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Bowman RL, Hennessey RC, Weiss TJ, Tallman DA, Crawford ER, Murphy BM, Webb A, Zhang S, La Perle KM, Burd CJ, Levine RL, Shain AH, Burd CE. UVB mutagenesis differs in Nras- and Braf-mutant mouse models of melanoma. Life Sci Alliance 2021; 4:e202101135. [PMID: 34210801 PMCID: PMC8321651 DOI: 10.26508/lsa.202101135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 06/22/2021] [Accepted: 06/22/2021] [Indexed: 12/14/2022] Open
Abstract
BRAF-mutant melanomas are more likely than NRAS-mutant melanomas to arise in anatomical locations protected from chronic sun damage. We hypothesized that this discrepancy in tumor location is a consequence of the differential sensitivity of BRAF and NRAS-mutant melanocytes to ultraviolet light (UV)-mediated carcinogenesis. We tested this hypothesis by comparing the mutagenic consequences of a single neonatal, ultraviolet-AI (UVA; 340-400 nm) or ultraviolet-B (UVB; 280-390 nm) exposure in mouse models heterozygous for mutant Braf or homozygous for mutant Nras Tumor onset was accelerated by UVB, but not UVA, and the resulting melanomas contained recurrent mutations affecting the RING domain of MAP3K1 and Actin-binding domain of Filamin A. Melanomas from UVB-irradiated, Braf-mutant mice averaged twice as many single-nucleotide variants and five times as many dipyrimidine variants than tumors from similarly irradiated Nras-mutant mice. A mutational signature discovered in UVB-accelerated tumors mirrored COSMIC signatures associated with human skin cancer and was more prominent in Braf- than Nras-mutant murine melanomas. These data show that a single UVB exposure yields a greater burden of mutations in murine tumors driven by oncogenic Braf.
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Affiliation(s)
- Robert L Bowman
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Rebecca C Hennessey
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
| | - Tirzah J Weiss
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
| | - David A Tallman
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
| | - Emma R Crawford
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Brandon M Murphy
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
| | - Amy Webb
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH, USA
| | - Souhui Zhang
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
| | - Krista Md La Perle
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
| | - Craig J Burd
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Ross L Levine
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - A Hunter Shain
- Department of Dermatology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Christin E Burd
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
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2
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Yushkova E, Bashlykova L. Transgenerational effects in offspring of chronically irradiated populations of Drosophila melanogaster after the Chernobyl accident. Environ Mol Mutagen 2021; 62:39-51. [PMID: 33233025 DOI: 10.1002/em.22416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/17/2020] [Accepted: 11/20/2020] [Indexed: 06/11/2023]
Abstract
The zone of the Chernobyl nuclear disaster represents the largest area of chronic low-intensity radioactive impact on the natural ecosystems. The effects of chronic low-dose irradiation for natural populations of organisms and their offspring are unknown. The natural populations of Drosophila melanogaster sampled in 2007 in Chernobyl sites with different levels of radiation contamination were investigated. The offspring of specimens from these populations were studied under laboratory conditions to assess the effects of parental irradiation on the mutation process and survival of the offspring. Transgenerational effects of radioactive contamination were observed at the level of gross chromosomal rearrangements (dominant lethal mutations). The frequency of point/gene mutations (recessive sex-linked lethal mutations) of the offspring of the irradiated parents corresponded to the actual level of spontaneous mutations. The survival rate of offspring decreased over 160 generations and significantly correlated with the dominant lethal mutation levels. Our results provide a compelling evidence that other factors (distance from the Chernobyl Nuclear Power Plant, time after the initial exposure, selection site and origin of population) can affect the changes in the levels of the studied parameters along with the parental radiation exposure. They can also make a significant contribution to the health of the offspring of animals exposed to radioactive contamination. These data should be useful for future radioecological studies which will clarify the true mechanisms of transgenerational inheritance and generation of mutations to the offspring of chronically irradiated animals and their reactions to the interaction of various environmental factors.
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Affiliation(s)
- Elena Yushkova
- Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Science, Syktyvkar, Russia
| | - Ludmila Bashlykova
- Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Science, Syktyvkar, Russia
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3
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Dutta S, Hazra P, Saha S, Acharya B, Bhattacharjee T, Kumar Maurya P, Banerjee S, Chakraborty I, Chattopadhyay A. Applied mutagenesis could improve economically important traits in bitter gourd ( Momordica charantia L.). J Genet 2021; 100:43. [PMID: 34282734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Mutants with unique characters have played a key role in discovery of gene, mapping, functional genomics and breeding in many vegetable crops, but information on bitter gourd is lacking. Induction of mutation by gamma rays (Co60 source) at five different doses (50 Gy, 100 Gy, 150 Gy, 200 Gy and 250 Gy) was studied in four widely divergent bitter gourd genotypes BG-1346501, Meghna-2, Special Boulder and Selection-1 in M1 generation. Reduction in seed germination percentage, vine length and pollen fertility occurred in M1 generation with the increasing doses of mutagens. LD50 dose for BG-1346501, Meghna-2, Special Boulder and Selection-1 corresponded to 290.76 Gy, 206.12 Gy, 212.81 Gy and 213.49 Gy ᵞ radiation, respectively suggested low to medium doses (200-250 Gy) of gamma rays would be helpful in producing useful and exploitable mutants for further breeding. No remarkable effect of ᵞ radiation on fruit physicochemical characters in M1 generation were observed. M2 generation, raised from two widely divergent genotypes, BG-1346501 and Meghna-2, were screened critically and observed no significant reduction in seed germination and pollen viability, however little damage occurred particularly in vine length. There is possibility of isolating segregates in M2 generation with enhanced nutrient contents at low radiation dose. Highest mutation frequency resulted by treating Meghna-2 at 200 Gy and BG-1346501 at 100 Gy. Both genotype and mutagenic doses influenced mutagenic effectiveness. Spectrum of mutation was very low; number of putative mutants isolated from M2 generation was five in Meghna-2 and three in BG-1346501. Among six putative macro mutants isolated from M3 generation, we could identify two putative mutants, namely Meghna-2 with gynoecious sex form and BG-1346501 with high charantin, appreciable β-carotene and high ascorbic acid contents having ample promise for further utilization in bitter gourd breeding after critical testing in subsequent generations for estimation of genetic gain and trait heritability to confirm the mutant stability.
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Affiliation(s)
- Subhramalya Dutta
- Faculty of Horticulture, Department of Vegetable Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur 741 252, India.
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4
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Gilchrest BA. Actinic Keratoses: Reconciling the Biology of Field Cancerization with Treatment Paradigms. J Invest Dermatol 2020; 141:727-731. [PMID: 32956650 DOI: 10.1016/j.jid.2020.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/07/2020] [Accepted: 09/18/2020] [Indexed: 02/04/2023]
Abstract
This Perspective briefly reviews the relationship between UV-induced mutations in habitually sun-exposed human skin and subsequent development of actinic keratoses (AKs) and skin cancers. It argues that field therapy rather than AK-selective therapy is the more logical approach to cancer prevention and hypothesizes that treatment early in the process of field cancerization, even prior to the appearance of AKs, may be more effective in preventing cancer as well as more beneficial for and better tolerated by at-risk individuals. Finally, the Perspective encourages use of rapidly advancing DNA analysis techniques to quantify mutational burden in sun-damaged skin and its reduction by various therapies.
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MESH Headings
- Administration, Cutaneous
- Carcinoma, Basal Cell/genetics
- Carcinoma, Basal Cell/pathology
- Carcinoma, Basal Cell/prevention & control
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/pathology
- Carcinoma, Squamous Cell/prevention & control
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/pathology
- Cell Transformation, Neoplastic/radiation effects
- Chemexfoliation/methods
- Chemexfoliation/trends
- Combined Modality Therapy/methods
- Combined Modality Therapy/trends
- Cryosurgery/methods
- Cryosurgery/trends
- Curettage/methods
- Curettage/trends
- DNA Damage/radiation effects
- DNA Mutational Analysis
- Dermatology/methods
- Dermatology/trends
- Disease Progression
- Electrocoagulation/methods
- Electrocoagulation/trends
- Fluorouracil/administration & dosage
- Humans
- Keratinocytes/pathology
- Keratinocytes/radiation effects
- Keratosis, Actinic/etiology
- Keratosis, Actinic/genetics
- Keratosis, Actinic/pathology
- Keratosis, Actinic/therapy
- Mutation/radiation effects
- Photochemotherapy/methods
- Photochemotherapy/trends
- Skin/drug effects
- Skin/pathology
- Skin/radiation effects
- Skin Neoplasms/genetics
- Skin Neoplasms/pathology
- Skin Neoplasms/prevention & control
- Sunscreening Agents/administration & dosage
- Ultraviolet Rays/adverse effects
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Affiliation(s)
- Barbara A Gilchrest
- Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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5
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Algwaiz HI. Cytological Effect of Gamma Radiation on Selected Mutants of Wheat <i>Triticum aestivum</i> L. in M3 Generation. Pak J Biol Sci 2020; 22:607-613. [PMID: 31930860 DOI: 10.3923/pjbs.2019.607.613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND OBJECTIVE Wheat (Triticum aestivum L.) offers some unique opportunities for the induction and exploitation of agronomic value. The use of gamma radiation has been proven to be an effective method to induce genetic variation in crops. We aimed to determine genetically stable mutants of wheat which could be utilized for breeding purposes. MATERIALS AND METHODS We did a cytological investigation of induced mutant's behavior and chiasma frequency. Selected mutant types induced in dry and soaked seeds were treated with different doses of gamma rays. Each treated sample and control were subjected to cytological examination of the fixed pollen mother cells in various meiotic stages. RESULTS The percentage of the total abnormal cells significantly increased in one mutant and significantly decreased in the other mutant. The percentage of total abnormal cells did not diminish from the first to the second meiotic division. The types of meiotic anomalies found included laggards (56.51%), univalent (9.43%), stickiness (45.45%) and bridges (19.32%). There were genotypic differences in the frequency of occurrence of multivalent (trivalent and quadrivalents). A marked reduction in the number of rod and ring bivalent/cell in some genotypes were noticed. The frequency of chiasmata per pollen mother cell was reduced subsequently. Depression index of mutants was negative compared with controls or treatments except for a few genotypes. CONCLUSION Selected mutants of wheat tend to be cytologically stable and can therefore, be utilized for breeding purposes.
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McAbee JH, Rath BH, Valdez K, Young DL, Wu X, Shankavaram UT, Camphausen K, Tofilon PJ. Radiation Drives the Evolution of Orthotopic Xenografts Initiated from Glioblastoma Stem-like Cells. Cancer Res 2019; 79:6032-6043. [PMID: 31615806 PMCID: PMC6891212 DOI: 10.1158/0008-5472.can-19-2452] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/10/2019] [Accepted: 10/10/2019] [Indexed: 12/11/2022]
Abstract
A consequence of the intratumor heterogeneity (ITH) of glioblastoma (GBM) is the susceptibility to treatment-driven evolution. To determine the potential of radiotherapy to influence GBM evolution, we used orthotopic xenografts initiated from CD133+ GBM stem-like cells (GSC). Toward this end, orthotopic xenografts grown in nude mice were exposed to a fractionated radiation protocol, which resulted in a significant increase in animal survival. Brain tumors from control and irradiated mice were then collected at morbidity and compared in terms of growth pattern, clonal diversity, and genomic architecture. In mice that received fractionated radiation, tumors were less invasive, with more clearly demarcated borders and tumor core hypercellularity as compared with controls, suggesting a fundamental change in tumor biology. Viral integration site analysis indicated a reduction in clonal diversity in the irradiated tumors, implying a decrease in ITH. Changes in clonal diversity were not detected after irradiation of GSCs in vitro, suggesting that the radiation-induced reduction in ITH was dependent on the brain microenvironment. Whole-exome sequencing revealed differences in mutation patterns between control and irradiated tumors, which included modifications in the presence and clonality of driver mutations associated with GBM. Moreover, changes in the distribution of mutations as a function of subpopulation size between control and irradiated tumors were consistent with subclone expansion and contraction, that is, subpopulation evolution. Taken together, these results indicate that radiation drives the evolution of the GSC-initiated orthotopic xenografts and suggest that radiation-driven evolution may have therapeutic implications for recurrent GBM. SIGNIFICANCE: Radiation drives the evolution of glioblastoma orthotopic xenografts; when translated to the clinic, this may have therapeutic implications for recurrent tumors.
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Affiliation(s)
- Joseph H McAbee
- Radiation Oncology Branch, NCI, Bethesda, Maryland
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
- Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | | | | | | | - Xiaolin Wu
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland
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Pirkkanen J, Tharmalingam S, Morais IH, Lam-Sidun D, Thome C, Zarnke AM, Benjamin LV, Losch AC, Borgmann AJ, Sinex HC, Mendonca MS, Boreham DR. Transcriptomic profiling of gamma ray induced mutants from the CGL1 human hybrid cell system reveals novel insights into the mechanisms of radiation-induced carcinogenesis. Free Radic Biol Med 2019; 145:300-311. [PMID: 31580949 DOI: 10.1016/j.freeradbiomed.2019.09.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 08/22/2019] [Accepted: 09/29/2019] [Indexed: 01/26/2023]
Abstract
BACKGROUND Somatic cell hybrid systems generated by combining cancerous with non-cancerous cells provide useful model systems to study neoplastic transformation. Combined with recent advances in omics-based technologies, novel molecular signatures that drive radiation-induced carcinogenesis can be analyzed at an exceptional global level. METHODS Here, we present a complete whole-transcriptome analysis of gamma-induced mutants (GIM) and gamma irradiated control (CON) segregants isolated from the CGL1 (HeLa x normal fibroblast) human hybrid cell-system exposed to high doses of radiation. Using the Human Transcriptome Array 2.0 microarray technology and conservative discrimination parameters, we have elucidated 1067 differentially expressed genes (DEGs) between tumorigenic and non-tumorigenic cells. RESULTS Gene ontology enrichment analysis revealed that tumorigenic cells demonstrated shifts in extracellular matrix (ECM) and cellular adhesion profiles, dysregulation of cyclic AMP (cAMP) signaling, and alterations in nutrient transport and cellular energetics. Furthermore, putative upstream master regulator analysis demonstrated that loss of TGFβ1 signaling due to reduced SMAD3 expression is involved in radiation-induced carcinogenesis. CONCLUSIONS Taken together, this study presents novel insights into specific gene expression and pathway level differences that contribute to radiation-induced carcinogenesis in a human cell-based model. This global transcriptomic analysis and our published tumor suppressor gene deletion loci analyses will allow us to identify and functionally test candidate nexus upstream tumor suppressor genes that are deleted or silenced after exposure to radiation.
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Affiliation(s)
- Jake Pirkkanen
- Laurentian University, 935 Ramsey Lake Rd, Sudbury, Ontario, P3E 2C6, Canada.
| | | | - Igor H Morais
- Laurentian University, 935 Ramsey Lake Rd, Sudbury, Ontario, P3E 2C6, Canada.
| | - Daniel Lam-Sidun
- Northern Ontario School of Medicine, 935 Ramsey Lake Rd, Sudbury, Ontario, P3E 2C6, Canada.
| | - Christopher Thome
- Northern Ontario School of Medicine, 935 Ramsey Lake Rd, Sudbury, Ontario, P3E 2C6, Canada.
| | - Andrew M Zarnke
- Laurentian University, 935 Ramsey Lake Rd, Sudbury, Ontario, P3E 2C6, Canada.
| | - Laura V Benjamin
- Department of Radiation Oncology, Radiation and Cancer Biology Laboratories, Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Adam C Losch
- Department of Radiation Oncology, Radiation and Cancer Biology Laboratories, Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Anthony J Borgmann
- Department of Radiation Oncology, Radiation and Cancer Biology Laboratories, Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Helen Chin Sinex
- Department of Radiation Oncology, Radiation and Cancer Biology Laboratories, Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Marc S Mendonca
- Department of Radiation Oncology, Radiation and Cancer Biology Laboratories, Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Douglas R Boreham
- Northern Ontario School of Medicine, 935 Ramsey Lake Rd, Sudbury, Ontario, P3E 2C6, Canada; Bruce Power, PO Box 1540, 177 Tie Rd, R.R. 2, Tiverton, Ontario, N0G 2T0, Canada.
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8
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Wolf Y, Bartok O, Patkar S, Eli GB, Cohen S, Litchfield K, Levy R, Jiménez-Sánchez A, Trabish S, Lee JS, Karathia H, Barnea E, Day CP, Cinnamon E, Stein I, Solomon A, Bitton L, Pérez-Guijarro E, Dubovik T, Shen-Orr SS, Miller ML, Merlino G, Levin Y, Pikarsky E, Eisenbach L, Admon A, Swanton C, Ruppin E, Samuels Y. UVB-Induced Tumor Heterogeneity Diminishes Immune Response in Melanoma. Cell 2019; 179:219-235.e21. [PMID: 31522890 PMCID: PMC6863386 DOI: 10.1016/j.cell.2019.08.032] [Citation(s) in RCA: 214] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 05/30/2019] [Accepted: 08/15/2019] [Indexed: 12/12/2022]
Abstract
Although clonal neo-antigen burden is associated with improved response to immune therapy, the functional basis for this remains unclear. Here we study this question in a novel controlled mouse melanoma model that enables us to explore the effects of intra-tumor heterogeneity (ITH) on tumor aggressiveness and immunity independent of tumor mutational burden. Induction of UVB-derived mutations yields highly aggressive tumors with decreased anti-tumor activity. However, single-cell-derived tumors with reduced ITH are swiftly rejected. Their rejection is accompanied by increased T cell reactivity and a less suppressive microenvironment. Using phylogenetic analyses and mixing experiments of single-cell clones, we dissect two characteristics of ITH: the number of clones forming the tumor and their clonal diversity. Our analysis of melanoma patient tumor data recapitulates our results in terms of overall survival and response to immune checkpoint therapy. These findings highlight the importance of clonal mutations in robust immune surveillance and the need to quantify patient ITH to determine the response to checkpoint blockade.
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Affiliation(s)
- Yochai Wolf
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Osnat Bartok
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Sushant Patkar
- Cancer Data Science Laboratory, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Gitit Bar Eli
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Sapir Cohen
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Kevin Litchfield
- Cancer Evolution and Genome Instability Laboratory, Francis Crick Institute, London NW1 1AT, UK; Cancer Research UK Lung Cancer Centre of Excellence London, University College London Cancer Institute, London WC1E 6DD, UK
| | - Ronen Levy
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Alejandro Jiménez-Sánchez
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Sophie Trabish
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Joo Sang Lee
- Cancer Data Science Laboratory, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Hiren Karathia
- Cancer Data Science Laboratory, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Eilon Barnea
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Chi-Ping Day
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Einat Cinnamon
- The Lautenberg Center for Immunology and Cancer Research, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ilan Stein
- The Lautenberg Center for Immunology and Cancer Research, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Adam Solomon
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Lital Bitton
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Eva Pérez-Guijarro
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Tania Dubovik
- Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Shai S Shen-Orr
- Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Martin L Miller
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Glenn Merlino
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Yishai Levin
- The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Eli Pikarsky
- The Lautenberg Center for Immunology and Cancer Research, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Lea Eisenbach
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Arie Admon
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Charles Swanton
- Cancer Evolution and Genome Instability Laboratory, Francis Crick Institute, London NW1 1AT, UK; Cancer Research UK Lung Cancer Centre of Excellence London, University College London Cancer Institute, London WC1E 6DD, UK; Department of Medical Oncology, University College London Hospitals, London NW1 2BU, UK
| | - Eytan Ruppin
- Cancer Data Science Laboratory, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA.
| | - Yardena Samuels
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
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Madas BG, Drozsdik EJ. COMPUTATIONAL MODELING OF LOW DOSE HYPER-RADIOSENSITIVITY AND INDUCED RADIORESISTANCE APPLYING THE PRINCIPLE OF MINIMUM MUTATION LOAD. Radiat Prot Dosimetry 2019; 183:147-150. [PMID: 30535421 DOI: 10.1093/rpd/ncy227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Low dose hyper-radiosensitivity (HRS) and induced radioresistance (IRR) can be observed in the dose dependence of survival of many different cell lines. While surviving fraction decreases exponentially in a large-scale view, a local minimum can be found at around 0.5 Gy. Although, there is evidence that the regulation of apoptosis and DNA repair are involved in HRS and IRR, the fundamental causes of the phenomena remain unclear. The objective of the present study is to test whether the principle of minimum mutation load can provide an explanation for both low dose HRS and IRR. For this purpose, a mathematical model was elaborated considering radiation induced mutagenic DNA lesions as well as cell divisions as sources of mutations. It was presumed that cell number is in dynamic equilibrium in the tissue, the number of mutations follows Poisson distribution, and its average is proportional to absorbed dose. For each value of absorbed dose, the minimum number of mutations were computed for different surviving fractions. Then that surviving fraction was plotted that results in the lowest number of mutations. One minimum or multiple minima can be seen in the dose dependence of surviving fractions with reasonable values for the model parameters: spontaneous and radiation induced mutation rate. Although the mechanisms remain unclear, the principle of minimum mutation load provides a potential explanation for low dose HRS and IRR and for the fact that they are mostly observed in cell lines with defected DNA repair.
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Affiliation(s)
- Balázs G Madas
- Radiation Biophysics Group, Environmental Physics Department, MTA Centre for Energy Research, Budapest, Hungary
| | - Emese J Drozsdik
- Radiation Biophysics Group, Environmental Physics Department, MTA Centre for Energy Research, Budapest, Hungary
- Department of Biological Physics, Doctoral School of Physics, ELTE Eötvös Loránd University, Budapest, Hungary
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Rollison DE, Viarisio D, Amorrortu RP, Gheit T, Tommasino M. An Emerging Issue in Oncogenic Virology: the Role of Beta Human Papillomavirus Types in the Development of Cutaneous Squamous Cell Carcinoma. J Virol 2019; 93:e01003-18. [PMID: 30700603 PMCID: PMC6430537 DOI: 10.1128/jvi.01003-18] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Evidence suggests that beta human papillomaviruses (HPVs), together with ultraviolet radiation, contribute to the development of cutaneous squamous cell carcinoma. Beta HPVs appear to be not the main drivers of carcinogenesis but rather facilitators of the accumulation of ultraviolet-induced DNA mutations. Beta HPVs are promoters of skin carcinogenesis, although they are dispensable for the maintenance of the malignant phenotype. Therefore, beta HPV represents a target for skin cancer prevention, especially in high-risk populations.
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Affiliation(s)
- Dana E Rollison
- Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Daniele Viarisio
- Infection and Cancer Epidemiology, Deutsches Krebsforschungszentrum, Heidelberg, Germany
| | | | - Tarik Gheit
- Infections and Cancer Biology Group, International Agency for Research on Cancer (IARC), Lyon, France
| | - Massimo Tommasino
- Infections and Cancer Biology Group, International Agency for Research on Cancer (IARC), Lyon, France
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Ichida H, Morita R, Shirakawa Y, Hayashi Y, Abe T. Targeted exome sequencing of unselected heavy-ion beam-irradiated populations reveals less-biased mutation characteristics in the rice genome. Plant J 2019; 98:301-314. [PMID: 30584677 PMCID: PMC6850588 DOI: 10.1111/tpj.14213] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/20/2018] [Accepted: 12/18/2018] [Indexed: 05/19/2023]
Abstract
Heavy-ion beams have been widely utilized as a novel and effective mutagen for mutation breeding in diverse plant species, but the induced mutation spectrum is not fully understood at the genome scale. We describe the development of a multiplexed and cost-efficient whole-exome sequencing procedure in rice, and its application to characterize an unselected population of heavy-ion beam-induced mutations. The bioinformatics pipeline identified single-nucleotide mutations as well as small and large (>63 kb) insertions and deletions, and showed good agreement with the results obtained with conventional polymerase chain reaction (PCR) and sequencing analyses. We applied the procedure to analyze the mutation spectrum induced by heavy-ion beams at the population level. In total, 165 individual M2 lines derived from six irradiation conditions as well as eight pools from non-irradiated 'Nipponbare' controls were sequenced using the newly established target exome sequencing procedure. The characteristics and distribution of carbon-ion beam-induced mutations were analyzed in the absence of bias introduced by visual mutant selections. The average (±SE) number of mutations within the target exon regions was 9.06 ± 0.37 induced by 150 Gy irradiation of dry seeds. The mutation frequency changed in parallel to the irradiation dose when dry seeds were irradiated. The total number of mutations detected by sequencing unselected M2 lines was correlated with the conventional mutation frequency determined by the occurrence of morphological mutants. Therefore, mutation frequency may be a good indicator for sequencing-based determination of the optimal irradiation condition for induction of mutations.
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Affiliation(s)
- Hiroyuki Ichida
- RIKEN Nishina Center for Accelerator‐Based ScienceWakoSaitama351‐0198Japan
| | - Ryouhei Morita
- RIKEN Nishina Center for Accelerator‐Based ScienceWakoSaitama351‐0198Japan
| | - Yuki Shirakawa
- RIKEN Nishina Center for Accelerator‐Based ScienceWakoSaitama351‐0198Japan
| | - Yoriko Hayashi
- RIKEN Nishina Center for Accelerator‐Based ScienceWakoSaitama351‐0198Japan
| | - Tomoko Abe
- RIKEN Nishina Center for Accelerator‐Based ScienceWakoSaitama351‐0198Japan
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12
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Roberts SA, Brown AJ, Wyrick JJ. Recurrent Noncoding Mutations in Skin Cancers: UV Damage Susceptibility or Repair Inhibition as Primary Driver? Bioessays 2019; 41:e1800152. [PMID: 30801747 PMCID: PMC6571124 DOI: 10.1002/bies.201800152] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/05/2018] [Indexed: 12/14/2022]
Abstract
Somatic mutations arising in human skin cancers are heterogeneously distributed across the genome, meaning that certain genomic regions (e.g., heterochromatin or transcription factor binding sites) have much higher mutation densities than others. Regional variations in mutation rates are typically not a consequence of selection, as the vast majority of somatic mutations in skin cancers are passenger mutations that do not promote cell growth or transformation. Instead, variations in DNA repair activity, due to chromatin organization and transcription factor binding, have been proposed to be a primary driver of mutational heterogeneity in melanoma. However, as discussed in this review here, recent studies indicate that chromatin organization and transcription factor binding also significantly modulate the rate at which UV lesions form in DNA. The authors propose that local variations in lesion susceptibility may be an important driver of mutational hotspots in melanoma and other skin cancers, particularly at binding sites for ETS transcription factors.
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Affiliation(s)
- Steven A. Roberts
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164
| | - Alexander J. Brown
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164
| | - John J. Wyrick
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164
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Boucai L, Falcone J, Ukena J, Coombs CC, Zehir A, Ptashkin R, Berger MF, Levine RL, Fagin JA. Radioactive Iodine-Related Clonal Hematopoiesis in Thyroid Cancer Is Common and Associated With Decreased Survival. J Clin Endocrinol Metab 2018; 103:4216-4223. [PMID: 30137527 PMCID: PMC6194804 DOI: 10.1210/jc.2018-00803] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/13/2018] [Indexed: 11/19/2022]
Abstract
CONTEXT Radioactive iodine (RAI) has been epidemiologically associated with the development of hematologic malignancies. Clonal hematopoiesis (CH) is a precursor clonal state that confers increased risk of leukemia and occurs at an elevated rate in patients with thyroid cancer relative to other solid tumors. OBJECTIVE We explore if the high prevalence of CH may be a result of RAI exposure and whether CH may be a surrogate in the association between RAI and leukemia. DESIGN CH, CH-potential driver (CH-PD), and overall survival were evaluated in 279 patients with advanced thyroid carcinoma. RESULTS The prevalence of CH in patients with thyroid cancer was 37%, and that of CH-PD was 5.2%. Age was the strongest predictor of CH and CH-PD. For every year increase in age, there was a 5% and 13% increase in the odds of CH and CH-PD, respectively. RAI dose was significantly associated with CH and CH-PD, even after adjustment for age, external beam radiation therapy, and chemotherapy. For every 10 mCi increase in the dose of RAI administered, there was a 2% and 4% increase in the odds of CH and CH-PD, respectively. Patients with CH-PD previously exposed to RAI had a significantly poorer survival, even when stratified by age (heart rate = 3.75, 95% CI = 1.23 to 11.5, P = 0.02). CONCLUSIONS RAI was associated with a high prevalence of CH, and CH is a precursor state of hematologic malignancies. The implications of this study may favor identification of CH in patients where the risks might outweigh the benefits of receiving RAI therapy for thyroid cancer.
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Affiliation(s)
- Laura Boucai
- Division of Endocrinology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York
- Correspondence and Reprint Requests: Laura Boucai, MD, MS, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 313, New York, New York 10065. E-mail:
| | - John Falcone
- Weill Cornell Medical College, New York, New York
| | - Jenny Ukena
- Division of Endocrinology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Catherine C Coombs
- Division of Hematology and Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Ahmet Zehir
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ryan Ptashkin
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Michael F Berger
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ross L Levine
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, New York
- Department of Medicine, Leukemia Service, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - James A Fagin
- Division of Endocrinology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, New York
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Abstract
BACKGROUND This paper assesses possible reasons why Hermann J. Muller avoided peer-review of data that became the basis of his Nobel Prize award for producing gene mutations in male Drosophila by X-rays. METHODS Extensive correspondence between Muller and close associates and other materials were obtained from preserved papers to compliment extensive publications by and about Muller in the open literature. These were evaluated for potential historical insights that clarify why he avoided peer-review of his Nobel Prize findings. RESULTS This paper clarifies the basis of Muller's (Muller HJ, Sci 66 84-87, 1927c) belief that he produced X-ray induced "gene" mutations in Drosophila. It then shows his belief was contemporaneously challenged by his longtime friend/confidant and Drosophila geneticist, Edgar Altenburg. Altenburg insisted that Muller may have simply poked large holes in chromosomes with massive doses of X-rays, and needed to provide proof of gene "point" mutations. Given the daunting and uncertain task to experimentally address this criticism, especially within the context of trying to become first to produce gene mutations, it is proposed that Muller purposely avoided peer-review while rushing to publish his paper in Science to claim discovery primacy without showing any data. The present paper also explores ethical issues surrounding these actions, including those of the editor of Science, James McKeen Catell and Altenburg, and their subsequent impact on the scientific and regulatory communities. CONCLUSION This historical analysis suggests that Muller deliberately avoided peer-review on his most significant findings because he was extremely troubled by the insightful and serious criticism of Altenburg, which suggested he had not produced gene mutations as he claimed. Nonetheless, Muller manipulated this situation (i.e., publishing a discussion within Science with no data, publishing a poorly written non-peer reviewed conference proceedings with no methods and materials, and no references) due to both the widespread euphoria over his claim of gene mutation and confidence that Altenburg would not publically challenge him. This situation permitted Muller to achieve his goal to be the first to produce gene mutations while buying him time to later try to experimentally address Altenburg's criticisms, and a possible way to avoid discovery of his questionable actions.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.
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15
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Stepchenkova EI, Shiriaeva AA, Pavlov YI. Deletion of the DEF1 gene does not confer UV-immutability but frequently leads to self-diploidization in yeast Saccharomyces cerevisiae. DNA Repair (Amst) 2018; 70:49-54. [PMID: 30172224 DOI: 10.1016/j.dnarep.2018.08.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/19/2018] [Accepted: 08/21/2018] [Indexed: 11/18/2022]
Abstract
In yeast Saccharomyces cerevisiae, the DEF1 gene is responsible for regulation of many cellular processes including ubiquitin-dependent degradation of DNA metabolism proteins. Recently it has been proposed that Def1 promotes degradation of the catalytic subunit of DNA polymerase δ at sites of DNA damage and regulates a switch to specialized polymerases and, as a consequence, DNA-damage induced mutagenesis. The idea was based substantially on the severe defects in induced mutagenesis observed in the def1 mutants. We describe that UV mutability of def1Δ strains is actually only moderately affected, while the virtual absence of UV mutagenesis in many def1Δ clones is caused by a novel phenotype of the def1 mutants, proneness to self-diploidization. Diploids are extremely frequent (90%) after transformation of wild-type haploids with def1::kanMX disruption cassette and are frequent (2.3%) in vegetative haploid def1 cultures. Such diploids look "UV immutable" when assayed for recessive forward mutations but have normal UV mutability when assayed for dominant reverse mutations. The propensity for frequent self-diploidization in def1Δ mutants should be taken into account in studies of the def1Δ effect on mutagenesis. The true haploids with def1Δ mutation are moderately UV sensitive but retain substantial UV mutagenesis for forward mutations: they are fully proficient at lower doses and only partially defective at higher doses of UV. We conclude that Def1 does not play a critical role in damage-induced mutagenesis.
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Affiliation(s)
- E I Stepchenkova
- Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, Saint-Petersburg, 199034, Russia; Department of Genetics, Saint-Petersburg State University, Saint-Petersburg, 199034, Russia; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - A A Shiriaeva
- Department of Genetics, Saint-Petersburg State University, Saint-Petersburg, 199034, Russia; Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Moscow, 143028, Russia; Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya, 29, Saint-Petersburg, 195251, Russia; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Y I Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Departments of Microbiology and Pathology, Biochemistry and Molecular Biology, Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA.
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16
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Calabrese EJ. Was Muller's 1946 Nobel Prize research for radiation-induced gene mutations peer-reviewed? Philos Ethics Humanit Med 2018; 13:6. [PMID: 29875023 PMCID: PMC5991452 DOI: 10.1186/s13010-018-0060-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/17/2018] [Indexed: 05/31/2023] Open
Abstract
This historical analysis indicates that it is highly unlikely that the Nobel Prize winning research of Hermann J. Muller was peer-reviewed. The published paper of Muller lacked a research methods section, cited no references, and failed to acknowledge and discuss the work of Gager and Blakeslee (PNAS 13:75-79, 1927) that claimed to have induced gene mutation via ionizing radiation six months prior to Muller's non-data Science paper (Muller, Science 66(1699):84-87, 1927a). Despite being well acclimated into the scientific world of peer-review, Muller choose to avoid the peer-review process on his most significant publication. It appears that Muller's actions were strongly influenced by his desire to claim primacy for the discovery of gene mutation. The actions of Muller have important ethical lessons and implications today, when self-interest trumps one's obligations to society and the scientific culture that supports the quest for new knowledge and discovery.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA, 01003, USA.
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17
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Abstract
Wild-type p53 is involved in cellular response to DNA damage including cell cycle control, DNA repair and activation of apoptosis. Accumulation of p53 protein following DNA damage may initiate the apoptotic process, resulting in cell death. DNA damage induced by radiation is an example of apoptotic stimulus involving p53. Regulation of apoptosis by p53 can occur through transcriptional regulation of pro-apoptotic (e.g. bax) and anti-apoptotic (e.g. bel-2) factors. Although wild-type p53 usually sensitizes cells to radiation therapy, p53 mutations have a variable effect on radiation response. For example p53 mutations in bone or breast tumors have been found to be associated with resistance to chemotherapeutic drugs or ionizing radiation. Mutated p53 has has been reported to increase sensitivity to radiation and drugs in colorectal and bladder tumors. The present brief commentary tries to find an explanation at molecular level of these conflicting results.
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Affiliation(s)
- V Chiarugi
- Laboratory of Molecular Biology, Institute of General Pathology, University of Florence, Italy
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18
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Gajowik A, Dobrzyńska MM. The evaluation of protective effect of lycopene against genotoxic influence of X-irradiation in human blood lymphocytes. Radiat Environ Biophys 2017; 56:413-422. [PMID: 28913689 PMCID: PMC5655585 DOI: 10.1007/s00411-017-0713-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 09/07/2017] [Indexed: 05/07/2023]
Abstract
Many studies suggest that exogenous antioxidants may protect cells against DNA damage caused with ionizing radiation. One of the most powerful antioxidants is lycopene (LYC), a carotenoid derived from tomatoes. The aim of this study was to investigate, using the comet assay, whether LYC can act as protectors/modifiers and prevent DNA damage induced in human blood lymphocytes, as well as to mitigate the effects of radiation exposure. In this project, LYC, dissolved in DMSO at a concentration of 10, 20 or 40 μM/ml of cell suspension, was added to the isolated lymphocytes from human blood at appropriate intervals before or after the X-irradiation at doses of 0.5, 1 and 2 Gy. Cell viability in all groups was maintained at above 70%. The results showed the decrease of DNA damage in cells treated with various concentrations of LYC directly and 1 h before exposure to X-rays compared to the control group exposed to irradiation alone. Contrary results were observed in cells exposed to LYC immediately after exposure to ionizing radiation. The studies confirmed the protective effect of LYC against DNA damage induced by ionizing radiation, but after irradiation the carotenoid did not stimulate of DNA repair and cannot act as modifier. However, supplementation with LYC, especially at lower doses, may be useful in protection from radiation-induced oxidative damage.
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Affiliation(s)
- Aneta Gajowik
- Department of Radiation Protection and Radiobiology, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Street, 00-791, Warsaw, Poland.
| | - Małgorzata M Dobrzyńska
- Department of Radiation Protection and Radiobiology, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska Street, 00-791, Warsaw, Poland
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19
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Calabrese EJ. Flaws in the LNT single-hit model for cancer risk: An historical assessment. Environ Res 2017; 158:773-788. [PMID: 28756009 DOI: 10.1016/j.envres.2017.07.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 05/10/2023]
Abstract
The LNT single-hit model was derived from the Nobel Prize-winning research of Herman J. Muller who showed that x-rays could induce gene mutations in Drosophila and that the dose response for these so-called mutational events was linear. Lewis J. Stadler, another well-known and respected geneticist at the time, strongly disagreed with and challenged Muller's claims. Detailed evaluations by Stadler over a prolonged series of investigations revealed that Muller's experiments had induced gross heritable chromosomal damage instead of specific gene mutations as had been claimed by Muller at his Nobel Lecture. These X-ray-induced alterations became progressively more frequent and were of larger magnitude (more destructive) with increasing doses. Thus, Muller's claim of having induced discrete gene mutations represented a substantial speculative overreach and was, in fact, without proof. The post hoc arguments of Muller to support his gene mutation hypothesis were significantly challenged and weakened by a series of new findings in the areas of cytogenetics, reverse mutation, adaptive and repair processes, and modern molecular methods for estimating induced genetic damage. These findings represented critical and substantial limitations to Muller's hypothesis of X-ray-induced gene mutations. Furthermore, they challenged the scientific foundations used in support of the LNT single-hit model by severing the logical nexus between Muller's data on radiation-induced inheritable alterations and the LNT single-hit model. These findings exposed fundamental scientific flaws that undermined not only the seminal recommendation of the 1956 BEAR I Genetics Panel to adopt the LNT single-hit Model for risk assessment but also any rationale for its continued use in the present day.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
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20
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Vo NTK, Sokeechand BSH, Seymour CB, Mothersill CE. Characterizing responses to gamma radiation by a highly clonogenic fish brain endothelial cell line. Environ Res 2017; 156:297-305. [PMID: 28376375 DOI: 10.1016/j.envres.2017.03.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE The clonogenic property and radiobiological responses of a fish brain endothelial cell line, eelB, derived from the American eel were studied. METHODS Clonogenic assays were performed to determine the plating efficiency of the eelB cells and to evaluate the clonogenic survival fractions after direct irradiation to low-dose low-LET gamma radiation or receiving irradiated cell conditioned medium in the bystander effect experiments. RESULT eelB had the second highest plating efficiency ever reported to date for fish cell lines. Large eelB macroscopic colonies could be formed in a short period of time and were easy to identify and count. Unlike with other fish clonogenic cell lines, which had a relatively slow proliferation profile, clonogenic assays with the eelB cells could be completed as early as 12 days in culture. After direct irradiation with gamma rays at low doses ranging from 0.1Gy to 5Gy, the dose-clonogenic survival curve of the eelB cell line showed a linear trend and did not develop a shoulder region. A classical radio-adaptive response was not induced with the clonogenic survival endpoint when the priming dose (0.1 or 0.5Gy) was delivered 6h before the challenge dose (3 or 5Gy). However, a radio-adaptive response was observed in progeny cells that survived 5Gy and developed lethal mutations. eelB appeared to lack the ability to produce damaging radiation-induced bystander signals on both eelB and HaCaT recipient cells. CONCLUSION eelB cell line could be a very useful cell model in the study of radiation impacts on the aquatic health.
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Affiliation(s)
- Nguyen T K Vo
- Radiation Sciences Program, School of Graduate and Postdoctoral Studies, McMaster University, Hamilton, ON, Canada.
| | - Bibi S H Sokeechand
- Radiation Sciences Program, School of Graduate and Postdoctoral Studies, McMaster University, Hamilton, ON, Canada
| | - Colin B Seymour
- Department of Biology, McMaster University, Hamilton, ON, Canada
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Abstract
The aim of this article is to offer a broader, mechanism-based, analytical tool than that used by (Rühm et al 2016 Ann. ICRP 45 262-79) for the interpretation of cancer induction relationships. The article explains the limitations of this broader analytical tool and the implications of its use in view of the publications by Leuraud et al 2015 (Lancet Haematol. 2 e276-81) and Richardson et al 2015 (Br. Med. J. 351 h5359). The publication by Rühm et al 2016 (Ann. ICRP 45 262-79), which is clearly work in progress, reviews the current status of the dose and dose-rate effectiveness factor (DDREF) as recommended by the ICRP. It also considers the issues which might influence a reassessment of both the value of the DDREF as well as its application in radiological protection. In this article, the problem is approached from a different perspective and starts by commenting on the limited scientific data used by Rühm et al 2016 (Ann. ICRP 45 262-79) to develop their analysis which ultimately leads them to use a linear-quadratic dose effect relationship to fit solid cancer mortality data from the Japanese life span study of atomic bomb survivors. The approach taken here includes more data on the induction of DNA double strand breaks and, using experimental data taken from the literature, directly relates the breaks to cell killing, chromosomal aberrations and somatic mutations. The relationships are expanded to describe the induction of cancer as arising from radiation induced cytological damage coupled to cell killing since the cancer mutated cell has to survive to express its malignant nature. Equations are derived for the induction of cancer after both acute and chronic exposure to sparsely ionising radiation. The equations are fitted to the induction of cancer in mice to illustrate a dose effect relationship over the total dose range. The 'DDREF' derived from the two equations varies with dose and the DDREF concept is called into question. Although the equation for acute exposure can be used to analyse atomic bomb survivor data, the fitting is dominated by the quadratic dose component. Thus, little useful information can be derived about the linear dose component which is important for the derivation of low dose rate risk. The ICRP are advised to derive the risk at low dose rates from epidemiological studies of, for example, worker populations, together with information from cellular radiation biological research.
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Calabrese EJ. The threshold vs LNT showdown: Dose rate findings exposed flaws in the LNT model part 1. The Russell-Muller debate. Environ Res 2017; 154:435-451. [PMID: 28109526 DOI: 10.1016/j.envres.2016.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/10/2016] [Indexed: 05/10/2023]
Abstract
This paper assesses the discovery of the dose-rate effect in radiation genetics and how it challenged fundamental tenets of the linear non-threshold (LNT) dose response model, including the assumptions that all mutational damage is cumulative and irreversible and that the dose-response is linear at low doses. Newly uncovered historical information also describes how a key 1964 report by the International Commission for Radiological Protection (ICRP) addressed the effects of dose rate in the assessment of genetic risk. This unique story involves assessments by two leading radiation geneticists, Hermann J. Muller and William L. Russell, who independently argued that the report's Genetic Summary Section on dose rate was incorrect while simultaneously offering vastly different views as to what the report's summary should have contained. This paper reveals occurrences of scientific disagreements, how conflicts were resolved, which view(s) prevailed and why. During this process the Nobel Laureate, Muller, provided incorrect information to the ICRP in what appears to have been an attempt to manipulate the decision-making process and to prevent the dose-rate concept from being adopted into risk assessment practices.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, United States.
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23
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Beyea J. Lessons to be learned from a contentious challenge to mainstream radiobiological science (the linear no-threshold theory of genetic mutations). Environ Res 2017; 154:362-379. [PMID: 28167448 DOI: 10.1016/j.envres.2017.01.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 06/06/2023]
Abstract
There are both statistically valid and invalid reasons why scientists with differing default hypotheses can disagree in high-profile situations. Examples can be found in recent correspondence in this journal, which may offer lessons for resolving challenges to mainstream science, particularly when adherents of a minority view attempt to elevate the status of outlier studies and/or claim that self-interest explains the acceptance of the dominant theory. Edward J. Calabrese and I have been debating the historical origins of the linear no-threshold theory (LNT) of carcinogenesis and its use in the regulation of ionizing radiation. Professor Calabrese, a supporter of hormesis, has charged a committee of scientists with misconduct in their preparation of a 1956 report on the genetic effects of atomic radiation. Specifically he argues that the report mischaracterized the LNT research record and suppressed calculations of some committee members. After reviewing the available scientific literature, I found that the contemporaneous evidence overwhelmingly favored a (genetics) LNT and that no calculations were suppressed. Calabrese's claims about the scientific record do not hold up primarily because of lack of attention to statistical analysis. Ironically, outlier studies were more likely to favor supra-linearity, not sub-linearity. Finally, the claim of investigator bias, which underlies Calabrese's accusations about key studies, is based on misreading of text. Attention to ethics charges, early on, may help seed a counter narrative explaining the community's adoption of a default hypothesis and may help focus attention on valid evidence and any real weaknesses in the dominant paradigm.
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Affiliation(s)
- Jan Beyea
- Consulting in the Public Interest, Lambertville, NJ 08530, United States.
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Calabrese EJ. The threshold vs LNT showdown: Dose rate findings exposed flaws in the LNT model part 2. How a mistake led BEIR I to adopt LNT. Environ Res 2017; 154:452-458. [PMID: 27974149 DOI: 10.1016/j.envres.2016.11.024] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 11/30/2016] [Indexed: 05/10/2023]
Abstract
This paper reveals that nearly 25 years after the National Academy of Sciences (NAS), Biological Effects of Ionizing Radiation (BEIR) I Committee (1972) used Russell's dose-rate data to support the adoption of the linear-no-threshold (LNT) dose response model for genetic and cancer risk assessment, Russell acknowledged a significant under-reporting of the mutation rate of the historical control group. This error, which was unknown to BEIR I, had profound implications, leading it to incorrectly adopt the LNT model, which was a decision that profoundly changed the course of risk assessment for radiation and chemicals to the present.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, School of Public Health and Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
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Cheng J, Liu M, Song W, Ding L, Liu J, Zhang L, Cen K. Enhanced hydrogen production of Enterobacter aerogenes mutated by nuclear irradiation. Bioresour Technol 2017; 227:50-55. [PMID: 28013136 DOI: 10.1016/j.biortech.2016.12.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 06/06/2023]
Abstract
Nuclear irradiation was used for the first time to generate efficient mutants of hydrogen-producing bacteria Enterobacter aerogenes, which were screened with larger colour circles of more fermentative acid by-products. E. aerogenes cells were mutated by nuclear irradiation of 60Co γ-rays. The screened E. aerogenes ZJU1 mutant with larger colour circles enhanced the hydrogenase activity from 89.8 of the wild strain to 157.4mLH2/(gDWh). The hereditary stability of the E. aerogenes ZJU1 mutant was certified after over ten generations of cultivation. The hydrogen yield of 301mLH2/gglucose with the mutant was higher by 81.8% than that of 166mL/gglucose with the wild strain. The peak hydrogen production rate of 27.2mL/(L·h) with the mutant was higher by 40.9% compared with that of 19.3mL/(L·h) with the wild strain. The mutant produced more acetate and butyrate but less ethanol compared with the wild strain during hydrogen fermentation.
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Affiliation(s)
- Jun Cheng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
| | - Min Liu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Wenlu Song
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China; Department of Life Science and Engineering, Jining University, Jining 273155, China
| | - Lingkan Ding
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Jianzhong Liu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Li Zhang
- Shandong Botong New Energy Company, Jining 272000, China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
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26
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Boaventura P, Batista R, Pestana A, Reis M, Mendes A, Eloy C, Sobrinho-Simões M, Soares P. TERT promoter mutations: a genetic signature of benign and malignant thyroid tumours occurring in the context of tinea capitis irradiation. Eur J Endocrinol 2017; 176:49-55. [PMID: 27760791 DOI: 10.1530/eje-16-0740] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/15/2016] [Accepted: 10/19/2016] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The aim of this study is to evaluate the frequency and molecular characteristics of TERTp mutations in thyroid adenomas and carcinomas occurring in the low-dose radiation exposure tinea capitis setting. DESIGN AND METHODS Twenty-seven patients with 34 well-differentiated thyroid carcinomas and 28 patients with 29 follicular adenomas diagnosed in a Portuguese tinea capitis cohort were studied. Blood samples were obtained from all the patients. Screening for TERTp mutations was performed by PCR amplification followed by Sanger sequencing. A series of 33 sporadic thyroid adenomas was used as control. RESULTS TERTp mutations were detected in six of the 28 patients with adenoma (21.4%) and in four of the 27 patients with carcinoma (14.8%). Three tumours (two carcinomas and one adenoma) had the tandem mutation -124/-125 GG>AA (30.0%), whereas the remaining seven had the -124G > A. The 20.7% frequency of TERTp mutations in adenomas contrasts with the absence of mutations in the adenomas from the control group and from most series on record, whereas the one found in carcinomas (11.8%) is similar to those reported in the literature for sporadic carcinomas. CONCLUSION TERTp mutations, including the tandem mutation -124/-125 GG>AA not described previously in thyroid tumours, appear to represent a genetic signature for thyroid tumours in patients submitted to low-dose X-ray irradiation. The high frequency of TERTp mutations in the adenomas of our cohort contrasts with their absence in sporadically occurring, as well as in adenomas of the Chernobyl series.
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Affiliation(s)
- Paula Boaventura
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
| | - Rui Batista
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
| | - Ana Pestana
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
| | - Marta Reis
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
| | - Adélia Mendes
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
| | - Catarina Eloy
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
| | - Manuel Sobrinho-Simões
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
- Faculty of MedicineUniversity of Porto, Porto, Portugal
- Department of PathologyCentro Hospitalar de S. João, Porto, Portugal
| | - Paula Soares
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of PortoPorto, Portugal
- i3S - Instituto de Investigação e Inovação em SaúdeUniversidade do Porto, Porto, Portugal
- Faculty of MedicineUniversity of Porto, Porto, Portugal
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Kurniasih SD, Yamasaki T, Kong F, Okada S, Widyaningrum D, Ohama T. UV-mediated Chlamydomonas mutants with enhanced nuclear transgene expression by disruption of DNA methylation-dependent and independent silencing systems. Plant Mol Biol 2016; 92:629-641. [PMID: 27761764 DOI: 10.1007/s11103-016-0529-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
In this investigation, we succeeded to generate Chlamydomonas mutants that bear dramatically enhanced ability for transgene expression. To yield these mutants, we utilized DNA methyltransferase deficient strain. These mutants must be useful as a plant cell factory. Chlamydomonas reinhardtii (hereafter Chlamydomonas) is a green freshwater microalga. It is a promising cell factory for the production of recombinant proteins because it rapidly grows in simple salt-based media. However, expression of transgenes integrated into the nuclear genome of Chlamydomonas is very poor, probably because of severe transcriptional silencing irrespective of the genomic position. In this study, we generated Chlamydomonas mutants by ultraviolet (UV)-mediated mutagenesis of maintenance-type DNA methyltransferase gene (MET1)-null mutants to overcome this disadvantage. We obtained several mutants with an enhanced ability to overexpress various transgenes irrespective of their integrated genomic positions. In addition, transformation efficiencies were significantly elevated. Our findings indicate that in addition to mechanisms involving MET1, transgene expression is regulated by a DNA methylation-independent transgene silencing system in Chlamydomonas. This is in agreement with the fact that DNA methylation occurs rarely in this organism. The generated mutants may be useful for the low-cost production of therapeutic proteins and eukaryotic enzymes based on their rapid growth in simple salt-based media.
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Affiliation(s)
- Sari Dewi Kurniasih
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kochi, 782-8502, Japan
| | - Tomohito Yamasaki
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kochi, 782-8502, Japan
| | - Fantao Kong
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kochi, 782-8502, Japan
| | - Sigeru Okada
- Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural & Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Dwiyantari Widyaningrum
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kochi, 782-8502, Japan
| | - Takeshi Ohama
- School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kochi, 782-8502, Japan.
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28
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Boubriak I, Akimkina T, Polischuk V, Dmitriev A, Mccready S, Grodzinsky D. [Not Available]. Tsitol Genet 2016; 50:34-59. [PMID: 30484602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Thirty years after the Chernobyl explosion we still lack information regarding the genetic effects of radionuclide contamination on the plant population. For example, are plants adapting to the low dose of chronic ionising irradiation and showing improved resistance to radiation damage? Are they coping with changing/increased pathogenicity of fungi and viruses in the Chernobyl exclusion zone? Are plant populations rapidly accumulating mutational load and should we expect rapid microevolutionary changes in plants in the Chernobyl area? This review will try to summarise the current knowledge on these aspects of plant genetics and ecology and draw conclusions on the importance of further studies in the area around Chernobyl.
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29
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Yemets AI, Blume RY, Sorochinsky BV. [Not Available]. Tsitol Genet 2016; 50:80-89. [PMID: 30484604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
It is known that the most suitable plant indicator targets for radiation pollution biomonitoring are conifers, because they have high radiosensitivity. In this review are briefly considered previously accumulated information about the genetic nature of morphological abnormalities in gymnosperms, induced by acute and chronic irradiation in the exclusion zone of the Chornobyl nuclear power plant. Since in the last decade appeared additional number of important research results, dedicated to the analysis of molecular biological and molecular genetic effects of chronic irradiation on the coniferous plants growing in the exclusion zone of the Chornobyl disaster, all these results are also analyzed in current review.
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30
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Saini N, Roberts SA, Klimczak LJ, Chan K, Grimm SA, Dai S, Fargo DC, Boyer JC, Kaufmann WK, Taylor JA, Lee E, Cortes-Ciriano I, Park PJ, Schurman SH, Malc EP, Mieczkowski PA, Gordenin DA. The Impact of Environmental and Endogenous Damage on Somatic Mutation Load in Human Skin Fibroblasts. PLoS Genet 2016; 12:e1006385. [PMID: 27788131 PMCID: PMC5082821 DOI: 10.1371/journal.pgen.1006385] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/23/2016] [Indexed: 12/24/2022] Open
Abstract
Accumulation of somatic changes, due to environmental and endogenous lesions, in the human genome is associated with aging and cancer. Understanding the impacts of these processes on mutagenesis is fundamental to understanding the etiology, and improving the prognosis and prevention of cancers and other genetic diseases. Previous methods relying on either the generation of induced pluripotent stem cells, or sequencing of single-cell genomes were inherently error-prone and did not allow independent validation of the mutations. In the current study we eliminated these potential sources of error by high coverage genome sequencing of single-cell derived clonal fibroblast lineages, obtained after minimal propagation in culture, prepared from skin biopsies of two healthy adult humans. We report here accurate measurement of genome-wide magnitude and spectra of mutations accrued in skin fibroblasts of healthy adult humans. We found that every cell contains at least one chromosomal rearrangement and 600–13,000 base substitutions. The spectra and correlation of base substitutions with epigenomic features resemble many cancers. Moreover, because biopsies were taken from body parts differing by sun exposure, we can delineate the precise contributions of environmental and endogenous factors to the accrual of genetic changes within the same individual. We show here that UV-induced and endogenous DNA damage can have a comparable impact on the somatic mutation loads in skin fibroblasts. Somatic genomes are constantly accumulating changes caused by endogenous lesions, errors in DNA replication and repair, as well as environmental insults. Despite the importance of somatic genome instability in aging and age-related pathologies, including cancers, accurate measurements of mutation loads in healthy cells is still missing. In this study, we developed an experimental approach to accurately determine the somatic genome changes accrued in cell lineages over the lifetime of healthy humans. We show that the amounts and types of mutations in skin cells resemble many cancers, thus indicating that the mechanisms that lead to carcinogenesis are also functional in healthy cells. Moreover, sun-exposed skin cells have a higher mutation load attributable to ultraviolet radiation (UV) unlike cells from hips that were protected by clothing. Our work provides precise measurements of the mutation loads in single cells in human skin. Furthermore our data allowed defining the mutagenic impacts of environmental and endogenous processes within the same individual and led to conclusion that these processes have a comparable impact on the somatic mutation load.
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Affiliation(s)
- Natalie Saini
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Steven A. Roberts
- School of Molecular Biosciences, Washington State University, Pullman, Washington, United States Of America
| | - Leszek J. Klimczak
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Kin Chan
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Sara A. Grimm
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Shuangshuang Dai
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - David C. Fargo
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Jayne C. Boyer
- Department of Environmental Science and Engineering, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - William K. Kaufmann
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - Jack A. Taylor
- Epidemiology Branch, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Eunjung Lee
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States Of America
- Division of Genetics, Brigham and Women’s Hospital, Boston, Massachusetts, United States Of America
| | - Isidro Cortes-Ciriano
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States Of America
| | - Peter J. Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States Of America
- Division of Genetics, Brigham and Women’s Hospital, Boston, Massachusetts, United States Of America
| | - Shepherd H. Schurman
- Clinical Research Unit, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Ewa P. Malc
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - Piotr A. Mieczkowski
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - Dmitry A. Gordenin
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
- * E-mail:
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31
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Li G, Chern M, Jain R, Martin JA, Schackwitz WS, Jiang L, Vega-Sánchez ME, Lipzen AM, Barry KW, Schmutz J, Ronald PC. Genome-Wide Sequencing of 41 Rice (Oryza sativa L.) Mutated Lines Reveals Diverse Mutations Induced by Fast-Neutron Irradiation. Mol Plant 2016; 9:1078-81. [PMID: 27018389 DOI: 10.1016/j.molp.2016.03.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/05/2016] [Accepted: 03/07/2016] [Indexed: 05/05/2023]
Affiliation(s)
- Guotian Li
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, USA; Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Mawsheng Chern
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, USA; Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Rashmi Jain
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, USA; Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Joel A Martin
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Wendy S Schackwitz
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Liangrong Jiang
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, USA; School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Miguel E Vega-Sánchez
- Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Anna M Lipzen
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Kerrie W Barry
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Jeremy Schmutz
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA; HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Pamela C Ronald
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616, USA; Feedstocks Division, Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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32
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Grygoryev D, Gauny S, Lasarev M, Ohlrich A, Kronenberg A, Turker MS. Charged particle mutagenesis at low dose and fluence in mouse splenic T cells. Mutat Res 2016; 788:32-40. [PMID: 27055360 DOI: 10.1016/j.mrfmmm.2016.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 06/05/2023]
Abstract
High-energy heavy charged particles (HZE ions) found in the deep space environment can significantly affect human health by inducing mutations and related cancers. To better understand the relation between HZE ion exposure and somatic mutation, we examined cell survival fraction, Aprt mutant frequencies, and the types of mutations detected for mouse splenic T cells exposed in vivo to graded doses of densely ionizing (48)Ti ions (1GeV/amu, LET=107 keV/μm), (56)Fe ions (1GeV/amu, LET=151 keV/μm) ions, or sparsely ionizing protons (1GeV, LET=0.24 keV/μm). The lowest doses for (48)Ti and (56)Fe ions were equivalent to a fluence of approximately 1 or 2 particle traversals per nucleus. In most cases, Aprt mutant frequencies in the irradiated mice were not significantly increased relative to the controls for any of the particles or doses tested at the pre-determined harvest time (3-5 months after irradiation). Despite the lack of increased Aprt mutant frequencies in the irradiated splenocytes, a molecular analysis centered on chromosome 8 revealed the induction of radiation signature mutations (large interstitial deletions and complex mutational patterns), with the highest levels of induction at 2 particles nucleus for the (48)Ti and (56)Fe ions. In total, the results show that densely ionizing HZE ions can induce characteristic mutations in splenic T cells at low fluence, and that at least a subset of radiation-induced mutant cells are stably retained despite the apparent lack of increased mutant frequencies at the time of harvest.
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Affiliation(s)
- Dmytro Grygoryev
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States
| | - Stacey Gauny
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Michael Lasarev
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States
| | - Anna Ohlrich
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States
| | - Amy Kronenberg
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Mitchell S Turker
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, United States; Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, United States.
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Smirnova SG, Orlova NV, Krikunova LI, Mkrtchyan LS, Zamulaeva IA. [Frequency of Lymphocytes with Mutations at the Locus of T-Cell Receptor in Residents of Radiation Polluted Bryansk Region 28 Years after the Chernobyl Nuclear Power Plant Accident]. Radiats Biol Radioecol 2016; 56:285-292. [PMID: 30629875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The aim of this study is to assess the level of somatic mutagenesis according to the frequency of lymphocytes bearing mutations at the locus of T-cell receptor (TCR) in the residents of the Bryansk region contaminated with radionuclides as a result of the Chernobyl accident. The study was :conducted in 2014 in two regional centers - Klintsy and Novozybkov (average¹³⁷Cs pollution density of 322 and 708 kBq/m²,.respectively). The average frequency of the TCR-mutant cells in the total group of examined residents of the Bryansk region (n = 237) was not significantly different from that in the group of agematched control persons living in un- contaminated areas (n = 146): 3.8 x 10⁻⁴ vs 3.5 x 10⁻⁴, respectively (p = 0.84). However, after separation of examinees into 3 groups depending on age at the start of irradiation (at.the moment of the Chernobyl acci- dent) it was found that the average frequency of the TCR-mutant cells in the persons exposed in utero was 1.6 higher than that in the control group (p = 0.04). Proportion of persons with an increased frequency of the mutant cells (more than the age norm of this indicator) among prenatally exposed population reached 23.8%; which was about.4 times higher than in the control group (p = 0.04). Proportion of persons with an increased frequency of the TCR-mutant cells in group "0-17 years at the start of irradiation", was about 2 times higher than in controls, but this difference was not statistically significant (8.0% vs 4.3%, respectively, p = 0.33). In the third group "18 or more years old at the start of irradiation" we could not register the difference in the average frequency of theTCR mutant cells or the proportion of persons with an increased frequency of these cells in comparison with the age-matched control group. In general, comparison with earlier data shows that age-related regularities of somatic mutagenesis established 15-18 years after the Chernobyl accident persist at a later date (after 28 years in this study).
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Tan D, Tong XL, Hu H, Wu SY, Li CL, Xiong G, Xiang ZH, Dai FY, Lu C. Morphological characterization and molecular mapping of an irradiation-induced Speckled mutant in the silkworm, Bombyx mori. Insect Mol Biol 2016; 25:93-104. [PMID: 26661290 DOI: 10.1111/imb.12205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Speckled (Spc), an X-ray-induced lethal mutant of Bombyx mori, exhibits a mosaic dark-brown-spotted larval epidermis in both sexes and egg-laying problems only in females. Here, we report the morphological characterization and molecular mapping of the Spc mutant. Morphological investigations revealed that the epidermal ultrastructure of the small, dark-brown spots was more dense than that of the white regions in both Spc/+ mutants and wild type, and that the lethality of the Spc/Spc mutants occurred during early embryogenesis. Furthermore, the ovarioles and ovipositor were disconnected in approximately 85.5% of Spc/+ females, a further 2.5% had a connection between the ovarioles and ovipositor that was too narrow to lay eggs. The remaining females showed a normal connection similar to that of the wild type. We successfully narrowed down the location of the Spc mutation to a region on chromosome 4 that was ∼1041 kb long. Gene-prediction analysis identified 25 candidate genes in this region. Chromosome structure analysis indicated that a ∼305 kb deletion was included in the mapping region. Temporal and spatial reverse transcription PCR (RT-PCR) analysis showed that several genes in the mapped region are associated with the Spc mutant. Although the genes responsible for the Spc mutation were not definitively identified, our results further the current understanding of the complex mechanism underlying the multiple morphological defects in Spc mutants.
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Affiliation(s)
- D Tan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - X-L Tong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - H Hu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - S-Y Wu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - C-L Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - G Xiong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Z-H Xiang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - F-Y Dai
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - C Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
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Abstract
The ability to create mutations is an important step towards understanding bacterial physiology and virulence. While targeted approaches are invaluable, the ability to produce genome-wide random mutations can lead to crucial discoveries. Transposon mutagenesis is a useful approach, but many interesting mutations can be missed by these insertions that interrupt coding and noncoding sequences due to the integration of an entire transposon. Chemical mutagenesis and UV-based random mutagenesis are alternate approaches to isolate mutations of interest with the potential of only single nucleotide changes. Once a standard method, difficulty in identifying mutation sites had decreased the popularity of this technique. However, thanks to the recent emergence of economical whole-genome sequencing, this approach to making mutations can once again become a viable option. Therefore, this chapter provides an overview protocol for random mutagenesis using UV light or DNA-damaging chemicals.
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Affiliation(s)
- Jeffrey L Bose
- Department of Microbiology, Molecular Genetics and Immunology, The University of Kansas Medical Center, MSN 3029, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA.
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Dubrova YE. [Mutation Induction in the Mouse and Human Germline]. Genetika 2016; 52:24-36. [PMID: 27183790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The review describes the effects of exposure to mutagens on mutation induction in human and mouse germlines. The results of studies that evaluated inductions of mutations in human families subjected to irradiation are presented and discussed. The effects of exposure to mutagens on mutation induction in the mouse germline are also considered. We analyze and discuss the recent data on the genome-wide effects of irradiation on mutation induction in the mouse germline obtained by next-generation sequencing and comparative genome hybridization.
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Zavilgelsky GB, Melkina OE, Kotova VY, Konopleva MN, Manukhov IV, Pustovoit KS. [Photoreactivating Activity of Bioluminescence: Repair of UV-damaged DNA of Escherichia coli Occurs with Assistance of lux-Genes of Marine Bacteria]. Biofizika 2015; 60:898-905. [PMID: 26591600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The UV resistance of luminescent bacteria Escherichia coli AB1886 uvrA6 (pLeo1) containing the plasmid with luxCDABE genes of marine bacteria Photobacterium leiognathi is approximately two times higher than the UV resistance of non-luminous bacteria E. coli AB1886 uvrA6. Introduction of phr::kan(r) mutations (a defect in the functional activity of photolyase) into the genome of E. coli AB1886 uvrA6 (pLeo1) completely removes the high UV resistance of the cells. Therefore, photoreactivation that involves bacterial photolyase contributes mainly to the bioluminescence-induced DNA repair. It is shown that photoreactivating activity of bioluminescence of P. leiognathi is about 2.5 times lower compared with that one induced by a light source with λ > 385 nm. It is also shown that an increase in the bioluminescence intensity, induced by UV radiation in E. coli bacterial cells with a plasmid containing the luxCD ABE genes under RecA-LexA-regulated promoters, occurs only 25-30 min later after UV irradiation of cells and does not contribute to DNA repair. A quorum sensing regulatory system is not involved in the DNA repair by photolyase.
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Martincorena I, Roshan A, Gerstung M, Ellis P, Van Loo P, McLaren S, Wedge DC, Fullam A, Alexandrov LB, Tubio JM, Stebbings L, Menzies A, Widaa S, Stratton MR, Jones PH, Campbell PJ. Tumor evolution. High burden and pervasive positive selection of somatic mutations in normal human skin. Science 2015; 348:880-6. [PMID: 25999502 PMCID: PMC4471149 DOI: 10.1126/science.aaa6806] [Citation(s) in RCA: 1115] [Impact Index Per Article: 123.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
How somatic mutations accumulate in normal cells is central to understanding cancer development but is poorly understood. We performed ultradeep sequencing of 74 cancer genes in small (0.8 to 4.7 square millimeters) biopsies of normal skin. Across 234 biopsies of sun-exposed eyelid epidermis from four individuals, the burden of somatic mutations averaged two to six mutations per megabase per cell, similar to that seen in many cancers, and exhibited characteristic signatures of exposure to ultraviolet light. Remarkably, multiple cancer genes are under strong positive selection even in physiologically normal skin, including most of the key drivers of cutaneous squamous cell carcinomas. Positively selected mutations were found in 18 to 32% of normal skin cells at a density of ~140 driver mutations per square centimeter. We observed variability in the driver landscape among individuals and variability in the sizes of clonal expansions across genes. Thus, aged sun-exposed skin is a patchwork of thousands of evolving clones with over a quarter of cells carrying cancer-causing mutations while maintaining the physiological functions of epidermis.
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Affiliation(s)
| | - Amit Roshan
- MRC Cancer Unit, Hutchison-MRC Research Centre, University of Cambridge, Cambridge, UK
| | - Moritz Gerstung
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | - Peter Ellis
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | - Peter Van Loo
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK. Francis Crick Institute, London, UK. Department of Human Genetics, University of Leuven, Leuven, Belgium
| | - Stuart McLaren
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | - David C Wedge
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | - Anthony Fullam
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | | | - Jose M Tubio
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | - Lucy Stebbings
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | - Andrew Menzies
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | - Sara Widaa
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK
| | | | - Philip H Jones
- MRC Cancer Unit, Hutchison-MRC Research Centre, University of Cambridge, Cambridge, UK.
| | - Peter J Campbell
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, Cambridgeshire, UK. Department of Haematology, University of Cambridge, Cambridge, UK.
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Kusama Y, Inoue S, Jimbo H, Takaichi S, Sonoike K, Hihara Y, Nishiyama Y. Zeaxanthin and Echinenone Protect the Repair of Photosystem II from Inhibition by Singlet Oxygen in Synechocystis sp. PCC 6803. Plant Cell Physiol 2015; 56:906-16. [PMID: 25663484 DOI: 10.1093/pcp/pcv018] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 01/30/2015] [Indexed: 05/15/2023]
Abstract
Carotenoids are important components of antioxidative systems in photosynthetic organisms. We investigated the roles of zeaxanthin and echinenone in the protection of PSII from photoinhibition in Synechocystis sp. PCC 6803, using mutants of the cyanobacterium that lack these carotenoids. The activity of PSII in mutant cells deficient in either zeaxanthin or echinenone was more sensitive to strong light than the activity in wild-type cells, and the activity in mutant cells deficient in both carotenoids was hypersensitive to strong light, indicating that the absence of these carotenoids increased the extent of photoinhibition. Nonetheless, the rate of photodamage to PSII, as measured in the presence of chloramphenicol, which blocks the repair of PSII, was unaffected by the absence of either carotenoid, suggesting that these carotenoids might act by protecting the repair of PSII. Knockout of the gene for the so-called orange carotenoid protein (OCP), in which the 3'-hydroxyechinenone cofactor, a derivative of echinenone, is responsible for the thermal dissipation of excitation energy, increased the extent of photoinhibition but did not affect photodamage, suggesting that thermal dissipation also protects the repair of PSII. In mutant cells lacking OCP, as well as those lacking zeaxanthin and echinenone, the production of singlet oxygen was stimulated and the synthesis de novo of various proteins, including the D1 protein, was markedly suppressed under strong light. These observations suggest that the carotenoids and thermal dissipation might protect the repair of photodamaged PSII by depressing the levels of singlet oxygen that inhibits protein synthesis.
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Affiliation(s)
- Yuri Kusama
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570 Japan
| | - Shuhei Inoue
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570 Japan
| | - Haruhiko Jimbo
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570 Japan
| | - Shinichi Takaichi
- Department of Biology, Nippon Medical School, Kyonan-cho, Musashino, Tokyo, 180-0023 Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480 Japan
| | - Yukako Hihara
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570 Japan Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570 Japan
| | - Yoshitaka Nishiyama
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570 Japan Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570 Japan
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Wang JS, Sui JM, Xie YD, Guo HJ, Qiao LX, Zhao LL, Yu SL, Liu LX. Generation of peanut mutants by fast neutron irradiation combined with in vitro culture. J Radiat Res 2015; 56:437-445. [PMID: 25653418 PMCID: PMC4426915 DOI: 10.1093/jrr/rru121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 11/17/2014] [Accepted: 11/24/2014] [Indexed: 06/01/2023]
Abstract
Induced mutations have played an important role in the development of new plant varieties. In this study, we investigated the effects of fast neutron irradiation on somatic embryogenesis combined with plant regeneration in embryonic leaflet culture to develop new peanut (Arachis hypogaea L.) germplasm for breeding. The dry seeds of the elite cultivar Luhua 11 were irradiated with fast neutrons at dosages of 9.7, 14.0 and 18.0 Gy. The embryonic leaflets were separated and incubated in a medium with 10.0-mg/l 2,4-D to induce somatic embryogenesis. Next, they were incubated in a medium with 4.0-mg/l BAP for plant regeneration. As the irradiation dosage increased, the frequency of both somatic embryo formation and plantlet regeneration decreased. The regenerated plantlets were grafted onto rootstocks and were transplanted into the field. Later, the mature seeds of the regenerated plants were harvested. The M2 generation plants from most of the regenerated cultivars exhibited variations and segregation in vigor, plant height, branch and pod number, pod size, and pod shape. To determine whether the phenotypes were associated with genomic modification, we compared the DNA polymorphisms between the wild-type plants and 19 M3-generation individuals from different regenerated plants. We used 20 pairs of simple sequence repeat (SSR) primers and detected polymorphisms between most of the mutants and the wild-type plants (Luhua 11). Our results indicate that using a combination of fast neutron irradiation and tissue culture is an effective approach for creating new peanut germplasm.
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Affiliation(s)
- Jing-Shan Wang
- College of Life Sciences, Qingdao Agricultural University/Key Lab of Plant Biotechnology in Universities of Shandong Province, Qingdao 266109, China
| | - Jiong-Ming Sui
- College of Life Sciences, Qingdao Agricultural University/Key Lab of Plant Biotechnology in Universities of Shandong Province, Qingdao 266109, China
| | - Yong-Dun Xie
- Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, National Center of Space Mutagenesis for Crop Improvement, Beijing 100081, China
| | - Hui-Jun Guo
- Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, National Center of Space Mutagenesis for Crop Improvement, Beijing 100081, China
| | - Li-Xian Qiao
- College of Life Sciences, Qingdao Agricultural University/Key Lab of Plant Biotechnology in Universities of Shandong Province, Qingdao 266109, China
| | - Li-Lan Zhao
- Shandong Agricultural Broadcasting and Television School, Penglai 265600, China
| | - Shan-Lin Yu
- Peanut Research Institute, Shandong Academy of Agricultural Sciences, Qingdao 266100, China
| | - Lu-Xiang Liu
- Institute of Crop Science, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, National Center of Space Mutagenesis for Crop Improvement, Beijing 100081, China
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Abstract
This article traces disagreements about the genetic effects of low-dose radiation exposure as waged by James Neel (1915-2000), a central figure in radiation studies of Japanese populations after World War II, and Yuri Dubrova (1955-), who analyzed the 1986 Chernobyl nuclear power plant accident. In a 1996 article in Nature, Dubrova reported a statistically significant increase in the minisatellite (junk) DNA mutation rate in the children of parents who received a high dose of radiation from the Chernobyl accident, contradicting studies that found no significant inherited genetic effects among offspring of Japanese A-bomb survivors. Neel's subsequent defense of his large-scale longitudinal studies of the genetic effects of ionizing radiation consolidated current scientific understandings of low-dose ionizing radiation. The article seeks to explain how the Hiroshima/Nagasaki data remain hegemonic in radiation studies, contextualizing the debate with attention to the perceived inferiority of Soviet genetic science during the Cold War.
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Affiliation(s)
- Donna M Goldstein
- Department of Anthropology Hale Building, Campus Box 233, University of Colorado-Boulder, Boulder, CO, 80309-0233, USA,
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Viros A, Sanchez-Laorden B, Pedersen M, Furney SJ, Rae J, Hogan K, Ejiama S, Girotti MR, Cook M, Dhomen N, Marais R. Ultraviolet radiation accelerates BRAF-driven melanomagenesis by targeting TP53. Nature 2014; 511:478-482. [PMID: 24919155 PMCID: PMC4112218 DOI: 10.1038/nature13298] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 03/31/2014] [Indexed: 12/19/2022]
Abstract
Cutaneous melanoma is epidemiologically linked to ultraviolet radiation (UVR), but the molecular mechanisms by which UVR drives melanomagenesis remain unclear. The most common somatic mutation in melanoma is a V600E substitution in BRAF, which is an early event. To investigate how UVR accelerates oncogenic BRAF-driven melanomagenesis, we used a BRAF(V600E) mouse model. In mice expressing BRAF(V600E) in their melanocytes, a single dose of UVR that mimicked mild sunburn in humans induced clonal expansion of the melanocytes, and repeated doses of UVR increased melanoma burden. Here we show that sunscreen (UVA superior, UVB sun protection factor (SPF) 50) delayed the onset of UVR-driven melanoma, but only provided partial protection. The UVR-exposed tumours showed increased numbers of single nucleotide variants and we observed mutations (H39Y, S124F, R245C, R270C, C272G) in the Trp53 tumour suppressor in approximately 40% of cases. TP53 is an accepted UVR target in human non-melanoma skin cancer, but is not thought to have a major role in melanoma. However, we show that, in mice, mutant Trp53 accelerated BRAF(V600E)-driven melanomagenesis, and that TP53 mutations are linked to evidence of UVR-induced DNA damage in human melanoma. Thus, we provide mechanistic insight into epidemiological data linking UVR to acquired naevi in humans. Furthermore, we identify TP53/Trp53 as a UVR-target gene that cooperates with BRAF(V600E) to induce melanoma, providing molecular insight into how UVR accelerates melanomagenesis. Our study validates public health campaigns that promote sunscreen protection for individuals at risk of melanoma.
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Affiliation(s)
- Amaya Viros
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
| | - Berta Sanchez-Laorden
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
| | - Malin Pedersen
- Signal Transduction Team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Simon J. Furney
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
| | - Joel Rae
- Signal Transduction Team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Kate Hogan
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
| | - Sarah Ejiama
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
| | - Maria Romina Girotti
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
| | - Martin Cook
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
- Histopathology, Royal Surrey County Hospital, Egerton Road, Guildford, GU2 7XX UK
| | - Nathalie Dhomen
- Signal Transduction Team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Richard Marais
- Molecular Oncology Group, Cancer Research UK Manchester Institute, The University of Manchester, Wilmslow Road, Manchester, M20 4BX, UK
- Signal Transduction Team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
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Andreassi MG. [Genetic and molecular effects from medical ionizing radiation exposure]. G Ital Cardiol (Rome) 2014; 15:283-5. [PMID: 25002166 DOI: 10.1714/1563.17021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Yang C, Zhu J, Jiang Y, Wang X, Gu M, Wang Y, Kang H, Fan X, Sha L, Zhang H, Xuan P, Zhou Y. 100 Gy 60 Co γ-ray induced novel mutations in tetraploid wheat. ScientificWorldJournal 2014; 2014:725813. [PMID: 24982985 PMCID: PMC4055256 DOI: 10.1155/2014/725813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/25/2014] [Accepted: 04/27/2014] [Indexed: 11/17/2022] Open
Abstract
10 accessions of tetraploid wheat were radiated with 100 Gy (60)Co γ -ray. The germination energy, germination rate, special characters (secondary tillering, stalk with wax powder, and dwarf), meiotic process, and high-molecular-weight glutenin subunits (HMW-GSs) were observed. Different species has different radiation sensibility. With 1 seed germinated (5%), T. dicoccum (PI434999) is the most sensitive to this dose of radiation. With a seed germination rate of 35% and 40%, this dose also affected T. polonicum (As304) and T. carthlicum (As293). Two mutant dwarf plants, T. turgidum (As2255) 253-10 and T. polonicum (As302) 224-14, were detected. Abnormal chromosome pairings were observed in pollen mother cells of both T. dicoccoides (As835) 237-9 and T. dicoccoides (As838) 239-8 with HMW-GS 1Ax silent in seeds from them. Compared with the unirradiated seed of T. polonicum (As304) CK, a novel HMW-GS was detected in seed of T. polonicum (As304) 230-7 and its electrophoretic mobility was between 1By8 and 1Dy12 which were the HMW-GSs of Chinese Spring. These mutant materials would be resources for wheat breeding.
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Affiliation(s)
- Chuntao Yang
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
- Key Laboratory of Crop Genetic Resources and Improvement, Ministry of Education, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Jianshu Zhu
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Yun Jiang
- Institute of Biological and Nuclear Technology, Sichuan Academy of Agricultural Sciences, Chengdu, Sichuan 610061, China
| | - Xiaolu Wang
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Mengxue Gu
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Yi Wang
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Houyang Kang
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Xing Fan
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Lina Sha
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Haiqin Zhang
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
| | - Pu Xuan
- Institute of Biological and Nuclear Technology, Sichuan Academy of Agricultural Sciences, Chengdu, Sichuan 610061, China
| | - Yonghong Zhou
- Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
- Key Laboratory of Crop Genetic Resources and Improvement, Ministry of Education, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan 611130, China
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Manesh SS, Deperas-Kaminska M, Fotouhi A, Sangsuwan T, Harms-Ringdahl M, Wojcik A, Haghdoost S. Mutations and chromosomal aberrations in hMTH1-transfected and non-transfected TK6 cells after exposure to low dose rates of gamma radiation. Radiat Environ Biophys 2014; 53:417-425. [PMID: 24549366 DOI: 10.1007/s00411-014-0521-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 02/02/2014] [Indexed: 06/03/2023]
Abstract
The aim of the present study was to analyse the dose rate effect of gamma radiation at the level of mutations, chromosomal aberrations, and cell growth in TK6 cells with normal as well as reduced levels of hMTH1 protein. TK6 cells were exposed to gamma radiation at dose rates ranging from 1.4 to 30.0 mGy/h (chronic exposure) as well as 24 Gy/h (acute exposure). Cell growth, frequency of thymidine kinase mutants, and of chromosomal aberrations in painted chromosomes 2, 8, and 14 were analysed. A decline in cell growth and an increase in unstable-type chromosomal aberrations with increasing dose rate were observed in both cell lines. A dose rate effect was not seen on mutations or stable-type chromosomal aberrations in any of the two cell lines. Reduction in the hMTH1 protein does not influence the sensitivity of TK6 cells to gamma radiation. This result fits well with data of others generated with the same cell line.
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Affiliation(s)
- Sara Shakeri Manesh
- Department of Molecular Biosciences, Centre for Radiation Protection Research (CRPR), The Wenner-Gren Institute, Stockholm University, 106 91, Stockholm, Sweden
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Rahman I, Karim A, Idrees M, Khan MI. Cellular and genomic toxicity produced by UV light in Chinese hamster ovary cells. Pak J Pharm Sci 2014; 27:295-301. [PMID: 24577918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
UVB and UVC toxicity was detected in Chinese Hamster Ovary (CHO) cell lines AA8, UV5 and XEM2 (a V79-derived cell line expressing rat P450 1A1). Unlike FICZ-HPLC assay that showed induction of CYP1A1 enzyme activity after 20 minutes and 2 hour UVC exposure, the EROD assay showed no difference in cytochrome P450 1A1 (CYP1A1) activity after exposure to different doses of UVB and UVC light. Different cytotoxic and mutagenic effect of photo lesions induced by UVC and UVB light was investigated with the DRAG and HPRT assays, comparing the wild type cell line AA8 and the Nucleotide Excision Repair (NER) deficient cell line UV5. DRAG assay showed a significant difference in UV induced cytotoxicity between UVC and UVB reflecting the larger energy and toxic effect of UVC along with significant difference in UV induced toxicity between AA8 and UV5 cell lines. This was further validated through the HPRT assay, which also showed a significant difference in UVC (5 J/m(2)) induced mutagenic effect between these cell lines. In addition, HPRT assay showed the mutagenic effect of photosensitizer, acetophenone. These results show that UVB and UVC generate serious damage through photo products on DNA, and might induce the metabolic activity of CYP1A1.
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Affiliation(s)
- Inayatur Rahman
- Gandhara College of Pharmacy, Gandhara University, Peshawar, KPK, Pakistan
| | - Abdul Karim
- Department of Genetics, Microbiology and Toxicology, Stockholm University, SE Stockholm, Sweden
| | - Muhammad Idrees
- Department of Pathology, Khyber medical College, Peshawar, KPK, Pakistan
| | - Mohammad Iqbal Khan
- Department of Chemistry, Kohat University of Science and Technology, Kohat, KPK, Pakistan
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48
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Modorov MV. [Radiation doses and allozyme variability in the population of the northern red-backed vole (Clethrionomys rutilus) from the east urals radioactive trace zone]. Genetika 2014; 50:181-188. [PMID: 25711026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The paper estimates the external (due to radionuclides accumulated in the soil) and internal (due to incorporated radionuclides) exposure of rodents that live in the head of the East Urals Radioactive Trace (EURT). It is shown that in the last decades the dose rates were lower than the values that lead to doubling the number of mutations in the allozyme loci in mammals. The variability ofthe eight allozyme loci in populations of northern red-backed voles from the EURT zone and their neighboring plots, as well as the territories of the Urals and Trans-Urals with background levels of radioactive contamination, are analyzed. No differences in the pattern and frequency of allozymes that would distinguish the EURT samples from a number of other populations of the Urals, were found. In the control sample "Sysert", "unique" for the Ural populations of northern red-backed voles, alleles of the loci Got and Sod were marked, conspecific to a closely related species--the bank vole. This fact can be regarded as evidence of recent cross-species hybridization.
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Iuzhakov VV, Sevan'kaeva LE, Ul'ianenko SE, Iakovleva ND, Kuznetsova MN, Tsyganova MG, Fomina NK, Ingel' IE, Lychagin AA. [The effectiveness of fractionated exposure of sarcoma M-1 to gamma-radiation and fast neutrons]. ACTA ACUST UNITED AC 2014; 53:267-79. [PMID: 24450208 DOI: 10.7868/s0869803113020148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effectiveness of fractionated exposure to gamma- and neutron radiation in their separate and combined use on the growth and functional morphology of mutant p53 sarcoma M-1 in rats was studied. Investigation techniques included immunostaining of PCNA and mutant p53 expressing cells, determination of mitotic activity and apoptotic death of tumor cells, as well as computer analysis of microscopic images. The antitumor efficacy of different types of radiation is shown to be determined by different levels of apoptosis induction, reduced proliferation and cellularity. Neutron radiation of the impulse generator has a marked damaging effect on the vasculature and the development of tumor necrosis. Fractionated irradiation at equal daily doses led to the decrease in the relative effectiveness of radio-inactivation of tumor cells. After 9 fractions of irradiation, the calculated value of the RBE of fast neutrons normalized to the input dose of 1 Gy by the coefficient of tumor growth inhibition, a reduced proliferative activity of PCNA and induced apoptosis of tumor cells was 3.4, 3.7 and 3.1, respectively. In the mode of daily superfractionation with splitting the dose in two fractions, the effectiveness of the combined exposure corresponded to the additive effect of gamma- and neutron radiation with a tendency toward synergism. There are reasons to believe that high resistance of sarcoma M-1 to the ionizing radiation impact is due not only to a fraction of hypoxic cells, but also the mutant status of p53 gene.
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Rainger J, Keighren M, Keene DR, Charbonneau NL, Rainger JK, Fisher M, Mella S, Huang JTJ, Rose L, van't Hof R, Sakai LY, Jackson IJ, FitzPatrick DR. A trans-acting protein effect causes severe eye malformation in the Mp mouse. PLoS Genet 2013; 9:e1003998. [PMID: 24348270 PMCID: PMC3861116 DOI: 10.1371/journal.pgen.1003998] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 10/18/2013] [Indexed: 12/18/2022] Open
Abstract
Mp is an irradiation-induced mouse mutation associated with microphthalmia, micropinna and hind limb syndactyly. We show that Mp is caused by a 660 kb balanced inversion on chromosome 18 producing reciprocal 3-prime gene fusion events involving Fbn2 and Isoc1. The Isoc1-Fbn2 fusion gene (Isoc1Mp) mRNA has a frameshift and early stop codon resulting in nonsense mediated decay. Homozygous deletions of Isoc1 do not support a significant developmental role for this gene. The Fbn2-Isoc1 fusion gene (Fbn2Mp) predicted protein consists of the N-terminal Fibrillin-2 (amino acids 1–2646, exons 1–62) lacking the C-terminal furin-cleavage site with a short out-of-frame extension encoded by the final exon of Isoc1. The Mp limb phenotype is consistent with that reported in Fbn2 null embryos. However, severe eye malformations, a defining feature of Mp, are not seen in Fbn2 null animals. Fibrillin-2Mp forms large fibrillar structures within the rough endoplasmic reticulum (rER) associated with an unfolded protein response and quantitative mass spectrometry shows a generalised defect in protein secretion in conditioned media from mutant cells. In the embryonic eye Fbn2 is expressed within the peripheral ciliary margin (CM). Mp embryos show reduced canonical Wnt-signalling in the CM – known to be essential for ciliary body development - and show subsequent aplasia of CM-derived structures. We propose that the Mp “worse-than-null” eye phenotype plausibly results from a failure in normal trafficking of proteins that are co-expressed with Fbn2 within the CM. The prediction of similar trans-acting protein effects will be an important challenge in the medical interpretation of human mutations from whole exome sequencing. With the current increase in large-scale sequencing efforts, correct interpretation of mutation consequences has never been more important. Here, we present evidence for a trans-acting protein effect in a novel mutation of Fbn2, associated with severe developmental eye defects not found in loss of function Fibrillin-2 alleles. The mutant protein is expressed in the developing eye but is unable to exit the cells, instead forming large protein aggregates within the endoplasmic reticulum. We observed ER-stress in mutant eyes, and detected a general reduction to secretion of co-expressed proteins in cell cultures. We propose that similar effects could be caused by mutations to other proteins that are trafficked through the ER, highlighting a disease mechanism that results in different clinical outcomes than observed, or predicted, from loss-off-function alleles.
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Affiliation(s)
- Joe Rainger
- The MRC Human Genetics Unit, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Margaret Keighren
- The MRC Human Genetics Unit, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Douglas R. Keene
- Shriners Hospital for Children, Portland, Oregon, United States of America
| | - Noe L. Charbonneau
- Shriners Hospital for Children, Portland, Oregon, United States of America
| | - Jacqueline K. Rainger
- The MRC Human Genetics Unit, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Malcolm Fisher
- The MRC Human Genetics Unit, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Sebastien Mella
- The MRC Human Genetics Unit, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Jeffrey T-J. Huang
- Biomarker and Drug Analysis Core Facility, Medical Research Institute, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Lorraine Rose
- Molecular Medicine Centre, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Rob van't Hof
- Molecular Medicine Centre, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Lynne Y. Sakai
- Shriners Hospital for Children, Portland, Oregon, United States of America
| | - Ian J. Jackson
- The MRC Human Genetics Unit, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
- * E-mail: (IJJ); (DRF)
| | - David R. FitzPatrick
- The MRC Human Genetics Unit, MRC Institute of Genetic and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
- * E-mail: (IJJ); (DRF)
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