation. Front Genet 2014; 5:135. [PMID: 24904636 PMCID: PMC4033010 DOI: 10.3389/fgene.2014.00135] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/25/2014] [Indexed: 11/30/2022] Open
Abstract
The CCR4-NOT complex is a highly conserved specific gene silencer that also serves more general post-transcriptional functions. Specific regulatory proteins including the miRNA-induced silencing complex and its associated proteins, bind to 3’-UTR elements of mRNA and recruit the CCR4-NOT complex thereby promoting poly(A) shortening and repressing translation and/or mRNA degradation. Recent studies have shown that the CCR4-NOT complex that is tethered to mRNA by such regulator(s) represses translation and facilitates mRNA decay independent of a poly(A) tail and its shortening. In addition to deadenylase activity, the CCR4-NOT complex also has an E3 ubiquitin ligase activity and is involved in a novel protein quality control system, i.e., co-translational proteasomal-degradation of aberrant proteins. In this review, we describe recent progress in elucidation of novel roles of the multi-functional complex CCR4-NOT in post-transcriptional regulation.
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Affiliation(s)
- Toshifumi Inada
- Laboratory of Gene Regulation, Graduate School of Pharmaceutical Sciences, Tohoku University Sendai, Japan
| | - Shiho Makino
- Laboratory of Gene Regulation, Graduate School of Pharmaceutical Sciences, Tohoku University Sendai, Japan
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31
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Yan YB. Deadenylation: enzymes, regulation, and functional implications. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:421-43. [PMID: 24523229 DOI: 10.1002/wrna.1221] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/20/2013] [Accepted: 12/21/2013] [Indexed: 12/27/2022]
Abstract
Lengths of the eukaryotic messenger RNA (mRNA) poly(A) tails are dynamically changed by the opposing effects of poly(A) polymerases and deadenylases. Modulating poly(A) tail length provides a highly regulated means to control almost every stage of mRNA lifecycle including transcription, processing, quality control, transport, translation, silence, and decay. The existence of diverse deadenylases with distinct properties highlights the importance of regulating poly(A) tail length in cellular functions. The deadenylation activity can be modulated by subcellular locations of the deadenylases, cis-acting elements in the target mRNAs, trans-acting RNA-binding proteins, posttranslational modifications of deadenylase and associated factors, as well as transcriptional and posttranscriptional regulation of the deadenylase genes. Among these regulators, the physiological functions of deadenylases are largely dependent on the interactions with the trans-acting RNA-binding proteins, which recruit deadenylases to the target mRNAs. The task of these RNA-binding proteins is to find and mark the target mRNAs based on their sequence features. Regulation of the regulators can switch on or switch off deadenylation and thereby destabilize or stabilize the targeted mRNAs, respectively. The distinct domain compositions and cofactors provide various deadenylases the structural basis for the recruitments by distinct RNA-binding protein subsets to meet dissimilar cellular demands. The diverse deadenylases, the numerous types of regulators, and the reversible posttranslational modifications together make up a complicated network to precisely regulate intracellular mRNA homeostasis. This review will focus on the diverse regulators of various deadenylases and will discuss their functional implications, remaining problems, and future challenges.
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Affiliation(s)
- Yong-Bin Yan
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China
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32
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Winkler GS, Balacco DL. Heterogeneity and complexity within the nuclease module of the Ccr4-Not complex. Front Genet 2013; 4:296. [PMID: 24391663 PMCID: PMC3870282 DOI: 10.3389/fgene.2013.00296] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/04/2013] [Indexed: 11/13/2022] Open
Abstract
The shortening of the poly(A) tail of cytoplasmic mRNA (deadenylation) is a pivotal step in the regulation of gene expression in eukaryotic cells. Deadenylation impacts on both regulated mRNA decay as well as the rate of mRNA translation. An important enzyme complex involved in poly(A) shortening is the Ccr4-Not deadenylase. In addition to at least six non-catalytic subunits, it contains two distinct subunits with ribonuclease activity: a Caf1 subunit, characterized by a DEDD (Asp-Glu-Asp-Asp) domain, and a Ccr4 component containing an endonuclease-exonuclease-phosphatase (EEP) domain. In vertebrate cells, the complexity of the complex is further increased by the presence of paralogs of the Caf1 subunit (encoded by either CNOT7 or CNOT8) and the occurrence of two Ccr4 paralogs (encoded by CNOT6 or CNOT6L). In plants, there are also multiple Caf1 and Ccr4 paralogs. Thus, the composition of the Ccr4-Not complex is heterogeneous. The potential differences in the intrinsic enzymatic activities of the paralogs will be discussed. In addition, the potential redundancy, cooperation, and/or the extent of unique roles for the deadenylase subunits of the Ccr4-Not complex will be reviewed. Finally, novel approaches to study the catalytic roles of the Caf1 and Ccr4 subunits will be discussed.
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Affiliation(s)
- G Sebastiaan Winkler
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park Nottingham, UK
| | - Dario L Balacco
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park Nottingham, UK
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Gosselin P, Martineau Y, Morales J, Czjzek M, Glippa V, Gauffeny I, Morin E, Le Corguillé G, Pyronnet S, Cormier P, Cosson B. Tracking a refined eIF4E-binding motif reveals Angel1 as a new partner of eIF4E. Nucleic Acids Res 2013; 41:7783-92. [PMID: 23814182 PMCID: PMC3763552 DOI: 10.1093/nar/gkt569] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The initiation factor 4E (eIF4E) is implicated in most of the crucial steps of the mRNA life cycle and is recognized as a pivotal protein in gene regulation. Many of these roles are mediated by its interaction with specific proteins generally known as eIF4E-interacting partners (4E-IPs), such as eIF4G and 4E-BP. To screen for new 4E-IPs, we developed a novel approach based on structural, in silico and biochemical analyses. We identified the protein Angel1, a member of the CCR4 deadenylase family. Immunoprecipitation experiments provided evidence that Angel1 is able to interact in vitro and in vivo with eIF4E. Point mutation variants of Angel1 demonstrated that the interaction of Angel1 with eIF4E is mediated through a consensus eIF4E-binding motif. Immunofluorescence and cell fractionation experiments showed that Angel1 is confined to the endoplasmic reticulum and Golgi apparatus, where it partially co-localizes with eIF4E and eIF4G, but not with 4E-BP. Furthermore, manipulating Angel1 levels in living cells had no effect on global translation rates, suggesting that the protein has a more specific function. Taken together, our results illustrate that we developed a powerful method for identifying new eIF4E partners and open new perspectives for understanding eIF4E-specific regulation.
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Affiliation(s)
- Pauline Gosselin
- UPMC Univ Paris 06, UMR 7150, Mer et Santé, Station Biologique, F-29680 Roscoff, France, CNRS, UMR 7150, Mer et Santé, Station Biologique, F-29680 Roscoff, France. Université Européenne de Bretagne, Bretagne, Roscoff, France, INSERM, UMR 1037, Centre de Recherche en Cancérologie de Toulouse, Toulouse 31432, France, UPMC Univ Paris 06, UMR 7139, Végétaux Marins et Biomolécules, Station Biologique, F-29680 Roscoff, France, CNRS, UMR 7139, Végétaux Marins et Biomolécules, Station Biologique, F-29680 Roscoff, France, UPMC Univ Paris 06, FR2424, ABiMS, Station Biologique, F-29680 Roscoff, France and CNRS, FR2424, ABiMS, Station Biologique, F-29680 Roscoff, France
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Intracellular ribonucleases involved in transcript processing and decay: precision tools for RNA. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:491-513. [PMID: 23545199 DOI: 10.1016/j.bbagrm.2013.03.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 03/19/2013] [Accepted: 03/22/2013] [Indexed: 12/15/2022]
Abstract
In order to adapt to changing environmental conditions and regulate intracellular events such as division, cells are constantly producing new RNAs while discarding old or defective transcripts. These functions require the coordination of numerous ribonucleases that precisely cleave and trim newly made transcripts to produce functional molecules, and rapidly destroy unnecessary cellular RNAs. In recent years our knowledge of the nature, functions and structures of these enzymes in bacteria, archaea and eukaryotes has dramatically expanded. We present here a synthetic overview of the recent development in this dynamic area which has seen the identification of many new endoribonucleases and exoribonucleases. Moreover, the increasing pace at which the structures of these enzymes, or of their catalytic domains, have been solved has provided atomic level detail into their mechanisms of action. Based on sequence conservation and structural data, these proteins have been grouped into families, some of which contain only ribonuclease members, others including a variety of nucleolytic enzymes that act upon DNA and/or RNA. At the other extreme some ribonucleases belong to families of proteins involved in a wide variety of enzymatic reactions. Functional characterization of these fascinating enzymes has provided evidence for the extreme diversity of their biological functions that include, for example, removal of poly(A) tails (deadenylation) or poly(U) tails from eukaryotic RNAs, processing of tRNA and mRNA 3' ends, maturation of rRNAs and destruction of unnecessary mRNAs. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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Virtanen A, Henriksson N, Nilsson P, Nissbeck M. Poly(A)-specific ribonuclease (PARN): an allosterically regulated, processive and mRNA cap-interacting deadenylase. Crit Rev Biochem Mol Biol 2013; 48:192-209. [PMID: 23496118 DOI: 10.3109/10409238.2013.771132] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Deadenylation of eukaryotic mRNA is a mechanism critical for mRNA function by influencing mRNA turnover and efficiency of protein synthesis. Here, we review poly(A)-specific ribonuclease (PARN), which is one of the biochemically best characterized deadenylases. PARN is unique among the currently known eukaryotic poly(A) degrading nucleases, being the only deadenylase that has the capacity to directly interact during poly(A) hydrolysis with both the m(7)G-cap structure and the poly(A) tail of the mRNA. In short, PARN is a divalent metal-ion dependent poly(A)-specific, processive and cap-interacting 3'-5' exoribonuclease that efficiently degrades poly(A) tails of eukaryotic mRNAs. We discuss in detail the mechanisms of its substrate recognition, catalysis, allostery and processive mode of action. On the basis of biochemical and structural evidence, we present and discuss a working model for PARN action. Models of regulation of PARN activity by trans-acting factors are discussed as well as the physiological relevance of PARN.
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Affiliation(s)
- Anders Virtanen
- Department of Cell and Molecular Biology, Program of Chemical Biology, Uppsala University, Uppsala, Sweden.
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Wahle E, Winkler GS. RNA decay machines: deadenylation by the Ccr4-not and Pan2-Pan3 complexes. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:561-70. [PMID: 23337855 DOI: 10.1016/j.bbagrm.2013.01.003] [Citation(s) in RCA: 173] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/14/2012] [Accepted: 01/09/2013] [Indexed: 12/20/2022]
Abstract
Shortening and removal of the 3' poly(A) tail of mature mRNA by poly(A)-specific 3' exonucleases (deadenylases) is the initial and often rate-limiting step in mRNA degradation. The majority of cytoplasmic deadenylase activity is associated with the Ccr4-Not and Pan2-Pan3 complexes. Two distinct catalytic subunits, Caf1/Pop2 and Ccr4, are associated with the Ccr4-Not complex, whereas the Pan2 enzymatic subunit forms a stable complex with Pan3. In this review, we discuss the composition and activity of these two deadenylases. In addition, we comment on generic and specific mechanisms of recruitment of Ccr4-Not and Pan2-Pan3 to mRNAs. Finally, we discuss specialised and redundant functions of the deadenylases and review the importance of Ccr4-Not subunits in the regulation of physiological processes. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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Affiliation(s)
- Elmar Wahle
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany.
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Godwin AR, Kojima S, Green CB, Wilusz J. Kiss your tail goodbye: the role of PARN, Nocturnin, and Angel deadenylases in mRNA biology. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:571-9. [PMID: 23274303 DOI: 10.1016/j.bbagrm.2012.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 12/12/2012] [Accepted: 12/16/2012] [Indexed: 01/06/2023]
Abstract
PARN, Nocturnin and Angel are three of the multiple deadenylases that have been described in eukaryotic cells. While each of these enzymes appear to target poly(A) tails for shortening and influence RNA gene expression levels and quality control, the enzymes differ in terms of enzymatic mechanisms, regulation and biological impact. The goal of this review is to provide an in depth biochemical and biological perspective of the PARN, Nocturnin and Angel deadenylases. Understanding the shared and unique roles of these enzymes in cell biology will provide important insights into numerous aspects of the post-transcriptional control of gene expression. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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Affiliation(s)
- Alan R Godwin
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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38
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Abstract
Shortening of the poly(A) tail is the first and often rate-limiting step in mRNA degradation. Three poly(A)-specific 3' exonucleases have been described that can carry out this reaction: PAN, composed of two subunits; PARN, a homodimer; and the CCR4-NOT complex, a heterooligomer that contains two catalytic subunits and may have additional functions in the cell. Current evidence indicates that all three enzymes use a two-metal ion mechanism to release nucleoside monophosphates in a hydrolytic reaction. The CCR4-NOT is the main deadenylase in all organisms examined, and mutations affecting the complex can be lethal. The contribution of PAN, apparently an initial deadenylation preceding the activity of CCR4-NOT, is less important, whereas the activity of PARN seems to be restricted to specific substrates or circumstances, for example, stress conditions. Rapid deadenylation and decay of specific mRNAs can be caused by recruitment of both PAN and the CCR4-NOT complex. This function can be carried out by RNA-binding proteins, for example, members of the PUF family. Alternatively, miRNAs can recruit the deadenylase complexes with the help of their associated GW182 proteins.
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Affiliation(s)
- Christiane Harnisch
- Martin-Luther-University of Halle-Wittenberg, Institute of Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, Halle, Germany
| | - Bodo Moritz
- Martin-Luther-University of Halle-Wittenberg, Institute of Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, Halle, Germany
| | - Christiane Rammelt
- Martin-Luther-University of Halle-Wittenberg, Institute of Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, Halle, Germany
| | - Claudia Temme
- Martin-Luther-University of Halle-Wittenberg, Institute of Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, Halle, Germany
| | - Elmar Wahle
- Martin-Luther-University of Halle-Wittenberg, Institute of Biochemistry and Biotechnology, Kurt-Mothes-Strasse 3, Halle, Germany.
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39
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Van Etten J, Schagat TL, Hrit J, Weidmann CA, Brumbaugh J, Coon JJ, Goldstrohm AC. Human Pumilio proteins recruit multiple deadenylases to efficiently repress messenger RNAs. J Biol Chem 2012; 287:36370-83. [PMID: 22955276 DOI: 10.1074/jbc.m112.373522] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PUF proteins are a conserved family of eukaryotic RNA-binding proteins that regulate specific mRNAs: they control many processes including stem cell proliferation, fertility, and memory formation. PUFs repress protein expression from their target mRNAs but the mechanism by which they do so remains unclear, especially for humans. Humans possess two PUF proteins, PUM1 and PUM2, which exhibit similar RNA binding specificities. Here we report new insights into their regulatory activities and mechanisms of action. We developed functional assays to measure sequence-specific repression by PUM1 and PUM2. Both robustly inhibit translation and promote mRNA degradation. Purified PUM complexes were found to contain subunits of the CCR4-NOT (CNOT) complex, which contains multiple enzymes that catalyze mRNA deadenylation. PUMs interact with the CNOT deadenylase subunits in vitro. We used three approaches to determine the importance of deadenylases for PUM repression. First, dominant-negative mutants of CNOT7 and CNOT8 reduced PUM repression. Second, RNA interference depletion of the deadenylases alleviated PUM repression. Third, the poly(A) tail was necessary for maximal PUM repression. These findings demonstrate a conserved mechanism of PUF-mediated repression via direct recruitment of the CCR4-POP2-NOT deadenylase leading to translational inhibition and mRNA degradation. A second, deadenylation independent mechanism was revealed by the finding that PUMs repress an mRNA that lacks a poly(A) tail. Thus, human PUMs are repressors capable of deadenylation-dependent and -independent modes of repression.
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Affiliation(s)
- Jamie Van Etten
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600, USA
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40
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Abstract
The Ccr4–Not complex is one of the major deadenylase factors present in eukaryotic cells. This multi-subunit protein complex is composed of at least seven stably associated subunits in mammalian cells including two enzymatic deadenylase subunits: one DEDD (Asp-Glu-Asp-Asp)-type deadenylase (either CNOT7/human Caf1/Caf1a or CNOT8/human Pop2/Caf1b/Calif) and one EEP (endonuclease–exonuclease–phosphatase)-type enzyme (either CNOT6/human Ccr4/Ccr4a or CNOT6L/human Ccr4-like/Ccr4b). Here, the role of the human Ccr4–Not complex in cytoplasmic deadenylation of mRNA is discussed, including the mechanism of its recruitment to mRNA and the role of the BTG/Tob proteins.
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41
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Abstract
The purpose of this review is to provide an analysis of the latest developments on the functions of the carbon catabolite-repression 4-Not (Ccr4-Not) complex in regulating eukaryotic gene expression. Ccr4-Not is a nine-subunit protein complex that is conserved in sequence and function throughout the eukaryotic kingdom. Although Ccr4-Not has been studied since the 1980s, our understanding of what it does is constantly evolving. Once thought to solely regulate transcription, it is now clear that it has much broader roles in gene regulation, such as in mRNA decay and quality control, RNA export, translational repression and protein ubiquitylation. The mechanism of actions for each of its functions is still being debated. Some of the difficulty in drawing a clear picture is that it has been implicated in so many processes that regulate mRNAs and proteins in both the cytoplasm and the nucleus. We will describe what is known about the Ccr4-Not complex in yeast and other eukaryotes in an effort to synthesize a unified model for how this complex coordinates multiple steps in gene regulation and provide insights into what questions will be most exciting to answer in the future.
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Affiliation(s)
- Jason E. Miller
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, Center for RNA Molecular Biology, Penn State University, University Park, PA 16802
| | - Joseph C. Reese
- Department of Biochemistry and Molecular Biology, Center for Eukaryotic Gene Regulation, Center for RNA Molecular Biology, Penn State University, University Park, PA 16802
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Feng LK, Yan YB. The N-terminus modulates human Caf1 activity, structural stability and aggregation. Int J Biol Macromol 2012; 51:497-503. [PMID: 22683897 DOI: 10.1016/j.ijbiomac.2012.05.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 05/24/2012] [Accepted: 05/29/2012] [Indexed: 12/22/2022]
Abstract
Caf1 is a deadenylase component of the CCR4-Not complex. Here we found that the removal of the N-terminus resulted in a 30% decrease in human Caf1 (hCaf1) activity, but had no significant influence on main domain structure. The removal of the N-terminus led to a decrease in the thermal stability, while the existence of the N-terminus promoted hCaf1 thermal aggregation. Homology modeling indicated that the N-terminus had a potency to form a short α-helix interacted with the main domain. Thus the N-terminus played a role in modulating hCaf1 activity, stability and aggregation.
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Affiliation(s)
- Li-Kui Feng
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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43
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Yi X, Hong M, Gui B, Chen Z, Li L, Xie G, Liang J, Wang X, Shang Y. RNA processing and modification protein, carbon catabolite repression 4 (Ccr4), arrests the cell cycle through p21-dependent and p53-independent pathway. J Biol Chem 2012; 287:21045-57. [PMID: 22547059 DOI: 10.1074/jbc.m112.355321] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Ccr4d is a new member of the Ccr4 (carbon catabolite repression 4) family of proteins that are implicated in the regulation of mRNA stability and translation through mRNA deadenylation. However, Ccr4d is not believed to be involved in mRNA deadenylation. Thus, its biological function and mechanistic activity remain to be determined. Here, we report that Ccr4d is broadly expressed in various normal tissues, and the expression of Ccr4d is markedly down-regulated during cell cycle progression. We showed that Ccr4d inhibits cell proliferation and induces cell cycle arrest at G(1) phase. Our experiments further revealed that Ccr4d regulates the expression of p21 in a p53-independent manner. Mechanistic studies indicated that Ccr4d strongly bound to the 3'-UTR of p21 mRNA, leading to the stabilization of p21 mRNA. Interestingly, we found that the expression of Ccr4d is down-regulated in various tumor tissues. Collectively, our data indicate that Ccr4d functions as an anti-proliferating protein through the induction of cell cycle arrest via a p21-dependent and p53-independent pathway and suggest that Ccr4d might have an important role in carcinogenesis.
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Affiliation(s)
- Xia Yi
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China
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44
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Niu S, Shingle DL, Garbarino-Pico E, Kojima S, Gilbert M, Green CB. The circadian deadenylase Nocturnin is necessary for stabilization of the iNOS mRNA in mice. PLoS One 2011; 6:e26954. [PMID: 22073225 PMCID: PMC3206874 DOI: 10.1371/journal.pone.0026954] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 10/06/2011] [Indexed: 01/05/2023] Open
Abstract
Nocturnin is a member of the CCR4 deadenylase family, and its expression is under circadian control with peak levels at night. Because it can remove poly(A) tails from mRNAs, it is presumed to play a role in post-transcriptional control of circadian gene expression, but its target mRNAs are not known. Here we demonstrate that Nocturnin expression is acutely induced by the endotoxin lipopolysaccharide (LPS). Mouse embryo fibroblasts (MEFs) lacking Nocturnin exhibit normal patterns of acute induction of TNFα and iNOS mRNAs during the first three hours following LPS treatment, but by 24 hours, while TNFα mRNA levels are indistinguishable from WT cells, iNOS message is significantly reduced 20-fold. Accordingly, analysis of the stability of the mRNAs showed that loss of Nocturnin causes a significant decrease in the half-life of the iNOS mRNA (t(1/2) = 3.3 hours in Nocturnin knockout MEFs vs. 12.4 hours in wild type MEFs), while having no effect on the TNFα message. Furthermore, mice lacking Nocturnin lose the normal nighttime peak of hepatic iNOS mRNA, and have improved survival following LPS injection. These data suggest that Nocturnin has a novel stabilizing activity that plays an important role in the circadian response to inflammatory signals.
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Affiliation(s)
- Shuang Niu
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Danielle L. Shingle
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Eduardo Garbarino-Pico
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Shihoko Kojima
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Misty Gilbert
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Carla B. Green
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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45
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Collart MA, Panasenko OO. The Ccr4--not complex. Gene 2011; 492:42-53. [PMID: 22027279 DOI: 10.1016/j.gene.2011.09.033] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/06/2011] [Accepted: 09/29/2011] [Indexed: 12/11/2022]
Abstract
The Ccr4-Not complex is a unique, essential and conserved multi-subunit complex that acts at the level of many different cellular functions to regulate gene expression. Two enzymatic activities, namely ubiquitination and deadenylation, are provided by different subunits of the complex. However, studies over the last decade have demonstrated a tantalizing multi-functionality of this complex that extends well beyond its identified enzymatic activities. Most of our initial knowledge about the Ccr4-Not complex stemmed from studies in yeast, but an increasing number of reports on this complex in other species are emerging. In this review we will discuss the structure and composition of the complex, and describe the different cellular functions with which the Ccr4-Not complex has been connected in different organisms. Finally, based upon our current state of knowledge, we will propose a model to explain how one complex can provide such multi-functionality. This model suggests that the Ccr4-Not complex might function as a "chaperone platform".
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Affiliation(s)
- Martine A Collart
- Dpt Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, 1211 Geneva 4, Switzerland.
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46
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Importin alpha-mediated nuclear import of cytoplasmic poly(A) binding protein occurs as a direct consequence of cytoplasmic mRNA depletion. Mol Cell Biol 2011; 31:3113-25. [PMID: 21646427 DOI: 10.1128/mcb.05402-11] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Recent studies have found the cytoplasmic poly(A) binding protein (PABPC) to have opposing effects on gene expression when concentrated in the cytoplasm versus in the nucleus. PABPC is predominantly cytoplasmic at steady state, where it enhances protein synthesis through simultaneous interactions with mRNA and translation factors. However, it accumulates dramatically within the nucleus in response to various pathogenic and nonpathogenic stresses, leading to an inhibition of mRNA export. The molecular events that trigger relocalization of PABPC and the mechanisms by which it translocates into the nucleus to block gene expression are not understood. Here, we reveal an RNA-based mechanism of retaining PABPC in the cytoplasm. Expression either of viral proteins that promote mRNA turnover or of a cytoplasmic deadenylase drives nuclear relocalization of PABPC in a manner dependent on the PABPC RNA recognition motifs (RRMs). Using multiple independent binding sites within its RRMs, PABPC interacts with importin α, a component of the classical import pathway. Finally, we demonstrate that the direct association of PABPC with importin α is antagonized by the presence of poly(A) RNA, supporting a model in which RNA binding masks nuclear import signals within the PABPC RRMs, thereby ensuring efficient cytoplasmic retention of this protein in normal cells. These findings further suggest that cells must carefully calibrate the ratio of PABPC to mRNA, as events that offset this balance can dramatically influence gene expression.
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47
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Mittal S, Aslam A, Doidge R, Medica R, Winkler GS. The Ccr4a (CNOT6) and Ccr4b (CNOT6L) deadenylase subunits of the human Ccr4-Not complex contribute to the prevention of cell death and senescence. Mol Biol Cell 2011; 22:748-58. [PMID: 21233283 PMCID: PMC3057700 DOI: 10.1091/mbc.e10-11-0898] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The human Ccr4-Not complex has two types of deadenylase subunits that shorten the polyadenylate tail of cytoplasmic mRNA. The authors present evidence for novel roles of the highly related Ccr4a/Ccr4b deadenylases in preventing cell death and senescence and show that they have distinct roles as compared with the Caf1a/Caf1b deadenylases. A key step in cytoplasmic mRNA degradation is the shortening of the poly(A) tail, which involves several deadenylase enzymes. Relatively little is known about the importance of these enzymes for the cellular physiology. Here we focused on the role of the highly similar Ccr4a (CNOT6) and Ccr4b (CNOT6L) deadenylase subunits of the Ccr4–Not complex. In addition to a role in cell proliferation, Ccr4a and Ccr4b play a role in cell survival, in contrast to the Caf1a (CNOT7) and Caf1b (CNOT8) deadenylase subunits or the CNOT1 and CNOT3 noncatalytic subunits of the Ccr4–Not complex. Underscoring the differential contributions of the deadenylase subunits, we found that knockdown of Caf1a/Caf1b or Ccr4a/Ccr4b differentially affects the formation of cytoplasmic foci by processing-body components. Furthermore, we demonstrated that the amino-terminal leucine-rich repeat (LRR) domain of Ccr4b influenced its subcellular localization but was not required for the deadenylase activity of Ccr4b. Moreover, overexpression of Ccr4b lacking the LRR domain interfered with cell cycle progression but not with cell viability. Finally, gene expression profiling indicated that distinct gene sets are regulated by Caf1a/Caf1b and Ccr4a/Ccr4b and identified Ccr4a/Ccr4b as a key regulator of insulin-like growth factor–binding protein 5, which mediates cell cycle arrest and senescence via a p53-dependent pathway.
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Affiliation(s)
- Saloni Mittal
- School of Pharmacy and Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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48
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Phosphorylation of tristetraprolin by MK2 impairs AU-rich element mRNA decay by preventing deadenylase recruitment. Mol Cell Biol 2010; 31:256-66. [PMID: 21078877 DOI: 10.1128/mcb.00717-10] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
mRNA turnover is a critical step in the control of gene expression. In mammalian cells, a subset of mRNAs regulated at the level of mRNA turnover contain destabilizing AU-rich elements (AREs) in their 3' untranslated regions. These transcripts are bound by a suite of ARE-binding proteins (AUBPs) that receive information from cell signaling events to modulate rates of ARE mRNA decay. Here we show that a key destabilizing AUBP, tristetraprolin (TTP), is repressed by the p38 mitogen-activated protein kinase (MAPK)-activated kinase MK2 due to the inability of phospho-TTP to recruit deadenylases to target mRNAs. TTP is tightly associated with cytoplasmic deadenylases and promotes rapid deadenylation of target mRNAs both in vitro and in cells. TTP can direct the deadenylation of substrate mRNAs when tethered to a heterologous mRNA, yet its ability to do so is inhibited upon phosphorylation by MK2. Phospho-TTP is not impaired in mRNA binding but does fail to recruit the major cytoplasmic deadenylases. These observations suggest that phosphorylation of TTP by MK2 primarily affects mRNA decay downstream of RNA binding by preventing recruitment of the deadenylation machinery. Thus, TTP may remain poised to rapidly reactivate deadenylation of bound transcripts to downregulate gene expression once the p38 MAPK pathway is deactivated.
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49
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Abstract
The CCR4-CAF1-NOT complex is a major cytoplasmic deadenylation complex in yeast and mammals. This complex associates with RNA-binding proteins and microRNAs to repress translation of target mRNAs. We sought to determine how CCR4 and CAF1 participate in repression and control of maternal mRNAs using Xenopus laevis oocytes. We show that Xenopus CCR4 and CAF1 enzymes are active deadenylases and repress translation of an adenylated mRNA. CAF1 also represses translation independent of deadenylation. The deadenylation-independent repression requires a 5' cap structure on the mRNA; however, deadenylation does not. We suggest that mere recruitment of CAF1 is sufficient for repression, independent of deadenylation.
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Affiliation(s)
- Amy Cooke
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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50
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Temme C, Zhang L, Kremmer E, Ihling C, Chartier A, Sinz A, Simonelig M, Wahle E. Subunits of the Drosophila CCR4-NOT complex and their roles in mRNA deadenylation. RNA (NEW YORK, N.Y.) 2010; 16:1356-1370. [PMID: 20504953 PMCID: PMC2885685 DOI: 10.1261/rna.2145110] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 04/16/2010] [Indexed: 05/27/2023]
Abstract
The CCR4-NOT complex is the main enzyme catalyzing the deadenylation of mRNA. We have investigated the composition of this complex in Drosophila melanogaster by immunoprecipitation with a monoclonal antibody directed against NOT1. The CCR4, CAF1 (=POP2), NOT1, NOT2, NOT3, and CAF40 subunits were associated in a stable complex, but NOT4 was not. Factors known to be involved in mRNA regulation were prominent among the other proteins coprecipitated with the CCR4-NOT complex, as analyzed by mass spectrometry. The complex was localized mostly in the cytoplasm but did not appear to be a major component of P bodies. Of the known CCR4 paralogs, Nocturnin was found associated with the subunits of the CCR4-NOT complex, whereas Angel and 3635 were not. RNAi experiments in Schneider cells showed that CAF1, NOT1, NOT2, and NOT3 are required for bulk poly(A) shortening and hsp70 mRNA deadenylation, but knock-down of CCR4, CAF40, and NOT4 did not affect these processes. Overexpression of catalytically dead CAF1 had a dominant-negative effect on mRNA decay. In contrast, overexpression of inactive CCR4 had no effect. We conclude that CAF1 is the major catalytically important subunit of the CCR4-NOT complex in Drosophila Schneider cells. Nocturnin may also be involved in mRNA deadenylation, whereas there is no evidence for a similar role of Angel and 3635.
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Affiliation(s)
- Claudia Temme
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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