1
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Cho E, Lee SH, Dean RA, Jeon J. Distinct dynamics of the nucleolus in response to nutrient availability and during development in the rice blast fungus. mBio 2023; 14:e0184423. [PMID: 37768072 PMCID: PMC10653916 DOI: 10.1128/mbio.01844-23] [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: 07/17/2023] [Accepted: 08/11/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE The nucleolus is a dynamic subnuclear structure that is involved in many fundamental processes of the nucleus. In higher eukaryotic cells, the size and shape of nucleoli correlate with nucleolar activities. For fungi, knowledge of the nucleolus and its functions is primarily gleaned from budding yeast. Whether such correlation is conserved and how nucleolar functions are regulated in filamentous fungi including important human and crop pathogens are largely unknown. Our observations reveal that the dynamics of nucleolus in a model plant pathogenic fungus, Magnaporthe oryzae, is distinct from those of animal and yeast nucleoli under low nutrient availability and during pathogenic development. Our data not only provide new insight into the nucleoli in filamentous fungi but also highlight the need for investigating how nucleolar dynamics is regulated in comparison to other eukaryotes.
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Affiliation(s)
- Eunbyeol Cho
- Department of Biotechnology, College of Life and Applied Sciences, Yeungnam University, Gyeongsan, Gyeongbuk, South Korea
| | - Song Hee Lee
- Department of Biotechnology, College of Life and Applied Sciences, Yeungnam University, Gyeongsan, Gyeongbuk, South Korea
- Plant Immunity Research Center, Seoul National University, Seoul, South Korea
| | - Ralph A. Dean
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Junhyun Jeon
- Department of Biotechnology, College of Life and Applied Sciences, Yeungnam University, Gyeongsan, Gyeongbuk, South Korea
- Plant Immunity Research Center, Seoul National University, Seoul, South Korea
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2
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Zhai F, Wang J, Luo X, Ye M, Jin X. Roles of NOLC1 in cancers and viral infection. J Cancer Res Clin Oncol 2023; 149:10593-10608. [PMID: 37296317 DOI: 10.1007/s00432-023-04934-5] [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: 04/15/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023]
Abstract
BACKGROUND The nucleolus is considered the center of metabolic control and an important organelle for the biogenesis of ribosomal RNA (rRNA). Nucleolar and coiled-body phosphoprotein 1(NOLC1), which was originally identified as a nuclear localization signal-binding protein is a nucleolar protein responsible for nucleolus construction and rRNA synthesis, as well as chaperone shuttling between the nucleolus and cytoplasm. NOLC1 plays an important role in a variety of cellular life activities, including ribosome biosynthesis, DNA replication, transcription regulation, RNA processing, cell cycle regulation, apoptosis, and cell regeneration. PURPOSE In this review, we introduce the structure and function of NOLC1. Then we elaborate its upstream post-translational modification and downstream regulation. Meanwhile, we describe its role in cancer development and viral infection which provide a direction for future clinical applications. METHODS The relevant literatures from PubMed have been reviewed for this article. CONCLUSION NOLC1 plays an important role in the progression of multiple cancers and viral infection. In-depth study of NOLC1 provides a new perspective for accurate diagnosis of patients and selection of therapeutic targets.
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Affiliation(s)
- Fengguang Zhai
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China
| | - Jie Wang
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China
| | - Xia Luo
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China
| | - Meng Ye
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China.
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China.
| | - Xiaofeng Jin
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China.
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China.
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3
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Astafiev AA, Shakhov AM, Osychenko AA, Martirosyan DY, Tochilo WA, Zalessky AD, Syrchina MS, Karmenyan AV, Cheng CL, Nadtochenko VA. Femtosecond Laser Microsurgery of Mouse Oocytes: Formation and Dynamics of Cavitation Bubbles Under the Action of Sharply Focused Laser Radiation on Various Oocyte Zones. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2023. [DOI: 10.1134/s1990793123010189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
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4
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Wu M, Lu L, Chen S, Li Y, Zhang Q, Fu S, Deng X. Natural products inducing nucleolar stress: implications in cancer therapy. Anticancer Drugs 2022; 33:e21-e27. [PMID: 34561998 DOI: 10.1097/cad.0000000000001146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The nucleolus is the site of ribosome biogenesis and is found to play an important role in stress sensing. For over 100 years, the increase in the size and number of nucleoli has been considered as a marker of aggressive tumors. Despite this, the contribution of the nucleolus and the biologic processes mediated by it to cancer pathogenesis has been largely overlooked. This state has been changed over the recent decades with the demonstration that the nucleolus controls numerous cellular functions associated with cancer development. Induction of nucleolar stress has recently been regarded as being superior to conventional cytotoxic/cytostatic strategy in that it is more selective to neoplastic cells while sparing normal cells. Natural products represent an excellent source of bioactive molecules and some of them have been found to be able to induce nucleolar stress. The demonstration of these nucleolar stress-inducing natural products has paved the way for a new therapeutic approach to more delicate tumor cell-killing. This review provides a contemporary summary of the role of the nucleolus as a novel promising target for cancer therapy, with particular emphasis on natural products as an exciting new class of anti-cancer drugs with nucleolar stress-inducing properties.
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Affiliation(s)
- Mi Wu
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University
- Department of Pathophysiology, Hunan Normal University School of Medicine, Changsha
| | - Lu Lu
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University
- Department of Pathophysiology, Hunan Normal University School of Medicine, Changsha
| | - Sisi Chen
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University
- Department of Pathophysiology, Hunan Normal University School of Medicine, Changsha
| | - Ying Li
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University
- Department of Pathophysiology, Hunan Normal University School of Medicine, Changsha
| | - Qiuting Zhang
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University
- Department of Pathophysiology, Hunan Normal University School of Medicine, Changsha
| | - Shujun Fu
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University
- Department of Pathophysiology, Hunan Normal University School of Medicine, Changsha
| | - Xiyun Deng
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University
- Department of Pathophysiology, Hunan Normal University School of Medicine, Changsha
- Department of Pathophysiology, Jishou University School of Medicine, Jishou, Hunan, China
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5
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Velázquez-Cruz A, Baños-Jaime B, Díaz-Quintana A, De la Rosa MA, Díaz-Moreno I. Post-translational Control of RNA-Binding Proteins and Disease-Related Dysregulation. Front Mol Biosci 2021; 8:658852. [PMID: 33987205 PMCID: PMC8111222 DOI: 10.3389/fmolb.2021.658852] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
Cell signaling mechanisms modulate gene expression in response to internal and external stimuli. Cellular adaptation requires a precise and coordinated regulation of the transcription and translation processes. The post-transcriptional control of mRNA metabolism is mediated by the so-called RNA-binding proteins (RBPs), which assemble with specific transcripts forming messenger ribonucleoprotein particles of highly dynamic composition. RBPs constitute a class of trans-acting regulatory proteins with affinity for certain consensus elements present in mRNA molecules. However, these regulators are subjected to post-translational modifications (PTMs) that constantly adjust their activity to maintain cell homeostasis. PTMs can dramatically change the subcellular localization, the binding affinity for RNA and protein partners, and the turnover rate of RBPs. Moreover, the ability of many RBPs to undergo phase transition and/or their recruitment to previously formed membrane-less organelles, such as stress granules, is also regulated by specific PTMs. Interestingly, the dysregulation of PTMs in RBPs has been associated with the pathophysiology of many different diseases. Abnormal PTM patterns can lead to the distortion of the physiological role of RBPs due to mislocalization, loss or gain of function, and/or accelerated or disrupted degradation. This Mini Review offers a broad overview of the post-translational regulation of selected RBPs and the involvement of their dysregulation in neurodegenerative disorders, cancer and other pathologies.
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Affiliation(s)
- Alejandro Velázquez-Cruz
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Blanca Baños-Jaime
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Antonio Díaz-Quintana
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Miguel A De la Rosa
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Irene Díaz-Moreno
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
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6
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Aladesuyi Arogundade O, Nguyen S, Leung R, Wainio D, Rodriguez M, Ravits J. Nucleolar stress in C9orf72 and sporadic ALS spinal motor neurons precedes TDP-43 mislocalization. Acta Neuropathol Commun 2021; 9:26. [PMID: 33588953 PMCID: PMC7885352 DOI: 10.1186/s40478-021-01125-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 01/30/2021] [Indexed: 12/11/2022] Open
Abstract
Nucleolar stress has been implicated in the pathology and disease pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) from repeat expansions of GGGGCC in C9orf72 (C9-ALS/FTLD) but not in sporadic ALS (SALS). Previously we reported that antisense RNA transcripts are unique in C9-ALS because of their nucleolar localization in spinal motor neurons and correlation with TDP-43 mislocalization, the hallmark proteinopathy of ALS and FTLD. Here we report our further studies of 11 SALS, 11 C9-ALS and 11 control spinal cords. We find that nucleolar stress manifests specifically as shrinkage in nucleoli of C9-ALS spinal motor neurons. Nucleolar size reduction is greatest in similarly sized alpha motor neurons from C9-ALS cases and results are not skewed by the number of surviving neurons from each ALS spinal cord. Surprisingly, nucleolar shrinkage occurs before main pathological hallmarks-TDP-43 mislocalization or antisense RNA foci-appear and this suggest that nucleolar stress can precede pathology in C9-ALS, findings previously identified in C9-FTLD using sense RNA foci and dipeptide repeat proteins as pathological markers. Importantly, these observations are also seen in SALS motor neurons and thus nucleolar stress appears to be a significant and probably upstream problem in sporadic disease.
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Affiliation(s)
| | - Sandra Nguyen
- University of California, San Diego, La Jolla, CA, USA
| | - Ringo Leung
- University of California, San Diego, La Jolla, CA, USA
| | | | | | - John Ravits
- University of California, San Diego, La Jolla, CA, USA.
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7
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Liu J, Li C, Xue H, Li L, Liu Q, Wang H, Wen T, Qian H. Cancer metastasis-associated protein 1 localizes to the nucleolus and regulates pre-rRNA synthesis in cancer cells. J Cell Biochem 2021; 122:180-188. [PMID: 32786109 DOI: 10.1002/jcb.29837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 04/07/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022]
Abstract
Metastasis-associated protein 1 (MTA1) is a critical component of the nucleosome remodeling and histone deacetylase (NuRD) complex. MTA1 has several biological functions, and it is closely associated with the malignant properties of human cancers; however, the mechanisms and subcellular localization of MTA1 in cells remain unclear. Some initial studies indicated that MTA1 was absent from the nucleolus; however, several NuRD components were recently found to be present in the nucleolus, where they regulate preribosomal RNA (pre-rRNA) transcription. In this study, we demonstrated that MTA1 is definitely localized to the nucleolus and regulates pre-rRNA transcription, which is consistent with the recent reports on NuRD. To determine if MTA1 was present in the nucleolus, we utilized the following complementary molecular approaches: immunofluorescence, GFP-tag tracking, immunoelectron microscopy, and immunoprecipitation (IP). To examine the role of MTA1 in rRNA synthesis, we performed quantitative polymerase chain reaction analysis. We revealed that both endogenous and exogenous MTA1 showed apparent granule-like nucleolar subcellular localization. MTA1 interacts with two major resident nucleolar proteins, nucleolin and nucleophosmin. Immunofluorescent colocalization analyses showed that MTA1 localizes to the fibrillarin-deficient regions of the nucleolus, and Co-IP experiments indicated that there was no interaction between MTA1 and fibrillarin; further, fibrillarin was not identified in the MTA1 interactome. Loss- and gain-of-function studies indicated that MTA1 promotes pre-rRNA transcription in cancer cells. Collectively, our data identify MTA1 as a novel nucleolar protein, and activation of pre-rRNA transcription in cancer cells may be an alternative mechanism by which MTA1 promotes malignancies.
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Affiliation(s)
- Jian Liu
- Medical Research Center, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Chunxiao Li
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Hongsheng Xue
- Department of Thoracic Surgery, The Affiliated Zhongshan Hospital of Dalian University, Dalian, China
| | - Lina Li
- Medical Research Center, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Qun Liu
- Department of Gynaecology and Obstetrics, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Haijuan Wang
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Tao Wen
- Medical Research Center, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Haili Qian
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
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8
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Balzano E, Pelliccia F, Giunta S. Genome (in)stability at tandem repeats. Semin Cell Dev Biol 2020; 113:97-112. [PMID: 33109442 DOI: 10.1016/j.semcdb.2020.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/26/2020] [Accepted: 10/10/2020] [Indexed: 12/12/2022]
Abstract
Repeat sequences account for over half of the human genome and represent a significant source of variation that underlies physiological and pathological states. Yet, their study has been hindered due to limitations in short-reads sequencing technology and difficulties in assembly. A important category of repetitive DNA in the human genome is comprised of tandem repeats (TRs), where repetitive units are arranged in a head-to-tail pattern. Compared to other regions of the genome, TRs carry between 10 and 10,000 fold higher mutation rate. There are several mutagenic mechanisms that can give rise to this propensity toward instability, but their precise contribution remains speculative. Given the high degree of homology between these sequences and their arrangement in tandem, once damaged, TRs have an intrinsic propensity to undergo aberrant recombination with non-allelic exchange and generate harmful rearrangements that may undermine the stability of the entire genome. The dynamic mutagenesis at TRs has been found to underlie individual polymorphism associated with neurodegenerative and neuromuscular disorders, as well as complex genetic diseases like cancer and diabetes. Here, we review our current understanding of the surveillance and repair mechanisms operating within these regions, and we describe how alterations in these protective processes can readily trigger mutational signatures found at TRs, ultimately resulting in the pathological correlation between TRs instability and human diseases. Finally, we provide a viewpoint to counter the detrimental effects that TRs pose in light of their selection and conservation, as important drivers of human evolution.
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Affiliation(s)
- Elisa Balzano
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy
| | - Franca Pelliccia
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy
| | - Simona Giunta
- The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy.
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9
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Chen PH, Chen YT, Chu TY, Ma TH, Wu MH, Lin HH, Chang YS, Tan BCM, Lo SJ. Nucleolar control by a non-apoptotic p53-caspases-deubiquitinylase axis promotes resistance to bacterial infection. FASEB J 2020; 34:1107-1121. [PMID: 31914708 DOI: 10.1096/fj.201901959r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/02/2019] [Accepted: 10/15/2019] [Indexed: 11/11/2022]
Abstract
The nucleolus is best known for its cellular role in regulating ribosome production and growth. More recently, an unanticipated role for the nucleolus in innate immunity has recently emerged whereby downregulation of fibrillarin and nucleolar contraction confers pathogen resistance across taxa. The mechanism of this downregulation, however, remains obscure. Here we report that rather than fibrillarin itself being the proximal factor in this pathway, the key player is a fibrillarin-stabilizing deubiquitinylase USP-33. This was discovered by a candidate-gene search of Caenorhabditis elegans in which CED-3 caspase was revealed to execute targeted cleavage of USP-33, thus destabilizing fibrillarin. We also showed that cep-1 and ced-3 mutant worms altered nucleolar size and decreased antimicrobial peptide gene, spp-1, expression rendering susceptibility to bacterial infection. These phenotypes were reversed by usp-33 knockdown, thus linking the CEP-1-CED-3-USP-33 pathway with nucleolar control and resistance to bacterial infection in worms. Parallel experiments with the human analogs of caspases and USP36 revealed similar roles in coordinating these two processes. In summary, our work outlined a conserved cascade that connects cell death signaling to nucleolar control and innate immune response.
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Affiliation(s)
- 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
| | - Yi-Tung Chen
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tai-Ying Chu
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
| | - Tian-Hsiang Ma
- Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Mei-Hsuan Wu
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Hsi-Hsien Lin
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Department of Microbiology and Immunology, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Sun Chang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Medicine Research Center, 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.,Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan.,Department of Neurosurgery, Lin-Kou Medical Center, Chang Gung Memorial Hospital, 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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10
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The Nopp140 gene in Drosophila melanogaster displays length polymorphisms in its large repetitive second exon. Mol Genet Genomics 2019; 294:1073-1083. [PMID: 31006039 DOI: 10.1007/s00438-019-01568-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 04/10/2019] [Indexed: 12/21/2022]
Abstract
Nopp140, often called the nucleolar and Cajal body phosphoprotein (NOLC1), is an evolutionarily conserved chaperone for the transcription and processing of rRNA during ribosome subunit assembly. Metazoan Nopp140 contains an amino terminal LisH dimerization domain and a highly conserved carboxyl domain. A large central domain consists of alternating basic and acidic motifs of low sequence complexity. Orthologous versions of Nopp140 contain variable numbers of repeating basic-acidic units. While vertebrate Nopp140 genes use multiple exons to encode the central domain, the Nopp140 gene in Drosophila uses exclusively exon 2 to encode the central domain. Here, we define three overlapping repeat sequence patterns (P, P', and P″) within the central domain of D. melanogaster Nopp140. These repeat patterns are poorly conserved in other Drosophila species. We also describe a length polymorphism in exon 2 that pertains specifically to the P' pattern in D. melanogaster. The pattern displays either two or three 96 base pair repeats, respectively, referred to as Nopp140-Short and Nopp140-Long. Fly lines homozygous for one or the other allele, or heterozygous for both alleles, show no discernible phenotypes. PCR characterization of the long and short alleles shows a poorly defined, artifactual bias toward amplifying the long allele over the short allele. The significance of this polymorphism will be in discerning the largely unknown properties of Nopp140's large central domain in rDNA transcription and ribosome biogenesis.
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11
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Vasaturo M, Cotugno R, Fiengo L, Vinegoni C, Dal Piaz F, De Tommasi N. The anti-tumor diterpene oridonin is a direct inhibitor of Nucleolin in cancer cells. Sci Rep 2018; 8:16735. [PMID: 30425290 PMCID: PMC6233161 DOI: 10.1038/s41598-018-35088-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/25/2018] [Indexed: 11/15/2022] Open
Abstract
The bioactive plant diterpene oridonin displays important pharmacological activities and is widely used in traditional Chinese medicine; however, its molecular mechanism of action is still incompletely described. In vitro and in vivo data have demonstrated anti-tumor activity of oridonin and its ability to interfere with several cell pathways; however, presently only the molecular chaperone HSP70 has been identified as a direct potential target of this compound. Here, using a combination of different proteomic approaches, innovative Cellular Thermal Shift Assay (CETSA) experiments, and classical biochemical methods, we demonstrate that oridonin interacts with Nucleolin, effectively modulating the activity of this multifunctional protein. The ability of oridonin to target Nucleolin and/or HSP70 could account for the bioactivity profile of this plant diterpene. Recently, Nucleolin has attracted attention as a druggable target, as its diverse functions are implicated in pathological processes such as cancer, inflammation, and viral infection. However, up to now, no small molecule as Nucleolin binders has been reported, thus our finding represents the first evidence of Nucleolin modulation by a small inhibitor.
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Affiliation(s)
- Michele Vasaturo
- Università degli Studi di Salerno, Department of Pharmacy, Via Giovanni Paolo II, 84084, Fisciano, (SA), Italy
- Università degli Studi di Salerno, Ph. D. School of Pharmacy, Via Giovanni Paolo II, 84084, Fisciano, (SA), Italy
| | - Roberta Cotugno
- Università degli Studi di Salerno, Department of Pharmacy, Via Giovanni Paolo II, 84084, Fisciano, (SA), Italy
| | - Lorenzo Fiengo
- Università degli Studi di Salerno, Department of Pharmacy, Via Giovanni Paolo II, 84084, Fisciano, (SA), Italy
- Università degli Studi di Salerno, Ph. D. School of Pharmacy, Via Giovanni Paolo II, 84084, Fisciano, (SA), Italy
| | - Claudio Vinegoni
- Harvard Medical School, MGH Center for Systems Biology, 185 Cambridge Steet, 02144, Boston, MA, USA
| | - Fabrizio Dal Piaz
- Università degli Studi di Salerno, Department of Medicine and Surgery, Via S. Allende, 84081, Baronissi, (SA), Italy.
| | - Nunziatina De Tommasi
- Università degli Studi di Salerno, Department of Pharmacy, Via Giovanni Paolo II, 84084, Fisciano, (SA), Italy
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12
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Lu L, Yi H, Chen C, Yan S, Yao H, He G, Li G, Jiang Y, Deng T, Deng X. Nucleolar stress: is there a reverse version? J Cancer 2018; 9:3723-3727. [PMID: 30405843 PMCID: PMC6216007 DOI: 10.7150/jca.27660] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/04/2018] [Indexed: 12/20/2022] Open
Abstract
The nucleolus is a dynamic structure that has roles in various physiological and pathophysiological processes. Perturbations on many aspects of the nucleolar functions are thought to cause “nucleolar stress”, which occurs in response to a variety of chemotherapeutic drugs. The main characteristic changes of nucleolar stress include: 1) reduction of the size and volume of the nucleolus; 2) inhibition of RNA Pol I-mediated rRNA synthesis; and 3) nucleoplasmic translocation of nucleolar stress-related proteins. In studying the apoptosis-inducing effect of the natural compound lovastatin (LV) on breast cancer stem cells, we unexpectedly uncovered a novel form of nucleolar stress, which we call “reverse nucleolar stress”. In our system, the canonical nucleolus stress inducer doxorubicin caused nucleoplasmic translocation of the nucleolar protein NPM and complete abolishment of Nolc1, an NPM-interacting protein and an activator of rRNA transcription. In contrast, the reverse nucleolar stress induced by LV is manifested as a more localized perinucleolar distribution of NPM and an increase in the protein level of Nolc1. Furthermore, translocation of the ribosomal protein RPL3 from the cytoplasm to the nucleolus and increased AgNOR staining were observed. These changes characterize a novel pattern of nucleolar stress doubtlessly distinguishable from the canonical one. The functional consequences of reverse nucleolar stress are not clear at present but may presumably be related to cell death or even normalization of the stressed cell. The discovery of reverse nucleolar stress opens up a new area of research in molecular and cellular biology and might have important implications in cancer therapy.
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Affiliation(s)
- Lu Lu
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China.,Departments of Pathology and Pathophysiology, Hunan Normal University School of Medicine, Changsha, Hunan 410013, China
| | - Huimei Yi
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China.,Departments of Pathology and Pathophysiology, Hunan Normal University School of Medicine, Changsha, Hunan 410013, China
| | - Chao Chen
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China.,Departments of Pathology and Pathophysiology, Hunan Normal University School of Medicine, Changsha, Hunan 410013, China
| | - Shichao Yan
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China.,Departments of Pathology and Pathophysiology, Hunan Normal University School of Medicine, Changsha, Hunan 410013, China
| | - Hui Yao
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China.,Departments of Pathology and Pathophysiology, Hunan Normal University School of Medicine, Changsha, Hunan 410013, China
| | - Guangchun He
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China.,Departments of Pathology and Pathophysiology, Hunan Normal University School of Medicine, Changsha, Hunan 410013, China
| | - Guifei Li
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China
| | - Yiqun Jiang
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China
| | - Tuo Deng
- Diabetes Research Center and Center for Bioenergetics, Houston Methodist Research Institute, Houston, Texas 77030, USA.,Department of Medicine, Weill Cornell Medical College at Cornell University, New York, New York 10021, USA
| | - Xiyun Deng
- Key Laboratory of Translational Cancer Stem Cell Research, Hunan Normal University, Changsha, Hunan 410013, China.,Departments of Pathology and Pathophysiology, Hunan Normal University School of Medicine, Changsha, Hunan 410013, China
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13
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Muñoz-Flores BM, Cabrera-González J, Viñas C, Chávez-Reyes A, Dias HVR, Jiménez-Pérez VM, Núñez R. Organotin Dyes Bearing Anionic Boron Clusters as Cell-Staining Fluorescent Probes. Chemistry 2018; 24:5601-5612. [PMID: 29338104 DOI: 10.1002/chem.201705804] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Indexed: 11/08/2022]
Abstract
Within the cell nucleus, in the nucleoli, ribosomal RNAs are synthesized and participate in several biological processes. To better understand nucleoli-related processes, their visualization is often required, for which specific markers are needed. Herein, we report the design of novel fluorescent organotin compounds derived from 4-hydroxy-N'-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide and their cytoplasm and nucleoli staining of B16F10 cells in vitro. Tin compounds bearing an aliphatic carbon chain (-C12 H25 ) and an electron-donating group (-OH) were prepared, and the latter could be derivatized to bear the boron cluster anions [B12 H12 ]2- and [3,3'-Co(1,2-C2 B9 H11 )2 ]- (COSAN). All of the conjugates have been fully characterized and their luminescence properties have been assessed. In general, they show good quantum yields in solution (24-49 %), those for the COSAN derivatives being lower. Remarkably, the linking of [B12 H12 ]2- and COSAN to the complexes made them more soluble, without being detrimental to their luminescence properties. Living B16F10 cells were treated with all of the compounds to determine their fluorescence staining properties; the compounds bearing the aliphatic chain showed a reduced staining capacity due to the formation of aggregates. Notably, the complexes bearing different boron clusters showed different staining effects; those bearing [B12 H12 ]2- showed extraordinary staining of the nucleoli and cytoplasm, whereas those bearing COSAN were only detected in the cytoplasm. The remarkable fluorescence staining properties shown by these organotin compounds make them excellent candidates for fluorescence bioimaging in vitro.
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Affiliation(s)
- Blanca M Muñoz-Flores
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Ciudad Universitaria, Av. Universidad s/n, C. P., 66451, Nuevo León, México
| | - Justo Cabrera-González
- Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC), Campus UAB, 08193, Bellaterra, Spain
| | - Clara Viñas
- Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC), Campus UAB, 08193, Bellaterra, Spain
| | - Arturo Chávez-Reyes
- Centro de Investigación y de Estudios Avanzados del IPN, Unidad Monterrey, PIIT, C.P., 66600 Apodaca, Nuevo León, México
| | - H V Rasika Dias
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065, United States
| | - Víctor M Jiménez-Pérez
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Ciudad Universitaria, Av. Universidad s/n, C. P., 66451, Nuevo León, México
| | - Rosario Núñez
- Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC), Campus UAB, 08193, Bellaterra, Spain
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14
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The flavivirus capsid protein: Structure, function and perspectives towards drug design. Virus Res 2017; 227:115-123. [DOI: 10.1016/j.virusres.2016.10.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 09/29/2016] [Accepted: 10/12/2016] [Indexed: 12/12/2022]
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15
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Hémonnot CYJ, Ranke C, Saldanha O, Graceffa R, Hagemann J, Köster S. Following DNA Compaction During the Cell Cycle by X-ray Nanodiffraction. ACS NANO 2016; 10:10661-10670. [PMID: 28024349 DOI: 10.1021/acsnano.6b05034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
X-ray imaging of intact biological cells is emerging as a complementary method to visible light or electron microscopy. Owing to the high penetration depth and small wavelength of X-rays, it is possible to resolve subcellular structures at a resolution of a few nanometers. Here, we apply scanning X-ray nanodiffraction in combination with time-lapse bright-field microscopy to nuclei of 3T3 fibroblasts and thus relate the observed structures to specific phases in the cell division cycle. We scan the sample at a step size of 250 nm and analyze the individual diffraction patterns according to a generalized Porod's law. Thus, we obtain information on the aggregation state of the nuclear DNA at a real space resolution on the order of the step size and in parallel structural information on the order of few nanometers. We are able to distinguish nucleoli, heterochromatin, and euchromatin in the nuclei and follow the compaction and decompaction during the cell division cycle.
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Affiliation(s)
- Clément Y J Hémonnot
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany
| | - Christiane Ranke
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany
| | - Oliva Saldanha
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany
| | - Rita Graceffa
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany
| | - Johannes Hagemann
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany
| | - Sarah Köster
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, Göttingen 37077, Germany
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16
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Nuclear bodies reorganize during myogenesis in vitro and are differentially disrupted by expression of FSHD-associated DUX4. Skelet Muscle 2016; 6:42. [PMID: 27906075 PMCID: PMC5134237 DOI: 10.1186/s13395-016-0113-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 11/17/2016] [Indexed: 11/18/2022] Open
Abstract
Background Nuclear bodies, such as nucleoli, PML bodies, and SC35 speckles, are dynamic sub-nuclear structures that regulate multiple genetic and epigenetic processes. Additional regulation is provided by RNA/DNA handling proteins, notably TDP-43 and FUS, which have been linked to ALS pathology. Previous work showed that mouse cell line myotubes have fewer but larger nucleoli than myoblasts, and we had found that nuclear aggregation of TDP-43 in human myotubes was induced by expression of DUX4-FL, a transcription factor that is aberrantly expressed and causes pathology in facioscapulohumeral dystrophy (FSHD). However, questions remained about nuclear bodies in human myogenesis and in muscle disease. Methods We examined nucleoli, PML bodies, SC35 speckles, TDP-43, and FUS in myoblasts and myotubes derived from healthy donors and from patients with FSHD, laminin-alpha-2-deficiency (MDC1A), and alpha-sarcoglycan-deficiency (LGMD2D). We further examined how these nuclear bodies and proteins were affected by DUX4-FL expression. Results We found that nucleoli, PML bodies, and SC35 speckles reorganized during differentiation in vitro, with all three becoming less abundant in myotube vs. myoblast nuclei. In addition, though PML bodies did not change in size, both nucleoli and SC35 speckles were larger in myotube than myoblast nuclei. Similar patterns of nuclear body reorganization occurred in healthy control, MDC1A, and LGMD2D cultures, as well as in the large fraction of nuclei that did not show DUX4-FL expression in FSHD cultures. In contrast, nuclei that expressed endogenous or exogenous DUX4-FL, though retaining normal nucleoli, showed disrupted morphology of some PML bodies and most SC35 speckles and also co-aggregation of FUS with TDP-43. Conclusions Nucleoli, PML bodies, and SC35 speckles reorganize during human myotube formation in vitro. These nuclear body reorganizations are likely needed to carry out the distinct gene transcription and splicing patterns that are induced upon myotube formation. DUX4-FL-induced disruption of some PML bodies and most SC35 speckles, along with co-aggregation of TDP-43 and FUS, could contribute to pathogenesis in FSHD, perhaps by locally interfering with genetic and epigenetic regulation of gene expression in the small subset of nuclei that express high levels of DUX4-FL at any one time.
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17
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Farhane Z, Bonnier F, Byrne HJ. Monitoring doxorubicin cellular uptake and trafficking using in vitro Raman microspectroscopy: short and long time exposure effects on lung cancer cell lines. Anal Bioanal Chem 2016; 409:1333-1346. [DOI: 10.1007/s00216-016-0065-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 10/18/2016] [Accepted: 10/26/2016] [Indexed: 01/01/2023]
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18
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Abstract
One of the original hypotheses of organismal longevity posits that aging is the natural result of entropy on the cells, tissues, and organs of the animal—a slow, inexorable slide into nonfunctionality caused by stochastic degradation of its parts. We now have evidence that aging is instead at least in part genetically regulated. Many mutations have been discovered to extend lifespan in organisms of all complexities, from yeast to mammals. The study of metazoan model organisms, such as Caenorhabditis elegans, has been instrumental in understanding the role of genetics in the cell biology of aging. Longevity mutants across the spectrum of model organisms demonstrate that rates of aging are regulated through genetic control of cellular processes. The regulation and subsequent breakdown of cellular processes represent a programmatic decision by the cell to either continue or abandon maintenance procedures with age. Our understanding of cell biological processes involved in regulating aging have been particularly informed by longevity mutants and treatments, such as reduced insulin/IGF-1 signaling and dietary restriction, which are critical in determining the distinction between causes of and responses to aging and have revealed a set of downstream targets that participate in a range of cell biological activities. Here we briefly review some of these important cellular processes.
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Affiliation(s)
- Race DiLoreto
- Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Coleen T Murphy
- Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
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19
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Hieber SE, Bikis C, Khimchenko A, Schweighauser G, Hench J, Chicherova N, Schulz G, Müller B. Tomographic brain imaging with nucleolar detail and automatic cell counting. Sci Rep 2016; 6:32156. [PMID: 27581254 PMCID: PMC5007499 DOI: 10.1038/srep32156] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 07/19/2016] [Indexed: 01/27/2023] Open
Abstract
Brain tissue evaluation is essential for gaining in-depth insight into its diseases and disorders. Imaging the human brain in three dimensions has always been a challenge on the cell level. In vivo methods lack spatial resolution, and optical microscopy has a limited penetration depth. Herein, we show that hard X-ray phase tomography can visualise a volume of up to 43 mm3 of human post mortem or biopsy brain samples, by demonstrating the method on the cerebellum. We automatically identified 5,000 Purkinje cells with an error of less than 5% at their layer and determined the local surface density to 165 cells per mm2 on average. Moreover, we highlight that three-dimensional data allows for the segmentation of sub-cellular structures, including dendritic tree and Purkinje cell nucleoli, without dedicated staining. The method suggests that automatic cell feature quantification of human tissues is feasible in phase tomograms obtained with isotropic resolution in a label-free manner.
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Affiliation(s)
- Simone E Hieber
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland
| | - Christos Bikis
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland
| | - Anna Khimchenko
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland
| | - Gabriel Schweighauser
- Institute of Pathology, Department of Neuropathology, University Hospital of Basel, Schönbeinstrasse 40, 4001 Basel, Switzerland
| | - Jürgen Hench
- Institute of Pathology, Department of Neuropathology, University Hospital of Basel, Schönbeinstrasse 40, 4001 Basel, Switzerland
| | - Natalia Chicherova
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland.,Medical Image Analysis Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland
| | - Georg Schulz
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland
| | - Bert Müller
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland
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20
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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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21
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Koné MC, Fleurot R, Chebrout M, Debey P, Beaujean N, Bonnet-Garnier A. Three-Dimensional Distribution of UBF and Nopp140 in Relationship to Ribosomal DNA Transcription During Mouse Preimplantation Development. Biol Reprod 2016; 94:95. [PMID: 26984997 DOI: 10.1095/biolreprod.115.136366] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 03/08/2016] [Indexed: 12/31/2022] Open
Abstract
The nucleolus is a dynamic nuclear compartment that is mostly involved in ribosome subunit biogenesis; however, it may also play a role in many other biological processes, such as stress response and the cell cycle. Mainly using electron microscopy, several studies have tried to decipher how active nucleoli are set up during early development in mice. In this study, we analyzed nucleologenesis during mouse early embryonic development using 3D-immunofluorescent detection of UBF and Nopp140, two proteins associated with different nucleolar compartments. UBF is a transcription factor that helps maintain the euchromatic state of ribosomal genes; Nopp140 is a phosphoprotein that has been implicated in pre-rRNA processing. First, using detailed image analyses and the in situ proximity ligation assay technique, we demonstrate that UBF and Nopp140 dynamic redistribution between the two-cell and blastocyst stages (time of implantation) is correlated with morphological and structural modifications that occur in embryonic nucleolar compartments. Our results also support the hypothesis that nucleoli develop at the periphery of nucleolar precursor bodies. Finally, we show that the RNA polymerase I inhibitor CX-5461: 1) disrupts transcriptional activity, 2) alters preimplantation development, and 3) leads to a complete reorganization of UBF and Nopp140 distribution. Altogether, our results underscore that highly dynamic changes are occurring in the nucleoli of embryos and confirm a close link between ribosomal gene transcription and nucleologenesis during the early stages of development.
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Affiliation(s)
| | - Renaud Fleurot
- UMR BDR, INRA, ENVA, Université Paris Saclay, Jouy en Josas, France
| | - Martine Chebrout
- UMR BDR, INRA, ENVA, Université Paris Saclay, Jouy en Josas, France
| | - Pascale Debey
- Sorbonne-Universités, MNHN, CNRS, INSERM, Structure et instabilité des génomes, Paris, France
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22
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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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23
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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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Procházková Schrumpfová P, Vychodilová I, Dvořáčková M, Majerská J, Dokládal L, Schořová Š, Fajkus J. Telomere repeat binding proteins are functional components of Arabidopsis telomeres and interact with telomerase. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:770-81. [PMID: 24397874 PMCID: PMC4282523 DOI: 10.1111/tpj.12428] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/06/2013] [Accepted: 12/23/2013] [Indexed: 05/19/2023]
Abstract
Although telomere-binding proteins constitute an essential part of telomeres, in vivo data indicating the existence of a structure similar to mammalian shelterin complex in plants are limited. Partial characterization of a number of candidate proteins has not identified true components of plant shelterin or elucidated their functional mechanisms. Telomere repeat binding (TRB) proteins from Arabidopsis thaliana bind plant telomeric repeats through a Myb domain of the telobox type in vitro, and have been shown to interact with POT1b (Protection of telomeres 1). Here we demonstrate co-localization of TRB1 protein with telomeres in situ using fluorescence microscopy, as well as in vivo interaction using chromatin immunoprecipitation. Classification of the TRB1 protein as a component of plant telomeres is further confirmed by the observation of shortening of telomeres in knockout mutants of the trb1 gene. Moreover, TRB proteins physically interact with plant telomerase catalytic subunits. These findings integrate TRB proteins into the telomeric interactome of A. thaliana.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- *For correspondence (e-mails or )
| | - Ivona Vychodilová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
| | - Martina Dvořáčková
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republicv.v.i, Královopolská 135, Brno, CZ, 61265, Czech Republic
| | - Jana Majerská
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- †Swiss Institute for Experimental Cancer Research, Ecole Polytechnique Fédérale de LausanneStation 19, 1015, Lausanne, Switzerland
| | - Ladislav Dokládal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republicv.v.i, Královopolská 135, Brno, CZ, 61265, Czech Republic
| | - Šárka Schořová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityKamenice 5, Brno, CZ, 62500, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republicv.v.i, Královopolská 135, Brno, CZ, 61265, Czech Republic
- *For correspondence (e-mails or )
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25
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Abstract
The transcription of rRNA is critical to all living cells and is tightly controlled at the level of chromatin structure. Although the widespread adoption of genomic technologies including chromatin immunoprecipitation with massively parallel short-read sequencing (ChIP-seq) has allowed for the interrogation of chromatin structure on a genome-wide scale, until recently rDNA has not been analyzed by this technique. We extended genomic analysis of rDNA to mouse (Mus musculus), in which rDNA is similar in structure but highly divergent in sequence compared with human rDNA. Comparison of rDNA histone marks between mouse embryonic stem cells (mESCs) and more differentiated mouse cell types revealed differences between pluripotent and differentiated states. We also observed substantial divergence in rDNA histone modification patterns between mESCs and human embryonic stem cells (hESCs). Surprisingly, we found that the pluripotency factor OCT4 was bound to rDNA in similar patterns in mESCs and hESCs. Extending this analysis, we found that an additional 17 pluripotency-associated factors were bound to rDNA in mESCs, suggesting novel modes of rDNA regulation in pluripotent cells. Taken together, our results provide a detailed view of rDNA chromatin structure in an important model system and enable high-resolution comparison of rDNA regulation between mouse and human.
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26
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Antoniali G, Lirussi L, Poletto M, Tell G. Emerging roles of the nucleolus in regulating the DNA damage response: the noncanonical DNA repair enzyme APE1/Ref-1 as a paradigmatical example. Antioxid Redox Signal 2014; 20:621-39. [PMID: 23879289 PMCID: PMC3901381 DOI: 10.1089/ars.2013.5491] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 07/22/2013] [Indexed: 12/25/2022]
Abstract
SIGNIFICANCE An emerging concept in DNA repair mechanisms is the evidence that some key enzymes, besides their role in the maintenance of genome stability, display also unexpected noncanonical functions associated with RNA metabolism in specific subcellular districts (e.g., nucleoli). During the evolution of these key enzymes, the acquisition of unfolded domains significantly amplified the possibility to interact with different partners and substrates, possibly explaining their phylogenetic gain of functions. RECENT ADVANCES After nucleolar stress or DNA damage, many DNA repair proteins can freely relocalize from nucleoli to the nucleoplasm. This process may represent a surveillance mechanism to monitor the synthesis and correct assembly of ribosomal units affecting cell cycle progression or inducing p53-mediated apoptosis or senescence. CRITICAL ISSUES A paradigm for this kind of regulation is represented by some enzymes of the DNA base excision repair (BER) pathway, such as apurinic/apyrimidinic endonuclease 1 (APE1). In this review, the role of the nucleolus and the noncanonical functions of the APE1 protein are discussed in light of their possible implications in human pathologies. FUTURE DIRECTIONS A productive cross-talk between DNA repair enzymes and proteins involved in RNA metabolism seems reasonable as the nucleolus is emerging as a dynamic functional hub that coordinates cell growth arrest and DNA repair mechanisms. These findings will drive further analyses on other BER proteins and might imply that nucleic acid processing enzymes are more versatile than originally thought having evolved DNA-targeted functions after a previous life in the early RNA world.
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Affiliation(s)
- Giulia Antoniali
- Department of Medical and Biological Sciences, University of Udine , Udine, Italy
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27
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Balinsky CA, Schmeisser H, Ganesan S, Singh K, Pierson TC, Zoon KC. Nucleolin interacts with the dengue virus capsid protein and plays a role in formation of infectious virus particles. J Virol 2013; 87:13094-106. [PMID: 24027323 PMCID: PMC3838225 DOI: 10.1128/jvi.00704-13] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 09/03/2013] [Indexed: 01/24/2023] Open
Abstract
Dengue virus (DENV) is a mosquito-transmitted flavivirus that can cause severe disease in humans and is considered a reemerging pathogen of significant importance to public health. The DENV capsid (C) protein functions as a structural component of the infectious virion; however, it may have additional functions in the virus replicative cycle. Here, we show that the DENV C protein interacts and colocalizes with the multifunctional host protein nucleolin (NCL). Furthermore, we demonstrate that this interaction can be disrupted by the addition of an NCL binding aptamer (AS1411). Knockdown of NCL with small interfering RNA (siRNA) or treatment of cells with AS1411 results in a significant reduction of viral titers after DENV infection. Western blotting and quantitative RT-PCR (qRT-PCR) analysis revealed no differences in viral RNA or protein levels at early time points postinfection, suggesting a role for NCL in viral morphogenesis. We support this hypothesis by showing that treatment with AS1411 alters the migration characteristics of the viral capsid, as visualized by native electrophoresis. Here, we identify a critical interaction between DENV C protein and NCL that represents a potential new target for the development of antiviral therapeutics.
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Affiliation(s)
- Corey A. Balinsky
- Cytokine Biology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Hana Schmeisser
- Cytokine Biology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Sundar Ganesan
- Biological Imaging Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Kavita Singh
- Structural Biology Unit, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Theodore C. Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Kathryn C. Zoon
- Cytokine Biology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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28
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Duan X, Zhang J, Liu S, Zhang M, Wang Q, Cheng J. Methylation of nucleolar and coiled-body phosphoprotein 1 is associated with the mechanism of tumorigenesis in hepatocellular carcinoma. Oncol Rep 2013; 30:2220-8. [PMID: 23970161 DOI: 10.3892/or.2013.2676] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 06/25/2013] [Indexed: 11/06/2022] Open
Abstract
Nucleolar and coiled-body phosphoprotein 1 (NOLC1) plays an essential role in the synthesis of rRNA and the biosynthesis of ribosomes. Previous studies suggest that NOLC1 is crucial for normal cell growth, and plays a role in the regulation of tumorigenesis of nasopharyngeal carcinoma (NPC) and demonstrate that both NOLC1 and tumor protein 53 work synergistically to activate the MDM2 promoter in NPC cells. Yet, the functioning of NOLC1 in liver cancer remains unknown. The aim of the present study was to understand how the NOLC1 gene is regulated in liver carcinogenesis. In this study, we showed that NOLC1 was silenced or downregulated in liver tumor tissues when compared with that in the matched non-cancer tissues. In addition, human hepatoma cells weakly expressed NOLC1, whereas cultured human normal liver cell lines expressed abundant levels. The hypermethylation status in the promoter CpG1 start region appeared to be correlated with the NOLC1 expression levels in liver cell lines or liver normal and tissue specimens. We found that four CpG dinucleotides were located at the CpG1 start region. Further molecular analysis of mutagenesis indicated that the four CpG dinucleotides play a role in the promoter activity of the NOLC1 gene. The expression of NOLC1 and DNA methylation of its promoter affected cell proliferation and apoptosis. The expression of NOLC1 in hepatoma cell lines was restored following exposure to the demethylation agent, 5-azacytidine. Low expression of NOLC1 in hepatoma cell lines and liver cancer tissues was associated with cyclin D3. In conclusion, our study demonstrated that DNA methylation is a key mechanism of silenced NOLC1 expression in human hepatocellular carcinoma cells, and NOLC1 gene hypermethylation of the four CpG dinucleotides is a potential biomarker for hepatocellular carcinoma.
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Affiliation(s)
- Xuefei Duan
- Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, P.R. China
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29
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Lee B, Jin S, Choi H, Kwon JT, Kim J, Jeong J, Kwon YI, Cho C. Expression and function of the testis-predominant protein LYAR in mice. Mol Cells 2013; 35:54-60. [PMID: 23212345 PMCID: PMC3887849 DOI: 10.1007/s10059-013-2271-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/13/2012] [Accepted: 11/14/2012] [Indexed: 11/28/2022] Open
Abstract
Mammalian spermatogenesis is a complex process involving an intrinsic genetic program of germ cell-specific and -predominant genes. In the present study, we analyzed the Ly-1 reactive clone (Lyar) gene in the mouse. Lyar, which is known to be expressed abundantly in the testis, encodes a nucleolar protein that contains a LYAR-type C2HC zinc finger motif and three nuclear localization signals. We herein confirmed that Lyar is expressed predominantly in the testis, and further showed that this expression is specific to germ cells. Protein analyses with an anti-LYAR antibody demonstrated that the LYAR protein is present in spermatocytes and spermatids, but not in sperm. To assess the functional role of LYAR in vivo, we used a genetrap mutagenesis approach to establish a LYAR-null mouse model. Lyar mutant mice were born live and developed normally. Male mutant mice lacking LYAR were fully fertile and showed intact spermatogenesis. Taken together, our results demonstrate that LYAR is strongly preferred in male germ cells, but has a dispensable role in spermatogenesis and fertility.
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Affiliation(s)
- Boyeon Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | - Sora Jin
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | - Heejin Choi
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | - Jun Tae Kwon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | - Jihye Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | - Juri Jeong
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
| | | | - Chunghee Cho
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712,
Korea
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30
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Jarboui MA, Bidoia C, Woods E, Roe B, Wynne K, Elia G, Hall WW, Gautier VW. Nucleolar protein trafficking in response to HIV-1 Tat: rewiring the nucleolus. PLoS One 2012; 7:e48702. [PMID: 23166591 PMCID: PMC3499507 DOI: 10.1371/journal.pone.0048702] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 10/03/2012] [Indexed: 12/20/2022] Open
Abstract
The trans-activator Tat protein is a viral regulatory protein essential for HIV-1 replication. Tat trafficks to the nucleoplasm and the nucleolus. The nucleolus, a highly dynamic and structured membrane-less sub-nuclear compartment, is the site of rRNA and ribosome biogenesis and is involved in numerous cellular functions including transcriptional regulation, cell cycle control and viral infection. Importantly, transient nucleolar trafficking of both Tat and HIV-1 viral transcripts are critical in HIV-1 replication, however, the role(s) of the nucleolus in HIV-1 replication remains unclear. To better understand how the interaction of Tat with the nucleolar machinery contributes to HIV-1 pathogenesis, we investigated the quantitative changes in the composition of the nucleolar proteome of Jurkat T-cells stably expressing HIV-1 Tat fused to a TAP tag. Using an organellar proteomic approach based on mass spectrometry, coupled with Stable Isotope Labelling in Cell culture (SILAC), we quantified 520 proteins, including 49 proteins showing significant changes in abundance in Jurkat T-cell nucleolus upon Tat expression. Numerous proteins exhibiting a fold change were well characterised Tat interactors and/or known to be critical for HIV-1 replication. This suggests that the spatial control and subcellular compartimentaliation of these cellular cofactors by Tat provide an additional layer of control for regulating cellular machinery involved in HIV-1 pathogenesis. Pathway analysis and network reconstruction revealed that Tat expression specifically resulted in the nucleolar enrichment of proteins collectively participating in ribosomal biogenesis, protein homeostasis, metabolic pathways including glycolytic, pentose phosphate, nucleotides and amino acids biosynthetic pathways, stress response, T-cell signaling pathways and genome integrity. We present here the first differential profiling of the nucleolar proteome of T-cells expressing HIV-1 Tat. We discuss how these proteins collectively participate in interconnected networks converging to adapt the nucleolus dynamic activities, which favor host biosynthetic activities and may contribute to create a cellular environment supporting robust HIV-1 production.
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Affiliation(s)
- Mohamed Ali Jarboui
- Centre for Research in Infectious Diseases (CRID), School of Medicine and Medical Science (SMMS), University College Dublin (UCD), Dublin, Ireland
| | - Carlo Bidoia
- Centre for Research in Infectious Diseases (CRID), School of Medicine and Medical Science (SMMS), University College Dublin (UCD), Dublin, Ireland
| | - Elena Woods
- Centre for Research in Infectious Diseases (CRID), School of Medicine and Medical Science (SMMS), University College Dublin (UCD), Dublin, Ireland
| | - Barbara Roe
- Centre for Research in Infectious Diseases (CRID), School of Medicine and Medical Science (SMMS), University College Dublin (UCD), Dublin, Ireland
| | - Kieran Wynne
- Mass Spectrometry Resource (MSR), Conway Institute for Biomolecular and Biomedical Research, University College Dublin (UCD), Dublin, Ireland
| | - Giuliano Elia
- Mass Spectrometry Resource (MSR), Conway Institute for Biomolecular and Biomedical Research, University College Dublin (UCD), Dublin, Ireland
| | - William W. Hall
- Centre for Research in Infectious Diseases (CRID), School of Medicine and Medical Science (SMMS), University College Dublin (UCD), Dublin, Ireland
| | - Virginie W. Gautier
- Centre for Research in Infectious Diseases (CRID), School of Medicine and Medical Science (SMMS), University College Dublin (UCD), Dublin, Ireland
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31
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Abstract
The nucleolus is a distinct subnuclear compartment known as the site for ribosome biogenesis in eukaryotes. Consequently, the nucleolus is also proposed to function in cell-cycle control, stress sensing and senescence, as well as in viral infection. An increasing number of viral proteins have been found to localize to the nucleolus. In this article, we review the current understanding of the functions of the nucleolus, the molecular mechanism of cellular and viral protein targeting to the nucleolus and the functional roles of the nucleolus during viral infection with a specific focus on the herpesvirus family.
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Affiliation(s)
- Liwen Ni
- Molecular Virology and Viral Immunology Research Group, State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Shuai Wang
- Molecular Virology and Viral Immunology Research Group, State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Chunfu Zheng
- Molecular Virology and Viral Immunology Research Group, State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
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32
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Kihira S, Yu EJ, Cunningham J, Cram EJ, Lee M. A novel mutation in β integrin reveals an integrin-mediated interaction between the extracellular matrix and cki-1/p27KIP1. PLoS One 2012; 7:e42425. [PMID: 22879977 PMCID: PMC3412830 DOI: 10.1371/journal.pone.0042425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 07/09/2012] [Indexed: 01/20/2023] Open
Abstract
The cell-extracellular matrix (ECM) interaction plays an essential role in maintaining tissue shapes and regulates cell behaviors such as cell adhesion, differentiation and proliferation. The mechanism by which the ECM influences the cell cycle in vivo is poorly understood. Here we demonstrate that the β integrin PAT-3 regulates the localization and expression of CKI-1, a C. elegans homologue of the cyclin dependent kinase inhibitor p27(KIP1). In nematodes expressing wild type PAT-3, CKI-1::GFP localizes primarily to nucleoli in hypodermal cells, whereas in animals expressing mutant pat-3 with a defective splice junction, CKI-1::GFP appears clumped and disorganized in nucleoplasm. RNAi analysis links cell adhesion genes to the regulation of CKI-1. RNAi of unc-52/perlecan, ina-1/α integrin, pat-4/ILK, and unc-97/PINCH resulted in abnormal CKI-1::GFP localization. Additional RNAi experiments revealed that the SCF E3 ubiquitin-ligase complex genes, skpt-1/SKP2, cul-1/CUL1 and lin-23/F-box, are required for the proper localization and expression of CKI-1, suggesting that integrin signaling and SCF E3 ligase work together to regulate the cellular distribution of CKI-1. These data also suggest that integrin plays a major role in maintaining proper CKI-1/p27(KIP1) levels in the cell. Perturbed integrin signaling may lead to the inhibition of SCF ligase activity, mislocalization and elevation of CKI-1/p27(KIP1). These results suggest that adhesion signaling is crucial for cell cycle regulation in vivo.
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Affiliation(s)
- Shingo Kihira
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Eun Jeong Yu
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Jessica Cunningham
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Erin J. Cram
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Myeongwoo Lee
- Department of Biology, Baylor University, Waco, Texas, United States of America
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33
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Abstract
Nucleolin is a multifunctional protein localized primarily in the nucleolus, but also found in the nucleoplasm, cytoplasm and cell membrane. It is involved in several aspects of DNA metabolism, and participates extensively in RNA regulatory mechanisms, including transcription, ribosome assembly, mRNA stability and translation, and microRNA processing. Nucleolin's implication in disease is linked to its ability to associate with target RNAs via its four RNA-binding domains and its arginine/glycin-rich domain. By modulating the post-transcriptional fate of target mRNAs, which typically bear AU-rich and/or G-rich elements, nucleolin has been linked to cellular events that influence disease, notably cell proliferation and protection against apoptotic death. Through its diverse RNA functions, nucleolin is increasingly implicated in pathological processes, particularly cancer and viral infection. Here, we review the RNA-binding activities of nucleolin, its influence on gene expression patterns, and its impact upon diseases. We also discuss the rising interest in targeting nucleolin therapeutically.
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Affiliation(s)
- Kotb Abdelmohsen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD, USA.
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34
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The nucleolus of Caenorhabditis elegans. J Biomed Biotechnol 2012; 2012:601274. [PMID: 22577294 PMCID: PMC3345250 DOI: 10.1155/2012/601274] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 12/15/2011] [Accepted: 01/09/2012] [Indexed: 12/31/2022] Open
Abstract
Nucleolar size and appearance correlate with ribosome biogenesis and cellular activity. The mechanisms underlying changes in nucleolar appearance and regulation of nucleolar size that occur during differentiation and cell cycle progression are not well understood. Caenorhabditis elegans provides a good model for studying these processes because of its small size and transparent body, well-characterized cell types and lineages, and because its cells display various sizes of nucleoli. This paper details the advantages of using C. elegans to investigate features of the nucleolus during the organism's development by following dynamic changes in fibrillarin (FIB-1) in the cells of early embryos and aged worms. This paper also illustrates the involvement of the ncl-1 gene and other possible candidate genes in nucleolar-size control. Lastly, we summarize the ribosomal proteins involved in life span and innate immunity, and those homologous genes that correspond to human disorders of ribosomopathy.
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35
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Abstract
Inositol serves as a module for the generation of a high level of molecular diversity through the combinatorial attachment and removal of phosphate groups. The array of potential inositol-containing molecules is further expanded by the generation of diphospho inositol polyphosphates, commonly referred as inositol pyrophosphates. All eukaryotic cells possess inositol pyrophosphates containing one or more diphospho- moieties. The metabolism of this class of molecules is highly dynamic, and the enzymes responsible for their metabolism are evolutionary conserved. This new, exciting class of molecules are uniquely chracterized by a high energetic diphospho- bound that is able to participate in phosphotrasfer reactions thereby generating pyrophosphorylation of protein. However, allosteric mechanisms of action have been also proposed. In the past decade several disparate nuclear and cytoplasmic functions have been attributed to inositol pyrophosphates, ranging from intracellular trafficking to telomere length control and from regulating apoptotic process to stimulating insulin secretion. The extraordinary range of cellular function controlled by inositol pyrophosphate underline their great importance.
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Affiliation(s)
- Adolfo Saiardi
- MRC-LMCB, Department of Cell and Developmental Biology, University College London, Gower Street, WC1E 6BT, London, UK,
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36
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Tajrishi MM, Tuteja R, Tuteja N. Nucleolin: The most abundant multifunctional phosphoprotein of nucleolus. Commun Integr Biol 2011; 4:267-75. [PMID: 21980556 DOI: 10.4161/cib.4.3.14884] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 01/18/2011] [Indexed: 01/08/2023] Open
Abstract
Nucleolin is a multifunctional phosphoprotein ubiquitously distributed in the nucleolus, nucleus and cytoplasm of the cell. Nucleolin has a bipartite nuclear localization signal sequence and is conserved in animals, plants and yeast. Its levels are correlated with the rate of functional activity of the nucleolus in exponentially growing cells. Nucleolin contains intrinsic DNA and RNA helicase, nucleic-acid-dependent ATPase and self-cleaving activities. It binds RNA through its RNA recognition motifs. It regulates various aspects of DNA and RNA metabolism, chromatin structure, rDNA transcription, rRNA maturation, cytokinesis, nucleogenesis, cell proliferation and growth, the folding, maturation and ribosome assembly and nucleocytoplasmic transport of newly synthesized pre-RNAs. In this review we present an overview on nucleolin, its localization, structure and various functions. We also describe the discovery and important studies of nucleolin in plants.
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Affiliation(s)
- Marjan M Tajrishi
- International Center for Genetic Engineering and Biotechnology; Aruna Asaf Ali Marg; New Delhi, Delhi India
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37
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Abbasi N, Kim HB, Park NI, Kim HS, Kim YK, Park YI, Choi SB. APUM23, a nucleolar Puf domain protein, is involved in pre-ribosomal RNA processing and normal growth patterning in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:960-76. [PMID: 21143677 DOI: 10.1111/j.1365-313x.2010.04393.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Pumilio, an RNA-binding protein that contains tandemly repeated Puf domains, is known to repress translational activity in early embryogenesis and polarized cells of non-plant species. Although Pumilio proteins have been characterized in many eukaryotes, their role in plants is unknown. In the present study, we characterized an Arabidopsis Pumilio-encoding gene, APUM23. APUM23 is constitutively expressed, with higher levels in metabolically active tissues, and its expression is up-regulated in the presence of either glucose or sucrose. The T-DNA insertion mutants apum23-1 and apum23-2 showed slow growth, with serrated and scrunched leaves, an abnormal venation pattern, and distorted organization of the palisade parenchyma cells - a phenotype that is reminiscent of nucleolin and ribosomal protein gene mutants. Intracellular localization studies indicate that APUM23 predominantly localizes to the nucleolus. Based on this localization, rRNA processing was examined. In apum23, 35S pre-rRNA, and unprocessed 18S and 5.8S poly(A) rRNAs, accumulated without affecting the steady-state levels of mature rRNAs, indicating that APUM23 is involved in the processing and/or degradation of 35S pre-rRNA and rRNA maturation by-products. The apum23 mutant showed increased levels of 18S rRNA biogenesis-related U3 and U14 small nucleolar RNAs (snoRNAs) and accumulated RNAs within the nucleolus. Our data suggest that APUM23 plays an important role in plant development via rRNA processing.
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Affiliation(s)
- Nazia Abbasi
- School of Biotechnology and Environmental Engineering, Myongji University, Yongin, Kyunggi-do 449-728, South Korea
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38
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Abstract
Nucleolus is the most prominent subnuclear structure, which performs a wide variety of functions in the eukaryotic cellular processes. In order to understand the structural and functional role of the nucleoli in bovine cells, we analyzed the proteomic composition of the bovine nucleoli. The nucleoli were isolated from Madin Darby bovine kidney cells and subjected to proteomic analysis by LC-MS/MS after fractionation by SDS-PAGE and strong cation exchange chromatography. Analysis of the data using the Mascot database search and the GPM database search identified 311 proteins in the bovine nucleoli, which contained 22 proteins previously not identified in the proteomic analysis of human nucleoli. Analysis of the identified proteins using the GoMiner software suggested that the bovine nucleoli contained proteins involved in ribosomal biogenesis, cell cycle control, transcriptional, translational and post-translational regulation, transport, and structural organization.
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Affiliation(s)
- Amrutlal K. Patel
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Canada
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Doug Olson
- National Research Council, Plant Biotechnology Institute, University of Saskatchewan, Saskatoon, Canada
| | - Suresh K. Tikoo
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Canada
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
- School of Public Health, University of Saskatchewan, Saskatoon, Canada
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39
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The chromosome peripheral proteins play an active role in chromosome dynamics. Biomol Concepts 2010; 1:157-64. [DOI: 10.1515/bmc.2010.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
AbstractThe chromosome periphery is a chromosomal structure that covers the surface of mitotic chromosomes. The structure and function of the chromosome periphery has been poorly understood since its first description in 1882. It has, however, been proposed to be an insulator or barrier to protect chromosomes from subcellular substances and to act as a carrier of nuclear and nucleolar components to direct their equal distribution to daughter cells because most chromosome peripheral proteins (CPPs) are derived from the nucleolus or nucleus. Until now, more than 30 CPPs were identified in mammalians. Recent immunostaining analyses of CPPs have revealed that the chromosome periphery covers the centromeric region of mitotic chromosomes in addition to telomeres and regions between two sister chromatids. Knockdown analyses of CPPs using RNAi have revealed functions in chromosome dynamics, including cohesion of sister chromatids, kinetochore-microtubule attachments, spindle assembly and chromosome segregation. Because most CPPs are involved in various subcellular events in the nucleolus or nuclear at interphase, a temporal and spatial-specific knockdown method of CPPs in the chromosome periphery will be useful to understand the function of chromosome periphery in cell division.
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Bański P, Mahboubi H, Kodiha M, Shrivastava S, Kanagaratham C, Stochaj U. Nucleolar targeting of the chaperone hsc70 is regulated by stress, cell signaling, and a composite targeting signal which is controlled by autoinhibition. J Biol Chem 2010; 285:21858-67. [PMID: 20457599 DOI: 10.1074/jbc.m110.117291] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hsc70s are constitutively synthesized members of the 70-kDa chaperone family; they are essential for viability and conserved among all organisms. When eukaryotic cells recover from stress, hsc70s accumulate in nucleoli by an unknown mechanism. Our studies were undertaken to characterize the signaling events and the targeting sequence required to concentrate hsc70 in the nucleoli of human cells. Here, we show that pharmacological inhibitors of phosphatidylinositol (PI) 3-kinase and MEK kinases as well as protein-tyrosine phosphatases abolished the stress-dependent nucleolar accumulation of hsc70. Furthermore, to identify the hsc70 nucleolar targeting sequence, green fluorescent protein-tagged fusion proteins with defined segments of hsc70 were generated and their subcellular distribution was analyzed in growing cells. These studies demonstrated that residues 225 to 297 serve as a heat-inducible nucleolar targeting signal. This segment directs green fluorescent protein to nucleoli in response to stress, but fails to do so under nonstress conditions. Fine mapping of the nucleolar targeting signal revealed that it has two separable functions. First, residues 225 to 262 direct reporter proteins constitutively to nucleoli, even without stress. Second, segment 263 to 287 functions as an autoinhibitory element that prevents hsc70 from concentrating in nucleoli when cells are not stressed. Taken together, PI 3-kinase and MEK kinase signaling as well as tyrosine dephosphorylation are essential for the accumulation of hsc70 in nucleoli of stressed cells. This process relies on a stress-dependent composite targeting signal that combines multiple functions.
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Affiliation(s)
- Piotr Bański
- Department of Physiology, McGill University, Montreal H3G 1Y6, Canada
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41
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Soft X-ray tomography of phenotypic switching and the cellular response to antifungal peptoids in Candida albicans. Proc Natl Acad Sci U S A 2009; 106:19375-80. [PMID: 19880740 DOI: 10.1073/pnas.0906145106] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The opportunistic pathogen Candida albicans can undergo phenotypic switching between a benign, unicellular phenotype and an invasive, multicellular form that causes candidiasis. Increasingly, strains of Candida are becoming resistant to antifungal drugs, making the treatment of candidiasis difficult, especially in immunocompromised or critically ill patients. Consequently, there is a pressing need to develop new drugs that circumvent fungal drug-resistance mechanisms. In this work we used soft X-ray tomography to image the subcellular changes that occur as a consequence of both phenotypic switching and of treating C. albicans with antifungal peptoids, a class of candidate therapeutics unaffected by drug resistance mechanisms. Peptoid treatment suppressed formation of the pathogenic hyphal phenotype and resulted in striking changes in cell and organelle morphology, most dramatically in the nucleus and nucleolus, and in the number, size, and location of lipidic bodies. In particular, peptoid treatment was seen to cause the inclusion of lipidic bodies into the nucleus.
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Hwang YC, Lu TY, Huang DY, Kuo YS, Kao CF, Yeh NH, Wu HC, Lin CT. NOLC1, an enhancer of nasopharyngeal carcinoma progression, is essential for TP53 to regulate MDM2 expression. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:342-54. [PMID: 19541936 PMCID: PMC2708820 DOI: 10.2353/ajpath.2009.080931] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/19/2009] [Indexed: 11/20/2022]
Abstract
Nasopharyngeal carcinoma (NPC) is one of the most common cancers among Chinese living in South China, Singapore, and Taiwan. At present, its etiological factors are not well defined. To identify which genetic alterations might be involved in NPC pathogenesis, we identified genes that were differentially expressed in NPC cell lines and normal nasomucosal cells using subtractive hybridization and microarray analysis. Most NPC cell lines and biopsy specimens were found to have higher expression levels of the gene encoding nucleolar and coiled-body phosphoprotein 1 (NOLC1) as compared with normal cells. Severe combined immunodeficiency mice bearing NPC xenografts derived from NOLC1-short hairpin-RNA-transfected animals were found to have 82% lower levels of tumor growth than control mice as well as marked tumor cell apoptosis. Measuring the expression levels of genes related to cell growth, apoptosis, and angiogenesis, we found that the MDM2 gene was down-regulated in the transfectants. Both co-transfection and chromatin immunoprecipitation experiments showed that tumor protein 53-regulated expression of the MDM2 gene requires co-activation of NOLC1. These findings suggest that NOLC1 plays a role in the regulation of tumorigenesis of NPC and demonstrate that both NOLC1 and tumor protein 53 work together synergistically to activate the MDM2 promoter in NPC cells.
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Affiliation(s)
- Yu-Chyi Hwang
- Institute of Pathology,College of Medicine, NationalTaiwan University, Taipei, Taiwan
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43
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Han Z, Alves C, Gudima S, Taylor J. Intracellular localization of hepatitis delta virus proteins in the presence and absence of viral RNA accumulation. J Virol 2009; 83:6457-63. [PMID: 19369324 PMCID: PMC2698582 DOI: 10.1128/jvi.00008-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2009] [Accepted: 04/11/2009] [Indexed: 02/08/2023] Open
Abstract
Hepatitis delta virus (HDV) encodes one protein, hepatitis delta antigen (deltaAg), a 195-amino-acid RNA binding protein essential for the accumulation of HDV RNA-directed RNA transcripts. It has been accepted that deltaAg localizes predominantly to the nucleolus in the absence of HDV genome replication while in the presence of replication, deltaAg facilitates HDV RNA transport to the nucleoplasm and helps redirect host RNA polymerase II (Pol II) to achieve transcription and accumulation of processed HDV RNA species. This study used immunostaining and confocal microscopy to evaluate factors controlling the localization of deltaAg in the presence and absence of replicating and nonreplicating HDV RNAs. When deltaAg was expressed in the absence of full-length HDV RNAs, it colocalized with nucleolin, a predominant nucleolar protein. With time, or more quickly after induced cell stress, there was a redistribution of both deltaAg and nucleolin to the nucleoplasm. Following expression of nonreplicating HDV RNAs, deltaAg moved to the nucleoplasm, but nucleolin was unchanged. When deltaAg was expressed along with replicating HDV RNA, it was found predominantly in the nucleoplasm along with Pol II. This localization was insensitive to inhibitors of HDV replication, suggesting that the majority of deltaAg in the nucleoplasm reflects ribonucleoprotein accumulation rather than ongoing transcription. An additional approach was to reevaluate several forms of deltaAg altered at specific locations considered to be essential for protein function. These studies provide evidence that deltaAg does not interact directly with either Pol II or nucleolin and that forms of deltaAg which support replication are also capable of prior nucleolar transit.
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Affiliation(s)
- Ziying Han
- Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111-2497, USA
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Fähling M. Cellular oxygen sensing, signalling and how to survive translational arrest in hypoxia. Acta Physiol (Oxf) 2009; 195:205-30. [PMID: 18764866 DOI: 10.1111/j.1748-1716.2008.01894.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Hypoxia is a consequence of inadequate oxygen availability. At the cellular level, lowered oxygen concentration activates signal cascades including numerous receptors, ion channels, second messengers, as well as several protein kinases and phosphatases. This, in turn, activates trans-factors like transcription factors, RNA-binding proteins and miRNAs, mediating an alteration in gene expression control. Each cell type has its unique constellation of oxygen sensors, couplers and effectors that determine the activation and predominance of several independent hypoxia-sensitive pathways. Hence, altered gene expression patterns in hypoxia result from a complex regulatory network with multiple divergences and convergences. Although hundreds of genes are activated by transcriptional control in hypoxia, metabolic rate depression, as a consequence of reduced ATP level, causes inhibition of mRNA translation. In a multi-phase response to hypoxia, global protein synthesis is suppressed, mainly by phosphorylation of eIF2-alpha by PERK and inhibition of mTOR, causing suppression of 5'-cap-dependent mRNA translation. Growing evidence suggests that mRNAs undergo sorting at stress granules, which determines the fate of mRNA as to whether being translated, stored, or degraded. Data indicate that translation is suppressed only at 'free' polysomes, but is active at subsets of membrane-bound ribosomes. The recruitment of specific mRNAs into subcellular compartments seems to be crucial for local mRNA translation in prolonged hypoxia. Furthermore, ribosomes themselves may play a significant role in targeting mRNAs for translation. This review summarizes the multiple facets of the cellular adaptation to hypoxia observed in mammals.
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Affiliation(s)
- M Fähling
- Institut für Vegetative Physiologie, Charité, Universitätsmedizin Berlin, Berlin, Germany.
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45
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46
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Abstract
NPM (nucleophosmin; also known as B23) is an abundantly and ubiquitously expressed multifunctional nucleolar phosphoprotein, which is involved in numerous cellular processes, including ribosome biogenesis, protein chaperoning and centrosome duplication; however, the role of NPM in the cell cycle still remains unknown. In the present study, we show dynamic localization of NPM throughout the cell cycle of HeLa cells. Using a combination of RNAi (RNA interference) and three-dimensional microscopy we show that NPM is localized at the chromosome periphery during mitosis. We also demonstrate that depletion of NPM causes distortion of nucleolar structure as expected and leads to unexpected dramatic changes in nuclear morphology with multiple micronuclei formation. The defect in nuclear shape of NPM-depleted cells, which is clearly observed by live-cell imaging, is due to the distortion of cytoskeletal (alpha-tubulin and beta-actin) structure, resulting from the defects in centrosomal microtubule nucleation. These results indicate that NPM is an essential protein not only for the formation of normal nucleolar structure, but also for the maintenance of regular nuclear shape in HeLa cells.
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47
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Ugrinova I, Monier K, Ivaldi C, Thiry M, Storck S, Mongelard F, Bouvet P. Inactivation of nucleolin leads to nucleolar disruption, cell cycle arrest and defects in centrosome duplication. BMC Mol Biol 2007; 8:66. [PMID: 17692122 PMCID: PMC1976620 DOI: 10.1186/1471-2199-8-66] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 08/10/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nucleolin is a major component of the nucleolus, but is also found in other cell compartments. This protein is involved in various aspects of ribosome biogenesis from transcription regulation to the assembly of pre-ribosomal particles; however, many reports suggest that it could also play an important role in non nucleolar functions. To explore nucleolin function in cell proliferation and cell cycle regulation we used siRNA to down regulate the expression of nucleolin. RESULTS We found that, in addition to the expected effects on pre-ribosomal RNA accumulation and nucleolar structure, the absence of nucleolin results in a cell growth arrest, accumulation in G2, and an increase of apoptosis. Numerous nuclear alterations, including the presence of micronuclei, multiple nuclei or large nuclei are also observed. In addition, a large number of mitotic cells showed a defect in the control of centrosome duplication, as indicated by the presence of more than 2 centrosomes per cell associated with a multipolar spindle structure in the absence of nucleolin. This phenotype is very similar to that obtained with the inactivation of another nucleolar protein, B23. CONCLUSION Our findings uncovered a new role for nucleolin in cell division, and highlight the importance of nucleolar proteins for centrosome duplication.
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Affiliation(s)
- Iva Ugrinova
- Laboratory Joliot-Curie, CNRS USR 3010, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
- Laboratory of molecular biology of the cell, CNRS UMR 5239, IFR128 Biosciences, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
| | - Karine Monier
- Laboratory of molecular biology of the cell, CNRS UMR 5239, IFR128 Biosciences, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
| | - Corinne Ivaldi
- Laboratory Joliot-Curie, CNRS USR 3010, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
- Laboratory of molecular biology of the cell, CNRS UMR 5239, IFR128 Biosciences, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
| | - Marc Thiry
- Laboratory of Cell Biology, Department of Life Sciences, Faculty of Sciences, University of Liege, Liege, Belgium
| | - Sébastien Storck
- Laboratory Joliot-Curie, CNRS USR 3010, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
- Laboratory of molecular biology of the cell, CNRS UMR 5239, IFR128 Biosciences, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
| | - Fabien Mongelard
- Laboratory Joliot-Curie, CNRS USR 3010, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
- Laboratory of molecular biology of the cell, CNRS UMR 5239, IFR128 Biosciences, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
| | - Philippe Bouvet
- Laboratory Joliot-Curie, CNRS USR 3010, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
- Laboratory of molecular biology of the cell, CNRS UMR 5239, IFR128 Biosciences, University of Lyon, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon, France
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48
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Fähling M, Mrowka R, Steege A, Nebrich G, Perlewitz A, Persson PB, Thiele BJ. Translational control of collagen prolyl 4-hydroxylase-alpha(I) gene expression under hypoxia. J Biol Chem 2006; 281:26089-101. [PMID: 16837461 DOI: 10.1074/jbc.m604939200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Hypoxia is a pro-fibrotic stimulus, which is associated with enhanced collagen synthesis, as well as with augmented collagen prolyl 4-hydroxylase (C-P4H) activity. C-P4H activity is controlled mainly by regulated expression of the alpha C-P4H subunit. In this study we demonstrate that the increased synthesis of C-P4H-alpha(I) protein in human HT1080 fibroblasts under long term hypoxia (36 h, 1% oxygen) is controlled at the translational level. This is mediated by an interaction of RNA-binding protein nucleolin (approximately 64 kDa form) at the 5'- and 3'-untranslated regions (UTR) of the mRNA. The 5'/3'-UTR-dependent mechanism elevates the C-P4H-alpha(I) expression rate 2.3-fold, and participates in a 5.3-fold increased protein level under long term hypoxia. The interaction of nucleolin at the 5'-UTR occurs directly and depends on the existence of an AU-rich element. Statistical evaluation of the approximately 64-kDa nucleolin/RNA interaction studies revealed a core binding sequence, corresponding to UAAAUC or AAAUCU. At the 3'-UTR, nucleolin assembles indirectly via protein/protein interaction, with the help of another 3'-UTR-binding protein, presumably annexin A2. The increased protein level of the approximately 64-kDa nucleolin under hypoxia can be attributed to an autocatalytic cleavage of a high molecular weight nucleolin form, without alterations in nucleolin mRNA concentration. Thus, the alteration of translational efficiency by nucleolin, which occurs through a hypoxia inducible factor independent pathway, is an important step in C-P4H-alpha(I) regulation under hypoxia.
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Affiliation(s)
- Michael Fähling
- Charité, Universitätsmedizin Berlin, Institut für Vegetative Physiologie, D-10117 Berlin, Germany.
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