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Yarmey VR, San-Miguel A. Biomarkers for aging in Caenorhabditis elegans high throughput screening. Biochem Soc Trans 2024; 52:1405-1418. [PMID: 38884801 DOI: 10.1042/bst20231303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/16/2024] [Accepted: 05/28/2024] [Indexed: 06/18/2024]
Abstract
Aging is characterized by a functional decline in organism fitness over time due to a complex combination of genetic and environmental factors [ 1-4]. With an increasing elderly population at risk of age-associated diseases, there is a pressing need for research dedicated to promoting health and longevity through anti-aging interventions. The roundworm Caenorhabditis elegans is an established model organism for aging studies due to its short life cycle, ease of culture, and conserved aging pathways. These benefits also make the worm well-suited for high-throughput screening (HTS) methods to study biomarkers of the molecular changes, cellular dysfunction, and physiological decline associated with aging. Within this review, we offer a summary of recent advances in HTS techniques to study biomarkers of aging in C. elegans.
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Affiliation(s)
- Victoria R Yarmey
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27603, U.S.A
| | - Adriana San-Miguel
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27603, U.S.A
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2
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Lessenger AT, Swaffer MP, Skotheim JM, Feldman JL. Somatic polyploidy supports biosynthesis and tissue function by increasing transcriptional output. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.25.586714. [PMID: 38585999 PMCID: PMC10996643 DOI: 10.1101/2024.03.25.586714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Cell size and biosynthetic capacity generally increase with increased DNA content. Polyploidy has therefore been proposed to be an adaptive strategy to increase cell size in specialized tissues with high biosynthetic demands. However, if and how DNA concentration limits cellular biosynthesis in vivo is not well understood, and the impacts of polyploidy in non-disease states is not well studied. Here, we show that polyploidy in the C. elegans intestine is critical for cell growth and yolk biosynthesis, a central role of this organ. Artificially lowering the DNA/cytoplasm ratio by reducing polyploidization in the intestine gave rise to smaller cells with more dilute mRNA. Highly-expressed transcripts were more sensitive to this mRNA dilution, whereas lowly-expressed genes were partially compensated - in part by loading more RNA Polymerase II on the remaining genomes. DNA-dilute cells had normal total protein concentration, which we propose is achieved by increasing production of translational machinery at the expense of specialized, cell-type specific proteins.
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Al-Refaie N, Padovani F, Binando F, Hornung J, Zhao Q, Towbin BD, Cenik ES, Stroustrup N, Schmoller KM, Cabianca DS. An mTOR/RNA pol I axis shapes chromatin architecture in response to fasting. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.22.550032. [PMID: 37503059 PMCID: PMC10370172 DOI: 10.1101/2023.07.22.550032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Chromatin architecture is a fundamental mediator of genome function. Fasting is a major environmental cue across the animal kingdom. Yet, how it impacts on 3D genome organization is unknown. Here, we show that fasting induces a reversible and large-scale spatial reorganization of chromatin in C. elegans . This fasting-induced 3D genome reorganization requires inhibition of the nutrient-sensing mTOR pathway, a major regulator of ribosome biogenesis. Remarkably, loss of transcription by RNA Pol I, but not RNA Pol II nor Pol III, induces a similar 3D genome reorganization in fed animals, and prevents the restoration of the fed-state architecture upon restoring nutrients to fasted animals. Our work documents the first large-scale chromatin reorganization triggered by fasting and reveals that mTOR and RNA Pol I shape genome architecture in response to nutrients.
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Costa DS, Kenny-Ganzert IW, Chi Q, Park K, Kelley LC, Garde A, Matus DQ, Park J, Yogev S, Goldstein B, Gibney TV, Pani AM, Sherwood DR. The Caenorhabditis elegans anchor cell transcriptome: ribosome biogenesis drives cell invasion through basement membrane. Development 2023; 150:dev201570. [PMID: 37039075 PMCID: PMC10259517 DOI: 10.1242/dev.201570] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 03/27/2023] [Indexed: 04/12/2023]
Abstract
Cell invasion through basement membrane (BM) barriers is important in development, immune function and cancer progression. As invasion through BM is often stochastic, capturing gene expression profiles of actively invading cells in vivo remains elusive. Using the stereotyped timing of Caenorhabditis elegans anchor cell (AC) invasion, we generated an AC transcriptome during BM breaching. Through a focused RNAi screen of transcriptionally enriched genes, we identified new invasion regulators, including translationally controlled tumor protein (TCTP). We also discovered gene enrichment of ribosomal proteins. AC-specific RNAi, endogenous ribosome labeling and ribosome biogenesis analysis revealed that a burst of ribosome production occurs shortly after AC specification, which drives the translation of proteins mediating BM removal. Ribosomes also enrich near the AC endoplasmic reticulum (ER) Sec61 translocon and the endomembrane system expands before invasion. We show that AC invasion is sensitive to ER stress, indicating a heightened requirement for translation of ER-trafficked proteins. These studies reveal key roles for ribosome biogenesis and endomembrane expansion in cell invasion through BM and establish the AC transcriptome as a resource to identify mechanisms underlying BM transmigration.
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Affiliation(s)
- Daniel S. Costa
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27708, USA
| | | | - Qiuyi Chi
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
| | - Kieop Park
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
| | - Laura C. Kelley
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
| | - Aastha Garde
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA
| | - David Q. Matus
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Junhyun Park
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Shaul Yogev
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Bob Goldstein
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Theresa V. Gibney
- Department of Biology, University of Virginia, Charlottesville, VA 29903, USA
| | - Ariel M. Pani
- Department of Biology, University of Virginia, Charlottesville, VA 29903, USA
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 29904, USA
| | - David R. Sherwood
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA
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Nucleophagy delays aging and preserves germline immortality. NATURE AGING 2022; 3:34-46. [PMID: 37118512 PMCID: PMC10154226 DOI: 10.1038/s43587-022-00327-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 11/03/2022] [Indexed: 12/24/2022]
Abstract
AbstractMarked alterations in nuclear ultrastructure are a universal hallmark of aging, progeroid syndromes and other age-related pathologies. Here we show that autophagy of nuclear proteins is an important determinant of fertility and aging. Impairment of nucleophagy diminishes stress resistance, germline immortality and longevity. We found that the nematode Caenorhabditis elegans nuclear envelope anchor protein, nuclear anchorage protein 1 (ANC-1) and its mammalian ortholog nesprin-2 are cleared out by autophagy and restrict nucleolar size, a biomarker of aging. We further uncovered a germline immortality assurance mechanism, which involves nucleolar degradation at the most proximal oocyte by ANC-1 and key autophagic components. Perturbation of this clearance pathway causes tumor-like structures in C. elegans, and genetic ablation of nesprin-2 causes ovarian carcinomas in mice. Thus, autophagic recycling of nuclear components is a conserved soma longevity and germline immortality mechanism that promotes youthfulness and delays aging under conditions of stress.
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Liao S, Chen X, Xu T, Jin Q, Xu Z, Xu D, Zhou X, Zhu C, Guang S, Feng X. Antisense ribosomal siRNAs inhibit RNA polymerase I-directed transcription in C. elegans. Nucleic Acids Res 2021; 49:9194-9210. [PMID: 34365510 PMCID: PMC8450093 DOI: 10.1093/nar/gkab662] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 07/13/2021] [Accepted: 07/23/2021] [Indexed: 11/16/2022] Open
Abstract
Eukaryotic cells express a wide variety of endogenous small regulatory RNAs that function in the nucleus. We previously found that erroneous rRNAs induce the generation of antisense ribosomal siRNAs (risiRNAs) which silence the expression of rRNAs via the nuclear RNAi defective (Nrde) pathway. To further understand the biological roles and mechanisms of this class of small regulatory RNAs, we conducted forward genetic screening to identify factors involved in risiRNA generation in Caenorhabditis elegans. We found that risiRNAs accumulated in the RNA exosome mutants. risiRNAs directed the association of NRDE proteins with pre-rRNAs and the silencing of pre-rRNAs. In the presence of risiRNAs, NRDE-2 accumulated in the nucleolus and colocalized with RNA polymerase I. risiRNAs inhibited the transcription elongation of RNA polymerase I by decreasing RNAP I occupancy downstream of the RNAi-targeted site. Meanwhile, exosomes mislocalized from the nucleolus to nucleoplasm in suppressor of siRNA (susi) mutants, in which erroneous rRNAs accumulated. These results established a novel model of rRNA surveillance by combining ribonuclease-mediated RNA degradation with small RNA-directed nucleolar RNAi system.
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Affiliation(s)
- Shimiao Liao
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Xiangyang Chen
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Ting Xu
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Qile Jin
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Zongxiu Xu
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Demin Xu
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Xufei Zhou
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Chengming Zhu
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
| | - Shouhong Guang
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China.,CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Hefei, Anhui 230027, P.R. China
| | - Xuezhu Feng
- Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, P.R. China
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Wang Y, Weng C, Chen X, Zhou X, Huang X, Yan Y, Zhu C. CDE-1 suppresses the production of risiRNA by coupling polyuridylation and degradation of rRNA. BMC Biol 2020; 18:115. [PMID: 32887607 PMCID: PMC7472701 DOI: 10.1186/s12915-020-00850-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 08/17/2020] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Modification of RNAs, particularly at the terminals, is critical for various essential cell processes; for example, uridylation is implicated in tumorigenesis, proliferation, stem cell maintenance, and immune defense against viruses and retrotransposons. Ribosomal RNAs can be regulated by antisense ribosomal siRNAs (risiRNAs), which downregulate pre-rRNAs through the nuclear RNAi pathway in Caenorhabditis elegans. However, the biogenesis and regulation of risiRNAs remain obscure. Previously, we showed that 26S rRNAs are uridylated at the 3'-ends by an unknown terminal polyuridylation polymerase before the rRNAs are degraded by a 3' to 5' exoribonuclease SUSI-1(ceDIS3L2). RESULTS Here, we found that CDE-1, one of the three C.elegans polyuridylation polymerases (PUPs), is specifically involved in suppressing risiRNA production. CDE-1 localizes to perinuclear granules in the germline and uridylates Argonaute-associated 22G-RNAs, 26S, and 5.8S rRNAs at the 3'-ends. Immunoprecipitation followed by mass spectrometry (IP-MS) revealed that CDE-1 interacts with SUSI-1(ceDIS3L2). Consistent with these results, both CDE-1 and SUSI-1(ceDIS3L2) are required for the inheritance of RNAi. CONCLUSIONS This work identified a rRNA surveillance machinery of rRNAs that couples terminal polyuridylation and degradation.
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Affiliation(s)
- Yun Wang
- National Science Center for Physical Sciences at Microscale Division of Molecular & Cell Biophysics, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China.
- School of Bioengineering, Huainan Normal University, Huainan, 232038, Anhui, People's Republic of China.
| | - Chenchun Weng
- National Science Center for Physical Sciences at Microscale Division of Molecular & Cell Biophysics, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
| | - Xiangyang Chen
- National Science Center for Physical Sciences at Microscale Division of Molecular & Cell Biophysics, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
| | - Xufei Zhou
- National Science Center for Physical Sciences at Microscale Division of Molecular & Cell Biophysics, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
| | - Xinya Huang
- National Science Center for Physical Sciences at Microscale Division of Molecular & Cell Biophysics, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
| | - Yonghong Yan
- National Institute of Biological Sciences, Beijing, 102206, People's Republic of China
| | - Chengming Zhu
- National Science Center for Physical Sciences at Microscale Division of Molecular & Cell Biophysics, School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China
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8
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Bo Otto F, Thumm M. Nucleophagy-Implications for Microautophagy and Health. Int J Mol Sci 2020; 21:ijms21124506. [PMID: 32599961 PMCID: PMC7352367 DOI: 10.3390/ijms21124506] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/18/2020] [Accepted: 06/22/2020] [Indexed: 12/12/2022] Open
Abstract
Nucleophagy, the selective subtype of autophagy that targets nuclear material for autophagic degradation, was not only shown to be a model system for the study of selective macroautophagy, but also for elucidating the role of the core autophagic machinery within microautophagy. Nucleophagy also emerged as a system associated with a variety of disease conditions including cancer, neurodegeneration and ageing. Nucleophagic processes are part of natural cell development, but also act as a response to various stress conditions. Upon releasing small portions of nuclear material, micronuclei, the autophagic machinery transfers these micronuclei to the vacuole for subsequent degradation. Despite sharing many cargos and requiring the core autophagic machinery, recent investigations revealed the aspects that set macro- and micronucleophagy apart. Central to the discrepancies found between macro- and micronucleophagy is the nucleus vacuole junction, a large membrane contact site formed between nucleus and vacuole. Exclusion of nuclear pore complexes from the junction and its exclusive degradation by micronucleophagy reveal compositional differences in cargo. Regarding their shared reliance on the core autophagic machinery, micronucleophagy does not involve normal autophagosome biogenesis observed for macronucleophagy, but instead maintains a unique role in overall microautophagy, with the autophagic machinery accumulating at the neck of budding vesicles.
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Hsiung KC, Liu KY, Tsai TF, Yoshina S, Mitani S, Chin-Ming Tan B, Lo SJ. Defects in CISD-1, a mitochondrial iron-sulfur protein, lower glucose level and ATP production in Caenorhabditis elegans. Biomed J 2020; 43:32-43. [PMID: 32200954 PMCID: PMC7090286 DOI: 10.1016/j.bj.2019.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/14/2019] [Accepted: 07/03/2019] [Indexed: 12/27/2022] Open
Abstract
Background CDGSH iron sulfur domain-containing protein 1 (CISD-1) belongs to the CISD protein family that is evolutionary conserved across different species. In mammals, CISD-1 protein has been implicated in diseases such as cancers and diabetes. As a tractable model organism to study disease-associated proteins, we employed Caenorhabditis elegans in this study with an aim to establish a model for interrogating the functional relevance of CISD-1 in human metabolic conditions. Methods We first bioinformatically identified the human Cisd-1 homologue in worms. We then employed N2 wild-type and cisd-1(tm4993) mutant to investigate the consequences of CISD-1 loss-of-function on: 1) the expression pattern of CISD-1, 2) mitochondrial morphology pattern, 3) mitochondrial function and bioenergetics, and 4) the effects of anti-diabetes drugs. Results We first identified C. elegans W02B12.15 gene as the human Cisd-1 homologous gene, and pinpointed the localization of CISD-1 to the outer membrane of mitochondria. As compared with the N2 wild-type worm, cisd-1(tm4993) mutant exhibited a higher proportion of hyperfused form of mitochondria. This structural abnormality was associated with the generation of higher levels of ROS and mitochondrial superoxide but lower ATP. These physiological changes in mutants did not result in discernable effects on animal motility and lifespan. Moreover, the amount of glucose in N2 wild-type worms treated with troglitazone and pioglitazone, derivatives of TZD, was reduced to a comparable level as in the mutant animals. Conclusions By focusing on the Cisd-1 gene, our study established a C. elegans genetic system suitable for modeling human diabetes-related diseases.
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Affiliation(s)
- Kuei-Ching Hsiung
- Department and Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuan-Yu Liu
- Department and Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ting-Fen Tsai
- National Yang Ming University, Department of Life Science, Taipei, Taiwan
| | - Sawako Yoshina
- Department of Physiology, Tokyo Women's Medical University, School of Medicine and CREST, Japan Science and Technology, Tokyo, Japan
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University, School of Medicine and CREST, Japan Science and Technology, Tokyo, Japan
| | - Bertrand Chin-Ming Tan
- Department and Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan; Department of Neurosurgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.
| | - Szecheng J Lo
- Department and Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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10
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Abstract
Individuals within a species can exhibit vast variation in copy number of repetitive DNA elements. This variation may contribute to complex traits such as lifespan and disease, yet it is only infrequently considered in genotype-phenotype associations. Although the possible importance of copy number variation is widely recognized, accurate copy number quantification remains challenging. Here, we assess the technical reproducibility of several major methods for copy number estimation as they apply to the large repetitive ribosomal DNA array (rDNA). rDNA encodes the ribosomal RNAs and exists as a tandem gene array in all eukaryotes. Repeat units of rDNA are kilobases in size, often with several hundred units comprising the array, making rDNA particularly intractable to common quantification techniques. We evaluate pulsed-field gel electrophoresis, droplet digital PCR, and Nextera-based whole genome sequencing as approaches to copy number estimation, comparing techniques across model organisms and spanning wide ranges of copy numbers. Nextera-based whole genome sequencing, though commonly used in recent literature, produced high error. We explore possible causes for this error and provide recommendations for best practices in rDNA copy number estimation. We present a resource of high-confidence rDNA copy number estimates for a set of S. cerevisiae and C. elegans strains for future use. We furthermore explore the possibility for FISH-based copy number estimation, an alternative that could potentially characterize copy number on a cellular level.
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Ma TH, Chen PH, Tan BCM, Lo SJ. Size scaling of nucleolus in Caenorhabditis elegans embryos. Biomed J 2018; 41:333-336. [PMID: 30580798 PMCID: PMC6306298 DOI: 10.1016/j.bj.2018.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/20/2018] [Accepted: 07/31/2018] [Indexed: 11/13/2022] Open
Abstract
Nucleolus is viewed as a plurifunctional center in the cell, tightly linked to ribosome biosynthesis. As a non-membranous structure, how the size of nucleolus is determined is a long outstanding question, and the possibility of “direct size scaling to the nucleus” was raised by genetic studies in fission yeast. Here, we used the model organism Caenorhabditis elegans to test this hypothesis in multi-cellular organisms. We depleted ani-2, ima-3, or C27D9.1 by RNAi feeding, which altered embryo sizes to different extents in ncl-1 mutant worms. DIC imaging provided evidence that in size-altering embryo nucleolar size decreases in small cells and increases in large cells. Furthermore, analyses of nucleolar size in four blastomeres (ABa, ABp, EMS, and P2) within the same embryo of ncl-1 mutants consistently demonstrated the correspondence between cell and nucleolar sizes – the small cells (EMS and P2) have smaller nucleoli in comparison to the large cells (ABa).
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Affiliation(s)
- Tian-Hsiang Ma
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Po-Hsiang Chen
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Bertrand Chin-Ming Tan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Neurosurgery, Chang Gung Memorial Hospital at Linlou, Taoyuan, Taiwan; Research Center for Emerging Viral Infections, Chang Gung Memorial Hospital at Linlou, Taoyuan, Taiwan.
| | - Szecheng J Lo
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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Erroneous ribosomal RNAs promote the generation of antisense ribosomal siRNA. Proc Natl Acad Sci U S A 2018; 115:10082-10087. [PMID: 30224484 DOI: 10.1073/pnas.1800974115] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Ribosome biogenesis is a multistep process, during which mistakes can occur at any step of pre-rRNA processing, modification, and ribosome assembly. Misprocessed rRNAs are usually detected and degraded by surveillance machineries. Recently, we identified a class of antisense ribosomal siRNAs (risiRNAs) that down-regulate pre-rRNAs through the nuclear RNAi pathway. To further understand the biological roles of risiRNAs, we conducted both forward and reverse genetic screens to search for more suppressor of siRNA (susi) mutants. We isolated a number of genes that are broadly conserved from yeast to humans and are involved in pre-rRNA modification and processing. Among them, SUSI-2(ceRRP8) is homologous to human RRP8 and engages in m1A methylation of the 26S rRNA. C27F2.4(ceBUD23) is an m7G-methyltransferase of the 18S rRNA. E02H1.1(ceDIMT1L) is a predicted m6(2)Am6(2)A-methyltransferase of the 18S rRNA. Mutation of these genes led to a deficiency in modification of rRNAs and elicited accumulation of risiRNAs, which further triggered the cytoplasmic-to-nuclear and cytoplasmic-to-nucleolar translocations of the Argonaute protein NRDE-3. The rRNA processing deficiency also resulted in accumulation of risiRNAs. We also isolated SUSI-3(RIOK-1), which is similar to human RIOK1, that cleaves the 20S rRNA to 18S. We further utilized RNAi and CRISPR-Cas9 technologies to perform candidate-based reverse genetic screens and identified additional pre-rRNA processing factors that suppressed risiRNA production. Therefore, we concluded that erroneous rRNAs can trigger risiRNA generation and subsequently, turn on the nuclear RNAi-mediated gene silencing pathway to inhibit pre-rRNA expression, which may provide a quality control mechanism to maintain homeostasis of rRNAs.
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Tiku V, Kew C, Mehrotra P, Ganesan R, Robinson N, Antebi A. Nucleolar fibrillarin is an evolutionarily conserved regulator of bacterial pathogen resistance. Nat Commun 2018; 9:3607. [PMID: 30190478 PMCID: PMC6127302 DOI: 10.1038/s41467-018-06051-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 07/19/2018] [Indexed: 02/04/2023] Open
Abstract
Innate immunity is the first line of defense against infections. Pathways regulating innate responses can also modulate other processes, including stress resistance and longevity. Increasing evidence suggests a role for the nucleolus in regulating cellular processes implicated in health and disease. Here we show the highly conserved nucleolar protein, fibrillarin, is a vital factor regulating pathogen resistance. Fibrillarin knockdown enhances resistance in C. elegans against bacterial pathogens, higher levels of fibrillarin induce susceptibility to infection. Pathogenic infection reduces nucleolar size, ribsosomal RNA, and fibrillarin levels. Genetic epistasis reveals fibrillarin functions independently of the major innate immunity mediators, suggesting novel mechanisms of pathogen resistance. Bacterial infection also reduces nucleolar size and fibrillarin levels in mammalian cells. Fibrillarin knockdown prior to infection increases intracellular bacterial clearance, reduces inflammation, and enhances cell survival. Collectively, these findings reveal an evolutionarily conserved role of fibrillarin in infection resistance and suggest the nucleolus as a focal point in innate immune responses.
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Affiliation(s)
- Varnesh Tiku
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674, Cologne, Germany.,Department of Infectious Diseases, Genentech Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Chun Kew
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931, Cologne, Germany
| | - Parul Mehrotra
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931, Cologne, Germany.,VIB-Center for Inflammation Research, VIB - Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Raja Ganesan
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674, Cologne, Germany.,Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, 50674, Cologne, Germany
| | - Nirmal Robinson
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674, Cologne, Germany. .,Centre for Cancer Biology, University of South Australia, HB11-35 UniSA CRI Building, North Terrace, 5001, Adelaide, Australia.
| | - Adam Antebi
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931, Cologne, Germany. .,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674, Cologne, Germany.
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14
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West SM, Mecenas D, Gutwein M, Aristizábal-Corrales D, Piano F, Gunsalus KC. Developmental dynamics of gene expression and alternative polyadenylation in the Caenorhabditis elegans germline. Genome Biol 2018; 19:8. [PMID: 29368663 PMCID: PMC5784609 DOI: 10.1186/s13059-017-1369-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 12/03/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The 3' untranslated regions (UTRs) of mRNAs play a major role in post-transcriptional regulation of gene expression. Selection of transcript cleavage and polyadenylation sites is a dynamic process that produces multiple transcript isoforms for the same gene within and across different cell types. Using LITE-Seq, a new quantitative method to capture transcript 3' ends expressed in vivo, we have characterized sex- and cell type-specific transcriptome-wide changes in gene expression and 3'UTR diversity in Caenorhabditis elegans germline cells undergoing proliferation and differentiation. RESULTS We show that nearly half of germline transcripts are alternatively polyadenylated, that differential regulation of endogenous 3'UTR variants is common, and that alternative isoforms direct distinct spatiotemporal protein expression patterns in vivo. Dynamic expression profiling also reveals temporal regulation of X-linked gene expression, selective stabilization of transcripts, and strong evidence for a novel developmental program that promotes nucleolar dissolution in oocytes. We show that the RNA-binding protein NCL-1/Brat is a posttranscriptional regulator of numerous ribosome-related transcripts that acts through specific U-rich binding motifs to down-regulate mRNAs encoding ribosomal protein subunits, rRNA processing factors, and tRNA synthetases. CONCLUSIONS These results highlight the pervasive nature and functional potential of patterned gene and isoform expression during early animal development.
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Affiliation(s)
- Sean M West
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, NY, 10012, USA
| | - Desirea Mecenas
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, NY, 10012, USA
| | - Michelle Gutwein
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, NY, 10012, USA
| | - David Aristizábal-Corrales
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, NY, 10012, USA
| | - Fabio Piano
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, NY, 10012, USA.
- Center for Genomics & Systems Biology, NYU Abu Dhabi, P.O. Box 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
| | - Kristin C Gunsalus
- Center for Genomics & Systems Biology, Department of Biology, New York University, New York, NY, 10012, USA.
- Center for Genomics & Systems Biology, NYU Abu Dhabi, P.O. Box 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates.
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15
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Zhao M, An J, Li H, Zhang J, Li ST, Li XM, Dong MQ, Mao H, Tao L. Segmentation and classification of two-channel C. elegans nucleus-labeled fluorescence images. BMC Bioinformatics 2017; 18:412. [PMID: 28915791 PMCID: PMC5602880 DOI: 10.1186/s12859-017-1817-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 09/06/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aging is characterized by a gradual breakdown of cellular structures. Nuclear abnormality is a hallmark of progeria in human. Analysis of age-dependent nuclear morphological changes in Caenorhabditis elegans is of great value to aging research, and this calls for an automatic image processing method that is suitable for both normal and abnormal structures. RESULTS Our image processing method consists of nuclear segmentation, feature extraction and classification. First, taking up the challenges of defining individual nuclei with fuzzy boundaries or in a clump, we developed an accurate nuclear segmentation method using fused two-channel images with seed-based cluster splitting and k-means algorithm, and achieved a high precision against the manual segmentation results. Next, we extracted three groups of nuclear features, among which five features were selected by minimum Redundancy Maximum Relevance (mRMR) for classifiers. After comparing the classification performances of several popular techniques, we identified that Random Forest, which achieved a mean class accuracy (MCA) of 98.69%, was the best classifier for our data set. Lastly, we demonstrated the method with two quantitative analyses of C. elegans nuclei, which led to the discovery of two possible longevity indicators. CONCLUSIONS We produced an automatic image processing method for two-channel C. elegans nucleus-labeled fluorescence images. It frees biologists from segmenting and classifying the nuclei manually.
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Affiliation(s)
- Mengdi Zhao
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Jie An
- LMAM, School of Mathematical Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Haiwen Li
- LMAM, School of Mathematical Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Jiazhi Zhang
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Shang-Tong Li
- National Institute of Biological Sciences, Beijing, Kexueyuan Road, Beijing, 102206, China
| | - Xue-Mei Li
- National Institute of Biological Sciences, Beijing, Kexueyuan Road, Beijing, 102206, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, Kexueyuan Road, Beijing, 102206, China
| | - Heng Mao
- LMAM, School of Mathematical Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China.
| | - Louis Tao
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Yiheyuan Road, Beijing, 100871, China. .,Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China.
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16
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Tiku V, Jain C, Raz Y, Nakamura S, Heestand B, Liu W, Späth M, Suchiman HED, Müller RU, Slagboom PE, Partridge L, Antebi A. Small nucleoli are a cellular hallmark of longevity. Nat Commun 2017; 8:16083. [PMID: 28853436 PMCID: PMC5582349 DOI: 10.1038/ncomms16083] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 05/26/2017] [Indexed: 12/21/2022] Open
Abstract
Animal lifespan is regulated by conserved metabolic signalling pathways and specific transcription factors, but whether these pathways affect common downstream mechanisms remains largely elusive. Here we show that NCL-1/TRIM2/Brat tumour suppressor extends lifespan and limits nucleolar size in the major C. elegans longevity pathways, as part of a convergent mechanism focused on the nucleolus. Long-lived animals representing distinct longevity pathways exhibit small nucleoli, and decreased expression of rRNA, ribosomal proteins, and the nucleolar protein fibrillarin, dependent on NCL-1. Knockdown of fibrillarin also reduces nucleolar size and extends lifespan. Among wildtype C. elegans, individual nucleolar size varies, but is highly predictive for longevity. Long-lived dietary restricted fruit flies and insulin-like-peptide mutants exhibit small nucleoli and fibrillarin expression, as do long-lived dietary restricted and IRS1 knockout mice. Furthermore, human muscle biopsies from individuals who underwent modest dietary restriction coupled with exercise also display small nucleoli. We suggest that small nucleoli are a cellular hallmark of longevity and metabolic health conserved across taxa. Animal lifespan is plastic and is regulated by conserved signalling pathways. Here, Tiku et al. show that longevity-enhancing mutations or interventions are associated with reduced nucleolar size in worms, flies, mice and humans, and that nucleolar size can predict life-expectancy in individual worms.
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Affiliation(s)
- Varnesh Tiku
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | - Chirag Jain
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931 Cologne, Germany
| | - Yotam Raz
- Section of Molecular Epidemiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Shuhei Nakamura
- Department of Genetics, Graduate School of Medicine, Osaka University 2-2 Yamadaoka, Suita 565-0871, Japan
| | - Bree Heestand
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA
| | - Wei Liu
- Department of Molecular and Cellular Biology, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Martin Späth
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | - H Eka D Suchiman
- Section of Molecular Epidemiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Roman-Ulrich Müller
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany.,Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, 50674 Cologne, Germany
| | - P Eline Slagboom
- Section of Molecular Epidemiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Linda Partridge
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | - Adam Antebi
- Max Planck Institute for Biology of Ageing, Joseph Stelzmann Strasse 9b, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
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17
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Ma TH, Lee LW, Lee CC, Yi YH, Chan SP, Tan BCM, Lo SJ. Genetic control of nucleolar size: An evolutionary perspective. Nucleus 2016; 7:112-20. [PMID: 27003693 DOI: 10.1080/19491034.2016.1166322] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Exploiting a C. elegans mutant (ncl-1) exhibiting nucleolar abnormalities, we recently identified the let-7/ncl-1/fib-1 genetic cascade underlying proper rRNA abundance and nucleolar size. These 3 factors, let-7 (a miRNA), NCL-1 (a member of the TRIM-NHL family), and fibrillarin (a nucleolar methyltransferase), are evolutionarily conserved across metazoans. In this article, we provide several lines of bioinformatic evidence showing that human and Drosophila homologues of C. elegans NCL-1, TRIM-71 and Brat, respectively, likely act as translational suppressors of fibrillarin. Moreover, since their 3'-UTRs contain putative target sites, they may also be under the control of the let-7 miRNA. We hypothesize that let-7, TRIM and fibrillarin contribute activities in concert, and constitute a conserved network controlling nucleolar size in eukaryotes. We provide an in-depth literature review of various molecular pathways, including the let-7/ncl-1/fib-1 genetic cascade, implicated in the regulation of nucleolar size.
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Affiliation(s)
- Tian-Hsiang Ma
- a Department of Biomedical Sciences, College of Medicine , Chang Gung University , TaoYuan , Taiwan.,b Graduate Institute of Biomedical Sciences , College of Medicine , Chang Gung University , TaoYuan , Taiwan
| | - Li-Wei Lee
- a Department of Biomedical Sciences, College of Medicine , Chang Gung University , TaoYuan , Taiwan.,c Molecular Medicine Research Center , College of Medicine , Chang Gung University , TaoYuan , Taiwan
| | - Chi-Chang Lee
- d Institute of Chemistry , Academia Sinica , Taipei , Taiwan
| | - Yung-Hsiang Yi
- a Department of Biomedical Sciences, College of Medicine , Chang Gung University , TaoYuan , Taiwan.,c Molecular Medicine Research Center , College of Medicine , Chang Gung University , TaoYuan , Taiwan
| | - Shih-Peng Chan
- e Graduate Institute of Microbiology , College of Medicine , National Taiwan University , Taipei , Taiwan
| | - Bertrand Chin-Ming Tan
- a Department of Biomedical Sciences, College of Medicine , Chang Gung University , TaoYuan , Taiwan.,b Graduate Institute of Biomedical Sciences , College of Medicine , Chang Gung University , TaoYuan , Taiwan.,c Molecular Medicine Research Center , College of Medicine , Chang Gung University , TaoYuan , Taiwan
| | - Szecheng J Lo
- a Department of Biomedical Sciences, College of Medicine , Chang Gung University , TaoYuan , Taiwan.,b Graduate Institute of Biomedical Sciences , College of Medicine , Chang Gung University , TaoYuan , Taiwan.,c Molecular Medicine Research Center , College of Medicine , Chang Gung University , TaoYuan , Taiwan
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18
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Yi YH, Ma TH, Lee LW, Chiou PT, Chen PH, Lee CM, Chu YD, Yu H, Hsiung KC, Tsai YT, Lee CC, Chang YS, Chan SP, Tan BCM, Lo SJ. A Genetic Cascade of let-7-ncl-1-fib-1 Modulates Nucleolar Size and rRNA Pool in Caenorhabditis elegans. PLoS Genet 2015; 11:e1005580. [PMID: 26492166 PMCID: PMC4619655 DOI: 10.1371/journal.pgen.1005580] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/15/2015] [Indexed: 11/20/2022] Open
Abstract
Ribosome biogenesis takes place in the nucleolus, the size of which is often coordinated with cell growth and development. However, how metazoans control nucleolar size remains largely unknown. Caenorhabditis elegans provides a good model to address this question owing to distinct tissue distribution of nucleolar sizes and a mutant, ncl-1, which exhibits larger nucleoli than wild-type worms. Here, through a series of loss-of-function analyses, we report that the nucleolar size is regulated by a circuitry composed of microRNA let-7, translation repressor NCL-1, and a major nucleolar pre-rRNA processing protein FIB-1/fibrillarin. In cooperation with RNA binding proteins PUF and NOS, NCL-1 suppressed the translation of FIB-1/fibrillarin, while let-7 targeted the 3’UTR of ncl-1 and inhibited its expression. Consequently, the abundance of FIB-1 is tightly controlled and correlated with the nucleolar size. Together, our findings highlight a novel genetic cascade by which post-transcriptional regulators interplay in developmental control of nucleolar size and function. Among the RNA/protein bodies within the nucleus, nucleoli are essential factories for ribosome production and assembly. The size and morphology of the nucleolus is thus a cytological manifestation of protein biosynthesis and is closely coordinated with cell biology and even malignancy. However, without membrane delimitation, the principles that define nucleoli size are poorly understood. Caenorhabditis elegans represents an ideal model to address this question owing to distinct tissue distribution of nucleolar sizes and a mutant, ncl-1, which exhibits larger-than-normal nucleoli. We report here a genetic cascade of microRNA let-7 and translation repressor NCL-1, which tightly controls abundance of FIB-1/fibrillarin. This network ultimately contributes to developmental control of nucleolar size and function.
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Affiliation(s)
- Yung-Hsiang Yi
- Molecular Medicine Research Center, Chang Gung University, TaoYuan, Taiwan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Tian-Hsiang Ma
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Li-Wei Lee
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Pey-Tsyr Chiou
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Po-Hsiang Chen
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Ching-Ming Lee
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Yu-De Chu
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hsiang Yu
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Kuei-Ching Hsiung
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Yi-Tzang Tsai
- Molecular Medicine Research Center, Chang Gung University, TaoYuan, Taiwan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Chi-Chang Lee
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Yu-Sun Chang
- Molecular Medicine Research Center, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
| | - Shih-Peng Chan
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan
- * E-mail: (SPC); (BCMT); (SJL)
| | - Bertrand Chin-Ming Tan
- Molecular Medicine Research Center, Chang Gung University, TaoYuan, Taiwan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- * E-mail: (SPC); (BCMT); (SJL)
| | - Szecheng J. Lo
- Molecular Medicine Research Center, Chang Gung University, TaoYuan, Taiwan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, TaoYuan, Taiwan
- * E-mail: (SPC); (BCMT); (SJL)
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19
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Bailly A, Perrin A, Bou Malhab LJ, Pion E, Larance M, Nagala M, Smith P, O'Donohue MF, Gleizes PE, Zomerdijk J, Lamond AI, Xirodimas DP. The NEDD8 inhibitor MLN4924 increases the size of the nucleolus and activates p53 through the ribosomal-Mdm2 pathway. Oncogene 2015; 35:415-26. [PMID: 25867069 DOI: 10.1038/onc.2015.104] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/10/2015] [Accepted: 03/03/2015] [Indexed: 12/19/2022]
Abstract
The ubiquitin-like molecule NEDD8 is essential for viability, growth and development, and is a potential target for therapeutic intervention. We found that the small molecule inhibitor of NEDDylation, MLN4924, alters the morphology and increases the surface size of the nucleolus in human and germline cells of Caenorhabditis elegans in the absence of nucleolar fragmentation. SILAC proteomics and monitoring of rRNA production, processing and ribosome profiling shows that MLN4924 changes the composition of the nucleolar proteome but does not inhibit RNA Pol I transcription. Further analysis demonstrates that MLN4924 activates the p53 tumour suppressor through the RPL11/RPL5-Mdm2 pathway, with characteristics of nucleolar stress. The study identifies the nucleolus as a target of inhibitors of NEDDylation and provides a mechanism for p53 activation upon NEDD8 inhibition. It also indicates that targeting the nucleolar proteome without affecting nucleolar transcription initiates the required signalling events for the control of cell cycle regulators.
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Affiliation(s)
- A Bailly
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - A Perrin
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - L J Bou Malhab
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - E Pion
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - M Larance
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - M Nagala
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - P Smith
- Millennium Pharmaceuticals Inc., Cambridge, MA, USA
| | - M-F O'Donohue
- Laboratoire de Biologie Moléculaire Eucaryote, UMR CNRS 5099, Bâtiment IBCG, Toulouse, France
| | - P-E Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, UMR CNRS 5099, Bâtiment IBCG, Toulouse, France
| | - J Zomerdijk
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - A I Lamond
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - D P Xirodimas
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
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20
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Abstract
This review summarizes the current understanding of the role of nuclear bodies in regulating gene expression. The compartmentalization of cellular processes, such as ribosome biogenesis, RNA processing, cellular response to stress, transcription, modification and assembly of spliceosomal snRNPs, histone gene synthesis and nuclear RNA retention, has significant implications for gene regulation. These functional nuclear domains include the nucleolus, nuclear speckle, nuclear stress body, transcription factory, Cajal body, Gemini of Cajal body, histone locus body and paraspeckle. We herein review the roles of nuclear bodies in regulating gene expression and their relation to human health and disease.
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Affiliation(s)
| | - Cornelius F. Boerkoel
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-604-875-2157; Fax: +1-604-875-2376
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21
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Lee CC, Tsai YT, Kao CW, Lee LW, Lai HJ, Ma TH, Chang YS, Yeh NH, Lo SJ. Mutation of a Nopp140 gene dao-5 alters rDNA transcription and increases germ cell apoptosis in C. elegans. Cell Death Dis 2014; 5:e1158. [PMID: 24722283 PMCID: PMC5424100 DOI: 10.1038/cddis.2014.114] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 02/17/2014] [Accepted: 02/20/2014] [Indexed: 01/03/2023]
Abstract
Human diseases of impaired ribosome biogenesis resulting from disruption of rRNA biosynthesis or loss of ribosomal components are collectively described as ‘ribosomopathies'. Treacher Collins syndrome (TCS), a representative human ribosomopathy with craniofacial abnormalities, is attributed to mutations in the tcof1 gene that has a homologous gene called nopp140. Previous studies demonstrated that the dao-5 (dauer and aged animal overexpression gene 5) of Caenorhabditis elegans is a member of nopp140 gene family and plays a role in nucleogenesis in the early embryo. Here, we established a C. elegans model for studying Nopp140-associated ribosomopathy. A null dao-5 mutant ok542 with a semi-infertile phenotype showed a delay in gonadogenesis, as well as a higher incidence of germline apoptosis. These phenotypes in dao-5(ok542) are likely resulted from inefficient rDNA transcription that was observed by run-on analyses and chromatin immunoprecipitation (ChIP) assays measuring the RNA Pol I occupancy on the rDNA promoter. ChIP assays further showed that the modifications of acetylated histone 4 (H4Ac) and dimethylation at the lysine 9 of histone 3 (H3K9me2) around the rDNA promoter were altered in dao-5 mutants compared with the N2 wild type. In addition, activated CEP-1 (a C. elegans p53 homolog) activity was also linked to the loss of DAO-5 in terms of the transcriptional upregulation of two CEP-1 downstream effectors, EGL-1 and CED-13. We propose that the dao-5 mutant of C. elegans can be a valuable model for studying human Nopp140-associated ribosomopathy at the cellular and molecular levels.
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Affiliation(s)
- C-C Lee
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan
| | - Y-T Tsai
- 1] Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan [2] Molecular Medicine Research Center, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - C-W Kao
- Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - L-W Lee
- Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - H-J Lai
- Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - T-H Ma
- 1] Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan [2] Molecular Medicine Research Center, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - Y-S Chang
- 1] Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan [2] Molecular Medicine Research Center, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - N-H Yeh
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan
| | - S J Lo
- 1] Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan [2] Department and Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
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Sharma R, Meister P. Nuclear organization in the nematode C. elegans. Curr Opin Cell Biol 2013; 25:395-402. [PMID: 23481208 DOI: 10.1016/j.ceb.2013.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 02/05/2013] [Indexed: 11/30/2022]
Abstract
With its invariant cell lineage, easy genetics and small genome, the nematode Caenorhabditis elegans has emerged as one of the prime models in developmental biology over the last 50 years. Surprisingly however, until a decade ago very little was known about nuclear organization in worms, even though it is an ideal model system to explore the link between nuclear organization and cell fate determination. Here, we review the latest findings that exploit the repertoire of genetic tools developed in worms, leading to the identification of important sequences and signals governing the changes in chromatin tridimensional architecture. We also highlight parallels and differences to other model systems.
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Affiliation(s)
- Rahul Sharma
- Cell Fate and Nuclear Organization, Institute of Cell Biology, University of Bern, CH-3012 Bern, Switzerland
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