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Guo D, Lin S, Wang X, Jiao Z, Li G, An L, Zhang Z, Zhang L. Establishment and Characterization of a Chicken Myoblast Cell Line. Int J Mol Sci 2024; 25:8340. [PMID: 39125909 PMCID: PMC11312951 DOI: 10.3390/ijms25158340] [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: 06/03/2024] [Revised: 07/17/2024] [Accepted: 07/28/2024] [Indexed: 08/12/2024] Open
Abstract
Skeletal muscle, which is predominantly constituted by multinucleated muscle fibers, plays a pivotal role in sustaining bodily movements and energy metabolism. Myoblasts, which serve as precursor cells for differentiation and fusion into muscle fibers, are of critical importance in the exploration of the functional genes associated with embryonic muscle development. However, the in vitro proliferation of primary myoblasts is inherently constrained. In this study, we achieved a significant breakthrough by successfully establishing a chicken myoblast cell line through the introduction of the exogenous chicken telomerase reverse transcriptase (chTERT) gene, followed by rigorous G418-mediated pressure screening. This newly developed cell line, which was designated as chTERT-myoblasts, closely resembled primary myoblasts in terms of morphology and exhibited remarkable stability in culture for at least 20 generations of population doublings without undergoing malignant transformation. In addition, we conducted an exhaustive analysis that encompassed cellular proliferation, differentiation, and transfection characteristics. Our findings revealed that the chTERT-myoblasts had the ability to proliferate, differentiate, and transfect after multiple rounds of population doublings. This achievement not only furnished a valuable source of homogeneous avian cell material for investigating embryonic muscle development, but also provided valuable insights and methodologies for establishing primary cell lines.
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Affiliation(s)
- Dongxue Guo
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
| | - Shudai Lin
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
| | - Xiaotong Wang
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
| | - Zhenhai Jiao
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
| | - Guo Li
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
| | - Lilong An
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
| | - Zihao Zhang
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
| | - Li Zhang
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, China
- Key Laboratory of Farm Animal Genetic Resources and Germplasm Innovation in Zhanjiang, Guangdong Ocean University, Zhanjiang 524088, China
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2
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Salimi-Jeda A, Badrzadeh F, Esghaei M, Abdoli A. The role of telomerase and viruses interaction in cancer development, and telomerase-dependent therapeutic approaches. Cancer Treat Res Commun 2021; 27:100323. [PMID: 33530025 DOI: 10.1016/j.ctarc.2021.100323] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 12/21/2022]
Abstract
Human telomerase reverse transcriptase (hTERT) is an enzyme that is critically involved in elongating and maintaining telomeres length to control cell life span and replicative potential. Telomerase activity is continuously expressed in human germ-line cells and most cancer cells, whereas it is suppressed in most somatic cells. In normal cells, by reducing telomerase activity and progressively shortening the telomeres, the cells progress to the senescence or apoptosis process. However, in cancer cells, telomere lengths remain constant due to telomerase's reactivation, and cells continue to proliferate and inhibit apoptosis, and ultimately lead to cancer development and human death due to metastasis. Studies demonstrated that several DNA and RNA oncoviruses could interact with telomerase by integrating their genome sequence within the host cell telomeres specifically. Through the activation of the hTERT promoter and lengthening the telomere, these cells contributes to cancer development. Since oncoviruses can activate telomerase and increase hTERT expression, there are several therapeutic strategies based on targeting the telomerase of cancer cells like telomerase-targeted peptide vaccines, hTERT-targeting dendritic cells (DCs), hTERT-targeting gene therapy, and hTERT-targeting CRISPR/Cas9 system that can overcome tumor-mediated toleration mechanisms and specifically apoptosis in cancer cells. This study reviews available data on the molecular structure of telomerase and the role of oncoviruses and telomerase interaction in cancer development and telomerase-dependent therapeutic approaches to conquest the cancer cells.
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Affiliation(s)
- Ali Salimi-Jeda
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Fariba Badrzadeh
- Faculti of Medicine, Golestan University of Medical sciences, Golestan, Iran.
| | - Maryam Esghaei
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Asghar Abdoli
- Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran.
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3
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Dratwa M, Wysoczańska B, Łacina P, Kubik T, Bogunia-Kubik K. TERT-Regulation and Roles in Cancer Formation. Front Immunol 2020; 11:589929. [PMID: 33329574 PMCID: PMC7717964 DOI: 10.3389/fimmu.2020.589929] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/16/2020] [Indexed: 12/16/2022] Open
Abstract
Telomerase reverse transcriptase (TERT) is a catalytic subunit of telomerase. Telomerase complex plays a key role in cancer formation by telomere dependent or independent mechanisms. Telomere maintenance mechanisms include complex TERT changes such as gene amplifications, TERT structural variants, TERT promoter germline and somatic mutations, TERT epigenetic changes, and alternative lengthening of telomere. All of them are cancer specific at tissue histotype and at single cell level. TERT expression is regulated in tumors via multiple genetic and epigenetic alterations which affect telomerase activity. Telomerase activity via TERT expression has an impact on telomere length and can be a useful marker in diagnosis and prognosis of various cancers and a new therapy approach. In this review we want to highlight the main roles of TERT in different mechanisms of cancer development and regulation.
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Affiliation(s)
- Marta Dratwa
- Laboratory of Clinical Immunogenetics and Pharmacogenetics, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Barbara Wysoczańska
- Laboratory of Clinical Immunogenetics and Pharmacogenetics, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Piotr Łacina
- Laboratory of Clinical Immunogenetics and Pharmacogenetics, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Tomasz Kubik
- Department of Computer Engineering, Faculty of Electronics, Wrocław University of Science and Technology, Wroclaw, Poland
| | - Katarzyna Bogunia-Kubik
- Laboratory of Clinical Immunogenetics and Pharmacogenetics, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
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Ségal-Bendirdjian E, Geli V. Non-canonical Roles of Telomerase: Unraveling the Imbroglio. Front Cell Dev Biol 2019; 7:332. [PMID: 31911897 PMCID: PMC6914764 DOI: 10.3389/fcell.2019.00332] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/27/2019] [Indexed: 12/11/2022] Open
Abstract
Telomerase plays a critical role in stem cell function and tissue regeneration that depends on its ability to elongate telomeres. For nearly two decades, it turned out that TERT regulates a broad spectrum of functions including signal transduction, gene expression regulation, and protection against oxidative damage that are independent of its telomere elongation activity. These conclusions that were mainly obtained in cell lines overexpressing telomerase were further strengthened by in vivo models of ectopic expression of telomerase or models of G1 TERT knockout mice without detectable telomere dysfunction. However, the later models were questioned due to the presence of aberrantly shortened telomere in the germline of the parents TERT+/- that were used to create the G1 TERT -/- mice. The physiological relevance of the functions associated with overexpressed telomerase raised also some concerns due to artifactual situations and localizations and complications to quantify the level of TERT. Another concern with non-canonical functions of TERT was the difficulty to separate a direct TERT-related function from secondary effects. Despite these concerns, more and more evidence accumulates for non-canonical roles of telomerase that are non-obligatory extra-telomeric. Here, we review these non-canonical roles of the TERT subunit of telomerase. Also, we emphasize recent results that link TERT to mitochondria and protection to reactive oxygen species suggesting a protective role of TERT in neurons. Throughout this review, we dissect some controversies regarding the non-canonical functions of telomerase and provide some insights to explain these discrepancies. Finally, we discuss the importance of understanding these alternative functions of telomerase for the development of anticancer strategies.
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Affiliation(s)
- Evelyne Ségal-Bendirdjian
- INSERM UMR-S 1124, Team: Cellular Homeostasis, Cancer and Therapies, INSERM US36, CNRS UMS 2009, BioMedTech Facilities, Université de Paris, Paris, France
| | - Vincent Geli
- Marseille Cancer Research Center, U1068 INSERM, UMR 7258 CNRS, Aix Marseille University, Institut Paoli-Calmettes, Equipe labellisée Ligue, Marseille, France
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5
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Li Y, McGrail DJ, Xu J, Mills GB, Sahni N, Yi S. Gene Regulatory Network Perturbation by Genetic and Epigenetic Variation. Trends Biochem Sci 2018; 43:576-592. [PMID: 29941230 DOI: 10.1016/j.tibs.2018.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 04/25/2018] [Accepted: 05/27/2018] [Indexed: 01/28/2023]
Abstract
Gene regulatory networks underlie biological function and cellular physiology. Alternative splicing (AS) is a fundamental step in gene regulatory networks and plays a key role in development and disease. In addition to the identification of aberrant AS events, an increasing number of studies are focusing on molecular determinants of AS, including genetic and epigenetic regulators. We review here recent efforts to identify various deregulated AS events as well as their molecular determinants that alter biological functions, and discuss clinical features of AS and their druggable potential.
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Affiliation(s)
- Yongsheng Li
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Harbin 150081, China
| | - Daniel J McGrail
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Juan Xu
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Harbin 150081, China
| | - Gordon B Mills
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Nidhi Sahni
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Program in Quantitative and Computational Biosciences (QCB), Baylor College of Medicine, Houston, TX 77030, USA; Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA; Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
| | - Song Yi
- Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA; Department of Biomedical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
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Jyotsana N, Heuser M. Exploiting differential RNA splicing patterns: a potential new group of therapeutic targets in cancer. Expert Opin Ther Targets 2017; 22:107-121. [PMID: 29235382 DOI: 10.1080/14728222.2018.1417390] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Mutations in genes associated with splicing have been found in hematologic malignancies, but also in solid cancers. Aberrant cancer specific RNA splicing either results from mutations or misexpression of the spliceosome genes directly, or from mutations in splice sites of oncogenes or tumor suppressors. Areas covered: In this review, we present molecular targets of aberrant splicing in various malignancies, information on existing and emerging therapeutics against such targets, and strategies for future drug development. Expert opinion: Alternative splicing is an important mechanism that controls gene expression, and hence pharmacologic and genetic control of aberrant alternative RNA splicing has been proposed as a potential therapy in cancer. To identify and validate aberrant RNA splicing patterns as therapeutic targets we need to (1) characterize the most common genetic aberrations of the spliceosome and of splice sites, (2) understand the dysregulated downstream pathways and (3) exploit in-vivo disease models of aberrant splicing. Antisense oligonucleotides show promising activity, but will benefit from improved delivery tools. Inhibitors of mutated splicing factors require improved specificity, as alternative and aberrant splicing are often intertwined like two sides of the same coin. In summary, targeting aberrant splicing is an early but emerging field in cancer treatment.
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Affiliation(s)
- Nidhi Jyotsana
- a Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation , Hannover Medical School , Hannover , Germany
| | - Michael Heuser
- a Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation , Hannover Medical School , Hannover , Germany
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Alternative splicing discriminates molecular subtypes and has prognostic impact in diffuse large B-cell lymphoma. Blood Cancer J 2017; 7:e596. [PMID: 28841210 PMCID: PMC5596382 DOI: 10.1038/bcj.2017.71] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/13/2017] [Accepted: 06/16/2017] [Indexed: 02/08/2023] Open
Abstract
Effect of alternative splicing (AS) on diffuse large B-cell lymphoma (DLBCL) pathogenesis and survival has not been systematically addressed. Here, we compared differentially expressed genes and exons in association with survival after chemoimmunotherapy, and between germinal center B-cell like (GCB) and activated B-cell like (ABC) DLBCLs. Genome-wide exon array-based screen was performed from samples of 38 clinically high-risk patients who were treated in a Nordic phase II study with dose-dense chemoimmunotherapy and central nervous system prophylaxis. The exon expression profile separated the patients according to molecular subgroups and survival better than the gene expression profile. Pathway analyses revealed enrichment of AS genes in inflammation and adhesion-related processes, and in signal transduction, such as phosphatidylinositol signaling system and adenosine triphosphate binding cassette transporters. Altogether, 49% of AS-related exons were protein coding, and domain prediction showed 28% of such exons to include a functional domain, such as transmembrane helix domain or phosphorylation sites. Validation in an independent cohort of 92 DLBCL samples subjected to RNA-sequencing confirmed differential exon usage of selected genes and association of AS with molecular subtypes and survival. The results indicate that AS events are able to discriminate GCB and ABC DLBCLs and have prognostic impact in DLBCL.
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8
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Pestana A, Vinagre J, Sobrinho-Simões M, Soares P. TERT biology and function in cancer: beyond immortalisation. J Mol Endocrinol 2017; 58:R129-R146. [PMID: 28057768 DOI: 10.1530/jme-16-0195] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 01/05/2017] [Indexed: 12/23/2022]
Abstract
Evasion of replicative senescence and proliferation without restriction, sometimes designated as immortalisation, is one of the hallmarks of cancer that may be attained through reactivation of telomerase in somatic cells. In contrast to most normal cells in which there is lack of telomerase activity, upregulation of TERT transcription/activity is detected in 80-90% of malignant tumours. In several types of cancer, there is a relationship between the presence of TERT promoter mutations, TERT mRNA expression and clinicopathological features, but the biological bridge between the occurrence of TERT promoter mutations and the aggressive/invasive features displayed by the tumours remains unidentified. We and others have associated the presence of TERT promoter mutations with metastisation/survival in several types of cancer. In follicular cell-derived thyroid cancer, such mutations are associated with worse prognostic features (age of patients, tumour size and tumour stage) as well as with distant metastases, worse response to treatment and poorer survival. In this review, we analyse the data reported in several studies that imply TERT transcription reactivation/activity with cell proliferation, tumour invasion and metastisation. A particular attention is given to the putative connections between TERT transcriptional reactivation and signalling pathways frequently altered in cancer, such as c-MYC, NF-κB and B-Catenin.
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Affiliation(s)
- Ana Pestana
- Institute of Molecular Pathology and ImmunologyUniversity of Porto (IPATIMUP), Porto, Portugal
- Institute for Research and Innovation in Health (I3S)University of Porto, Porto, Portugal
| | - João Vinagre
- Institute of Molecular Pathology and ImmunologyUniversity of Porto (IPATIMUP), Porto, Portugal
- Institute for Research and Innovation in Health (I3S)University of Porto, Porto, Portugal
| | - Manuel Sobrinho-Simões
- Institute of Molecular Pathology and ImmunologyUniversity of Porto (IPATIMUP), Porto, Portugal
- Institute for Research and Innovation in Health (I3S)University of Porto, Porto, Portugal
- Medical FacultyUniversity of Porto, Porto, Portugal
- Department of PathologyCentro Hospitalar S. João, Porto, Portugal
- Department of PathologyMedical Faculty, University of Porto, Porto, Portugal
| | - Paula Soares
- Institute of Molecular Pathology and ImmunologyUniversity of Porto (IPATIMUP), Porto, Portugal
- Institute for Research and Innovation in Health (I3S)University of Porto, Porto, Portugal
- Medical FacultyUniversity of Porto, Porto, Portugal
- Department of PathologyMedical Faculty, University of Porto, Porto, Portugal
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Liss AS, Bose HR. Characterization of ATF2 in Rel/NFκB oncogenesis reveals its role in the regulation of Ras signaling. Small GTPases 2014; 2:89-94. [PMID: 21776408 DOI: 10.4161/sgtp.2.2.15310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 02/25/2011] [Accepted: 03/01/2011] [Indexed: 02/06/2023] Open
Abstract
The v-Rel oncoprotein is the acutely transforming member of the Rel/NFκB family of transcription factors. v-Rel transforms cells through the inappropriate activation and suppression of genes normally regulated by cellular Rel/NFκB family members. We have recently demonstrated that activation of Ha-Ras by v-Rel contributes to transformation. Characterization of AP-1 family members in v-Rel-mediated transformation revealed ectopic expression of ATF2 inhibited transformation by blocking Ha-Ras activity. This lack of Ha-Ras activity prevented downstream activation of the Raf-MEK-ERK pathway, a critical pathway for v-Rel-mediated transformation. Microarray analysis of cells treated with an inhibitor to the ERK pathway revealed a relatively small number of genes that are specifically regulated by ERK activity in cells expressing v-Rel. These studies suggest the main contribution of ERK activity is to temper the expression of genes in v-Rel transformed cells. The mechanism by which ATF2 regulates Ras-Raf-MEK-ERK signaling appears to be a context dependent event. The ectopic expression of ATF2 in cells that are not expressing v-Rel results in the activation of Ha-Ras. However, activation of downstream Raf-MEK-ERK signaling pathway is blocked, likely through the recruitment of inhibitory 14-3-3 proteins to c-Raf. These results suggest a diverse role for ATF2 in the regulation of the Ras-Raf-MEK-ERK pathway.
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Affiliation(s)
- Andrew S Liss
- Section of Molecular Genetics and Microbiology and the Institute of Cellular and Molecular Biology; University of Texas at Austin; Austin, TX USA
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Radan L, Hughes CS, Teichroeb JH, Vieira Zamora FM, Jewer M, Postovit LM, Betts DH. Microenvironmental regulation of telomerase isoforms in human embryonic stem cells. Stem Cells Dev 2014; 23:2046-66. [PMID: 24749509 DOI: 10.1089/scd.2013.0373] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Recent evidence points to extra-telomeric, noncanonical roles for telomerase in regulating stem cell function. In this study, human embryonic stem cells (hESCs) were cultured in 20% or 2% O2 microenvironments for up to 5 days and evaluated for telomerase reverse transcriptase (TERT) expression and telomerase activity. Results showed increased cell survival and maintenance of the undifferentiated state with elevated levels of nuclear TERT in 2% O2-cultured hESCs despite no significant difference in telomerase activity compared with their high-O2-cultured counterparts. Pharmacological inhibition of telomerase activity using a synthetic tea catechin resulted in spontaneous hESC differentiation, while telomerase inhibition with a phosphorothioate oligonucleotide telomere mimic did not. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed variations in transcript levels of full-length and alternate splice variants of TERT in hESCs cultured under varying O2 atmospheres. Steric-blocking of Δα and Δβ hTERT splicing using morpholino oligonucleotides altered the hTERT splicing pattern and rapidly induced spontaneous hESC differentiation that appeared biased toward endomesodermal and neuroectodermal cell fates, respectively. Together, these results suggest that post-transcriptional regulation of TERT under varying O2 microenvironments may help regulate hESC survival, self-renewal, and differentiation capabilities through expression of extra-telomeric telomerase isoforms.
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Affiliation(s)
- Lida Radan
- 1 Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario , London, Ontario, Canada
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Oltean S, Bates DO. Hallmarks of alternative splicing in cancer. Oncogene 2013; 33:5311-8. [PMID: 24336324 DOI: 10.1038/onc.2013.533] [Citation(s) in RCA: 455] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 11/04/2013] [Accepted: 11/04/2013] [Indexed: 12/17/2022]
Abstract
The immense majority of genes are alternatively spliced and there are many isoforms specifically associated with cancer progression and metastasis. The splicing pattern of specific isoforms of numerous genes is altered as cells move through the oncogenic process of gaining proliferative capacity, acquiring angiogenic, invasive, antiapoptotic and survival properties, becoming free from growth factor dependence and growth suppression, altering their metabolism to cope with hypoxia, enabling them to acquire mechanisms of immune escape, and as they move through the epithelial-mesenchymal and mesenchymal-epithelial transitions and metastasis. Each of the 'hallmarks of cancer' is associated with a switch in splicing, towards a more aggressive invasive cancer phenotype. The choice of isoforms is regulated by several factors (signaling molecules, kinases, splicing factors) currently being identified systematically by a number of high-throughput, independent and unbiased methodologies. Splicing factors are de-regulated in cancer, and in some cases are themselves oncogenes or pseudo-oncogenes and can contribute to positive feedback loops driving cancer progression. Tumour progression may therefore be associated with a coordinated splicing control, meaning that there is the potential for a relatively small number of splice factors or their regulators to drive multiple oncogenic processes. The understanding of how splicing contributes to the various phenotypic traits acquired by tumours as they progress and metastasise, and in particular how alternative splicing is coordinated, can and is leading to the development of a new class of anticancer therapeutics-the alternative-splicing inhibitors.
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Affiliation(s)
- S Oltean
- School of Physiology and Pharmacology, University of Bristol, Bristol, UK
| | - D O Bates
- Division of Pre-clinical Oncology, School of Clinical Sciences, University of Nottingham, Queen's Medical Center, Nottingham, UK
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Chen X, Zhou X, Xi L, Li J, Zhao R, Ma N, Zhao L. Roles of DgBRC1 in regulation of lateral branching in chrysanthemum (Dendranthema ×grandiflora cv. Jinba). PLoS One 2013; 8:e61717. [PMID: 23613914 PMCID: PMC3629106 DOI: 10.1371/journal.pone.0061717] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 03/17/2013] [Indexed: 01/05/2023] Open
Abstract
The diverse plasticity of plant architecture is largely determined by shoot branching. Shoot branching is an event regulated by multiple environmental, developmental and hormonal stimuli through triggering lateral bud response. After perceiving these signals, the lateral buds will respond and make a decision on whether to grow out. TCP transcriptional factors, BRC1/TB1/FC1, were previously proven to be involved in local inhibition of shoot branching in Arabidopsis, pea, tomato, maize and rice. To investigate the function of BRC1, we isolated the BRC1 homolog from chrysanthemum. There were two transcripts of DgBRC1 coming from two alleles in one locus, both of which complemented the multiple branches phenotype of Arabidopsis brc1-1, indicating that both are functionally conserved. DgBRC1 was mainly expressed in dormant axillary buds, and down-regulated at the bud activation stage, and up-regulated by higher planting densities. DgBRC1 transcripts could respond to apical auxin supply and polar auxin transport. Moreover, we found that the acropetal cytokinin stream promoted branch outgrowth whether or not apical auxin was present. Basipetal cytokinin promoted outgrowth of branches in the absence of apical auxin, while strengthening the inhibitory effects on lower buds in the presence of apical auxin. The influence of auxin and strigolactons (SLs) on the production of cytokinin was investigated, we found that auxin locally down-regulated biosynthesis of cytokinin in nodes, SLs also down-regulated the biosynthesis of cytokinin, the interactions among these phytohormones need further investigation.
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Affiliation(s)
- Xiaoli Chen
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing, China
| | - Xiaoyang Zhou
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing, China
| | - Lin Xi
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing, China
| | - Junxiang Li
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing, China
| | - Ruiyan Zhao
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing, China
| | - Nan Ma
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing, China
| | - Liangjun Zhao
- Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing, China
- * E-mail:
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Alternatively spliced telomerase reverse transcriptase variants lacking telomerase activity stimulate cell proliferation. Mol Cell Biol 2012; 32:4283-96. [PMID: 22907755 DOI: 10.1128/mcb.00550-12] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eight human and six chicken novel alternatively spliced (AS) variants of telomerase reverse transcriptase (TERT) were identified, including a human variant (Δ4-13) containing an in-frame deletion which removed exons 4 through 13, encoding the catalytic domain of telomerase. This variant was expressed in telomerase-negative normal cells and tissues as well as in transformed telomerase-positive cell lines and cells which employ an alternative method to maintain telomere length. The overexpression of the Δ4-13 variant significantly elevated the proliferation rates of several cell types without enhancing telomerase activity, while decreasing the endogenous expression of this variant by use of small interfering RNA (siRNA) technology reduced cell proliferation. The expression of the Δ4-13 variant stimulated Wnt signaling. In chicken cells, AS TERT variants containing internal deletions or insertions that eliminated or reduced telomerase activity also enhanced cell proliferation. This is the first report that naturally occurring AS TERT variants which lack telomerase activity stimulate cell proliferation.
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Hrdličková R, Nehyba J, Lim SL, Grützner F, Bose HR. Insights into the evolution of mammalian telomerase: platypus TERT shares similarities with genes of birds and other reptiles and localizes on sex chromosomes. BMC Genomics 2012; 13:216. [PMID: 22655747 PMCID: PMC3546421 DOI: 10.1186/1471-2164-13-216] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 05/04/2012] [Indexed: 01/05/2023] Open
Abstract
Background The TERT gene encodes the catalytic subunit of the telomerase complex and is responsible for maintaining telomere length. Vertebrate telomerase has been studied in eutherian mammals, fish, and the chicken, but less attention has been paid to other vertebrates. The platypus occupies an important evolutionary position, providing unique insight into the evolution of mammalian genes. We report the cloning of a platypus TERT (OanTERT) ortholog, and provide a comparison with genes of other vertebrates. Results The OanTERT encodes a protein with a high sequence similarity to marsupial TERT and avian TERT. Like the TERT of sauropsids and marsupials, as well as that of sharks and echinoderms, OanTERT contains extended variable linkers in the N-terminal region suggesting that they were present already in basal vertebrates and lost independently in ray-finned fish and eutherian mammals. Several alternatively spliced OanTERT variants structurally similar to avian TERT variants were identified. Telomerase activity is expressed in all platypus tissues like that of cold-blooded animals and murine rodents. OanTERT was localized on pseudoautosomal regions of sex chromosomes X3/Y2, expanding the homology between human chromosome 5 and platypus sex chromosomes. Synteny analysis suggests that TERT co-localized with sex-linked genes in the last common mammalian ancestor. Interestingly, female platypuses express higher levels of telomerase in heart and liver tissues than do males. Conclusions OanTERT shares many features with TERT of the reptilian outgroup, suggesting that OanTERT represents the ancestral mammalian TERT. Features specific to TERT of eutherian mammals have, therefore, evolved more recently after the divergence of monotremes.
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Affiliation(s)
- Radmila Hrdličková
- Section of Molecular Genetics and Microbiology, School of Biological Science, University of Texas at Austin, 78712-1095, USA
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15
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The human T-lymphotropic virus type 1 tax protein inhibits nonsense-mediated mRNA decay by interacting with INT6/EIF3E and UPF1. J Virol 2012; 86:7530-43. [PMID: 22553336 DOI: 10.1128/jvi.07021-11] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this report, we analyzed whether the degradation of mRNAs by the nonsense-mediated mRNA decay (NMD) pathway was affected in human T-lymphotropic virus type 1 (HTLV-1)-infected cells. This pathway was indeed strongly inhibited in C91PL, HUT102, and MT2 cells, and such an effect was also observed by the sole expression of the Tax protein in Jurkat and HeLa cells. In line with this activity, Tax binds INT6/EIF3E (here called INT6), which is a subunit of the translation initiation factor eukaryotic initiation factor 3 (eIF3) required for efficient NMD, as well as the NMD core factor upstream frameshift protein 1 (UPF1). It was also observed that Tax expression alters the morphology of processing bodies (P-bodies), the cytoplasmic structures which concentrate RNA degradation factors. The presence of UPF1 in these subcellular compartments was increased by Tax, whereas that of INT6 was decreased. In line with these effects, the level of the phosphorylated form of UPF1 was increased in the presence of Tax. Analysis of several mutants of the viral protein showed that the interaction with INT6 is necessary for NMD inhibition. The alteration of mRNA stability was observed to affect viral transcripts, such as that coding for the HTLV-1 basic leucine zipper factor (HBZ), and also several cellular mRNAs sensitive to the NMD pathway. Our data indicate that the effect of Tax on viral and cellular gene expression is not restricted to transcriptional control but can also involve posttranscriptional regulation.
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16
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Abstract
The intron–exon architecture of many eukaryotic genes raises the intriguing question of whether this unique organization serves any function, or is it simply a result of the spread of functionless introns in eukaryotic genomes. In this review, we show that introns in contemporary species fulfill a broad spectrum of functions, and are involved in virtually every step of mRNA processing. We propose that this great diversity of intronic functions supports the notion that introns were indeed selfish elements in early eukaryotes, but then independently gained numerous functions in different eukaryotic lineages. We suggest a novel criterion of evolutionary conservation, dubbed intron positional conservation, which can identify functional introns.
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Affiliation(s)
- Michal Chorev
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem Jerusalem, Israel
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17
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Cifuentes-Rojas C, Shippen DE. Telomerase regulation. Mutat Res 2012; 730:20-7. [PMID: 22032831 PMCID: PMC3256259 DOI: 10.1016/j.mrfmmm.2011.10.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 09/15/2011] [Accepted: 10/12/2011] [Indexed: 02/05/2023]
Abstract
The intimate connection between telomerase regulation and human disease is now well established. The molecular basis for telomerase regulation is highly complex and entails multiple layers of control. While the major target of enzyme regulation is the catalytic subunit TERT, the RNA subunit of telomerase is also implicated in telomerase control. In addition, alterations in gene dosage and alternative isoforms of core telomerase components have been described. Finally, telomerase localization, recruitment to the telomere and enzymology at the chromosome terminus are all subject to modulation. In this review we summarize recent advances in understanding fundamental mechanisms of telomerase regulation.
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Affiliation(s)
| | - Dorothy E. Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
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18
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Zhang L, Katselis GS, Moore RE, Lekpor K, Goto RM, Lee TD, Miller MM. Proteomic Analysis of Surface and Endosomal Membrane Proteins from the Avian LMH Epithelial Cell Line. J Proteome Res 2011; 10:3973-82. [DOI: 10.1021/pr200179r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lei Zhang
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - George S. Katselis
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Roger E. Moore
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Kossi Lekpor
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Ronald M. Goto
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Terry D. Lee
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
| | - Marcia M. Miller
- Department of Molecular and Cellular Biology and ‡Department of Immunology, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, California 91010-3000, United States
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Amor S, Strassheim S, Dambrine G, Remy S, Rasschaert D, Laurent S. ICP27 protein of Marek's disease virus interacts with SR proteins and inhibits the splicing of cellular telomerase chTERT and viral vIL8 transcripts. J Gen Virol 2011; 92:1273-1278. [PMID: 21325479 DOI: 10.1099/vir.0.028969-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
All herpesviruses have a post-transcriptional regulatory protein that prevents precursor mRNA splicing and leads to the shutting off of host protein synthesis. The ICP27 protein of herpes simplex virus 1 (HSV-1) is the prototype of these proteins. Marek's disease virus (MDV-1), an alphaherpesvirus that induces lymphoma in birds, also has an ICP27 protein that is produced in lytic MDV-1-infected cells. We characterized this protein. We demonstrated ICP27 production in latently infected MSB-1 cells, but only on MDV-1 reactivation. ICP27 was found predominantly in specific structures within the nucleus. The ICP27 of MDV-1 colocalized and interacted with SR proteins. We demonstrated inhibitory effects of MDV-1 ICP27 on the splicing of both the viral vIL8 and cellular chTERT (telomerase reverse transcriptase) genes. Thus, the ICP27 of MDV-1 plays a similar role to the ICP27 of HSV-1 and may be involved in MDV-1 replication and the development of Marek's disease.
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Affiliation(s)
- S Amor
- Equipe TLVI, Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France
| | - S Strassheim
- Equipe TLVI, Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France
| | - G Dambrine
- INRA, Département de Santé Animale, Centre de recherches de Tours, 37380 Nouzilly, France.,Equipe TLVI, Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France
| | - S Remy
- INRA, Département de Santé Animale, Centre de recherches de Tours, 37380 Nouzilly, France
| | - D Rasschaert
- Equipe TLVI, Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France
| | - S Laurent
- INRA, Département de Santé Animale, Centre de recherches de Tours, 37380 Nouzilly, France.,Equipe TLVI, Université François Rabelais de Tours, UFR Sciences et Techniques, Parc de Grandmont, 37200 Tours, France
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