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Movafagh A, Abadi A, Mazloumi Z, Kolahi A, Sheikhpour M, Rezaei-Tavirani M, Moradi A, Ahadi M, Aghamaleki F, Safavi N, Heidary M, Zamani M, Rad S, Entezari M, Hashemi M. Comparison and frequency of cell cultured in 48-h and 72-h mitotically treated with phytohemagglutinin-M: Both promise for normal and cancer cells. CLINICAL CANCER INVESTIGATION JOURNAL 2020. [DOI: 10.4103/ccij.ccij_6_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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2
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Kaushal S, Freudenreich CH. The role of fork stalling and DNA structures in causing chromosome fragility. Genes Chromosomes Cancer 2019; 58:270-283. [PMID: 30536896 DOI: 10.1002/gcc.22721] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/13/2018] [Accepted: 12/03/2018] [Indexed: 12/19/2022] Open
Abstract
Alternative non-B form DNA structures, also called secondary structures, can form in certain DNA sequences under conditions that produce single-stranded DNA, such as during replication, transcription, and repair. Direct links between secondary structure formation, replication fork stalling, and genomic instability have been found for many repeated DNA sequences that cause disease when they expand. Common fragile sites (CFSs) are known to be AT-rich and break under replication stress, yet the molecular basis for their fragility is still being investigated. Over the past several years, new evidence has linked both the formation of secondary structures and transcription to fork stalling and fragility of CFSs. How these two events may synergize to cause fragility and the role of nuclease cleavage at secondary structures in rare and CFSs are discussed here. We also highlight evidence for a new hypothesis that secondary structures at CFSs not only initiate fragility but also inhibit healing, resulting in their characteristic appearance.
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Affiliation(s)
- Simran Kaushal
- Department of Biology, Tufts University, Medford, Massachusetts
| | - Catherine H Freudenreich
- Department of Biology, Tufts University, Medford, Massachusetts.,Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts
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Cytosine deamination and base excision repair cause R-loop-induced CAG repeat fragility and instability in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2017; 114:E8392-E8401. [PMID: 28923949 DOI: 10.1073/pnas.1711283114] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
CAG/CTG repeats are structure-forming repetitive DNA sequences, and expansion beyond a threshold of ∼35 CAG repeats is the cause of several human diseases. Expanded CAG repeats are prone to breakage, and repair of the breaks can cause repeat contractions and expansions. In this study, we found that cotranscriptional R-loops formed at a CAG-70 repeat inserted into a yeast chromosome. R-loops were further elevated upon deletion of yeast RNaseH genes and caused repeat fragility. A significant increase in CAG repeat contractions was also observed, consistent with previous human cell studies. Deletion of yeast cytosine deaminase Fcy1 significantly decreased the rate of CAG repeat fragility and contractions in the rnh1Δrnh201Δ background, indicating that Fcy1-mediated deamination is one cause of breakage and contractions in the presence of R-loops. Furthermore, base excision repair (BER) is responsible for causing CAG repeat contractions downstream of Fcy1, but not fragility. The Rad1/XPF and Rad2/XPG nucleases were also important in protecting against contractions, but through BER rather than nucleotide excision repair. Surprisingly, the MutLγ (Mlh1/Mlh3) endonuclease caused R-loop-dependent CAG fragility, defining an alternative function for this complex. These findings provide evidence that breakage at expanded CAG repeats occurs due to R-loop formation and reveal two mechanisms for CAG repeat instability: one mediated by cytosine deamination of DNA engaged in R-loops and the other by MutLγ cleavage. Since disease-causing CAG repeats occur in transcribed regions, our results suggest that R-loop-mediated fragility is a mechanism that could cause DNA damage and repeat-length changes in human cells.
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Gadgil R, Barthelemy J, Lewis T, Leffak M. Replication stalling and DNA microsatellite instability. Biophys Chem 2016; 225:38-48. [PMID: 27914716 DOI: 10.1016/j.bpc.2016.11.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/05/2016] [Accepted: 11/05/2016] [Indexed: 01/08/2023]
Abstract
Microsatellites are short, tandemly repeated DNA motifs of 1-6 nucleotides, also termed simple sequence repeats (SRSs) or short tandem repeats (STRs). Collectively, these repeats comprise approximately 3% of the human genome Subramanian et al. (2003), Lander and Lander (2001) [1,2], and represent a large reservoir of loci highly prone to mutations Sun et al. (2012), Ellegren (2004) [3,4] that contribute to human evolution and disease. Microsatellites are known to stall and reverse replication forks in model systems Pelletier et al. (2003), Samadashwily et al. (1997), Kerrest et al. (2009) [5-7], and are hotspots of chromosomal double strand breaks (DSBs). We briefly review the relationship of these repeated sequences to replication stalling and genome instability, and present recent data on the impact of replication stress on DNA fragility at microsatellites in vivo.
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Affiliation(s)
- R Gadgil
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - J Barthelemy
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - T Lewis
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - M Leffak
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA.
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Palmieri MJ, Andrade-Vieira LF, Campos JMS, Dos Santos Gedraite L, Davide LC. Cytotoxicity of Spent Pot Liner on Allium cepa root tip cells: A comparative analysis in meristematic cell type on toxicity bioassays. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 133:442-447. [PMID: 27517141 DOI: 10.1016/j.ecoenv.2016.07.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 07/06/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
Spent Pot Liner (SPL) is a waste generated during the production of aluminum. It is comprised of a mixture of substances most of which, like cyanide, aluminum and fluoride, are toxic. Previous studies indicate the highly toxic nature of SPL. However studies using cells of the differentiation/elongation zone of the root meristem (referred as M2 cells in this study) after a proper recovery period in water were never considered. Using these cells could be useful to further understanding the toxicity mechanisms of SPL. A comparative approach between the effects on M2 cells and meristematic cells of the proximal meristem zone (referred as M1 cells in this study) could lead to understanding how DNA damage caused by SPL behaves on successive generations of cells. Allium cepa cells were exposed to 4 different concentrations of SPL (2.5, 5, 7.5 and 10gL(-1)) mixed with soil and diluted in a CaCl2 0.01M to simulate the ionic forces naturally encountered on the environment. A solution containing only soil diluted on CaCl2 0.01M was used as control. M1 and M2 cells were evaluated separately, taking into account four different parameters: (1) mitotic alterations (MA); (2) presence of condensed nuclei (CN); (3) mitotic index (MI); (4) presence of micronucleus (MCN). Significant differences were observed between M1 and M2 roots tip cells for these four parameters accessed. M1 cells was more prompt to reveal citogenotoxicity through the higher frequency of MA observed. Meanwhile, for M2 cells higher frequencies of MCN and CN was noticed, followed by a reduction of MI. Also, it was possible to detect significant differences between the tested treatments and the control on every case. These results indicate SPL toxic effects carries on to future cells generations. This emphasizes the need to properly manage this waste. Joint evaluation of cells from both M1 and M2 regions was proven valuable for the evaluation of a series of parameters on all toxicity tests.
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Affiliation(s)
- Marcel José Palmieri
- Departament of Biology, Universidade Federal de Lavras (UFLA), Campus Universitário, Zip Code 37200-000, Lavras, Minas Gerais State, Brazil
| | - Larissa Fonseca Andrade-Vieira
- Departament of Biology, Universidade Federal de Lavras (UFLA), Campus Universitário, Zip Code 37200-000, Lavras, Minas Gerais State, Brazil
| | - José Marcello Salabert Campos
- Biological Sciences Institute, Universidade Federal de Juiz de Fora (UFJF), Campus Martelos, Zip Code 36036-900, Juiz de Fora, Minas Gerais State, Brazil
| | - Leonardo Dos Santos Gedraite
- Departament of Biology, Universidade Federal de Lavras (UFLA), Campus Universitário, Zip Code 37200-000, Lavras, Minas Gerais State, Brazil
| | - Lisete Chamma Davide
- Departament of Biology, Universidade Federal de Lavras (UFLA), Campus Universitário, Zip Code 37200-000, Lavras, Minas Gerais State, Brazil.
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Usdin K, House NCM, Freudenreich CH. Repeat instability during DNA repair: Insights from model systems. Crit Rev Biochem Mol Biol 2015; 50:142-67. [PMID: 25608779 DOI: 10.3109/10409238.2014.999192] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The expansion of repeated sequences is the cause of over 30 inherited genetic diseases, including Huntington disease, myotonic dystrophy (types 1 and 2), fragile X syndrome, many spinocerebellar ataxias, and some cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Repeat expansions are dynamic, and disease inheritance and progression are influenced by the size and the rate of expansion. Thus, an understanding of the various cellular mechanisms that cooperate to control or promote repeat expansions is of interest to human health. In addition, the study of repeat expansion and contraction mechanisms has provided insight into how repair pathways operate in the context of structure-forming DNA, as well as insights into non-canonical roles for repair proteins. Here we review the mechanisms of repeat instability, with a special emphasis on the knowledge gained from the various model systems that have been developed to study this topic. We cover the repair pathways and proteins that operate to maintain genome stability, or in some cases cause instability, and the cross-talk and interactions between them.
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Affiliation(s)
- Karen Usdin
- Laboratory of Cell and Molecular Biology, NIDDK, NIH , Bethesda, MD , USA
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Simi S, Ballardin M, Casella M, De Marchi D, Hartwig V, Giovannetti G, Vanello N, Gabbriellini S, Landini L, Lombardi M. Is the genotoxic effect of magnetic resonance negligible? Low persistence of micronucleus frequency in lymphocytes of individuals after cardiac scan. Mutat Res 2008; 645:39-43. [PMID: 18804118 DOI: 10.1016/j.mrfmmm.2008.08.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/01/2008] [Accepted: 08/08/2008] [Indexed: 11/24/2022]
Abstract
Magnetic resonance imaging is a diagnostic technique widely used in medicine and showing a growing impact in cardiology. Biological effects associated to magnetic resonance electromagnetic fields have received far little attention, but it cannot be ruled out that these fields can alter DNA structure. The present study aimed at to identify possible DNA damage induced by magnetic resonance scan in humans. Lymphocyte cultures from healthy subjects had been exposed into magnetic resonance device for different times and under different variable magnetic exposure in order to build dose-effect curves, using micronuclei induction as biological marker. Replicate cultures were also left for 24h at room temperature before stimulation, to verify possible damage recovery. Furthermore, micronuclei induction and recovery up to 120h have been also evaluated in circulating lymphocytes of individuals after cardiac scan. A dose-dependent increase of micronuclei frequency was observed in vitro. However after 24h, the frequency returns to control value when the exposure is within diagnostic dosage. After in vivo scan, a significant increase in micronuclei is found till 24h, after the frequencies slowly return to control value.
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Affiliation(s)
- Silvana Simi
- Cell Biology and Cytogenetics Unit, Institute of Clinical Physiology, C.N.R., Pisa, Italy.
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Casella M, Miniati M, Monti S, Minichilli F, Bianchi F, Simi S. No evidence of chromosome damage in chronic obstructive pulmonary disease (COPD). Mutagenesis 2006; 21:167-71. [PMID: 16567348 DOI: 10.1093/mutage/gel015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality in industrialized countries. It is characterized by a progressive airflow limitation resulting from an abnormal inflammatory response of the lungs to inhaled gases and particles. Since oxidative stress is thought to play a role in COPD, and since increased oxidative stress is associated with chromosomal instability in several diseases, we investigated whether such relationship also exists in COPD. Whole blood lymphocytes from 49 COPD patients and 48 age- and sex-matched controls were cultivated in vitro and cytogenetic damage was evaluated by micronucleus (MN) and sister-chromatid-exchange (SCE) assays. In patients with COPD, MN frequency was not significantly different from that of controls. Similarly, SCE frequency did not differ in the two groups suggesting no disturbance in DNA replication. Unlike other diseases characterized by oxidative stress, COPD does not appear to be associated with DNA damage.
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Affiliation(s)
- Marta Casella
- Cell Biology and Cytogenetics Unit, Institute of Clinical Physiology, National Research Council, Pisa, Italy
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Casella M, Manfredi S, Andreassi MG, Vassalle C, Prontera C, Simi S, Maffei S. Hormone replacement therapy: One-year follow up of DNA damage. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2005; 585:14-20. [PMID: 15996896 DOI: 10.1016/j.mrgentox.2005.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Revised: 01/24/2005] [Accepted: 03/17/2005] [Indexed: 11/23/2022]
Abstract
Although hormone replacement therapy (HRT) may offer considerable benefits for menopausal women, the potential cancer risk may limit its use. This work aimed at assessing whether HRT is able to induce DNA damage in postmenopausal women monitored by the micronucleus (MN) test, which provides a reliable biomarker of genotoxicity and cancer risk assessment. A group of 16 healthy women (non-smokers) in spontaneous menopause were given oral estradiol (2 mg oral micronized 17-beta estradiol daily) for 1 month, followed by a 30-day wash-out period and a transdermal treatment with 17-beta estradiol (1.5 mg gel daily) during 1 month. Oral intake of dihydrogesterone (10 mg/day for 12 days/month) was cyclically combined with oral or transdermal estradiol during the next 9 months. Venous blood samples were collected before the treatment, and after 1, 3, 6 and 12 months of therapy. Slides were scored blind and MN frequency was evaluated as number of micronuclei per 1000 binucleated cells. The baseline plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E2) were simultaneously measured. The means of MN frequency were 18.2+/-1.6, 18.6+/-2.1, 14.8+/-1.5, 15.9+/-1.0 and 17.7+/-1.3 for samples collected before and at 1, 3, 6 and 12 months, respectively. The MN frequencies at every sampling time did not statistically differ from the basal values. In addition, no statistically significant associations between MN values and hormone levels of E2 and FSH were observed throughout the entire study. This study shows the absence of any significant increase of MN frequencies in women undergoing oral and/or transdermal HRT, sequentially monitored for up to 12 months of therapy.
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Affiliation(s)
- Marta Casella
- Institute of Clinical Physiology, CNR-CREAS, Via Moruzzi 1, 56124 Pisa, Italy
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Del Carratore R, Ciucci F, Beffy P, Casella M, Puntoni M, Simi S, Simili M. Human myotonic dystrophy protein kinase effect in S. cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1745:74-83. [PMID: 15894391 DOI: 10.1016/j.bbamcr.2005.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 03/23/2005] [Accepted: 04/08/2005] [Indexed: 11/29/2022]
Abstract
Human myotonic dystrophy protein kinase (DMPK), the product of the myotonic dystrophy (DM) locus, is a member of a novel class of multidomain serine-threonine protein kinases, which interacts with members of the Rho family of small GTPases. DMPK has been shown to affect the cell growth, size and shape in different organisms, from fission yeast to man, but its physiological role is still unclear. We examined the effect of the overexpression of two forms of human DMPK, full-length (DMFL) and a C-terminal truncated form (DMT) on the growth and cell morphology of S. cerevisiae, which possesses a DMPK homologous gene (CBK1) important for polarized growth and cell division. We report that the overexpression of either forms of human DMPK did not complement the CBK1 function in the haploid strain WR208-1a, deleted for CBK1. The truncated form, but not the full length one, slowed down growth rate and induced elongation of the haploid wild type strain CBK1. Similar results were obtained in the diploid wild type strain RS112 of S. cerevisiae where also the full-length form was effective. These effects were abolished when either DMFL or DMT were mutated in the ATP binding site (K100R mutation), suggesting that the kinase activity of DMPK is required. Interestingly, DMPK localization in yeast is similar to that of Cbk1 protein suggesting that it might affect a pathway, which regulates cell morphogenesis and progression through cell cycle, possibly involving CBK1.
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Affiliation(s)
- Renata Del Carratore
- Institute of Clinical Physiology, National Council of Research, Via Moruzzi 1, 56100 Pisa, Italy.
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Andreassi MG, Botto N, Simi S, Casella M, Manfredi S, Lucarelli M, Venneri L, Biagini A, Picano E. Diabetes and chronic nitrate therapy as co-determinants of somatic DNA damage in patients with coronary artery disease. J Mol Med (Berl) 2005; 83:279-86. [PMID: 15770499 DOI: 10.1007/s00109-005-0634-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Accepted: 12/16/2004] [Indexed: 02/02/2023]
Abstract
Somatic DNA damage has been linked to coronary artery disease (CAD). However, whether genetic instability is linked to CAD per se or to concomitant potentially genotoxic metabolic and pharmacological factors remains still unclear. The aim of this study was to evaluate the determinants of somatic DNA damage in a large population of patients undergoing coronary angiography. A total of 278 in-hospital patients (215 men, age 61.8+/-0.7 years) were studied by using micronucleus assay (MN) in human lymphocytes, which is one of the most commonly used biomarker for somatic DNA damage. Significant CAD (>50% diameter stenosis) was present in 210 patients (179 men, age 62.3+/-0.7 years). Normal coronary arteries were observed in 68 patients (35 men, age 60.2+/-1.7 years). There were no significant differences between patients with and without CAD, but patients with multivessel disease had the highest MN levels (P=0.01). MN frequency was also found significantly higher in presence of type 2 diabetes (P<0.0001), dyslipidemia (P=0.048) and nitrate therapy (P=0.0002). A significant additive effect was also observed between diabetes and nitrate therapy (P=0.02). On multivariate logistic regression analysis, diabetes [odds ratio=6.8 (95% confidence interval, 3.2-14.5), P<0.0001] and nitrate therapy [odds ratio=2.4 (95% confidence interval, 1.3-4.7), P=0.01] remained the only significant determinants for the 50th percentile of MN (>12 per thousand). These results indicated that diabetes and, to a lesser extent, chronic nitrate therapy are major determinants of somatic DNA instability in patients with CAD. DNA damage might represent an additional pathogenetic dimension and a possible therapeutic target in the still challenging management of coronary artery disease concerning diabetics.
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