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da Mota THA, Camargo R, Biojone ER, Guimarães AFR, Pittella-Silva F, de Oliveira DM. The Relevance of Telomerase and Telomere-Associated Proteins in B-Acute Lymphoblastic Leukemia. Genes (Basel) 2023; 14:genes14030691. [PMID: 36980962 PMCID: PMC10048576 DOI: 10.3390/genes14030691] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/04/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023] Open
Abstract
Telomeres and telomerase are closely linked to uncontrolled cellular proliferation, immortalization and carcinogenesis. Telomerase has been largely studied in the context of cancer, including leukemias. Deregulation of human telomerase gene hTERT is a well-established step in leukemia development. B-acute lymphoblastic leukemia (B-ALL) recovery rates exceed 90% in children; however, the relapse rate is around 20% among treated patients, and 10% of these are still incurable. This review highlights the biological and clinical relevance of telomerase for B-ALL and the implications of its canonical and non-canonical action on signaling pathways in the context of disease and treatment. The physiological role of telomerase in lymphocytes makes the study of its biomarker potential a great challenge. Nevertheless, many works have demonstrated that high telomerase activity or hTERT expression, as well as short telomeres, correlate with poor prognosis in B-ALL. Telomerase and related proteins have been proven to be promising pharmacological targets. Likewise, combined therapy with telomerase inhibitors may turn out to be an alternative strategy for B-ALL.
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Affiliation(s)
- Tales Henrique Andrade da Mota
- Laboratory of Molecular Pathology of Cancer, University of Brasilia, Brasilia 70910-900, Brazil
- Laboratory of Molecular Analysis, Faculty of Ceilândia, University of Brasilia, Brasilia 72220-275, Brazil
- Correspondence:
| | - Ricardo Camargo
- Brasília Children’s Hospital José Alencar, Brasilia 70684-831, Brazil
| | | | - Ana Flávia Reis Guimarães
- Laboratory of Molecular Analysis, Faculty of Ceilândia, University of Brasilia, Brasilia 72220-275, Brazil
| | - Fabio Pittella-Silva
- Laboratory of Molecular Pathology of Cancer, University of Brasilia, Brasilia 70910-900, Brazil
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Novakov V, Novakova O, Churnosova M, Sorokina I, Aristova I, Polonikov A, Reshetnikov E, Churnosov M. Intergenic Interactions of SBNO1, NFAT5 and GLT8D1 Determine the Susceptibility to Knee Osteoarthritis among Europeans of Russia. Life (Basel) 2023; 13:life13020405. [PMID: 36836762 PMCID: PMC9960278 DOI: 10.3390/life13020405] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
This study was conducted to examine the associations between genome-wide association studies (GWAS)-important single nucleotide polymorphisms (SNPs) and knee osteoarthritis (KOA) among Europeans of Russia. The present replicative study ("patient-control" design has been used) was carried out on 1000 DNA samples from KOA (n = 500) and KOA-free (n = 500) participants. Ten GWAS-important for KOA SNPs of eight candidate genes (LYPLAL1, GNL3, GLT8D1, SBNO1, WWP2, NFAT5, TGFA, GDF5) were studied. To assess the link between SNPs and KOA susceptibility, logistic regression (to establish independent SNP effects) and MB-MDR (to identify SNP-SNP interactions) were used. As a result of this genetic analysis, the associations of individual SNPs with KOA have not been proven. Eight loci out of ten tested SNPs interacted with each other (within twelve genetic models) and determined susceptibility to KOA. The greatest contribution to the disease development were made by three polymorphisms/genes such as rs6976 (C>T) GLT8D1, rs56116847 (G>A) SBNO1, rs6499244 (T>A) NFAT5 (each was included in 2/3 [8 out 12] KOA-responsible genetic interaction models). A two-locus epistatic interaction of rs56116847 (G >A) SBNO1 × rs6499244 (T>A) NFAT5 determined the maximum percentage (0.86%) of KOA entropy. KOA-associated SNPs are regulatory polymorphisms that affect the expression/splicing level, epigenetic modification of 72 genes in KOA-pathogenetically significant organs such as skeletal muscles, tibial arteries/nerves, thyroid, adipose tissue, etc. These putative KOA-effector genes are mainly involved in the organization/activity of the exoribonuclease complex and antigen processing/presentation pathways. In conclusion, KOA susceptibility among Europeans of Russia is mediated by intergenic interactions (but not the main effects) of GWAS-important SNPs.
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Affiliation(s)
- Vitaly Novakov
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
| | - Olga Novakova
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
| | - Maria Churnosova
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
| | - Inna Sorokina
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
| | - Inna Aristova
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
| | - Alexey Polonikov
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
- Department of Biology, Medical Genetics and Ecology and Research Institute for Genetic and Molecular Epidemiology, Kursk State Medical University, 305041 Kursk, Russia
| | - Evgeny Reshetnikov
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
| | - Mikhail Churnosov
- Department of Medical Biological Disciplines, Belgorod State National Research University, 308015 Belgorod, Russia
- Correspondence:
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Thompson CA, Wong JM. Non-canonical Functions of Telomerase Reverse Transcriptase: Emerging Roles and Biological Relevance. Curr Top Med Chem 2020; 20:498-507. [DOI: 10.2174/1568026620666200131125110] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/10/2020] [Accepted: 01/21/2020] [Indexed: 12/11/2022]
Abstract
Increasing evidence from research on telomerase suggests that in addition to its catalytic telomere
repeat synthesis activity, telomerase may have other biologically important functions. The canonical
roles of telomerase are at the telomere ends where they elongate telomeres and maintain genomic
stability and cellular lifespan. The catalytic protein component Telomerase Reverse Transcriptase
(TERT) is preferentially expressed at high levels in cancer cells despite the existence of an alternative
mechanism for telomere maintenance (alternative lengthening of telomeres or ALT). TERT is also expressed
at higher levels than necessary for maintaining functional telomere length, suggesting other possible
adaptive functions. Emerging non-canonical roles of TERT include regulation of non-telomeric
DNA damage responses, promotion of cell growth and proliferation, acceleration of cell cycle kinetics,
and control of mitochondrial integrity following oxidative stress. Non-canonical activities of TERT primarily
show cellular protective effects, and nuclear TERT has been shown to protect against cell death
following double-stranded DNA damage, independent of its role in telomere length maintenance. TERT
has been suggested to act as a chromatin modulator and participate in the transcriptional regulation of
gene expression. TERT has also been reported to regulate transcript levels through an RNA-dependent
RNA Polymerase (RdRP) activity and produce siRNAs in a Dicer-dependent manner. At the mitochondria,
TERT is suggested to protect against oxidative stress-induced mtDNA damage and promote mitochondrial
integrity. These extra-telomeric functions of TERT may be advantageous in the context of increased
proliferation and metabolic stress often found in rapidly-dividing cancer cells. Understanding
the spectrum of non-canonical functions of telomerase may have important implications for the rational
design of anti-cancer chemotherapeutic drugs.
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Affiliation(s)
- Connor A.H. Thompson
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Judy M.Y. Wong
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
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Ribosome and Translational Control in Stem Cells. Cells 2020; 9:cells9020497. [PMID: 32098201 PMCID: PMC7072746 DOI: 10.3390/cells9020497] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/11/2020] [Accepted: 02/17/2020] [Indexed: 12/16/2022] Open
Abstract
Embryonic stem cells (ESCs) and adult stem cells (ASCs) possess the remarkable capacity to self-renew while remaining poised to differentiate into multiple progenies in the context of a rapidly developing embryo or in steady-state tissues, respectively. This ability is controlled by complex genetic programs, which are dynamically orchestrated at different steps of gene expression, including chromatin remodeling, mRNA transcription, processing, and stability. In addition to maintaining stem cell homeostasis, these molecular processes need to be rapidly rewired to coordinate complex physiological modifications required to redirect cell fate in response to environmental clues, such as differentiation signals or tissue injuries. Although chromatin remodeling and mRNA expression have been extensively studied in stem cells, accumulating evidence suggests that stem cell transcriptomes and proteomes are poorly correlated and that stem cell properties require finely tuned protein synthesis. In addition, many studies have shown that the biogenesis of the translation machinery, the ribosome, is decisive for sustaining ESC and ASC properties. Therefore, these observations emphasize the importance of translational control in stem cell homeostasis and fate decisions. In this review, we will provide the most recent literature describing how ribosome biogenesis and translational control regulate stem cell functions and are crucial for accommodating proteome remodeling in response to changes in stem cell fate.
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Liu B, Cheng H, Ma W, Gong F, Wang X, Duan N, Dang X. Common variants in the GNL3 contribute to the increasing risk of knee osteoarthritis in Han Chinese population. Sci Rep 2018; 8:9610. [PMID: 29942097 PMCID: PMC6018215 DOI: 10.1038/s41598-018-27971-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/08/2018] [Indexed: 01/05/2023] Open
Abstract
Osteoarthritis (OA) is a complex degenerative joint disorder, which is caused by both environmental and genetic factors. Previous studies have indicated that the GNL3 gene is associated with knee osteoarthritis (KOA) susceptibility in Europeans; however, the exact molecular mechanism is still unclear. In the present study, we investigated the potential genetic association of GNL3 with KOA in a two-stage sample of 6,704 individuals from the Han Chinese population. Subjects containing 1,052 KOA patients and 2,117 controls were considered the discovery dataset, while subjects consisting of 1,173 KOA patients and 2,362 controls were utilized as the replication dataset. Single-SNP association, imputation, and haplotypic association analyses were performed. The SNP of rs11177 in GNL3 was identified to be significantly associated with KOA after accounting for age, gender and BMI in both stages. The imputed SNP of rs6617 in SPCS1 was found to be strongly associated with KOA risk, and the significant association signal was confirmed in the replication stage. Moreover, a haplotype-based analysis also indicated a positive genetic effect of GNL3 on KOA susceptibility. In summary, our results proved that GNL3 plays an important role in the etiology of KOA, suggesting that GNL3 is a potential genetic modifier for KOA development.
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Affiliation(s)
- Bo Liu
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.,Department of Orthopedics and Traumatology, Xi'an Hospital of Traditional Chinese Medicine, Xi'an, Shaanxi, China
| | - Huiguang Cheng
- Department of Hip Joint, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Wenlong Ma
- Department of Hip Injury and Disease, Luoyang Orthopedic Hospital of Henan Province, Luoyang, Henan, China
| | - Futai Gong
- Department of Orthopedics and Traumatology, Xi'an Hospital of Traditional Chinese Medicine, Xi'an, Shaanxi, China
| | - Xiangyang Wang
- Department of Orthopedics and Traumatology, Xi'an Hospital of Traditional Chinese Medicine, Xi'an, Shaanxi, China
| | - Ning Duan
- Department of Traumatic Orthopaedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
| | - Xiaoqian Dang
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.
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Pervasive Protein Thermal Stability Variation during the Cell Cycle. Cell 2018; 173:1495-1507.e18. [PMID: 29706546 PMCID: PMC5998384 DOI: 10.1016/j.cell.2018.03.053] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/18/2018] [Accepted: 03/21/2018] [Indexed: 11/21/2022]
Abstract
Quantitative mass spectrometry has established proteome-wide regulation of protein abundance and post-translational modifications in various biological processes. Here, we used quantitative mass spectrometry to systematically analyze the thermal stability and solubility of proteins on a proteome-wide scale during the eukaryotic cell cycle. We demonstrate pervasive variation of these biophysical parameters with most changes occurring in mitosis and G1. Various cellular pathways and components vary in thermal stability, such as cell-cycle factors, polymerases, and chromatin remodelers. We demonstrate that protein thermal stability serves as a proxy for enzyme activity, DNA binding, and complex formation in situ. Strikingly, a large cohort of intrinsically disordered and mitotically phosphorylated proteins is stabilized and solubilized in mitosis, suggesting a fundamental remodeling of the biophysical environment of the mitotic cell. Our data represent a rich resource for cell, structural, and systems biologists interested in proteome regulation during biological transitions.
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Zhao S, Xia Y, Zhang F, Xiong Z, Li Y, Yan W, Chen X, Wang W, Wang H, Gao E, Lee Y, Li C, Wang S, Zhang L, Tao L. Nucleostemin dysregulation contributes to ischemic vulnerability of diabetic hearts: Role of ribosomal biogenesis. J Mol Cell Cardiol 2017; 108:106-113. [PMID: 28549781 DOI: 10.1016/j.yjmcc.2017.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 04/29/2017] [Accepted: 05/22/2017] [Indexed: 01/20/2023]
Abstract
Diabetes is a major health problem worldwide. As well-known, diabetes greatly increases cardiac vulnerability to ischemia/reperfusion (I/R) injury, but the underlying mechanisms remain elusive. Nucleostemin (NS) is a nucleolar protein that controls ribosomal biogenesis and exerts cardioprotective effects against I/R injury. However, whether NS-mediated ribosomal biogenesis regulates ischemic vulnerability of diabetic hearts remains unanswered. Utilizing myocardial I/R mouse models, we found that cardiac NS expression significantly increased in response to I/R in normal diet (ND)-fed mice. Surprisingly, cardiac NS failed to be upregulated in high fat diet (HFD)-induced diabetic mice, accompanied by obvious ribosomal dysfunction. Compared with ND group, cardiac specific overexpression of NS by adenovirus (AV) injection significantly restored I/R-induced ribosomal function enhancement, reduced cardiomyocyte apoptosis, improved cardiac function, and decreased infarct sizes in diabetic mice. Notably, co-treatment of homoharringtonine (HHT), a selective inhibitor of ribosomal function, totally blocked NS-mediated cardioprotective effects against I/R injury. Furthermore, in cultured cardiomyocytes, saturated fatty acids treatment, but not high glucose exposure, significantly inhibited simulated I/R-induced NS upregulation and ribosomal function improvement. In conclusion, these data for the first time demonstrate that NS dysregulation induced by saturated fatty acids exposure might be an important cause of increased ischemic vulnerability to I/R injury in diabetic hearts. Targeting NS dysregulation and subsequent ribosomal dysfunction could be a promising therapeutic strategy for diabetic I/R injury management.
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Affiliation(s)
- Shihao Zhao
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Yunlong Xia
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Fuyang Zhang
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China; Department of Physiology, the Fourth Military Medical University, China; Department of Cardiology, the 201st Hospital of People's Liberation Army, China
| | - Zhenyu Xiong
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Yueyang Li
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Wenjun Yan
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Xiyao Chen
- Department of Geriatrics, Xijing Hospital, the Fourth Military Medical University, China
| | - Wei Wang
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Helin Wang
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Erhe Gao
- Center for Translational Medicine, Temple University, United States
| | - Yan Lee
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Congye Li
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Shan Wang
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Ling Zhang
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China
| | - Ling Tao
- Department of Cardiology, Xijing Hospital, the Fourth Military Medical University, China.
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8
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Grigoryan EN, Markitantova YV. Cellular and Molecular Preconditions for Retinal Pigment Epithelium (RPE) Natural Reprogramming during Retinal Regeneration in Urodela. Biomedicines 2016; 4:E28. [PMID: 28536395 PMCID: PMC5344269 DOI: 10.3390/biomedicines4040028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/26/2016] [Accepted: 11/26/2016] [Indexed: 12/25/2022] Open
Abstract
Many regeneration processes in animals are based on the phenomenon of cell reprogramming followed by proliferation and differentiation in a different specialization direction. An insight into what makes natural (in vivo) cell reprogramming possible can help to solve a number of biomedical problems. In particular, the first problem is to reveal the intrinsic properties of the cells that are necessary and sufficient for reprogramming; the second, to evaluate these properties and, on this basis, to reveal potential endogenous sources for cell substitution in damaged tissues; and the third, to use the acquired data for developing approaches to in vitro cell reprogramming in order to obtain a cell reserve for damaged tissue repair. Normal cells of the retinal pigment epithelium (RPE) in newts (Urodela) can change their specialization and transform into retinal neurons and ganglion cells (i.e., actualize their retinogenic potential). Therefore, they can serve as a model that provides the possibility to identify factors of the initial competence of vertebrate cells for reprogramming in vivo. This review deals mainly with the endogenous properties of native newt RPE cells themselves and, to a lesser extent, with exogenous mechanisms regulating the process of reprogramming, which are actively discussed.
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Affiliation(s)
- Eleonora N Grigoryan
- Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow 119334, Russia.
| | - Yuliya V Markitantova
- Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow 119334, Russia.
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Markitantova YV, Avdonin PP, Grigoryan EN. Identification of the gene encoding nucleostemin in the eye tissues of Pleurodeles waltl. BIOL BULL+ 2015. [DOI: 10.1134/s1062359015050088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Park H, Han SS, Sako Y, Pack CG. Dynamic and unique nucleolar microenvironment revealed by fluorescence correlation spectroscopy. FASEB J 2014; 29:837-48. [PMID: 25404711 DOI: 10.1096/fj.14-254110] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Organization and functions of the nucleolus is maintained by mobilities and interactions of nucleolar factors. Because the nucleolus is a densely packed structure, molecular crowding effects determined by the molecular concentrations and mobilities in the nucleolus should also be important for regulating nucleolar organization and functions. However, such molecular property of nucleolar organization is not fully understood. To understand the biophysical property of nucleolar organization, the diffusional behaviors of inert green fluorescent protein (GFP) oligomers with or without nuclear localization signals (NLSs) were analyzed under various conditions by fluorescence correlation spectroscopy. Our result demonstrates that the mobility of GFPs inside the nucleolus and the nucleoplasm can be represented by single free diffusion under normal conditions, even though the mobility in the nucleolus is considerably slower than that in the chromatin region. Moreover, the free diffusion of GFPs is found to be significantly size- and NLS-dependent only in the nucleolus. Interestingly, the mobility in the nucleolus is highly sensitive to ATP depletion, as well as actinomycin D (ActD) treatment. In contrast, the ultra-structure of the nucleolus was not significantly changed by ATP depletion but was changed by ActD treatment. These results suggest that the nucleolus behaves similarly to an open aqueous-phase medium with an increased molecular crowding effect that depends on both energy and transcription.
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Affiliation(s)
- Hweon Park
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Sung-Sik Han
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Yasushi Sako
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Chan-Gi Pack
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
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Ali MAE, Naka K, Yoshida A, Fuse K, Kasada A, Hoshii T, Tadokoro Y, Ueno M, Ohta K, Kobayashi M, Takahashi C, Hirao A. Association of a murine leukaemia stem cell gene signature based on nucleostemin promoter activity with prognosis of acute myeloid leukaemia in patients. Biochem Biophys Res Commun 2014; 450:837-43. [PMID: 24960197 DOI: 10.1016/j.bbrc.2014.06.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 06/15/2014] [Indexed: 10/25/2022]
Abstract
Acute myeloid leukaemia (AML) is a heterogeneous neoplastic disorder in which a subset of cells function as leukaemia-initiating cells (LICs). In this study, we prospectively evaluated the leukaemia-initiating capacity of AML cells fractionated according to the expression of a nucleolar GTP binding protein, nucleostemin (NS). To monitor NS expression in living AML cells, we generated a mouse AML model in which green fluorescent protein (GFP) is expressed under the control of a region of the NS promoter (NS-GFP). In AML cells, NS-GFP levels were correlated with endogenous NS mRNA. AML cells with the highest expression of NS-GFP were very immature blast-like cells, efficiently formed leukaemia colonies in vitro, and exhibited the highest leukaemia-initiating capacity in vivo. Gene expression profiling analysis revealed that cell cycle regulators and nucleotide metabolism-related genes were highly enriched in a gene set associated with leukaemia-initiating capacity that we termed the 'leukaemia stem cell gene signature'. This gene signature stratified human AML patients into distinct clusters that reflected prognosis, demonstrating that the mouse leukaemia stem cell gene signature is significantly associated with the malignant properties of human AML. Further analyses of gene regulation in leukaemia stem cells could provide novel insights into diagnostic and therapeutic approaches to AML.
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Affiliation(s)
- Mohamed A E Ali
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuhito Naka
- Exploratory Project on Cancer Stem Cells, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Akiyo Yoshida
- Division of Oncology and Molecular Biology, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kyoko Fuse
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Atsuo Kasada
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Takayuki Hoshii
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Yuko Tadokoro
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Masaya Ueno
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kumiko Ohta
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Masahiko Kobayashi
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Chiaki Takahashi
- Division of Oncology and Molecular Biology, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Atsushi Hirao
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
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SUN XIAOLI, JIA YU, WEI YUANYU, LIU SHUAI, YUE BAOHONG. Gene expression profiling of HL-60 cells following knockdown of nucleostemin using DNA microarrays. Oncol Rep 2014; 32:739-47. [DOI: 10.3892/or.2014.3240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/29/2014] [Indexed: 11/05/2022] Open
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Hariharan N, Sussman MA. Stressing on the nucleolus in cardiovascular disease. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:798-801. [PMID: 24514103 PMCID: PMC3972279 DOI: 10.1016/j.bbadis.2013.09.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/18/2013] [Indexed: 12/23/2022]
Abstract
The nucleolus is a multifunctional organelle with multiple roles involving cell proliferation, growth, survival, ribosome biogenesis and stress response signaling. Alteration of nucleolar morphology and architecture signifies an early response to increased cellular stress. This review briefly summarizes nucleolar response to cardiac stress signals and details the role played by nucleolar proteins in cardiovascular pathophysiology. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.
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Affiliation(s)
- Nirmala Hariharan
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, CA 92182, USA
| | - Mark A Sussman
- Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, CA 92182, USA.
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Gee F, Clubbs CF, Raine EVA, Reynard LN, Loughlin J. Allelic expression analysis of the osteoarthritis susceptibility locus that maps to chromosome 3p21 reveals cis-acting eQTLs at GNL3 and SPCS1. BMC MEDICAL GENETICS 2014; 15:53. [PMID: 24886551 PMCID: PMC4101866 DOI: 10.1186/1471-2350-15-53] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/23/2014] [Indexed: 11/27/2022]
Abstract
Background An osteoarthritis (OA) susceptibility locus has been mapped to chromosome 3p21, to a region of high linkage disequilibrium encompassing twelve genes. Six of these genes are expressed in joint tissues and we therefore assessed whether any of the six were subject to cis-acting regulatory polymorphisms active in these tissues and which could therefore account for the association signal. Methods We measured allelic expression using pyrosequencing assays that can distinguish mRNA output from each allele of a transcript single nucleotide polymorphism. We assessed RNA extracted from the cartilage and other joint tissues of OA patients who had undergone elective joint replacement surgery. A two-tailed Mann–Whitney exact test was used to test the significance of any allelic differences. Results GNL3 and SPCS1 demonstrated significant allelic expression imbalance (AEI) in OA cartilage (GNL3, mean AEI = 1.04, p = 0.0002; SPCS1, mean AEI = 1.07, p < 0.0001). Similar results were observed in other tissues. Expression of the OA-associated allele was lower than that of the non-associated allele for both genes. Conclusions cis-acting regulatory polymorphisms acting on GNL3 and SPCS1 contribute to the OA association signal at chromosome 3p21, and these genes therefore merit further investigation.
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Affiliation(s)
- Fiona Gee
- Institute of Cellular Medicine, Musculoskeletal Research Group, Newcastle University, Newcastle-upon-Tyne, UK.
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15
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Lo D, Zhang Y, Dai MS, Sun XX, Zeng SX, Lu H. Nucleostemin stabilizes ARF by inhibiting the ubiquitin ligase ULF. Oncogene 2014; 34:1688-97. [PMID: 24769896 PMCID: PMC4212020 DOI: 10.1038/onc.2014.103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 02/02/2014] [Accepted: 03/13/2014] [Indexed: 12/18/2022]
Abstract
Up-regulated expression of nucleolar GTPase Nucleostemin (NS) has been associated with increased cellular proliferation potential and tumor malignancy during cancer development. Recent reports attribute the growth regulatory effects of NS protein to its role in facilitating ribosome production. However, the oncogenic potential of NS remains unclear since imbalanced levels of NS have been reported to exert growth inhibitory effect by modulating p53 tumor suppressor activity. It also remains in questions if aberrant NS levels might play a p53-independent role in regulation of cell proliferation and growth. In this study, we performed affinity purification and mass spectrometry analysis to explore protein-protein interactions influencing NS growth regulatory properties independently of p53 tumor suppressor. We identified the Alternative Reading Frame (ARF) protein as a key protein associating with NS and further verified the interaction through in vitro and in vivo assays. We demonstrated that NS is able to regulate cell cycle progression by regulating the stability of the ARF tumor suppressor. Furthermore, overexpression of NS suppressed ARF polyubiquitination by its E3 ligase ULF and elongated its half-life, while knockdown of NS led to the decrease of ARF levels. Also, we found that NS can enhance NPM stabilization of ARF. Thus, we propose that in the absence of p53, ARF can be stabilized by NS and NPM to serve as an alternative tumor suppressor surveillance, preventing potential cellular transformation resulting from the growth inducing effects of NS overexpression.
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Affiliation(s)
- D Lo
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA
| | - Y Zhang
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA
| | - M-S Dai
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - X-X Sun
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - S X Zeng
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA
| | - H Lu
- Department of Biochemistry and Molecular Biology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA, USA
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Lin T, Meng L, Lin TC, Wu LJ, Pederson T, Tsai RYL. Nucleostemin and GNL3L exercise distinct functions in genome protection and ribosome synthesis, respectively. J Cell Sci 2014; 127:2302-12. [PMID: 24610951 DOI: 10.1242/jcs.143842] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The mammalian nucleolar proteins nucleostemin and GNL3-like (GNL3L) are encoded by paralogous genes that arose from an ancestral invertebrate gene, GNL3. Invertebrate GNL3 has been implicated in ribosome biosynthesis, as has its mammalian descendent, GNL3L. The paralogous mammalian nucleostemin protein has, instead, been implicated in cell renewal. Here, we found that depletion of nucleostemin in a human breast carcinoma cell line triggers prompt and significant DNA damage in S-phase cells without perturbing the initial step of ribosomal (r)RNA synthesis and only mildly affects the total ribosome production. By contrast, GNL3L depletion markedly impairs ribosome production without inducing appreciable DNA damage. These results indicate that, during vertebrate evolution, GNL3L retained the role of the ancestral gene in ribosome biosynthesis, whereas the paralogous nucleostemin acquired a novel genome-protective function. Our results provide a coherent explanation for what had seemed to be contradictory findings about the functions of the invertebrate versus vertebrate genes and are suggestive of how the nucleolus was fine-tuned for a role in genome protection and cell-cycle control as the vertebrates evolved.
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Affiliation(s)
- Tao Lin
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Lingjun Meng
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Tsung-Chin Lin
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Laura J Wu
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Thoru Pederson
- Program in Cell and Developmental Dynamics, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Robert Y L Tsai
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
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Reňák D, Gibalová A, Solcová K, Honys D. A new link between stress response and nucleolar function during pollen development in Arabidopsis mediated by AtREN1 protein. PLANT, CELL & ENVIRONMENT 2014; 37:670-83. [PMID: 23961845 DOI: 10.1111/pce.12186] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Heat shock transcription factors (Hsfs) are involved in multiple aspects of stress response and plant growth. However, their role during male gametophyte development is largely unknown, although the generative phase is the most sensitive and critical period in the plant life cycle. Based on a wide screen of T-DNA mutant lines, we identified the atren1 mutation (restricted to nucleolus1) in early male gametophytic gene At1g77570, which has the closest homology to HSFA5 gene, the member of a heat shock transcription factor (HSF) gene family. The mutation causes multiple defects in male gametophyte development in both structure and function. Because the mutation disrupts an early acting (AtREN1) gene, these pollen phenotype abnormalities appear from bicellular pollen stage to pollen maturation. Moreover, the consequent progamic phase is compromised as well as documented by pollen germination defects and limited transmission via male gametophyte. In addition, atren1/- plants are defective in heat stress (HS) response and produce notably higher proportion of aberrant pollen grains. AtREN1 protein is targeted specifically to the nucleolus that, together with the increased size of the nucleolus in atren1 pollen, suggests that it is likely to be involved in ribosomal RNA biogenesis or other nucleolar functions.
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Affiliation(s)
- David Reňák
- Laboratory of Pollen Biology, Institute of Experimental Botany v.v.i. ASCR, Rozvojová 263, Prague 6, 165 02, Czech Republic
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18
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Guo Y, Liao YP, Zhang D, Xu LS, Li N, Guan WJ, Liu CQ. In vitro Study of Nucleostemin as a Potential Therapeutic Target in Human Breast Carcinoma SKBR-3 Cells. Asian Pac J Cancer Prev 2014; 15:2291-5. [DOI: 10.7314/apjcp.2014.15.5.2291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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19
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Transcript level of nucleostemin in newly diagnosed acute myeloid leukemia patients. Leuk Res 2013; 37:1636-41. [DOI: 10.1016/j.leukres.2013.09.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 09/13/2013] [Accepted: 09/20/2013] [Indexed: 12/30/2022]
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20
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Alawi F, Lin P. Dyskerin localizes to the mitotic apparatus and is required for orderly mitosis in human cells. PLoS One 2013; 8:e80805. [PMID: 24303026 PMCID: PMC3841160 DOI: 10.1371/journal.pone.0080805] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 10/15/2013] [Indexed: 11/18/2022] Open
Abstract
Dyskerin is a highly conserved, nucleolar RNA-binding protein with established roles in small nuclear ribonucleoprotein biogenesis, telomerase and telomere maintenance and precursor rRNA processing. Telomerase is functional during S phase and the bulk of rRNA maturation occurs during G1 and S phases; both processes are inactivated during mitosis. Yet, we show that during the course of cell cycle progression, human dyskerin expression peaks during G2/M in parallel with the upregulation of pro-mitotic factors. Dyskerin redistributed from the nucleolus in interphase cells to the perichromosomal region during prometaphase, metaphase and anaphase. With continued anaphase progression, dyskerin also localized to the cytoplasm within the mid-pole region. Loss of dyskerin function via siRNA-mediated depletion promoted G2/M accumulation and this was accompanied by an increased mitotic index and activation of the spindle assembly checkpoint. Live cell imaging further revealed an array of mitotic defects including delayed prometaphase progression, a significantly increased incidence of multi-polar spindles, and anaphase bridges culminating in micronucleus formation. Together, these findings suggest that dyskerin is a highly dynamic protein throughout the cell cycle and increases the repertoire of fundamental cellular processes that are disrupted by absence of its normal function.
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Affiliation(s)
- Faizan Alawi
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Ping Lin
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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21
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Su H, Kodiha M, Lee S, Stochaj U. Identification of novel markers that demarcate the nucleolus during severe stress and chemotherapeutic treatment. PLoS One 2013; 8:e80237. [PMID: 24223222 PMCID: PMC3819286 DOI: 10.1371/journal.pone.0080237] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 10/01/2013] [Indexed: 01/08/2023] Open
Abstract
The nucleolus, the ribosomal factory of the cell, has emerged as a key player that regulates many aspects of cell biology. Several thousand proteins associate at least transiently with nucleoli, thereby generating a highly dynamic compartment with a protein profile which is sensitive to changes in cell physiology and pharmacological agents. Powerful tools that reliably demarcate the nucleoli are a prerequisite to measure their composition and activities. Previously, we developed quantitative methods to measure fluorescently labeled molecules in nucleoli. While these tools identify nucleoli under control and mild stress conditions, the accurate detection of nucleolar boundaries under harsh experimental conditions is complicated by the lack of appropriate markers for the nucleolar compartment. Using fluorescence microscopy we have now identified new marker proteins to detect nucleoli upon (a) severe stress and (b) drug treatments that trigger a pronounced reorganization of nucleoli. Our results demonstrate that nucleolin is an ideal marker to delimit nucleoli when cells are exposed to heat or oxidative stress. Furthermore, we show for the first time that cellular apoptosis susceptibility protein (CAS) and human antigen R protein (HuR) are excluded from nucleoli and can be employed to delimit these compartments under severe conditions that redistribute major nucleolar proteins. As proof-of-principle, we used these markers to demarcate nucleoli in cells treated with pharmacological compounds that disrupt the nucleolar organization. Furthermore, to gain new insights into the biology of the nucleolus, we applied our protocols and quantified stress- and drug-induced changes in nucleolar organization and function. Finally, we show that CAS, HuR and nucleolin not only identify nucleoli in optical sections, but are also suitable to demarcate the nucleolar border following 3D reconstruction. Taken together, our studies present novel marker proteins that delimit nucleoli with high confidence under a variety of experimental settings.
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Affiliation(s)
- Haitong Su
- McGill University, Department of Physiology, Montreal, Quebec, Canada
| | - Mohamed Kodiha
- McGill University, Department of Physiology, Montreal, Quebec, Canada
| | - Sunghoon Lee
- McGill University, Department of Physiology, Montreal, Quebec, Canada
| | - Ursula Stochaj
- McGill University, Department of Physiology, Montreal, Quebec, Canada
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Markitantova YV, Zinovieva RD. Expression of nucleostemin in proliferating and differentiating cells of the human retina during prenatal development. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2012; 445:244-6. [PMID: 22945526 DOI: 10.1134/s0012496612040084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Indexed: 11/23/2022]
Affiliation(s)
- Yu V Markitantova
- Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
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23
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Kinor N, Shav-Tal Y. The dynamics of the alternatively spliced NOL7 gene products and role in nucleolar architecture. Nucleus 2012; 2:229-45. [PMID: 21818416 DOI: 10.4161/nucl.2.3.15893] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 04/05/2011] [Accepted: 04/21/2011] [Indexed: 11/19/2022] Open
Abstract
Three alternatively spliced forms of the human NOL7 gene coding for relatively small proteins were identified. The two shorter forms were generated by intron retention events, and each isoform was differently localized within the cell. The NOL7-SP1 long form (29 kD) localized to the nucleolus, SP2 was nucleoplasmic, while SP3 was distributed throughout the whole cell. NOL7-SP1 was confined to the nucleolar granular component, and during cell division disassociated from the nucleolus. Knockdown of NOL7-SP1 levels abrogated nucleolar architecture, in particular the internal regions, and reduced cell proliferation. Analysis of the nucleolar dynamics of the SP1 protein during interphase showed nucleolar high binding affinity. Dissection of protein domains showed that nucleolar targeting was mediated by a unique C-terminal nucleolar localization sequence (NoLS). However, this sequence was not sufficient for conferring high binding affinity, which required additional regions of the protein. Our analysis shows that NOL7 is important for maintaining internal nucleolar structure and cell growth rates, and that while specific protein localization can be obtained by specific short localization motifs, nucleolar residency through binding must be mediated by a synergistic combination of protein modules.
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Affiliation(s)
- Noa Kinor
- The Mina & Everard Goodman Institute of Nanotechnology, Bar-Ilan University; Ramat Gan, Israel
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24
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Wang X, Xie B, Zhu M, Zhang Z, Hong Z. Nucleostemin-like 1 is required for embryogenesis and leaf development in Arabidopsis. PLANT MOLECULAR BIOLOGY 2012; 78:31-44. [PMID: 22058024 DOI: 10.1007/s11103-011-9840-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 10/19/2011] [Indexed: 05/31/2023]
Abstract
Arabidopsis NSN1 encodes a nucleolar GTP-binding protein and is required for flower development. Defective flowers were formed in heterozygous nsn1/+ plants. Homozygous nsn1 plants were dwarf and exhibited severe defects in reproduction. Arrests in embryo development in nsn1 could occur at any stage of embryogenesis. Cotyledon initiation and development during embryogenesis were distorted in nsn1 plants. At the seedling stage, cotyledons and leaves of nsn1 formed upward curls. The curled leaves developed meristem-like outgrowths or hyperplasia tissues in the adaxial epidermis. Long and enlarged pavement cells, characteristic of the abaxial epidermis of wild type plants, were found in the adaxial epidermis in nsn1 leaves, suggesting a disoriented leaf polarity in the mutant. The important role of NSN1 in embryo development and leaf differentiation was consistent with the high level expression of the NSN1 gene in the developing embryos and the primordia of cotyledons and leaves. The CLAVATA 3 (CLV3) gene, a stem cell marker in the Arabidopsis shoot apical meristem (SAM), was expressed in expanded regions surrounding the SAM of nsn1 plants, and induced ectopically in the meristem-like outgrowths in cotyledons and leaves. The nsn1 mutation up-regulated the expression levels of several genes implicated in the meristem identity and the abaxial cell fate, and repressed the expression of other genes related to the specification of cotyledon boundary and abaxial identity. These results demonstrate that NSN1 represents a novel GTPase required for embryogenesis, leaf development and leaf polarity establishment in Arabidopsis.
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Affiliation(s)
- Xiaomin Wang
- Department of Plant, Soil and Entomological Sciences and Program of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, ID 83844-3052, USA
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25
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Gil-Ranedo J, Mendiburu-Eliçabe M, García-Villanueva M, Medina D, del Álamo M, Izquierdo M. An off-target nucleostemin RNAi inhibits growth in human glioblastoma-derived cancer stem cells. PLoS One 2011; 6:e28753. [PMID: 22174890 PMCID: PMC3236221 DOI: 10.1371/journal.pone.0028753] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 11/14/2011] [Indexed: 12/03/2022] Open
Abstract
Glioblastomas (GBM) may contain a variable proportion of active cancer stem cells (CSCs) capable of self-renewal, of aggregating into CD133+ neurospheres, and to develop intracranial tumors that phenocopy the original ones. We hypothesized that nucleostemin may contribute to cancer stem cell biology as these cells share characteristics with normal stem cells. Here we report that nucleostemin is expressed in GBM-CSCs isolated from patient samples, and that its expression, conversely to what it has been described for ordinary stem cells, does not disappear when cells are differentiated. The significance of nucleostemin expression in CSCs was addressed by targeting the corresponding mRNA using lentivirally transduced short hairpin RNA (shRNA). In doing so, we found an off-target nucleostemin RNAi (shRNA22) that abolishes proliferation and induces apoptosis in GBM-CSCs. Furthermore, in the presence of shRNA22, GBM-CSCs failed to form neurospheres in vitro or grow on soft agar. When these cells are xenotransplanted into the brains of nude rats, tumor development is significantly delayed. Attempts were made to identify the primary target/s of shRNA22, suggesting a transcription factor involved in one of the MAP-kinases signaling-pathways or multiple targets. The use of this shRNA may contribute to develop new therapeutic approaches for this incurable type of brain tumor.
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Affiliation(s)
- Jon Gil-Ranedo
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | - Marina Mendiburu-Eliçabe
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | | | - Diego Medina
- Servicio de Neurocirugía, Hospital Universitario Ramón y Cajal, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | - Marta del Álamo
- Servicio de Neurocirugía, Hospital Universitario Ramón y Cajal, Instituto Sanitario Ramón y Cajal, Madrid, Spain
| | - Marta Izquierdo
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Instituto Sanitario Ramón y Cajal, Madrid, Spain
- * E-mail:
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Drosophila GTPase nucleostemin 2 changes cellular distribution during larval development and the GTP-binding motif is essential to nucleoplasmic localization. Biosci Biotechnol Biochem 2011; 75:1511-5. [PMID: 21821926 DOI: 10.1271/bbb.110212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nucleostemin (NS), a nucleolar guanosine triphosphate (GTP)-binding protein, plays significant roles in cell cycle progression and ribosomal biogenesis. Drosophila Nucleostemin 2 (NS2), a member of the Drosophila NS family, regulates early eye development and is essential to cell survival in vivo, but the underlying mechanisms have yet to be clarified. Biochemical analysis using the recombinant NS2 protein indicated that NS2 has GTPase activity. Immunohistochemistry revealed that NS2 changes in subcellular locus from the nucleolus to the nucleoplasm during larval development, and that a mutation in the ATP/GTP-binding site motif A (p-loop) prevents nuclear localization of NS2 and results in cytoplasmic distribution. Furthermore, downregulation of NS2 altered the rRNA proportions between the nucleus and the cytoplasm. These results suggest that NS2 at least requires GTP to import into the nucleoplasm.
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Rimsza LM, Unger JM, Tome ME, Leblanc ML. A strategy for full interrogation of prognostic gene expression patterns: exploring the biology of diffuse large B cell lymphoma. PLoS One 2011; 6:e22267. [PMID: 21829609 PMCID: PMC3150354 DOI: 10.1371/journal.pone.0022267] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 06/21/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Gene expression profiling yields quantitative data on gene expression used to create prognostic models that accurately predict patient outcome in diffuse large B cell lymphoma (DLBCL). Often, data are analyzed with genes classified by whether they fall above or below the median expression level. We sought to determine whether examining multiple cut-points might be a more powerful technique to investigate the association of gene expression with outcome. METHODOLOGY/PRINCIPAL FINDINGS We explored gene expression profiling data using variable cut-point analysis for 36 genes with reported prognostic value in DLBCL. We plotted two-group survival logrank test statistics against corresponding cut-points of the gene expression levels and smooth estimates of the hazard ratio of death versus gene expression levels. To facilitate comparisons we also standardized the expression of each of the genes by the fraction of patients that would be identified by any cut-point. A multiple comparison adjusted permutation p-value identified 3 different patterns of significance: 1) genes with significant cut-point points below the median, whose loss is associated with poor outcome (e.g. HLA-DR); 2) genes with significant cut-points above the median, whose over-expression is associated with poor outcome (e.g. CCND2); and 3) genes with significant cut-points on either side of the median, (e.g. extracellular molecules such as FN1). CONCLUSIONS/SIGNIFICANCE Variable cut-point analysis with permutation p-value calculation can be used to identify significant genes that would not otherwise be identified with median cut-points and may suggest biological patterns of gene effects.
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Affiliation(s)
- Lisa M Rimsza
- Department of Pathology, University of Arizona, Tucson, Arizona, United States of America.
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Hao H, Liu M, Wu P, Cai L, Tang K, Yi P, Li Y, Chen Y, Ye D. Lipoxin A4 and its analog suppress hepatocellular carcinoma via remodeling tumor microenvironment. Cancer Lett 2011; 309:85-94. [PMID: 21683517 DOI: 10.1016/j.canlet.2011.05.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 05/11/2011] [Accepted: 05/18/2011] [Indexed: 12/25/2022]
Abstract
Macrophages play an important role in tumor inflammatory microenvironment, lipoxin (LX), the 'stop signal' for inflammation, has been extensively studied preclinically for its anti-inflammatory or inflammatory pro-resolving effect. Here, we showed that LXA(4) could promote the apoptosis and inhibit the proliferation, migration and angiogenesis of HepG2 hepatocarcinoma cells stimulated by lipopolysaccharide (LPS) or activated macrophage-conditioned media (ACM). Moreover, BML-111, the analog of LXA(4), effectively inhibited the proliferation, invasion and angiogenesis of tumor in H22 hepatocarcinoma cell bearing mice. These results showed that LXA(4) could be a possible candidate for liver cancer therapy, and blocking the activation of macrophages would be an effective drug target.
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Affiliation(s)
- Hua Hao
- Department of Pathophysiology, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
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Parry EM, Alder JK, Lee SS, Phillips JA, Loyd JE, Duggal P, Armanios M. Decreased dyskerin levels as a mechanism of telomere shortening in X-linked dyskeratosis congenita. J Med Genet 2011; 48:327-33. [PMID: 21415081 PMCID: PMC3088476 DOI: 10.1136/jmg.2010.085100] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dyskeratosis congenita (DC) is a premature ageing syndrome characterised by short telomeres. An X-linked form of DC is caused by mutations in DKC1 which encodes dyskerin, a telomerase component that is essential for telomerase RNA stability. However, mutations in DKC1 are identifiable in only half of X-linked DC families. A four generation family with pulmonary fibrosis and features of DC was identified. Affected males showed the classic mucocutaneous features of DC and died prematurely from pulmonary fibrosis. Although there were no coding sequence or splicing variants, genome wide linkage analysis of 16 individuals across four generations identified significant linkage at the DKC1 locus, and was accompanied by reduced dyskerin protein levels in affected males. Decreased dyskerin levels were associated with compromised telomerase RNA levels and very short telomeres. These data identify decreased dyskerin levels as a novel mechanism of DC, and indicate that intact dyskerin levels, in the absence of coding mutations, are critical for telomerase RNA stability and for in vivo telomere maintenance.
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Affiliation(s)
- Erin M Parry
- Department of Oncology and Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- Medical Scientist Training Progra, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Jonathan K Alder
- Department of Oncology and Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Stella S Lee
- Pre-doctoral Training Program in Human Genetics, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - John A Phillips
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - James E Loyd
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Priya Duggal
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Mary Armanios
- Department of Oncology and Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
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Huang M, Whang P, Chodaparambil JV, Pollyea DA, Kusler B, Xu L, Felsher DW, Mitchell BS. Reactive oxygen species regulate nucleostemin oligomerization and protein degradation. J Biol Chem 2011; 286:11035-46. [PMID: 21242306 DOI: 10.1074/jbc.m110.208470] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nucleostemin (NS) is a nucleolar-nucleoplasmic shuttle protein that regulates cell proliferation, binds p53 and Mdm2, and is highly expressed in tumor cells. We have identified NS as a target of oxidative regulation in transformed hematopoietic cells. NS oligomerization occurs in HL-60 leukemic cells and Raji B lymphoblasts that express high levels of c-Myc and have high intrinsic levels of reactive oxygen species (ROS); reducing agents dissociate NS into monomers and dimers. Exposure of U2OS osteosarcoma cells with low levels of intrinsic ROS to hydrogen peroxide (H(2)O(2)) induces thiol-reversible disulfide bond-mediated oligomerization of NS. Increased exposure to H(2)O(2) impairs NS degradation, immobilizes the protein within the nucleolus, and results in detergent-insoluble NS. The regulation of NS by ROS was validated in a murine lymphoma tumor model in which c-Myc is overexpressed and in CD34+ cells from patients with chronic myelogenous leukemia in blast crisis. In both instances, increased ROS levels were associated with markedly increased expression of NS protein and thiol-reversible oligomerization. Site-directed mutagenesis of critical cysteine-containing regions of nucleostemin altered both its intracellular localization and its stability. MG132, a potent proteasome inhibitor and activator of ROS, markedly decreased degradation and increased nucleolar retention of NS mutants, whereas N-acetyl-L-cysteine largely prevented the effects of MG132. These results indicate that NS is a highly redox-sensitive protein. Increased intracellular ROS levels, such as those that result from oncogenic transformation in hematopoietic malignancies, regulate the ability of NS to oligomerize, prevent its degradation, and may alter its ability to regulate cell proliferation.
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Affiliation(s)
- Min Huang
- Department of Medicine, Divisions of Oncology and Hematology, Stanford University School of Medicine, Stanford, California 94305, USA
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Hernandez-Verdun D, Roussel P, Thiry M, Sirri V, Lafontaine DLJ. The nucleolus: structure/function relationship in RNA metabolism. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 1:415-31. [PMID: 21956940 DOI: 10.1002/wrna.39] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The nucleolus is the ribosome factory of the cells. This is the nuclear domain where ribosomal RNAs are synthesized, processed, and assembled with ribosomal proteins. Here we describe the classical tripartite organization of the nucleolus in mammals, reflecting ribosomal gene transcription and pre-ribosomal RNA (pre-rRNA) processing efficiency: fibrillar center, dense fibrillar component, and granular component. We review the nucleolar organization across evolution from the bipartite organization in yeast to the tripartite organization in humans. We discuss the basic principles of nucleolar assembly and nucleolar structure/function relationship in RNA metabolism. The control of nucleolar assembly is presented as well as the role of pre-existing machineries and pre-rRNAs inherited from the previous cell cycle. In addition, nucleoli carry many essential extra ribosomal functions and are closely linked to cellular homeostasis and human health. The last part of this review presents recent advances in nucleolar dysfunctions in human pathology such as cancer and virus infections that modify the nucleolar organization.
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Affiliation(s)
- Danièle Hernandez-Verdun
- Nuclei and cell cycle, Institut Jacques Monod-UMR 7592 CNRS, Université Paris Diderot, 75205 Paris cedex 13, France.
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Westman BJ, Verheggen C, Hutten S, Lam YW, Bertrand E, Lamond AI. A proteomic screen for nucleolar SUMO targets shows SUMOylation modulates the function of Nop5/Nop58. Mol Cell 2010; 39:618-31. [PMID: 20797632 PMCID: PMC2938476 DOI: 10.1016/j.molcel.2010.07.025] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 04/30/2010] [Accepted: 06/08/2010] [Indexed: 11/23/2022]
Abstract
Posttranslational SUMO modification is an important mechanism of regulating protein function, especially in the cell nucleus. The nucleolus is the subnuclear organelle responsible for rRNA synthesis, processing, and assembly of the large and small ribosome subunits. Here, we have used SILAC-based quantitative proteomics to identify nucleolar SUMOylated proteins. This reveals a role for SUMOylation in the biogenesis and/or function of small nucleolar ribonucleoprotein complexes (snoRNPs) via the targeting of Nhp2 and Nop58. Using combined in vitro and in vivo approaches, both Nhp2 and Nop58 (also known as Nop5) are shown to be substrates for SUMOylation. Mutational analyses revealed the sites of modification on Nhp2 as K5, and on Nop58 as K467 and K497. Unlike Nop58 and Nhp2, the closely related Nop56 and 15.5K proteins appear not to be SUMO targets. SUMOylation is essential for high-affinity Nop58 binding to snoRNAs. This study provides direct evidence linking SUMO modification with snoRNP function.
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Affiliation(s)
- Belinda J Westman
- Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee DD15EH, UK
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