Telomere-mediated chromosomal instability triggers TLR4 induced inflammation and death in mice.

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Rabindra N Bhattacharjee

Full Text Available BACKGROUND: Telomeres are essential to maintain chromosomal stability. Cells derived from mice lacking telomerase RNA component (mTERC-/- mice display elevated telomere-mediated chromosome instability. Age-dependent telomere shortening and associated chromosome instability reduce the capacity to respond to cellular stress occurring during inflammation and cancer. Inflammation is one of the important risk factors in cancer progression. Controlled innate immune responses mediated by Toll-like receptors (TLR are required for host defense against infection. Our aim was to understand the role of chromosome/genome instability in the initiation and maintenance of inflammation. METHODOLOGY/PRINCIPAL FINDINGS: We examined the function of TLR4 in telomerase deficient mTERC-/- mice harbouring chromosome instability which did not develop any overt immunological disorder in pathogen-free condition or any form of cancers at this stage. Chromosome instability was measured in metaphase spreads prepared from wildtype (mTERC+/+, mTERC+/- and mTERC-/- mouse splenocytes. Peritoneal and/or bone marrow-derived macrophages were used to examine the responses of TLR4 by their ability to produce inflammatory mediators TNFalpha and IL6. Our results demonstrate that TLR4 is highly up-regulated in the immune cells derived from telomerase-null (mTERC-/- mice and lipopolysaccharide, a natural ligand for TLR4 stabilises NF-kappaB binding to its promoter by down-regulating ATF-3 in mTERC-/- macrophages. CONCLUSIONS/SIGNIFICANCE: Our findings implied that background chromosome instability in the cellular level stabilises the action of TLR4-induced NF-kappaB action and sensitises cells to produce excess pro-inflammatory mediators. Chromosome/genomic instability data raises optimism for controlling inflammation by non-toxic TLR antagonists among high-risk groups.

Sister chromatid cohesion defects are associated with chromosome instability in Hodgkin lymphoma cells

International Nuclear Information System (INIS)

Sajesh, Babu V; Lichtensztejn, Zelda; McManus, Kirk J

2013-01-01

Chromosome instability manifests as an abnormal chromosome complement and is a pathogenic event in cancer. Although a correlation between abnormal chromosome numbers and cancer exist, the underlying mechanisms that cause chromosome instability are poorly understood. Recent data suggests that aberrant sister chromatid cohesion causes chromosome instability and thus contributes to the development of cancer. Cohesion normally functions by tethering nascently synthesized chromatids together to prevent premature segregation and thus chromosome instability. Although the prevalence of aberrant cohesion has been reported for some solid tumors, its prevalence within liquid tumors is unknown. Consequently, the current study was undertaken to evaluate aberrant cohesion within Hodgkin lymphoma, a lymphoid malignancy that frequently exhibits chromosome instability. Using established cytogenetic techniques, the prevalence of chromosome instability and aberrant cohesion was examined within mitotic spreads generated from five commonly employed Hodgkin lymphoma cell lines (L-1236, KM-H2, L-428, L-540 and HDLM-2) and a lymphocyte control. Indirect immunofluorescence and Western blot analyses were performed to evaluate the localization and expression of six critical proteins involved in the regulation of sister chromatid cohesion. We first confirmed that all five Hodgkin lymphoma cell lines exhibited chromosome instability relative to the lymphocyte control. We then determined that each Hodgkin lymphoma cell line exhibited cohesion defects that were subsequently classified into mild, moderate or severe categories. Surprisingly, ~50% of the mitotic spreads generated from L-540 and HDLM-2 harbored cohesion defects. To gain mechanistic insight into the underlying cause of the aberrant cohesion we examined the localization and expression of six critical proteins involved in cohesion. Although all proteins produced the expected nuclear localization pattern, striking differences in RAD21

Aurora-A Expression Is Independently Associated with Chromosomal Instability in Colorectal Cancer

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Yoshifumi Baba

2009-05-01

Full Text Available AURKA (the official symbol for Aurora-A, STK15, or BTAK regulates the function of centrosomes, spindles, and kinetochores for proper mitotic progression. AURKA overexpression is observed in various cancers including colon cancer, and a link between AURKA and chromosomal instability (CIN has been proposed. However, no study has comprehensively examined AURKA expression in relation to CIN or prognosis using a large number of tumors. Using 517 colorectal cancers in two prospective cohort studies, we detected AURKA overexpression (by immunohistochemistry in 98 tumors (19%. We assessed other molecular events including loss of heterozygosity (LOH in 2p, 5q, 17q, and 18q, the CpG island methylation phenotype (CIMP, and microsatellite instability (MSI. Prognostic significance of AURKA was evaluated by Cox regression and Kaplan-Meier method. In both univariate and multivariate logistic regressions, AURKA overexpression was significantly associated with CIN (defined as the presence of LOH in any of the chromosomal segments; multivariate odds ratio, 2.97; 95% confidence interval, 1.40–6.29; P = .0045. In multivariate analysis, AURKA was associated with cyclin D1 expression (P = .010 and inversely with PIK3CA mutation (P=.014, fatty acid synthase expression (P=.028, and family history of colorectal cancer (P = .050, but not with sex, age, body mass index, tumor location, stage, CIMP, MSI, KRAS, BRAF, BMI, LINE-1 hypomethylation, p53, p21, β-catenin, or cyclooxygenase 2. AURKA was not significantly associated with clinical outcome or survival. In conclusion, AURKA overexpression is independently associated with CIN in colorectal cancer, supporting a potential role of Aurora kinase-A in colorectal carcinogenesis through genomic instability (rather than epigenomic instability.

APC/C Dysfunction Limits Excessive Cancer Chromosomal Instability.

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Sansregret, Laurent; Patterson, James O; Dewhurst, Sally; López-García, Carlos; Koch, André; McGranahan, Nicholas; Chao, William Chong Hang; Barry, David J; Rowan, Andrew; Instrell, Rachael; Horswell, Stuart; Way, Michael; Howell, Michael; Singleton, Martin R; Medema, René H; Nurse, Paul; Petronczki, Mark; Swanton, Charles

2017-02-01

Intercellular heterogeneity, exacerbated by chromosomal instability (CIN), fosters tumor heterogeneity and drug resistance. However, extreme CIN correlates with improved cancer outcome, suggesting that karyotypic diversity required to adapt to selection pressures might be balanced in tumors against the risk of excessive instability. Here, we used a functional genomics screen, genome editing, and pharmacologic approaches to identify CIN-survival factors in diploid cells. We find partial anaphase-promoting complex/cyclosome (APC/C) dysfunction lengthens mitosis, suppresses pharmacologically induced chromosome segregation errors, and reduces naturally occurring lagging chromosomes in cancer cell lines or following tetraploidization. APC/C impairment caused adaptation to MPS1 inhibitors, revealing a likely resistance mechanism to therapies targeting the spindle assembly checkpoint. Finally, CRISPR-mediated introduction of cancer somatic mutations in the APC/C subunit cancer driver gene CDC27 reduces chromosome segregation errors, whereas reversal of an APC/C subunit nonsense mutation increases CIN. Subtle variations in mitotic duration, determined by APC/C activity, influence the extent of CIN, allowing cancer cells to dynamically optimize fitness during tumor evolution. We report a mechanism whereby cancers balance the evolutionary advantages associated with CIN against the fitness costs caused by excessive genome instability, providing insight into the consequence of CDC27 APC/C subunit driver mutations in cancer. Lengthening of mitosis through APC/C modulation may be a common mechanism of resistance to cancer therapeutics that increase chromosome segregation errors. Cancer Discov; 7(2); 218-33. ©2017 AACR.See related commentary by Burkard and Weaver, p. 134This article is highlighted in the In This Issue feature, p. 115. ©2017 American Association for Cancer Research.

CINcere Modelling : What Have Mouse Models for Chromosome Instability Taught Us?

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Simon, Judith E; Bakker, Bjorn; Foijer, Floris

2015-01-01

Chromosomal instability (CIN) is a process leading to errors in chromosome segregation and results in aneuploidy, a state in which cells have an abnormal number of chromosomes. CIN is a hallmark of cancer, and furthermore linked to ageing and age-related diseases such as Alzheimer's. Various mouse

Chromosomal instability and double minute chromosomes in a breast cancer patient

International Nuclear Information System (INIS)

Lalic, H.; Radosevic-Stasic, B.

2004-01-01

Cytogenetic analysis was performed in peripheral blood lymphocytes (PBL) of a woman with ductal breast carcinoma, who as a hospital employee was exposed professionally for 15 years to low doses of ionizing radiation. The most important finding after the chemotherapy in combination with radiotherapy was the presence of double minutes (DM) chromosomes, in combination with other chromosomal abnormalities (on 200 scored metaphases were found 2 chromatid breaks, 10 dicentrics, 11 acentric fragments, 2 gaps, and 3 double min chromosomes). In a repeated analysis (after 6 months), DM chromosomes were still present. To rule out the possibility that the patient was overexposed to ionizing radiation at work, her blood test was compared with a group of coworkers as well as with a group of professionally unexposed people. The data rejected this possibility, but the retroactive analysis showed that the patient even at the time of employment had a moderately increased number of chromosomal aberrations (3.5%) consisting of 3 isochromatids and 4 gaps, suggesting that her initial genomic instability enhanced the later development. The finding of a continuous presence of rare DM chromosomes in her PBL (4 and 10 months after radio-chemotherapy) was considered as an indicator of additional risk, which might have some prognostic significance. (author)

Trans-generational radiation-induced chromosomal instability in the female enhances the action of chemical mutagens

International Nuclear Information System (INIS)

Camats, Nuria; Garcia, Francisca; Parrilla, Juan Jose; Calaf, Joaquim; Martin, Miguel; Caldes, Montserrat Garcia

2008-01-01

Genomic instability can be produced by ionising radiation, so-called radiation-induced genomic instability, and chemical mutagens. Radiation-induced genomic instability occurs in both germinal and somatic cells and also in the offspring of irradiated individuals, and it is characterised by genetic changes including chromosomal rearrangements. The majority of studies of trans-generational, radiation-induced genomic instability have been described in the male germ line, whereas the authors who have chosen the female as a model are scarce. The aim of this work is to find out the radiation-induced effects in the foetal offspring of X-ray-treated female rats and, at the same time, the possible impact of this radiation-induced genomic instability on the action of a chemical mutagen. In order to achieve both goals, the quantity and quality of chromosomal damage were analysed. In order to detect trans-generational genomic instability, a total of 4806 metaphases from foetal tissues from the foetal offspring of X-irradiated female rats (5 Gy, acute dose) were analysed. The study's results showed that there is radiation-induced genomic instability: the number of aberrant metaphases and the breaks per total metaphases studied increased and were found to be statistically significant (p ≤ 0.05), with regard to the control group. In order to identify how this trans-generational, radiation-induced chromosomal instability could influence the chromosomal behaviour of the offspring of irradiated rat females in front of a chemical agent (aphidicolin), a total of 2481 metaphases were studied. The observed results showed that there is an enhancement of the action of the chemical agent: chromosomal breaks per aberrant metaphases show significant differences (p ≤ 0.05) in the X-ray- and aphidicolin-treated group as regards the aphidicolin-treated group. In conclusion, our findings indicate that there is trans-generational, radiation-induced chromosomal instability in the foetal cells

Trans-generational radiation-induced chromosomal instability in the female enhances the action of chemical mutagens

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Camats, Nuria [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Garcia, Francisca [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Parrilla, Juan Jose [Servicio de Ginecologia y Obstetricia, Hospital Universitario Virgen de la Arrixaca, 30120 El Palmar, Murcia (Spain); Calaf, Joaquim [Servei de Ginecologia i Obstetricia, Hospital Universitari de la Santa Creu i Sant Pau, 08025 Barcelona (Spain); Martin, Miguel [Departament de Pediatria, d' Obstetricia i Ginecologia i de Medicina Preventiva, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Caldes, Montserrat Garcia [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain)], E-mail: Montserrat.Garcia.Caldes@uab.es

2008-04-02

Genomic instability can be produced by ionising radiation, so-called radiation-induced genomic instability, and chemical mutagens. Radiation-induced genomic instability occurs in both germinal and somatic cells and also in the offspring of irradiated individuals, and it is characterised by genetic changes including chromosomal rearrangements. The majority of studies of trans-generational, radiation-induced genomic instability have been described in the male germ line, whereas the authors who have chosen the female as a model are scarce. The aim of this work is to find out the radiation-induced effects in the foetal offspring of X-ray-treated female rats and, at the same time, the possible impact of this radiation-induced genomic instability on the action of a chemical mutagen. In order to achieve both goals, the quantity and quality of chromosomal damage were analysed. In order to detect trans-generational genomic instability, a total of 4806 metaphases from foetal tissues from the foetal offspring of X-irradiated female rats (5 Gy, acute dose) were analysed. The study's results showed that there is radiation-induced genomic instability: the number of aberrant metaphases and the breaks per total metaphases studied increased and were found to be statistically significant (p {<=} 0.05), with regard to the control group. In order to identify how this trans-generational, radiation-induced chromosomal instability could influence the chromosomal behaviour of the offspring of irradiated rat females in front of a chemical agent (aphidicolin), a total of 2481 metaphases were studied. The observed results showed that there is an enhancement of the action of the chemical agent: chromosomal breaks per aberrant metaphases show significant differences (p {<=} 0.05) in the X-ray- and aphidicolin-treated group as regards the aphidicolin-treated group. In conclusion, our findings indicate that there is trans-generational, radiation-induced chromosomal instability in the foetal

Critical target and dose and dose-rate responses for the induction of chromosomal instability by ionizing radiation

Science.gov (United States)

Limoli, C. L.; Corcoran, J. J.; Milligan, J. R.; Ward, J. F.; Morgan, W. F.

1999-01-01

To investigate the critical target, dose response and dose-rate response for the induction of chromosomal instability by ionizing radiation, bromodeoxyuridine (BrdU)-substituted and unsubstituted GM10115 cells were exposed to a range of doses (0.1-10 Gy) and different dose rates (0.092-17.45 Gy min(-1)). The status of chromosomal stability was determined by fluorescence in situ hybridization approximately 20 generations after irradiation in clonal populations derived from single progenitor cells surviving acute exposure. Overall, nearly 700 individual clones representing over 140,000 metaphases were analyzed. In cells unsubstituted with BrdU, a dose response was found, where the probability of observing delayed chromosomal instability in any given clone was 3% per gray of X rays. For cells substituted with 25-66% BrdU, however, a dose response was observed only at low doses (1.0 Gy), the incidence of chromosomal instability leveled off. There was an increase in the frequency and complexity of chromosomal instability per unit dose compared to cells unsubstituted with BrdU. The frequency of chromosomal instability appeared to saturate around approximately 30%, an effect which occurred at much lower doses in the presence of BrdU. Changing the gamma-ray dose rate by a factor of 190 (0.092 to 17.45 Gy min(-1)) produced no significant differences in the frequency of chromosomal instability. The enhancement of chromosomal instability promoted by the presence of the BrdU argues that DNA comprises at least one of the critical targets important for the induction of this end point of genomic instability.

Dysregulation of gene expression in the artificial human trisomy cells of chromosome 8 associated with transformed cell phenotypes.

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Hisakatsu Nawata

Full Text Available A change in chromosome number, known as aneuploidy, is a common characteristic of cancer. Aneuploidy disrupts gene expression in human cancer cells and immortalized human epithelial cells, but not in normal human cells. However, the relationship between aneuploidy and cancer remains unclear. To study the effects of aneuploidy in normal human cells, we generated artificial cells of human primary fibroblast having three chromosome 8 (trisomy 8 cells by using microcell-mediated chromosome transfer technique. In addition to decreased proliferation, the trisomy 8 cells lost contact inhibition and reproliferated after exhibiting senescence-like characteristics that are typical of transformed cells. Furthermore, the trisomy 8 cells exhibited chromosome instability, and the overall gene expression profile based on microarray analyses was significantly different from that of diploid human primary fibroblasts. Our data suggest that aneuploidy, even a single chromosome gain, can be introduced into normal human cells and causes, in some cases, a partial cancer phenotype due to a disruption in overall gene expression.

Lack of specificity of chromosome breaks resulting from radiation-induced genomic instability in Chinese hamster cells

International Nuclear Information System (INIS)

Trott, K.-R.; Teibe, A.

1998-01-01

In V79 Chinese hamster cells, radiation-induced genomic instability results in a persistently increased frequency of micronuclei, dicentric chromosomes and apoptosis and in decreased colony-forming ability. These manifestations of radiation-induced genomic instability may be attributed to an increased rate of chromosome breakage events many generations after irradiation. This chromosomal instability does not seem to be a property which has been inflicted on individual chromosomes at the time of irradiation. Rather, it appears to be secondary to an increased level of non-specific clastogenic factors in the progeny of most if not all irradiated cells. This conclusion is drawn from the observations presented here, that all the chromosomes in surviving V79 cells are involved in the formation of dicentric chromosome aberrations 1 or 2 weeks after irradiation with about equal probability if corrections are made for chromosome length. (orig.)

Chromosomal instability in women with primary ovarian insufficiency.

Science.gov (United States)

Katari, Sunita; Aarabi, Mahmoud; Kintigh, Angela; Mann, Susan; Yatsenko, Svetlana A; Sanfilippo, Joseph S; Zeleznik, Anthony J; Rajkovic, Aleksandar

2018-02-07

What is the prevalence of somatic chromosomal instability among women with idiopathic primary ovarian insufficiency (POI)? A subset of women with idiopathic POI may have functional impairment in DNA repair leading to chromosomal instability in their soma. The formation and repair of DNA double-strand breaks during meiotic recombination are fundamental processes of gametogenesis. Oocytes with compromised DNA integrity are susceptible to apoptosis which could trigger premature ovarian aging and accelerated wastage of the human follicle reserve. Genomewide association studies, as well as whole exome sequencing, have implicated multiple genes involved in DNA damage repair. However, the prevalence of defective DNA damage repair in the soma of women with POI is unknown. In total, 46 women with POI and 15 family members were evaluated for excessive mitomycin-C (MMC)-induced chromosome breakage. Healthy fertile females (n = 20) and two lymphoblastoid cell lines served as negative and as positive controls, respectively. We performed a pilot functional study utilizing MMC to assess chromosomal instability in the peripheral blood of participants. A high-resolution array comparative genomic hybridization (aCGH) was performed on 16 POI patients to identify copy number variations (CNVs) for a set of 341 targeted genes implicated in DNA repair. Array CGH revealed three POI patients (3/16, 18.8%) with pathogenic CNVs. Excessive chromosomal breakage suggestive of a constitutional deficiency in DNA repair was detected in one POI patient with the 16p12.3 duplication. In two patients with negative chromosome breakage analysis, aCGH detected a Xq28 deletion comprising the Centrin EF-hand Protein 2 (CETN2) and HAUS Augmin Like Complex Subunit 7 (HAUS7) genes essential for meiotic DNA repair, and a duplication in the 3p22.2 region comprising a part of the ATPase domain of the MutL Homolog 1 (MLH1) gene. Peripheral lymphocytes, used as a surrogate tissue to quantify induced chromosome

Potential Role of Meiosis Proteins in Melanoma Chromosomal Instability

International Nuclear Information System (INIS)

Lindsey, S. F.; Byrnes, D. M.; Eller, M. S.; Rosa, A. M.; Dabas, N.; Escandon, J.; Grichnik, J. M.; Grichnik, J. M.; Grichnik, J. M.; Grichnik, J. M.

2013-01-01

Melanomas demonstrate chromosomal instability (CIN). In fact, CIN can be used to differentiate melanoma from benign nevi. The exact molecular mechanisms that drive CIN in melanoma have yet to be fully elucidated. Cancer/testis antigens are a unique group of germ cell proteins that are found to be primarily expressed in melanoma as compared to benign nevi. The abnormal expression of these germ cell proteins, normally expected only in the testis and ovaries, in somatic cells may lead to interference with normal cellular pathways. Germ cell proteins that may be particularly critical in CIN are meiosis proteins. Here, we review pathways unique to meiosis with a focus on how the aberrant expression of meiosis proteins in normal mitotic cells "meiomitosis"could impact chromosomal instability in melanoma and other cancers.

Prader-Willi-like phenotypes: a systematic review of their chromosomal abnormalities.

Science.gov (United States)

Rocha, C F; Paiva, C L A

2014-03-31

Prader-Willi syndrome (PWS) is caused by the lack of expression of genes located on paternal chromosome 15q11-q13. This lack of gene expression may be due to a deletion in this chromosomal segment, to maternal uniparental disomy of chromosome 15, or to a defect in the imprinting center on 15q11-q13. PWS is characterized by hypotonia during the neonatal stage and in childhood, accompanied by a delay in neuropsychomotor development. Overeating, obesity, and mental deficiency arise later on. The syndrome has a clinical overlap with other diseases, which makes it difficult to accurately diagnose. The purpose of this article is to review the Prader-Willi-like phenotype in the scientific literature from 2000 to 2013, i.e., to review the cases of PWS caused by chromosomal abnormalities different from those found on chromosome 15. A search was carried out using the "National Center for Biotechnology Information" (www.pubmed.com) and "Scientific Electronic Library Online (www.scielo.br) databases and combinations of key words such as "Prader-Willi-like phenotype" and "Prader-Willi syndrome phenotype". Editorials, letters, reviews, and guidelines were excluded. Articles chosen contained descriptions of patients diagnosed with the PWS phenotype but who were negative for alterations on 15q11-q13. Our search found 643 articles about PWS, but only 14 of these matched with the Prader-Willi-like phenotype and with the selected years of publication (2000-2013). If two or more articles reported the same chromosomal alterations for Prader-Willi-like phenotype, the most recent was chosen. Twelve articles of 14 were case reports and 2 reported series of cases.

Ataxia telangiectasia derived iPS cells show preserved x-ray sensitivity and decreased chromosomal instability

OpenAIRE

Fukawatase, Yoshihiro; Toyoda, Masashi; Okamura, Kohji; Nakamura, Ken-ichi; Nakabayashi, Kazuhiko; Takada, Shuji; Yamazaki-Inoue, Mayu; Masuda, Akira; Nasu, Michiyo; Hata, Kenichiro; Hanaoka, Kazunori; Higuchi, Akon; Takubo, Kaiyo; Umezawa, Akihiro

2014-01-01

Ataxia telangiectasia is a neurodegenerative inherited disease with chromosomal instability and hypersensitivity to ionizing radiation. iPS cells lacking ATM (AT-iPS cells) exhibited hypersensitivity to X-ray irradiation, one of the characteristics of the disease. While parental ataxia telangiectasia cells exhibited significant chromosomal abnormalities, AT-iPS cells did not show any chromosomal instability in vitro for at least 80 passages (560 days). Whole exome analysis also showed a compa...

JC Virus T-Antigen in Colorectal Cancer Is Associated with p53 Expression and Chromosomal Instability, Independent of CpG Island Methylator Phenotype

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Katsuhiko Nosho

2009-01-01

Full Text Available JC virus has a transforming gene encoding JC virus T-antigen (JCVT. JCVT may inactivate wild-type p53, cause chromosomal instability (CIN, and stabilize β-catenin. A link between JCVT and CpG island methylator phenotype (CIMP has been suggested. However, no large-scale study has examined the relations of JCVT with molecular alterations, clinical outcome, or prognosis in colon cancer. We detected JCVT expression (by immunohistochemistry in 271 (35% of 766 colorectal cancers. We quantified DNA methylation in eight CIMP-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1 and eight other loci (CHFR, HIC1, IGFBP3, MGMT, MINT1, MINT31, p14, WRN by MethyLight. We examined loss of heterozygosity in 2p, 5q, 17q, and 18q. JCVT was significantly associated with p53 expression (P < .0001, p21 loss (P < .0001, CIN (≥2 chromosomal segments with LOH; P < .0001, nuclear β-catenin (P = .006, LINE-1 hypomethylation (P = .002, and inversely with CIMP-high (P = .0005 and microsatellite instability (MSI (P < .0001, but not with PIK3CA mutation. In multivariate logistic regression analysis, the associations of JCVT with p53 [adjusted odds ratio (OR, 8.45; P < .0001], CIN (adjusted OR, 2.53; P = .003, cyclin D1 (adjusted OR, 1.57; P = .02, LINE-1 hypomethylation (adjusted OR, 1.97 for a 30% decline as a unit; P = .03, BRAF mutation (adjusted OR, 2.20; P = .04, and family history of colorectal cancer (adjusted OR, 0.64; P = .04 remained statistically significant. However, JCVT was no longer significantly associated with CIMP, MSI, β-catenin, or cyclooxygenase-2 expression in multivariate analysis. JCVT was unrelated with patient survival. In conclusion, JCVT expression in colorectal cancer is independently associated with p53 expression and CIN, which may lead to uncontrolled cell proliferation.

Alternative Splicing of CHEK2 and Codeletion with NF2 Promote Chromosomal Instability in Meningioma

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Hong Wei Yang

2012-01-01

Full Text Available Mutations of the NF2 gene on chromosome 22q are thought to initiate tumorigenesis in nearly 50% of meningiomas, and 22q deletion is the earliest and most frequent large-scale chromosomal abnormality observed in these tumors. In aggressive meningiomas, 22q deletions are generally accompanied by the presence of large-scale segmental abnormalities involving other chromosomes, but the reasons for this association are unknown. We find that large-scale chromosomal alterations accumulate during meningioma progression primarily in tumors harboring 22q deletions, suggesting 22q-associated chromosomal instability. Here we show frequent codeletion of the DNA repair and tumor suppressor gene, CHEK2, in combination with NF2 on chromosome 22q in a majority of aggressive meningiomas. In addition, tumor-specific splicing of CHEK2 in meningioma leads to decreased functional Chk2 protein expression. We show that enforced Chk2 knockdown in meningioma cells decreases DNA repair. Furthermore, Chk2 depletion increases centrosome amplification, thereby promoting chromosomal instability. Taken together, these data indicate that alternative splicing and frequent codeletion of CHEK2 and NF2 contribute to the genomic instability and associated development of aggressive biologic behavior in meningiomas.

Survivin and chromosome instability induced by X-irradiation

International Nuclear Information System (INIS)

Shen Bo; Ju Guizhi; Liu Yang

2006-01-01

Objective: To explore the biological effect of survivin on chromosome instability induced by X-ray irradiation. Methods: Immunocytochemistry was used to detect the expression of sutvivin in HeLa cells. Carrier pSUPER-SVV was transfected into HeLa cells to interfere the expression of survivin. Flow cytometry assay was applied to detect the occurrence of polyploid at 0 h, 4 h, 12 h, and 48 h after the HeLa cells transfected with pSUPER-SVV and irradiated with 4 Gy X-rays irradiation, and compared with the group irradiated with 4 Gy X-rays but no transfection. Results: The expression of survivin was down-regulated by transfecting with small hair RNA, its depression rate was estimated to be about 32.16% at 48 h after transfection. The occurrence of polyploid giant cells was higher in the 4 Gy X-ray irradiated group at 48 h after the irradiation than the control groups (P<0.001). Being expression of survivin interfered, the occurrence at 12 h or 48 h after irradiation, however, was about two times higher than that in the control group. Conclusion: X-ray irradiation can induce chromosome instability in HeLa cells and the effect could be enhanced by interfering the expression of surviving. It was suggested that survivin plays an important role in maintaining the stability of chromosome. (authors)

Mechanisms of telomere loss and their consequences for chromosome instability

International Nuclear Information System (INIS)

Muraki, Keiko; Nyhan, Kristine; Han, Limei; Murnane, John P.

2012-01-01

The ends of chromosomes in mammals, called telomeres, are composed of a 6-bp repeat sequence, TTAGGG, which is added on by the enzyme telomerase. In combination with a protein complex called shelterin, these telomeric repeat sequences form a cap that protects the ends of chromosomes. Due to insufficient telomerase expression, telomeres shorten gradually with each cell division in human somatic cells, which limits the number of times they can divide. The extensive cell division involved in cancer cell progression therefore requires that cancer cells must acquire the ability to maintain telomeres, either through expression of telomerase, or through an alternative mechanism involving recombination. It is commonly thought that the source of many chromosome rearrangements in cancer cells is a result of the extensive telomere shortening that occurs prior to the expression of telomerase. However, despite the expression of telomerase, tumor cells can continue to show chromosome instability due to telomere loss. Dysfunctional telomeres in cancer cells can result from oncogene-induced replication stress, which results in double-strand breaks (DSBs) at fragile sites, including telomeres. DSBs near telomeres are especially prone to chromosome rearrangements, because telomeric regions are deficient in DSB repair. The deficiency in DSB repair near telomeres is also an important mechanism for ionizing radiation-induced replicative senescence in normal human cells. In addition, DSBs near telomeres can result in chromosome instability in mouse embryonic stem cells, suggesting that telomere loss can contribute to heritable chromosome rearrangements. Consistent with this possibility, telomeric regions in humans are highly heterogeneous, and chromosome rearrangements near telomeres are commonly involved in human genetic disease. Understanding the mechanisms of telomere loss will therefore provide important insights into both human cancer and genetic disease.

Mechanisms of telomere loss and their consequences for chromosome instability

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Keiko eMuraki

2012-10-01

Full Text Available The ends of chromosomes in mammals, called telomeres, are composed of a 6 base pair repeat sequence, TTAGGG, which is added on by the enzyme telomerase. In combination with a protein complex called shelterin, these telomeric repeat sequences form a cap that protects the ends of chromosomes. Due to insufficient telomerase expression, telomeres shorten gradually with each cell division in human somatic cells, which limits the number of times they can divide. The extensive cell division involved in cancer cell progression therefore requires that cancer cells must acquire the ability to maintain telomeres, either through expression of telomerase, or through an alternative mechanism involving recombination. It is commonly thought that the source of many chromosome rearrangements in cancer cells is a result of the extensive telomere shortening that occurs prior to the expression of telomerase. However, despite the expression of telomerase, tumor cells can continue to show chromosome instability due to telomere loss. Dysfunctional telomeres in cancer cells can result from oncogene-induced replication stress, which results in double-strand breaks (DSBs at fragile sites, including telomeres. DSBs near telomeres are especially prone to chromosome rearrangements, because telomeric regions are deficient in DSB repair. The deficiency in DSB repair near telomeres is also an important mechanism for ionizing radiation-induced replicative senescence in normal human cells. In addition, DSBs near telomeres can result in chromosome instability in mouse embryonic stem cells, suggesting that telomere loss can contribute to heritable chromosome rearrangements. Consistent with this possibility, telomeric regions in humans are highly heterogeneous, and chromosome rearrangements near telomeres are commonly involved in human genetic disease. Understanding the mechanisms of telomere loss will therefore provide important insights into both human cancer and genetic disease.

Mechanisms of telomere loss and their consequences for chromosome instability

Energy Technology Data Exchange (ETDEWEB)

Muraki, Keiko; Nyhan, Kristine; Han, Limei; Murnane, John P., E-mail: jmurnane@radonc.ucsf.edu [Department of Radiation Oncology, University of California at San Francisco, San Francisco, CA (United States)

2012-10-04

The ends of chromosomes in mammals, called telomeres, are composed of a 6-bp repeat sequence, TTAGGG, which is added on by the enzyme telomerase. In combination with a protein complex called shelterin, these telomeric repeat sequences form a cap that protects the ends of chromosomes. Due to insufficient telomerase expression, telomeres shorten gradually with each cell division in human somatic cells, which limits the number of times they can divide. The extensive cell division involved in cancer cell progression therefore requires that cancer cells must acquire the ability to maintain telomeres, either through expression of telomerase, or through an alternative mechanism involving recombination. It is commonly thought that the source of many chromosome rearrangements in cancer cells is a result of the extensive telomere shortening that occurs prior to the expression of telomerase. However, despite the expression of telomerase, tumor cells can continue to show chromosome instability due to telomere loss. Dysfunctional telomeres in cancer cells can result from oncogene-induced replication stress, which results in double-strand breaks (DSBs) at fragile sites, including telomeres. DSBs near telomeres are especially prone to chromosome rearrangements, because telomeric regions are deficient in DSB repair. The deficiency in DSB repair near telomeres is also an important mechanism for ionizing radiation-induced replicative senescence in normal human cells. In addition, DSBs near telomeres can result in chromosome instability in mouse embryonic stem cells, suggesting that telomere loss can contribute to heritable chromosome rearrangements. Consistent with this possibility, telomeric regions in humans are highly heterogeneous, and chromosome rearrangements near telomeres are commonly involved in human genetic disease. Understanding the mechanisms of telomere loss will therefore provide important insights into both human cancer and genetic disease.

Two siblings with immunodeficiency, facial abnormalities and chromosomal instability without mutation in DNMT3B gene but liability towards malignancy; a new chromatin disorder delineation?

Science.gov (United States)

Polityko, Anna; Khurs, Olga; Rumyantseva, Natalia; Naumchik, Irina; Kosyakova, Nadezda; Tönnies, Holger; Sperling, Karl; Neitzel, Heidemarie; Weise, Anja; Liehr, Thomas

2010-03-08

ICF syndrome (standing for Immunodeficiency, Centromere instability and Facial anomalies syndrome) is a very rare autosomal recessive immune disorder caused by mutations of the gene de novo DNA-methyltransferase 3B (DNMT3B). However, in the literature similar clinical cases without such mutations are reported, as well. We report on a family in which the unrelated spouses had two female siblings sharing similar phenotypic features resembling ICF-syndrome, i.e. congenital abnormalities, immunodeficiency, developmental delay and high level of chromosomal instability, including high frequency of centromeric/pericentromeric rearrangements and breaks, chromosomal fragments despiralization or pulverization. However, mutations in DNMT3B could not be detected. The discovery of a new so-called 'chromatin disorder' is suggested. Clinical, molecular genetic and cytogenetic characteristics are reported and compared to other 'chromatin disorders'.

Phenotypic consequences of a mosaic marker chromosome identified by fluorescence in situ hybridization (FISH) as being derived from chromosome 16

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Ray, J.H.; Zhou, X.; Pletcher, B.A. [Cornell Univ. Medical College, Manhasset, NY (United States)] [and others

1994-09-01

De novo marker chromosomes are detected in 1 in 2500 amniotic fluid samples and are associated with a 10-15% risk for phenotypic abnormality. FISH can be utilized as a research tool to identify the origins of marker chromosomes. The phenotypic consequences of a marker chromosome derived from the short arm of chromosome 16 are described. A 26-year-old woman underwent amniocentesis at 28 weeks gestation because of a prenatally diagnosed tetralogy of Fallot. Follow-up ultrasounds also showed ventriculomegaly and cleft lip and palate. 32 of 45 cells had the karyotype 47,XY,+mar; the remaining cells were 46,XY. The de novo marker chromosome was C-band positive and non-satellited and failed to stain with distamycin A/DAPI. At birth the ultrasound findings were confirmed and dysmorphic features and cryptorchidism were noted. Although a newborn blood sample contained only normal cells, mosaicism was confirmed in 2 skin biopsies. FISH using whole-chromosome painting and alpha-satellite DNA probes showed that the marker chromosome had originated from chromosome 16. As proximal 16q is distamycin A/DAPI positive, the marker is apparently derived from proximal 16p. At 15 months of age, this child is hypotonic, globally delayed and is gavage-fed. His physical examination is significant for microbrachycephaly, a round face, sparse scalp hair, ocular hypertelorism, exotropia, a flat, wide nasal bridge and tip, mild micrognathia, and tapered fingers with lymphedema of hands and feet. Inguinal hernias have been repaired. His features are consistent with those described for patients trisomic for most or all of the short arm of chromosome 16. Marker chromosomes derived from the short arm of chromosome 16 appear to have phenotypic consequences. As the origin of more marker chromosomes are identified using FISH, their karyotype/phenotype correlations will become more apparent, which will permit more accurate genetic counseling.

Cytokinesis-block micronucleus assay evolves into a 'cytome' assay of chromosomal instability, mitotic dysfunction and cell death

International Nuclear Information System (INIS)

Fenech, Michael

2006-01-01

The cytokinesis-block micronucleus (CBMN) assay was originally developed as an ideal system for measuring micronuclei (MNi) however it can also be used to measure nucleoplasmic bridges (NPBs), nuclear buds (NBUDs), cell death (necrosis or apoptosis) and nuclear division rate. Current evidence suggests that (a) NPBs originate from dicentric chromosomes in which the centromeres have been pulled to the opposite poles of the cell at anaphase and are therefore indicative of DNA mis-repair, chromosome rearrangement or telomere end-fusions, (b) NPBs may break to form MNi, (c) the nuclear budding process is the mechanism by which cells remove amplified and/or excess DNA and is therefore a marker of gene amplification and/or altered gene dosage, (d) cell cycle checkpoint defects result in micronucleus formation and (e) hypomethylation of DNA, induced nutritionally or by inhibition of DNA methyl transferase can lead to micronucleus formation either via chromosome loss or chromosome breakage. The strong correlation between micronucleus formation, nuclear budding and NPBs (r = 0.75-0.77, P < 0.001) induced by either folic acid deficiency or exposure to ionising radiation is supportive of the hypothesis that folic acid deficiency and/or ionising radiation cause genomic instability and gene amplification by the initiation of breakage-fusion-bridge cycles. In its comprehensive mode, the CBMN assay measures all cells including necrotic and apoptotic cells as well as number of nuclei per cell to provide a measure of cytotoxicity and mitotic activity. The CBMN assay has in fact evolved into a 'cytome' method for measuring comprehensively chromosomal instability phenotype and altered cellular viability caused by genetic defects and/or nutrional deficiencies and/or exogenous genotoxins thus opening up an exciting future for the use of this methodology in the emerging fields of nutrigenomics and toxicogenomics and their combinations

Detection of chromosomal instability in α-irradiated and bystander human fibroblasts

International Nuclear Information System (INIS)

Ponnaiya, Brian; Jenkins-Baker, Gloria; Bigelow, Alan; Marino, Stephen; Geard, Charles R.

2004-01-01

There is increasing evidence biological responses to ionizing radiation are not confined to those cells that are directly hit, but may be seen in the progeny at subsequent generations (genomic instability) and in non-irradiated neighbors of irradiated cells (bystander effects). These so called non-targeted phenomena would have significant contributions to radiation-induced carcinogenesis, especially at low doses where only a limited number of cells in a population are directed hit. Here we present data using a co-culturing protocol examining chromosomal instability in α-irradiated and bystander human fibroblasts BJ1-htert. At the first cell division following exposure to 0.1 and 1 Gy α-particles, irradiated populations demonstrated a dose dependent increase in chromosome-type aberrations. At this time bystander BJ1-htert populations demonstrated elevated chromatid-type aberrations when compared to controls. Irradiated and bystander populations were also analyzed for chromosomal aberrations as a function of time post-irradiation. When considered over 25 doublings, all irradiated and bystander populations had significantly higher frequencies of chromatid aberrations when compared to controls (2-3-fold over controls) and were not dependent on dose. The results presented here support the link between the radiation-induced phenomena of genomic instability and the bystander effect

Evidence of Chromosomal Instability in Prostate Cancer Determined by Spectral Karyotyping (SKY and Interphase FISH Analysis

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Ben Beheshti

2001-01-01

Full Text Available The way in which cytogenetic aberrations develop in prostate cancer (Cap is poorly understood. Spectral karyotype (SKY analysis of Cap cell lines has shown that they have unstable karyotypes and also have features associated with chromosomal instability (CIN. To accurately determine the incidence of de novo structural and numerical aberrations in vitro in Cap, we performed SKY analysis of three independent clones derived from one representative cell line, DU145. The frequent generation of new chromosomal rearrangements and a wide variation in the number of structural aberrations within two to five passages suggested that this cell line exhibited some of the features associated with a CIN phenotype. To study numerical cell-to-cell variation, chromosome 8 aneusomy was assessed in the LNCaP, DU145, and PC-3 cell lines and a patient cohort of 15 Cap primary tumors by interphase fluorescence in situ hybridization (FISH. This analysis showed that a high frequency of numerical alteration affecting chromosome 8 was present in both in vitro and in Cap tissues. In comparison to normal controls, the patient cohort had a statistically significant (P<.05, greater frequency of cells with one and three centromere 8 copies. These data suggest that a CIN-like process may be contributing towards the generation of de novo numerical and structural chromosome abnormalities in Cap.

Epstein–Barr virus particles induce centrosome amplification and chromosomal instability

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Shumilov, Anatoliy; Tsai, Ming-Han; Schlosser, Yvonne T.; Kratz, Anne-Sophie; Bernhardt, Katharina; Fink, Susanne; Mizani, Tuba; Lin, Xiaochen; Jauch, Anna; Mautner, Josef; Kopp-Schneider, Annette; Feederle, Regina; Hoffmann, Ingrid; Delecluse, Henri-Jacques

2017-01-01

Infections with Epstein–Barr virus (EBV) are associated with cancer development, and EBV lytic replication (the process that generates virus progeny) is a strong risk factor for some cancer types. Here we report that EBV infection of B-lymphocytes (in vitro and in a mouse model) leads to an increased rate of centrosome amplification, associated with chromosomal instability. This effect can be reproduced with virus-like particles devoid of EBV DNA, but not with defective virus-like particles that cannot infect host cells. Viral protein BNRF1 induces centrosome amplification, and BNRF1-deficient viruses largely lose this property. These findings identify a new mechanism by which EBV particles can induce chromosomal instability without establishing a chronic infection, thereby conferring a risk for development of tumours that do not necessarily carry the viral genome. PMID:28186092

Two siblings with immunodeficiency, facial abnormalities and chromosomal instability without mutation in DNMT3B gene but liability towards malignancy; a new chromatin disorder delineation?

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Neitzel Heidemarie

2010-03-01

Full Text Available Abstract Background ICF syndrome (standing for Immunodeficiency, Centromere instability and Facial anomalies syndrome is a very rare autosomal recessive immune disorder caused by mutations of the gene de novo DNA-methyltransferase 3B (DNMT3B. However, in the literature similar clinical cases without such mutations are reported, as well. Results We report on a family in which the unrelated spouses had two female siblings sharing similar phenotypic features resembling ICF-syndrome, i.e. congenital abnormalities, immunodeficiency, developmental delay and high level of chromosomal instability, including high frequency of centromeric/pericentromeric rearrangements and breaks, chromosomal fragments despiralization or pulverization. However, mutations in DNMT3B could not be detected. Conclusion The discovery of a new so-called 'chromatin disorder' is suggested. Clinical, molecular genetic and cytogenetic characteristics are reported and compared to other 'chromatin disorders'.

A molecular deletion of distal chromosome 4p in two families with a satellited chromosome 4 lacking the Wolf-Hirschhorn syndrome phenotype.

Science.gov (United States)

Estabrooks, L L; Lamb, A N; Kirkman, H N; Callanan, N P; Rao, K W

1992-11-01

We report two families with a satellited chromosome 4 short arm (4ps). Satellites and stalks normally occur on the short arms of acrocentric chromosomes; however, the literature cites several reports of satellited nonacrocentric chromosomes, which presumably result from a translocation with an acrocentric chromosome. This is the first report of 4ps chromosomes. Our families are remarkable in that both unaffected and affected individuals carry the 4ps chromosome. The phenotypes observed in affected individuals, although dissimilar, were sufficient to encourage a search for a deletion of chromosome 4p. By Southern blot analysis and fluorescence in situ hybridization, a deletion of material mapping approximately 150 kb from chromosome 4pter was discovered. This deletion is notable because it does not result in the Wolf-Hirschhorn syndrome and can result in an apparently normal phenotype. We speculate that homology between subterminal repeat sequences on 4p and sequences on the acrocentric short arms may explain the origin of the rearrangement and that position effect may play a role in the expression of the abnormal phenotype.

Reprogramming suppresses premature senescence phenotypes of Werner syndrome cells and maintains chromosomal stability over long-term culture.

Science.gov (United States)

Shimamoto, Akira; Kagawa, Harunobu; Zensho, Kazumasa; Sera, Yukihiro; Kazuki, Yasuhiro; Osaki, Mitsuhiko; Oshimura, Mitsuo; Ishigaki, Yasuhito; Hamasaki, Kanya; Kodama, Yoshiaki; Yuasa, Shinsuke; Fukuda, Keiichi; Hirashima, Kyotaro; Seimiya, Hiroyuki; Koyama, Hirofumi; Shimizu, Takahiko; Takemoto, Minoru; Yokote, Koutaro; Goto, Makoto; Tahara, Hidetoshi

2014-01-01

Werner syndrome (WS) is a premature aging disorder characterized by chromosomal instability and cancer predisposition. Mutations in WRN are responsible for the disease and cause telomere dysfunction, resulting in accelerated aging. Recent studies have revealed that cells from WS patients can be successfully reprogrammed into induced pluripotent stem cells (iPSCs). In the present study, we describe the effects of long-term culture on WS iPSCs, which acquired and maintained infinite proliferative potential for self-renewal over 2 years. After long-term cultures, WS iPSCs exhibited stable undifferentiated states and differentiation capacity, and premature upregulation of senescence-associated genes in WS cells was completely suppressed in WS iPSCs despite WRN deficiency. WS iPSCs also showed recapitulation of the phenotypes during differentiation. Furthermore, karyotype analysis indicated that WS iPSCs were stable, and half of the descendant clones had chromosomal profiles that were similar to those of parental cells. These unexpected properties might be achieved by induced expression of endogenous telomerase gene during reprogramming, which trigger telomerase reactivation leading to suppression of both replicative senescence and telomere dysfunction in WS cells. These findings demonstrated that reprogramming suppressed premature senescence phenotypes in WS cells and WS iPSCs could lead to chromosomal stability over the long term. WS iPSCs will provide opportunities to identify affected lineages in WS and to develop a new strategy for the treatment of WS.

Reprogramming suppresses premature senescence phenotypes of Werner syndrome cells and maintains chromosomal stability over long-term culture.

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Akira Shimamoto

Full Text Available Werner syndrome (WS is a premature aging disorder characterized by chromosomal instability and cancer predisposition. Mutations in WRN are responsible for the disease and cause telomere dysfunction, resulting in accelerated aging. Recent studies have revealed that cells from WS patients can be successfully reprogrammed into induced pluripotent stem cells (iPSCs. In the present study, we describe the effects of long-term culture on WS iPSCs, which acquired and maintained infinite proliferative potential for self-renewal over 2 years. After long-term cultures, WS iPSCs exhibited stable undifferentiated states and differentiation capacity, and premature upregulation of senescence-associated genes in WS cells was completely suppressed in WS iPSCs despite WRN deficiency. WS iPSCs also showed recapitulation of the phenotypes during differentiation. Furthermore, karyotype analysis indicated that WS iPSCs were stable, and half of the descendant clones had chromosomal profiles that were similar to those of parental cells. These unexpected properties might be achieved by induced expression of endogenous telomerase gene during reprogramming, which trigger telomerase reactivation leading to suppression of both replicative senescence and telomere dysfunction in WS cells. These findings demonstrated that reprogramming suppressed premature senescence phenotypes in WS cells and WS iPSCs could lead to chromosomal stability over the long term. WS iPSCs will provide opportunities to identify affected lineages in WS and to develop a new strategy for the treatment of WS.

Overexpression of eIF-5A2 in mice causes accelerated organismal aging by increasing chromosome instability

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Chen Leilei

2011-05-01

Full Text Available Abstract Background Amplification of 3q26 is one of the most frequent genetic alterations in many human malignancies. Recently, we isolated a novel oncogene eIF-5A2 within the 3q26 region. Functional study has demonstrated the oncogenic role of eIF-5A2 in the initiation and progression of human cancers. In the present study, we aim to investigate the physiological and pathological effect of eIF-5A2 in an eIF-5A2 transgenic mouse model. Methods An eIF-5A2 transgenic mouse model was generated using human eIF-5A2 cDNA. The eIF-5A2 transgenic mice were characterized by histological and immunohistochemistry analyses. The aging phenotypes were further characterized by wound healing, bone X-ray imaging and calcification analysis. Mouse embryo fibroblasts (MEF were isolated to further investigate molecular mechanism of eIF-5A2 in aging. Results Instead of resulting in spontaneous tumor formation, overexpression of eIF-5A2 accelerated the aging process in adult transgenic mice. This included decreased growth rate and body weight, shortened life span, kyphosis, osteoporosis, delay of wound healing and ossification. Investigation of the correlation between cellular senescence and aging showed that cellular senescence is not required for the aging phenotypes in eIF-5A2 mice. Interestingly, we found that activation of eIF-5A2 repressed p19 level and therefore destabilized p53 in transgenic mouse embryo fibroblast (MEF cells. This subsequently allowed for the accumulation of chromosomal instability, such as errors in cell dividing during metaphase and anaphase. Additionally, a significantly increase in number of aneuploidy cells (p Conclusion These observations suggest that eIF-5A2 mouse models could accelerate organismal aging by increasing chromosome instability.

Chromosomal instability as a prognostic marker in cervical cancer

International Nuclear Information System (INIS)

How, Christine; Bruce, Jeff; So, Jonathan; Pintilie, Melania; Haibe-Kains, Benjamin; Hui, Angela; Clarke, Blaise A; Hedley, David W; Hill, Richard P; Milosevic, Michael; Fyles, Anthony; Liu, Fei-Fei

2015-01-01

Cervical cancer is the third most common cancer in women globally, and despite treatment, distant metastasis and nodal recurrence will still develop in approximately 30% of patients. The ability to predict which patients are likely to experience distant relapse would allow clinicians to better tailor treatment. Previous studies have investigated the role of chromosomal instability (CIN) in cancer, which can promote tumour initiation and growth; a hallmark of human malignancies. In this study, we sought to examine the published CIN70 gene signature in a cohort of cervical cancer patients treated at the Princess Margaret (PM) Cancer Centre and an independent cohort of The Cancer Genome Atlas (TCGA) cervical cancer patients, to determine if this CIN signature associated with patient outcome. Cervical cancer samples were collected from 79 patients, treated between 2000–2007 at the PM, prior to undergoing curative chemo-radiation. Total RNA was extracted from each patient sample and analyzed using the GeneChip Human Genome U133 Plus 2.0 array (Affymetrix). High CIN70 scores were significantly related to increased chromosomal alterations in TCGA cervical cancer patients, including a higher percentage of genome altered and a higher number of copy number alterations. In addition, this same CIN70 signature was shown to be predictive of para-aortic nodal relapse in the PM Cancer Centre cohort. These findings demonstrate that chromosomal instability plays an important role in cervical cancer, and is significantly associated with patient outcome. For the first time, this CIN70 gene signature provided prognostic value for patients with cervical cancer

Correlation of chromosomal instability, telomere length and telomere maintenance in microsatellite stable rectal cancer: a molecular subclass of rectal cancer.

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Lisa A Boardman

Full Text Available Colorectal cancer (CRC tumor DNA is characterized by chromosomal damage termed chromosomal instability (CIN and excessively shortened telomeres. Up to 80% of CRC is microsatellite stable (MSS and is historically considered to be chromosomally unstable (CIN+. However, tumor phenotyping depicts some MSS CRC with little or no genetic changes, thus being chromosomally stable (CIN-. MSS CIN- tumors have not been assessed for telomere attrition.MSS rectal cancers from patients ≤50 years old with Stage II (B2 or higher or Stage III disease were assessed for CIN, telomere length and telomere maintenance mechanism (telomerase activation [TA]; alternative lengthening of telomeres [ALT]. Relative telomere length was measured by qPCR in somatic epithelial and cancer DNA. TA was measured with the TRAPeze assay, and tumors were evaluated for the presence of C-circles indicative of ALT. p53 mutation status was assessed in all available samples. DNA copy number changes were evaluated with Spectral Genomics aCGH.Tumors were classified as chromosomally stable (CIN- and chromosomally instable (CIN+ by degree of DNA copy number changes. CIN- tumors (35%; n=6 had fewer copy number changes (<17% of their clones with DNA copy number changes than CIN+ tumors (65%; n=13 which had high levels of copy number changes in 20% to 49% of clones. Telomere lengths were longer in CIN- compared to CIN+ tumors (p=0.0066 and in those in which telomerase was not activated (p=0.004. Tumors exhibiting activation of telomerase had shorter tumor telomeres (p=0.0040; and tended to be CIN+ (p=0.0949.MSS rectal cancer appears to represent a heterogeneous group of tumors that may be categorized both on the basis of CIN status and telomere maintenance mechanism. MSS CIN- rectal cancers appear to have longer telomeres than those of MSS CIN+ rectal cancers and to utilize ALT rather than activation of telomerase.

Molecular cytogenetic and phenotypic characterization of ring chromosome 13 in three unrelated patients

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Abdallah-Bouhjar, Inesse B.; Mougou-Zerelli, Soumaya; Hannachi, Hanene; Gmidène, Abir; Labalme, Audrey; Soyah, Najla; Sanlaville, Damien; Saad, Ali; Elghezal, Hatem

2013-01-01

We report on the cytogenetic and molecular investigations of constitutional de-novo ring chromosome 13s in three unrelated patients for better understanding and delineation of the phenotypic variability characterizing this genomic rearrangement. The patient’s karyotypes were as follows: 46,XY,r(13)(p11q34) dn for patients 1 and 2 and 46,XY,r(13)(p11q14) dn for patient 3, as a result of the deletion in the telomeric regions of chromosome 13. The patients were, therefore, monosomic for the segment 13q34 → 13qter; in addition, for patient 3, the deletion was larger, encompassing the segment 13q14 → 13qter. Fluorescence in situ hybridization confirmed these rearrangement and array CGH technique showed the loss of at least 2.9 Mb on the short arm and 4.7 Mb on the long arm of the chromosome 13 in patient 2. Ring chromosome 13 (r(13)) is associated with several phenotypic features like intellectual disability, marked short stature, brain and heart defects, microcephaly and genital malformations in males, including undescended testes and hypospadias. However, the hearing loss and speech delay that were found in our three patients have rarely been reported with ring chromosome 13. Although little is known about its etiology, there is interesting evidence for a genetic cause for the ring chromosome 13. We thus performed a genotype-phenotype correlation analysis to ascertain the contribution of ring chromosome 13 to the clinical features of our three cases. PMID:27625853

Molecular causes and consequences of genetic instability with respect to the FA/BRCA Caretaker Pathway

OpenAIRE

Neveling, Kornelia

2012-01-01

In the context of this thesis, I investigated the molecular causes and functional consequences of genetic instability using a human inherited disease, Fanconi anemia. FA patients display a highly variable clinical phenotype, including congenital abnormalities, progressive bone marrow failure and a high cancer risk. The FA cellular phenotype is characterized by spontaneous and inducible chromosomal instability, and a typical S/G2 phase arrest after exposure to DNA-damaging agents. So far, 13 g...

Global chromosomal structural instability in a subpopulation of starving Escherichia coli cells.

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Dongxu Lin

2011-08-01

Full Text Available Copy-number variations (CNVs constitute very common differences between individual humans and possibly all genomes and may therefore be important fuel for evolution, yet how they form remains elusive. In starving Escherichia coli, gene amplification is induced by stress, controlled by the general stress response. Amplification has been detected only encompassing genes that confer a growth advantage when amplified. We studied the structure of stress-induced gene amplification in starving cells in the Lac assay in Escherichia coli by array comparative genomic hybridization (aCGH, with polymerase chain reaction (pcr and DNA sequencing to establish the structures generated. About 10% of 300 amplified isolates carried other chromosomal structural change in addition to amplification. Most of these were inversions and duplications associated with the amplification event. This complexity supports a mechanism similar to that seen in human non-recurrent copy number variants. We interpret these complex events in terms of repeated template switching during DNA replication. Importantly, we found a significant occurrence (6 out of 300 of chromosomal structural changes that were apparently not involved in the amplification event. These secondary changes were absent from 240 samples derived from starved cells not carrying amplification, suggesting that amplification happens in a differentiated subpopulation of stressed cells licensed for global chromosomal structural change and genomic instability. These data imply that chromosomal structural changes occur in bursts or showers of instability that may have the potential to drive rapid evolution.

Folic acid deficiency increases chromosomal instability, chromosome 21 aneuploidy and sensitivity to radiation-induced micronuclei

International Nuclear Information System (INIS)

Beetstra, Sasja; Thomas, Philip; Salisbury, Carolyn; Turner, Julie; Fenech, Michael

2005-01-01

Folic acid deficiency can lead to uracil incorporation into DNA, hypomethylation of DNA, inefficient DNA repair and increase chromosome malsegregation and breakage. Because ionising radiation increases demand for efficient DNA repair and also causes chromosome breaks we hypothesised that folic acid deficiency may increase sensitivity to radiation-induced chromosome breakage. We tested this hypothesis by using the cytokinesis-block micronucleus assay in 10 day WIL2-NS cell cultures at four different folic acid concentrations (0.2, 2, 20, and 200 nM) that span the 'normal' physiological range in humans. The study showed a significant dose-dependent increase in frequency of binucleated cells with micronuclei and/or nucleoplasmic bridges with decreasing folic acid concentration (P < 0.0001, P = 0.028, respectively). These biomarkers of chromosomal instability were also increased in cells irradiated (1.5 Gy γ-rays) on day 9 relative to un-irradiated controls (P < 0.05). Folic acid deficiency and γ-irradiation were shown to have a significant interactive effect on frequency of cells containing micronuclei (two-way ANOVA, interaction P 0.0039) such that the frequency of radiation-induced micronucleated cells (i.e. after subtracting base-line frequency of un-irradiated controls) increased with decreasing folic acid concentration (P-trend < 0.0001). Aneuploidy of chromosome 21, apoptosis and necrosis were increased by folic acid deficiency but not by ionising radiation. The results of this study show that folate status has an important impact on chromosomal stability and is an important modifying factor of cellular sensitivity to radiation-induced genome damage

A Marfan syndrome-like phenotype caused by a neocentromeric supernumerary ring chromosome 15.

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Quinonez, Shane C; Gelehrter, Thomas D; Uhlmann, Wendy R

2017-01-01

Small supernumerary marker chromosomes (sSMC) are abnormal chromosomes that cannot be characterized by standard banding cytogenetic techniques. A minority of sSMC contain a neocentromere, which is an ectopic centromere lacking the characteristic alpha-satellite DNA. The phenotypic manifestations of sSMC and neocentromeric sSMC are variable and range from severe intellectual disability and multiple congenital anomalies to a normal phenotype. Here we report a patient with a diagnosis of Marfan syndrome and infertility found to have an abnormal karyotype consisting of a chromosome 15 deletion and a ring-type sSMC likely stabilized by a neocentromere derived via a mechanism initially described by Barbara McClintock in 1938. Analysis of the sSMC identified that it contained the deleted chromosome 15 material and also one copy of FBN1, the gene responsible for Marfan syndrome. We propose that the patient's diagnosis arose from disruption of the FBN1 allele on the sSMC. To date, a total of 29 patients have been reported with an sSMC derived from a chromosomal deletion. We review these cases with a specific focus on the resultant phenotypes and note significant difference between this class of sSMC and other types of sSMC. Through this review we also identified a patient with a clinical diagnosis of neurofibromatosis type 1 who lacked a family history of the condition but was found to have a chromosome 17-derived sSMC that likely contained NF1 and caused the patient's disorder. We also review the genetic counseling implications and recommendations for a patient or family harboring an sSMC. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Phenotype and 244k array-CGH characterization of chromosome 13q deletions: an update of the phenotypic map of 13q21.1-qter

DEFF Research Database (Denmark)

Kirchhoff, Maria; Bisgaard, Anne-Marie; Stoeva, Radka

2009-01-01

Partial deletions of the long arm of chromosome 13 lead to variable phenotypes dependant on the size and position of the deleted region. In order to update the phenotypic map of chromosome 13q21.1-qter deletions, we applied 244k Agilent oligonucleotide-based array-CGH to determine the exact break......-genotype correlation on chromosome 13. In contrast to previous reports of carriers of 13q32 band deletions as the most seriously affected patients, we present two such individuals with long-term survival, 28 and 2.5 years....

Targeting Chromosomal Instability and Tumour Heterogeneity in HER2-Positive Breast Cancer

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Burrell, Rebecca A.; Birkbak, Nicolai Juul; Johnston, Stephen R.

2010-01-01

Chromosomal instability (CIN) is a common cause of tumour heterogeneity and poor prognosis in solid tumours and describes cell-cell variation in chromosome structure or number across a tumour population. In this article we consider evidence suggesting that CIN may be targeted and may influence...... response to distinct chemotherapy regimens, using HER2-positive breast cancer as an example. Pre-clinical models have indicated a role for HER2 signalling in initiating CIN and defective cell-cycle control, and evidence suggests that HER2-targeting may attenuate this process. Anthracyclines and platinum...... agents may target tumours with distinct patterns of karyotypic complexity, whereas taxanes may have preferential activity in tumours with relative chromosomal stability. A greater understanding of karyotypic complexity and identification of methods to directly examine and target CIN may support novel...

Tolerance of Whole-Genome Doubling Propagates Chromosomal Instability and Accelerates Cancer Genome Evolution

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Dewhurst, Sally M.; McGranahan, Nicholas; Burrell, Rebecca A.

2014-01-01

The contribution of whole-genome doubling to chromosomal instability (CIN) and tumor evolution is unclear. We use long-term culture of isogenic tetraploid cells from a stable diploid colon cancer progenitor to investigate how a genome-doubling event affects genome stability over time. Rare cells...

Chromosomal Replication Complexity: A Novel DNA Metrics and Genome Instability Factor.

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Andrei Kuzminov

2016-10-01

Full Text Available As the ratio of the copy number of the most replicated to the unreplicated regions in the same chromosome, the definition of chromosomal replication complexity (CRC appears to leave little room for variation, being either two during S-phase or one otherwise. However, bacteria dividing faster than they replicate their chromosome spike CRC to four and even eight. A recent experimental inquiry about the limits of CRC in Escherichia coli revealed two major reasons to avoid elevating it further: (i increased chromosomal fragmentation and (ii complications with subsequent double-strand break repair. Remarkably, examples of stable elevated CRC in eukaryotic chromosomes are well known under various terms like "differential replication," "underreplication," "DNA puffs," "onion-skin replication," or "re-replication" and highlight the phenomenon of static replication fork (sRF. To accurately describe the resulting "amplification by overinitiation," I propose a new term: "replification" (subchromosomal overreplication. In both prokaryotes and eukaryotes, replification, via sRF processing, causes double-strand DNA breaks and, with their repair elevating chromosomal rearrangements, represents a novel genome instability factor. I suggest how static replication bubbles could be stabilized and speculate that some tandem duplications represent such persistent static bubbles. Moreover, I propose how static replication bubbles could be transformed into tandem duplications, double minutes, or inverted triplications. Possible experimental tests of these models are discussed.

Mouse Chromosome 4 Is Associated with the Baseline and Allergic IgE Phenotypes

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Cynthia Kanagaratham

2017-08-01

Full Text Available Regulation of IgE concentration in the blood is a complex trait, with high concentrations associated with parasitic infections as well as allergic diseases. A/J strain mice have significantly higher plasma concentrations of IgE, both at baseline and after ovalbumin antigen exposure, when compared to C57BL/6J strain mice. Our objective was to determine the genomic regions associated with this difference in phenotype. To achieve this, we used a panel of recombinant congenic strains (RCS derived from A/J and C57BL/6J strains. We measured IgE in the RCS panel at baseline and following allergen exposure. Using marker by marker analysis of the RCS genotype and phenotype data, we identified multiple regions associated with the IgE phenotype. A single region was identified to be associated with baseline IgE level, while multiple regions wereassociated with the phenotype after allergen exposure. The most significant region was found on Chromosome 4, from 81.46 to 86.17 Mbp. Chromosome 4 substitution strain mice had significantly higher concentration of IgE than their background parental strain mice, C57BL/6J. Our data presents multiple candidate regions associated with plasma IgE concentration at baseline and following allergen exposure, with the most significant one located on Chromosome 4.

Recombinant Chromosome 4 from a Familial Pericentric Inversion: Prenatal and Adulthood Wolf-Hirschhorn Phenotypes

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Francesca Malvestiti

2013-01-01

Full Text Available Pericentric inversion of chromosome 4 can give rise to recombinant chromosomes by duplication or deletion of 4p. We report on a familial case of Wolf-Hirschhorn Syndrome characterized by GTG-banding karyotypes, FISH, and array CGH analysis, caused by a recombinant chromosome 4 with terminal 4p16.3 deletion and terminal 4q35.2 duplication. This is an aneusomy due to a recombination which occurred during the meiosis of heterozygote carrier of cryptic pericentric inversion. We also describe the adulthood and prenatal phenotypes associated with the recombinant chromosome 4.

Tumor-specific chromosome mis-segregation controls cancer plasticity by maintaining tumor heterogeneity.

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Yuanjie Hu

Full Text Available Aneuploidy with chromosome instability is a cancer hallmark. We studied chromosome 7 (Chr7 copy number variation (CNV in gliomas and in primary cultures derived from them. We found tumor heterogeneity with cells having Chr7-CNV commonly occurs in gliomas, with a higher percentage of cells in high-grade gliomas carrying more than 2 copies of Chr7, as compared to low-grade gliomas. Interestingly, all Chr7-aneuploid cell types in the parental culture of established glioma cell lines reappeared in single-cell-derived subcultures. We then characterized the biology of three syngeneic glioma cultures dominated by different Chr7-aneuploid cell types. We found phenotypic divergence for cells following Chr7 mis-segregation, which benefited overall tumor growth in vitro and in vivo. Mathematical modeling suggested the involvement of chromosome instability and interactions among cell subpopulations in restoring the optimal equilibrium of tumor cell types. Both our experimental data and mathematical modeling demonstrated that the complexity of tumor heterogeneity could be enhanced by the existence of chromosomes with structural abnormality, in addition to their mis-segregations. Overall, our findings show, for the first time, the involvement of chromosome instability in maintaining tumor heterogeneity, which underlies the enhanced growth, persistence and treatment resistance of cancers.

Chromosomal duplication strains of Aspergillus nidulans and their instability

International Nuclear Information System (INIS)

Azevedo, J.L. de; Almeida Okino, L.M. de

1981-01-01

Strains of Aspergillus nidulans with chromosomal duplication were obtained after gamma irradiation followed by crossing of the translocated strains with normal strains. From 20 analysed colonies, 12 have shown translocations induced by irradiation. Segregants from four of these translocation strains crossed to normal strains have shown to be unstable although presenting normal morphology. Two segregants were genetically analysed. The first one has shown a duplication of part of linkage groups VIII and the second one presented a duplication of a segment of linkage group V. These new duplication strains in A. nidulans open new perspectives of a more detailed study of the instability phenomenon in this fungus. (Author) [pt

A mutation in the centriole-associated protein centrin causes genomic instability via increased chromosome loss in Chlamydomonas reinhardtii

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Marshall Wallace F

2005-05-01

Full Text Available Abstract Background The role of centrioles in mitotic spindle function remains unclear. One approach to investigate mitotic centriole function is to ask whether mutation of centriole-associated proteins can cause genomic instability. Results We addressed the role of the centriole-associated EF-hand protein centrin in genomic stability using a Chlamydomonas reinhardtii centrin mutant that forms acentriolar bipolar spindles and lacks the centrin-based rhizoplast structures that join centrioles to the nucleus. Using a genetic assay for loss of heterozygosity, we found that this centrin mutant showed increased genomic instability compared to wild-type cells, and we determined that the increase in genomic instability was due to a 100-fold increase in chromosome loss rates compared to wild type. Live cell imaging reveals an increased rate in cell death during G1 in haploid cells that is consistent with an elevated rate of chromosome loss, and analysis of cell death versus centriole copy number argues against a role for multipolar spindles in this process. Conclusion The increased chromosome loss rates observed in a centrin mutant that forms acentriolar spindles suggests a role for centrin protein, and possibly centrioles, in mitotic fidelity.

Hexavalent chromium induces chromosome instability in human urothelial cells

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Wise, Sandra S. [Wise Laboratory of Environmental and Genetic Toxicology, Maine Center for Toxicology and Environmental Health, Department of Applied Medical Science, University of Southern Maine, Science Building, 96 Falmouth Street, Portland, ME 04103 (United States); Holmes, Amie L. [Wise Laboratory of Environmental and Genetic Toxicology, Maine Center for Toxicology and Environmental Health, Department of Applied Medical Science, University of Southern Maine, Science Building, 96 Falmouth Street, Portland, ME 04103 (United States); Department of Radiation Oncology, Dana Farber Cancer Institute, 450 Brookline Ave., Boston, MA 02215 (United States); Liou, Louis [Department of Pathology, Boston University School of Medicine, 670 Albany St., Boston, MA 02118 (United States); Adam, Rosalyn M. [Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Wise, John Pierce Sr., E-mail: john.wise@louisville.edu [Wise Laboratory of Environmental and Genetic Toxicology, Maine Center for Toxicology and Environmental Health, Department of Applied Medical Science, University of Southern Maine, Science Building, 96 Falmouth Street, Portland, ME 04103 (United States)

2016-04-01

Numerous metals are well-known human bladder carcinogens. Despite the significant occupational and public health concern of metals and bladder cancer, the carcinogenic mechanisms remain largely unknown. Chromium, in particular, is a metal of concern as incidences of bladder cancer have been found elevated in chromate workers, and there is an increasing concern for patients with metal hip implants. However, the impact of hexavalent chromium (Cr(VI)) on bladder cells has not been studied. We compared chromate toxicity in two bladder cell lines; primary human urothelial cells and hTERT-immortalized human urothelial cells. Cr(VI) induced a concentration- and time-dependent increase in chromosome damage in both cell lines, with the hTERT-immortalized cells exhibiting more chromosome damage than the primary cells. Chronic exposure to Cr(VI) also induced a concentration-dependent increase in aneuploid metaphases in both cell lines which was not observed after a 24 h exposure. Aneuploidy induction was higher in the hTERT-immortalized cells. When we correct for uptake, Cr(VI) induces a similar amount of chromosome damage and aneuploidy suggesting that the differences in Cr(VI) sensitivity between the two cells lines were due to differences in uptake. The increase in chromosome instability after chronic chromate treatment suggests this may be a mechanism for chromate-induced bladder cancer, specifically, and may be a mechanism for metal-induced bladder cancer, in general. - Highlights: • Hexavalent chromium is genotoxic to human urothelial cells. • Hexavalent chromium induces aneuploidy in human urothelial cells. • hTERT-immortalized human urothelial cells model the effects seen in primary urothelial cells. • Hexavalent chromium has a strong likelihood of being carcinogenic for bladder tissue.

Loss of centrioles causes chromosomal instability in vertebrate somatic cells.

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Sir, Joo-Hee; Pütz, Monika; Daly, Owen; Morrison, Ciaran G; Dunning, Mark; Kilmartin, John V; Gergely, Fanni

2013-12-09

Most animal cells contain a centrosome, which comprises a pair of centrioles surrounded by an ordered pericentriolar matrix (PCM). Although the role of this organelle in organizing the mitotic spindle poles is well established, its precise contribution to cell division and cell survival remains a subject of debate. By genetically ablating key components of centriole biogenesis in chicken DT40 B cells, we generated multiple cell lines that lack centrioles. PCM components accumulated in acentriolar microtubule (MT)-organizing centers but failed to adopt a higher-order structure, as shown by three-dimensional structured illumination microscopy. Cells without centrioles exhibited both a delay in bipolar spindle assembly and a high rate of chromosomal instability. Collectively, our results expose a vital role for centrosomes in establishing a mitotic spindle geometry that facilitates correct kinetochore-MT attachments. We propose that centrosomes are essential in organisms in which rapid segregation of a large number of chromosomes needs to be attained with fidelity.

Familial colorectal cancer, can it be identified by microsatellite instability and chromosomal instability? - A case-control study

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Sunde, Lone; Bisgaard, Marie Luise; Soll-Johanning, Helle

2009-01-01

(Chromosome INstability=LOH (loss of heterozygosity) and/or DNA-aneuploidy (abnormal nuclear DNA contents)) could be used as predictors of familial CRC. Formalin-fixed tissue from 97 patients with CRC (29 patients with 2 or more affected first-degree relatives (="cases"), 29 matched CRC controls without......Colonoscopy is recommended for persons with a familial risk of colorectal cancer (CRC). A familial risk is identified by a family history with CRC and/or predisposing mutation(s). However, such information may not be available. We analysed whether MSI (MicroSatellite Instability) and/or CIN...... a family history, and 39 relatives to cases) were analysed for MSI and CIN. In this small case-control study, no significant differences in the frequencies of MSI and CIN were observed between cases with a family history and their controls without a family history. MSI+;CIN- was observed in 6/29 cases...

The CpG island methylator phenotype (CIMP) in colorectal cancer.

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Nazemalhosseini Mojarad, Ehsan; Kuppen, Peter Jk; Aghdaei, Hamid Asadzadeh; Zali, Mohammad Reza

2013-01-01

It is clear that colorectal cancer (CRC) develops through multiple genetic and epigenetic pathways. These pathways may be determined on the basis of three molecular features: (i) mutations in DNA mismatch repair genes, leading to a DNA microsatellite instability (MSI) phenotype, (ii) mutations in APC and other genes that activate Wnt pathway, characterized by chromosomal instability (CIN) phenotype, and (iii) global genome hypermethylation, resulting in switch off of tumor suppressor genes, indicated as CpG island methylator phenotype (CIMP). Each of these pathways is characterized by specific pathological features, mechanisms of carcinogenesis and process of tumor development. The molecular aspects of these pathways have been used clinically in the diagnosis, screening and management of patients with colorectal cancer. In this review we especially describe various aspects of CIMP, one of the important and rather recently discovered pathways that lead to colorectal cancer.

Chromosomal instability in acute myelocytic leukemia and myelodysplastic syndrome patients among atomic bomb survivors

International Nuclear Information System (INIS)

Nakanishi, Mitsue; Tanaka, Kimio; Shintani, Takahiro; Takahashi, Tomoko; Kamada, Nanao

1999-01-01

To clarify the mechanism of leukemogenesis in atomic bomb survivors, leukemic cells were investigated using fluorescence in situ hybridization (FISH) analysis on the basis of conventional G-banding in patients with a history of radiation exposure and also in de novo patients. Conventional G-banding showed higher incidences (p<0.005) of structural and numerical abnormalities without any specific types of chromosome aberrations in the group exposed to a dose of more than one Gy, compared to the non-exposed group. FISH analysis revealed significantly higher incidences (P<0.05) of subclones with monosomy 7 and deletion of the 20q13.2 region, which were not found in conventional cytogenetic analysis in the exposed group (more than one Gy) compared to the non-exposed controls. Furthermore, segmental jumping translocation (SJT) of the c-MYC gene region was observed only in the exposed group. These chromosomal instability suggested that the leukemic cells from the heavily exposed patients contained persistent cellular genetic instability which may strongly influence the development of leukemia in people exposed to radiation. (author)

High chromosomal instability in workers occupationally exposed to solvents and paint removers.

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Villalba-Campos, Mónica; Chuaire-Noack, Lilian; Sánchez-Corredor, Magda Carolina; Rondón-Lagos, Milena

2016-01-01

Painters are exposed to an extensive variety of harmful substances like aromatic hydrocarbons used as solvents and paint removers, some of which have shown clastogenic activity. These substances constitute a complex mixture of chemicals which contain well-known genotoxicants, such as Benzene, Toluene and Xylene. Thus, chronic occupational exposure to such substances may be considered to possess genotoxic risk. In Colombia the information available around the genotoxic damage (Chromosomal and DNA damage) in car paint shop workers is limited and the knowledge of this damage could contribute not only to a better understanding of the carcinogenic effect of this kind of substances but also could be used as biomarkers of occupational exposure to genotoxic agents. In this study, the genotoxic effect of aromatic hydrocarbons was assessed in peripheral blood lymphocytes of 24 workers occupationally exposed and 24 unexposed donors, by using Cytogenetic analysis and comet assay. A high frequency of Chromosomal alterations was found in the exposed group in comparison with those observed in the unexposed group. Among the total of CAs observed in the exposed group, fragilities were most frequently found (100 %), followed by chromosomal breaks (58 %), structural (41.2 %) and numerical chromosomal alterations (21 %). Numerical chromosomal alterations, fragilities and chromosomal breaks showed significant differences between exposed and unexposed groups. Among the fragilities, fra(9)(q12) was the most frequently observed. DNA damage index was also significantly higher in the exposed group compared to the unexposed group (p car paint shops workers and are also indicative of high chromosomal instability. The high frequency of both Chromosomal Alterations and DNA Damage Index observed in this study indicates an urgent need of intervention not only to prevent the increased risk of developing cancer but also to the application of strict health control and motivation to the use of

The induction of genomic instability in related human lymphoblasts following exposure to Cs gamma radiation vs accelerated 56Fe Ions

International Nuclear Information System (INIS)

Evans, H.H.; Horng, M.-F.; Ricanati, M.; Diaz-Insua, M.

2003-01-01

Full text: The induction of genomic instability by exposure to Cs-137 gamma radiation and Fe-56 accelerated ions was investigated by measuring the frequency and characteristics of TK6 and WTK1 unstable clones isolated 36 generations after exposure. While the two cell lines are related, TK6 is more sensitive to radiation, has normal p53 expression, and is repair deficient. Clones surviving the radiation and respective controls were analyzed for 17 characteristics including chromosomal aberrations, growth defects, alterations in response to a second radiation and mutant frequencies at two different loci. Putative unstable clones were defined as those exhibiting a significant alteration in one or more characteristics as compared to the respective control medians. Over half of the unstable WTK1 clones and over 90% of the TK6 unstable clones surviving exposure to either radiation exhibited chromosomal instability, the major aberrations consisting of chromatid breaks and dicentric chromosomes formed by end-to-end fusions. Alterations in the other measured characteristics occurred much less often than cytogenetic alterations in the TK6 unstable clones. The phenotype of the WTK1 unstable clones was more diverse and complex than in the case of TK6 unstable clones. The phenotype of the TK6 unstable clones differed in the survivors of Cs-137 vs. Fe-56. In the clones surviving Cs-137, the aberrations consisted mainly of dicentric chromosomes, while clones surviving exposure to Fe-56 exhibited both breaks and dicentrics. The uniform prevalence of chromosomal aberrations in the unstable TK6 clones vs. the relatively diverse phenotype of the unstable WTK1 clones suggests that the deficiency in DNA double-strand break repair in TK6 cells may be accompanied by a deficiency in telomere maintenance that leads to telomere fusion, dicentric chromosomes, anaphase bridges, breakage and the occurrence of chromosomal instability in the majority of clones isolated following exposure

Reprogramming to pluripotency can conceal somatic cell chromosomal instability.

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Masakazu Hamada

Full Text Available The discovery that somatic cells are reprogrammable to pluripotency by ectopic expression of a small subset of transcription factors has created great potential for the development of broadly applicable stem-cell-based therapies. One of the concerns regarding the safe use of induced pluripotent stem cells (iPSCs in therapeutic applications is loss of genomic integrity, a hallmark of various human conditions and diseases, including cancer. Structural chromosome defects such as short telomeres and double-strand breaks are known to limit reprogramming of somatic cells into iPSCs, but whether defects that cause whole-chromosome instability (W-CIN preclude reprogramming is unknown. Here we demonstrate, using aneuploidy-prone mouse embryonic fibroblasts (MEFs in which chromosome missegregation is driven by BubR1 or RanBP2 insufficiency, that W-CIN is not a barrier to reprogramming. Unexpectedly, the two W-CIN defects had contrasting effects on iPSC genomic integrity, with BubR1 hypomorphic MEFs almost exclusively yielding aneuploid iPSC clones and RanBP2 hypomorphic MEFs karyotypically normal iPSC clones. Moreover, BubR1-insufficient iPSC clones were karyotypically unstable, whereas RanBP2-insufficient iPSC clones were rather stable. These findings suggest that aneuploid cells can be selected for or against during reprogramming depending on the W-CIN gene defect and present the novel concept that somatic cell W-CIN can be concealed in the pluripotent state. Thus, karyotypic analysis of somatic cells of origin in addition to iPSC lines is necessary for safe application of reprogramming technology.

Arsenic-induced Aurora-A activation contributes to chromosome instability and tumorigenesis

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Wu, Chin-Han; Tseng, Ya-Shih; Yang, Chao-Chun; Kao, Yu-Ting; Sheu, Hamm-Ming; Liu, Hsiao-Sheng

2013-11-01

Arsenic may cause serious environmental pollution and is a serious industrial problem. Depending on the dosage, arsenic may trigger the cells undergoing either proliferation or apoptosis-related cell death. Because of lack of the proper animal model to study arsenic induced tumorigenesis, the accurate risk level of arsenic exposure has not been determined. Arsenic shows genotoxic effect on human beings who uptake water contaminated by arsenic. Chromosome aberration is frequently detected in arsenic exposure-related diseases and is associated with increased oxidative stress and decreased DNA repairing activity, but the underlying mechanism remains elusive. Aurora-A is a mitotic kinase, over-expression of Aurora-A leads to centrosome amplification, chromosomal instability and cell transformation. We revealed that Aurora-A is over-expressed in the skin and bladder cancer patients from blackfoot-disease endemic areas. Our cell line studies reveal that arsenic exposure between 0.5 μM and 1 μM for 2-7 days are able to induce Aurora-A expression and activation based on promoter activity, RNA and protein analysis. Aurora-A overexpression further increases the frequency of unsymmetrical chromosome segregation through centrosome amplification followed by cell population accumulated at S phase in immortalized keratinocyte (HaCaT) and uroepithelial cells (E7). Furthermore, Aurora-A over-expression was sustained for 1-4 weeks by chronic treatment of immortalized bladder and skin cells with NaAsO2. Aurora-A promoter methylation and gene amplification was not detected in the long-term arsenic treated E7 cells. Furthermore, the expression level of E2F1 transcription factor (E2F1) is increased in the presence of arsenic, and arsenic-related Aurora-A over-expression is transcriptionally regulated by E2F1. We further demonstrated that overexpression of Aurora-A and mutant Ha-ras or Aurora-A and mutant p53 may act additively to trigger arsenic-related bladder and skin cancer

Suppression of Genomic Instabilities Caused by Chromosome Mis-segregation: A Perspective From Studying BubR1 and Sgo1

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Dai, Wei

2013-01-01

Aneuploidy is a major manifestation of chromosomal instability, which is defined as a numerical abnormality of chromosomes in diploid cells. It is highly prevalent in a variety of human malignancies. Increased chromosomal instability is the major driving force for tumor development and progression. To suppress genomic stability during cell division, eukaryotic cells have evolved important molecular mechanisms, commonly referred to as checkpoints. The spindle checkpoint ensures that cells with defective mitotic spindles or a defective interaction between the spindles and kinetochores do not initiate chromosomal segregation during mitosis. Extensive studies have identified and characterized more than a dozen genes that play important roles in the regulation of the spindle checkpoint in mammalian cells. During the past decade, we have carried out extensive investigation of the role of BubR1 (Bub1-related kinase) and Sgo1 (shugoshin 1), two important gene products that safeguard accurate chromosome segregation during mitosis. This mini-review summarizes our studies, as well as those by other researchers in the field, on the functions of these two checkpoint proteins and their molecular regulation during mitosis. Further elucidation of the molecular mechanisms of the spindle checkpoint regulation has the potential to identify important mitotic targets for rational anticancer drug design. PMID:20040454

Suppression of Genomic Instabilities Caused by Chromosome Mis-segregation: A Perspective From Studying BubR1 and Sgo1

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Wei Dai

2009-12-01

Full Text Available Aneuploidy is a major manifestation of chromosomal instability, which is defined as a numerical abnormality of chromosomes in diploid cells. It is highly prevalent in a variety of human malignancies. Increased chromosomal instability is the major driving force for tumor development and progression. To suppress genomic stability during cell division, eukaryotic cells have evolved important molecular mechanisms, commonly referred to as checkpoints. The spindle checkpoint ensures that cells with defective mitotic spindles or a defective interaction between the spindles and kinetochores do not initiate chromosomal segregation during mitosis. Extensive studies have identified and characterized more than a dozen genes that play important roles in the regulation of the spindle checkpoint in mammalian cells. During the past decade, we have carried out extensive investigation of the role of BubR1 (Bub1-related kinase and Sgo1 (shugoshin 1, two important gene products that safeguard accurate chromosome segregation during mitosis. This mini-review summarizes our studies, as well as those by other researchers in the field, on the functions of these two checkpoint proteins and their molecular regulation during mitosis. Further elucidation of the molecular mechanisms of the spindle checkpoint regulation has the potential to identify important mitotic targets for rational anticancer drug design.

Gene Expression Signature TOPFOX Reflecting Chromosomal Instability Refines Prediction of Prognosis in Grade 2 Breast Cancer

DEFF Research Database (Denmark)

Szasz, A.; Li, Qiyuan; Sztupinszki, Z.

2011-01-01

Purpose: To assess the ability of genes selected from those reflecting chromosomal instability to identify good and poor prognostic subsets of Grade 2 breast carcinomas. Methods: We selected genes for splitting grade 2 tumours into low and high grade type groups by using public databases. Patient...

Chromosomal instability and telomere shortening in long-term culture of hematopoietic stem cells: insights from a cell culture model of RPS14 haploinsufficiency.

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Thomay, K; Schienke, A; Vajen, B; Modlich, U; Schambach, A; Hofmann, W; Schlegelberger, B; Göhring, G

2014-01-01

The fate of cultivated primary hematopoietic stem cells (HSCs) with respect to genetic instability and telomere attrition has not yet been described in great detail. Thus, knowledge of the genetic constitution of HSCs is important when interpreting results of HSCs in culture. While establishing a cell culture model for myelodysplastic syndrome with a deletion in 5q by performing RPS14 knockdown, we found surprising data that may be of importance for any CD34+ cell culture experiments. We performed cytogenetic analyses and telomere length measurement on transduced CD34+ cells and untransduced control cells to observe the effects of long-term culturing. Initially, CD34+ cells had a normal median telomere length of about 12 kb and showed no signs of chromosomal instability. During follow-up, the median telomere length seemed to decrease and, simultaneously, increased chromosomal instability could be observed - in modified and control cells. One culture showed a clonal monosomy 7 - independent of prior RPS14 knockdown. During further culturing, it seemed that the telomeres re-elongated, and chromosomes stabilized, while TERT expression was not elevated. In summary, irrespective of our results of RPS14 knockdown in the long-term culture of CD34+ cells, it becomes clear that cell culture artefacts inducing telomere shortening and chromosomal instability have to be taken into account and regular cytogenetic analyses should always be performed. © 2013 S. Karger AG, Basel.

Chromosomal instability in mouse embryonic fibroblasts null for the transcriptional co-repressor Ski

OpenAIRE

Marcelain, Katherine; Armisen, Ricardo; Aguirre, Adam; Ueki, Nobuhide; Toro, Jessica; Colmenares, Clemencia; Hayman, Michael J

2012-01-01

Ski is a transcriptional regulator that has been considered an oncoprotein, given its ability to induce oncogenic transformation in avian model systems. However, studies in mouse and in some human tumor cells have also indicated a tumor suppressor activity for this protein. We found that Ski−/− mouse embryo fibroblasts exhibit high levels of genome instability, namely aneuploidy, consistent with a tumor suppressor function for Ski. Time-lapse microscopy revealed lagging chromosomes and chroma...

Determination of hidden chromosome instability in persons suffered from the action of factors of the Chernobyl accident by the modified 'G2 bleomycin sensitivity assay'

International Nuclear Information System (INIS)

Dibs'kij, S.S.; Dibs'ka, O.B.; Pedan, L.P.; Pyilyins'ka, M.A.

2009-01-01

With the help of the modified 'G 2 -bleomycin sensitivity assay' the voluntary investigation of hidden chromosome instability in 53 persons with different radiation exposures had been fulfilled. In all examined groups, the individual levels of chromosome injuries under identical bleomycin exposure varied in a wide range and didn't depend on their initial values in intact cultures. Among control donors and individuals with low radiation exposure, ∼ 33 % hypertensive persons had been identified that can be considered as a genetically caused phenomenon. In patients recovered from acute radiation, 57.9 % persons expressed the hidden chromosome instability. The data obtained allow us to assume that high doses of ionizing radiation can modify the inherited susceptibility of human chromosomes to a mutagen exposure.

Mitotic chromosome transmission fidelity mutants in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Spencer, F.; Gerring, S.L.; Connelly, C.; Hieter, P.

1990-01-01

The authors have isolated 136 independent EMS-induced mutations in haploid yeast strains that exhibit decreased chromosome transmission fidelity in mitosis. Eight-five percent of the mutations are recessive and 15% are partially dominant. Complementation analysis between MATa and MATα isolates identifies 11 chromosome transmission fidelity (CTF) complementation groups, the largest of which is identical to CHL1. For 49 independent mutations, no corresponding allele has been recovered in the opposite mating type. The initial screen monitored the stability of a centromere-linked color marker on a nonessential yeast chromosome fragment; the mitotic inheritance of natural yeast chromosome III is also affected by the ctf mutations. Of the 136 isolates identified, seven were inviable at 37 degree and five were inviable at 11 degree. In all cases tested, these temperature conditional lethalities cosegregated with the chromosome instability phenotype. Five additional complementation groups (ctf12 through ctf16) have been defined by complementation analysis of the mutations causing inviability at 37 degree. All of the mutant strains showed normal sensitivity to ultraviolet and γ-irradiation

HEK293 in cell biology and cancer research: phenotype, karyotype, tumorigenicity, and stress-induced genome-phenotype evolution.

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Stepanenko, A A; Dmitrenko, V V

2015-09-15

293 cell line (widely known as the Human Embryonic Kidney 293 cells) and its derivatives were the most used cells after HeLa in cell biology studies and after CHO in biotechnology as a vehicle for the production of adenoviral vaccines and recombinant proteins, for analysis of the neuronal synapse formation, in electrophysiology and neuropharmacology. Despite the historically long-term productive exploitation, the origin, phenotype, karyotype, and tumorigenicity of 293 cells are still debated. 293 cells were considered the kidney epithelial cells or even fibroblasts. However, 293 cells demonstrate no evident tissue-specific gene expression signature and express the markers of renal progenitor cells, neuronal cells and adrenal gland. This complicates efforts to reveal the authentic cell type/tissue of origin. On the other hand, the potential to propagate the highly neurotropic viruses, inducible synaptogenesis, functionality of the endogenous neuron-specific voltage-gated channels, and response to the diverse agonists implicated in neuronal signaling give credibility to consider 293 cells of neuronal lineage phenotype. The compound phenotype of 293 cells can be due to heterogeneous, unstable karyotype. The mean chromosome number and chromosome aberrations differ between 293 cells and derivatives as well as between 293 cells from the different cell banks/labs. 293 cells are tumorigenic, whereas acute changes of expression of the cancer-associated genes aggravate tumorigenicity by promoting chromosome instability. Importantly, the procedure of a stable empty vector transfection can also impact karyotype and phenotype. The discussed issues caution against misinterpretations and pitfalls during the different experimental manipulations with 293 cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Introduction of a normal human chromosome 8 corrects abnormal phenotypes of Werner syndrome cells immortalized by expressing an hTERT gene

International Nuclear Information System (INIS)

Ariyoshi, Kentaro; Kodama, Seiji; Suzuki, Keiji; Goto, Makoto; Oshimura, Mitsuo; Ishizaki, Kanji; Watanabe, Masami

2009-01-01

Werner syndrome (WS) is an autosomal recessive disease characterized by premature aging and caused by mutations of the WRN gene mapped at 8p12. To examine functional complementation of WS phenotypes, we introduced a normal human chromosome 8 into a strain of WS fibroblasts (WS3RGB) immortalized by expressing a human telomerase reverse transcriptase subunit (hTERT) gene. Here, we demonstrate that the abnormal WS phenotypes including cellular sensitivities to 4-nitroquinoline-1-oxide (4NQO) and hydroxy urea (HU), and chromosomal radiosensitivity at G 2 phase are corrected by expression of the WRN gene mediated by introducing a chromosome 8. This indicates that those multiple abnormal WS phenotypes are derived from a primary, but not secondary, defect in the WRN gene. (author)

Genotype-phenotype analysis of recombinant chromosome 4 syndrome: an array-CGH study and literature review.

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Hemmat, Morteza; Hemmat, Omid; Anguiano, Arturo; Boyar, Fatih Z; El Naggar, Mohammed; Wang, Jia-Chi; Wang, Borris T; Sahoo, Trilochan; Owen, Renius; Haddadin, Mary

2013-05-02

Recombinant chromosome 4, a rare constitutional rearrangement arising from pericentric inversion, comprises a duplicated segment of 4p13~p15→4pter and a deleted segment of 4q35→4qter. To date, 10 cases of recombinant chromosome 4 have been reported. We describe the second case in which array-CGH was used to characterize recombinant chromosome 4 syndrome. The patient was a one-year old boy with consistent clinical features. Conventional cytogenetics and FISH documented a recombinant chromosome 4, derived from a paternal pericentric inversion, leading to partial trisomy 4p and partial monosomy of 4q. Array-CGH, performed to further characterize the rearranged chromosome 4 and delineate the breakpoints, documented a small (4.36 Mb) 4q35.1 terminal deletion and a large (23.81 Mb) 4p15.1 terminal duplication. Genotype-phenotype analysis of 10 previously reported cases and the present case indicated relatively consistent clinical features and breakpoints. This consistency was more evident in our case and another characterized by array-CGH, where both showed the common breakpoints of p15.1 and q35.1. A genotype-phenotype correlation study between rec(4), dup(4p), and del(4q) syndromes revealed that urogenital and cardiac defects are probably due to the deletion of 4q whereas the other clinical features are likely due to 4p duplication. Our findings support that the clinical features of patients with rec(4) are relatively consistent and specific to the regions of duplication or deletion. Recombinant chromosome 4 syndrome thus appears to be a discrete entity that can be suspected on the basis of clinical features or specific deleted and duplicated chromosomal regions.

Frequent induction of chromosomal aberrations in in vivo skin fibroblasts after allogeneic stem cell transplantation: hints to chromosomal instability after irradiation

International Nuclear Information System (INIS)

Massenkeil, G.; Zschieschang, P.; Thiel, G.; Hemmati, P. G.; Budach, V.; Dörken, B.; Pross, J.; Arnold, R.

2015-01-01

Total body irradiation (TBI) has been part of standard conditioning regimens before allogeneic stem cell transplantation for many years. Its effect on normal tissue in these patients has not been studied extensively. We studied the in vivo cytogenetic effects of TBI and high-dose chemotherapy on skin fibroblasts from 35 allogeneic stem cell transplantation (SCT) patients. Biopsies were obtained prospectively (n = 18 patients) before, 3 and 12 months after allogeneic SCT and retrospectively (n = 17 patients) 23–65 months after SCT for G-banded chromosome analysis. Chromosomal aberrations were detected in 2/18 patients (11 %) before allogeneic SCT, in 12/13 patients (92 %) after 3 months, in all patients after 12 months and in all patients in the retrospective group after allogeneic SCT. The percentage of aberrant cells was significantly higher at all times after allogeneic SCT compared to baseline analysis. Reciprocal translocations were the most common aberrations, but all other types of stable, structural chromosomal aberrations were also observed. Clonal aberrations were observed, but only in three cases they were detected in independently cultured flasks. A tendency to non-random clustering throughout the genome was observed. The percentage of aberrant cells was not different between patients with and without secondary malignancies in this study group. High-dose chemotherapy and TBI leads to severe chromosomal damage in skin fibroblasts of patients after SCT. Our long-term data suggest that this damage increases with time, possibly due to in vivo radiation-induced chromosomal instability

Clonal chromosomal and genomic instability during human multipotent mesenchymal stromal cells long-term culture.

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Victoria Nikitina

Full Text Available Spontaneous mutagenesis often leads to appearance of genetic changes in cells. Although human multipotent mesenchymal stromal cells (hMSC are considered as genetically stable, there is a risk of genomic and structural chromosome instability and, therefore, side effects of cell therapy associated with long-term effects. In this study, the karyotype, genetic variability and clone formation analyses have been carried out in the long-term culture MSC from human gingival mucosa.The immunophenotype of MSC has been examined using flow cytofluorometry and short tandem repeat (STR analysis has been carried out for authentication. The karyotype has been examined using GTG staining and mFISH, while the assessment of the aneuploidy 8 frequency has been performed using centromere specific chromosome FISH probes in interphase cells.The immunophenotype and STR loci combination did not change during the process of cultivation. From passage 23 the proliferative activity of cultured MSCs was significantly reduced. From passage 12 of cultivation, clones of cells with stable chromosome aberrations have been identified and the biggest of these (12% are tetrasomy of chromosome 8. The random genetic and structural chromosomal aberrations and the spontaneous level of chromosomal aberrations in the hMSC long-term cultures were also described.The spectrum of spontaneous chromosomal aberrations in MSC long-term cultivation has been described. Clonal chromosomal aberrations have been identified. A clone of cells with tetrasomy 8 has been detected in passage 12 and has reached the maximum size by passage 18 before and decreased along with the reduction of proliferative activity of cell line by passage 26. At later passages, the MSC line exhibited a set of cells with structural variants of the karyotype with a preponderance of normal diploid cells. The results of our study strongly suggest a need for rigorous genetic analyses of the clone formation in cultured MSCs before

Genetic instability in urinary bladder cancer: An evolving hallmark.

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Wadhwa, N; Mathew, B B; Jatawa, S K; Tiwari, A

2013-01-01

Bladder cancer is a major health-care concern. A successful treatment of bladder cancer depends on its early diagnosis at the initial stage. Genetic instability is an essential early step toward the development of bladder cancer. This instability is found more often at the chromosomal level than at the nucleotide level. Microsatellite and chromosomal instability markers can be used as a prognostic marker for screening bladder cancer. Bladder cancer can be distinguished in two different categories according to genetic instability: Cancers with chromosomal level instability and cancers with nucleotide level instability. Deoxyribonucleic acid (DNA) mismatch repair (MMR) system and its correlation with other biologic pathway, both are essential to understand the basic mechanisms of cancer development. Microsatellite instability occurs due to defects in DNA MMR genes, including human mutL homolog 1 and human mutL homolog 2. Chromosomal alterations including deletions on chromosome 3, 8, 9, 11, 13, 17 have been detected in bladder cancer. In the current review, the most recent literature of genetic instability in urinary bladder cancer has been summarized.

Genetic instability in urinary bladder cancer: An evolving hallmark

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N Wadhwa

2013-01-01

Full Text Available Bladder cancer is a major health-care concern. A successful treatment of bladder cancer depends on its early diagnosis at the initial stage. Genetic instability is an essential early step toward the development of bladder cancer. This instability is found more often at the chromosomal level than at the nucleotide level. Microsatellite and chromosomal instability markers can be used as a prognostic marker for screening bladder cancer. Bladder cancer can be distinguished in two different categories according to genetic instability: Cancers with chromosomal level instability and cancers with nucleotide level instability. Deoxyribonucleic acid (DNA mismatch repair (MMR system and its correlation with other biologic pathway, both are essential to understand the basic mechanisms of cancer development. Microsatellite instability occurs due to defects in DNA MMR genes, including human mutL homolog 1 and human mutL homolog 2. Chromosomal alterations including deletions on chromosome 3, 8, 9, 11, 13, 17 have been detected in bladder cancer. In the current review, the most recent literature of genetic instability in urinary bladder cancer has been summarized.

Centrosome Dysfunction Contributes To Chromosome Instability, Chromoanagenesis And Genome Reprograming In Cancer.

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German A Pihan

2013-11-01

Full Text Available The unique ability of centrosomes to nucleate and organize microtubules makes them unrivaled conductors of important interphase processes, such as intracellular payload traffic, cell polarity, cell locomotion, and organization of the immunologic synapse. But it is in mitosis that centrosomes loom large, for they orchestrate, with clockmaker’s precision, the assembly and functioning of the mitotic spindle, ensuring the equal partitioning of the replicated genome into daughter cells. Centrosome dysfunction is inextricably linked to aneuploidy and chromosome instability, both hallmarks of cancer cells. Several aspects of centrosome function in normal and cancer cells have been molecularly characterized during the last two decades, greatly enhancing our mechanistic understanding of this tiny organelle. Whether centrosome defects alone can cause cancer, remains unanswered. Until recently, the aggregate of the evidence had suggested that centrosome dysfunction, by deregulating the fidelity of chromosome segregation, promotes and accelerates the characteristic Darwinian evolution of the cancer genome enabled by increased mutational load and/or decreased DNA repair. Very recent experimental work has shown that missegreated chromosomes resulting from centrosome dysfunction may experience extensive DNA damage, suggesting additional dimensions to the role of centrosomes in cancer. Centrosome dysfunction is particularly prevalent in tumors in which the genome has undergone extensive structural rearrangements and chromosome domain reshuffling. Ongoing gene reshuffling reprograms the genome for continuous growth, survival, and evasion of the immune system. Manipulation of molecular networks controlling centrosome function may soon become a viable target for specific therapeutic intervention in cancer, particularly since normal cells, which lack centrosome alterations, may be spared the toxicity of such therapies.

Appearance and evolution of the specific chromosomal rearrangements associated with malignant transformation of mouse m5S cells

International Nuclear Information System (INIS)

Kodama, S.; Okumura, Y.; Komatsu, K.; Sasaki, M.S.

1991-01-01

Chromosomal alterations were studied during the acquisition of malignant phenotypes in two karyotypically distinct cells isolated from transformed foci induced by x-irradiation in mouse m5S cells. Because the transformants, despite foci origin, showed low ability to grow in agar, they were cultured in vitro with serial transfer schedules to allow further cell generations and assayed for anchorage independence (AI) at each passage level. The AI frequency increased with the cell doubling numbers. Chromosome analysis showed that a focus was one cell origin, but the transformants showed karyotypic instability during cell proliferation, giving rise to the rearrangements clustered in the distal region of the specific chromosomes. These rearrangements appeared to be directed toward the acquisition of malignant phenotypes. Analysis of the types and sites of rearrangements indicated that a mechanism exists that induces frequent rearrangements of the specific region of a chromosome during the process of transformation into the malignant state

Application of molecular cytogenetic techniques to clarify apparently balanced complex chromosomal rearrangements in two patients with an abnormal phenotype: case report

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Rongen Michel A

2009-07-01

Full Text Available Abstract Background Complex chromosomal rearrangements (CCR are rare cytogenetic findings that are difficult to karyotype by conventional cytogenetic analysis partially because of the relative low resolution of this technique. High resolution genotyping is necessary in order to identify cryptic imbalances, for instance near the multiple breakpoints, to explain the abnormal phenotype in these patients. We applied several molecular techniques to elucidate the complexity of the CCRs of two adult patients with abnormal phenotypes. Results Multicolour fluorescence in situ hybridization (M-FISH showed that in patient 1 the chromosomes 1, 10, 15 and 18 were involved in the rearrangement whereas for patient 2 the chromosomes 5, 9, 11 and 13 were involved. A 250 k Nsp1 SNP-array analysis uncovered a deletion in chromosome region 10p13 for patient 1, harbouring 17 genes, while patient 2 showed no pathogenic gains or losses. Additional FISH analysis with locus specific BAC-probes was performed, leading to the identification of cryptic interstitial structural rearrangements in both patients. Conclusion Application of M-FISH and SNP-array analysis to apparently balanced CCRs is useful to delineate the complex chromosomal rearrangement in detail. However, it does not always identify cryptic imbalances as an explanation for the abnormal phenotype in patients with a CCR.

Inversion duplication deletions involving the long arm of chromosome 13: phenotypic description of additional three fetuses and genotype-phenotype correlation.

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Quelin, Chloe; Spaggiari, Emmanuel; Khung-Savatovsky, Suonavy; Dupont, Celine; Pasquier, Laurent; Loeuillet, Laurence; Jaillard, Sylvie; Lucas, Josette; Marcorelles, Pascale; Journel, Hubert; Pluquailec-Bilavarn, Khantaby; Bazin, Anne; Verloes, Alain; Delezoide, Anne-Lise; Aboura, Azzedine; Guimiot, Fabien

2014-10-01

Inversion duplication and terminal deletion of the long arm of chromosome 13 (inv dup del 13q) is a rare chromosomal rearrangement: only five patients have been reported, mostly involving a ring chromosome 13. We report on additional three fetuses with pure inv dup del 13q: Patient 1 had macrosomia, enlarged kidneys, hypersegmented lungs, unilateral moderate ventriculomegaly, and a mild form of hand and feet preaxial polydactyly; Patient 2 had intrauterine growth retardation, widely spaced eyes, left microphthalmia, right anophthalmia, short nose, bilateral absent thumbs, cutaneous syndactyly of toes 4 and 5, bifid third metacarpal, a small left kidney, hyposegmented lungs, and partial agenesis of the corpus callosum; Patient 3 had widely spaced eyes, long and smooth philtrum, low-set ears, median notch in the upper alveolar ridge, bifid tongue, cutaneous syndactyly of toes 2 and 3, enlarged kidneys and pancreas, arhinencephaly, and partial agenesis of the corpus callosum. We compared the phenotypes of these patients to those previously reported for ring chromosome 13, pure 13q deletions and duplications. We narrowed some critical regions previously reported for lung, kidney and fetal growth, and for thumb, cerebral, and eye anomalies. © 2014 Wiley Periodicals, Inc.

In vivo overexpression of Emi1 promotes chromosome instability and tumorigenesis.

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Vaidyanathan, S; Cato, K; Tang, L; Pavey, S; Haass, N K; Gabrielli, B G; Duijf, P H G

2016-10-13

Cell cycle genes are often aberrantly expressed in cancer, but how their misexpression drives tumorigenesis mostly remains unclear. From S phase to early mitosis, EMI1 (also known as FBXO5) inhibits the anaphase-promoting complex/cyclosome, which controls cell cycle progression through the sequential degradation of various substrates. By analyzing 7403 human tumor samples, we find that EMI1 overexpression is widespread in solid tumors but not in blood cancers. In solid cancers, EMI1 overexpression is a strong prognostic marker for poor patient outcome. To investigate causality, we generated a transgenic mouse model in which we overexpressed Emi1. Emi1-overexpressing animals develop a wide variety of solid tumors, in particular adenomas and carcinomas with inflammation and lymphocyte infiltration, but not blood cancers. These tumors are significantly larger and more penetrant, abundant, proliferative and metastatic than control tumors. In addition, they are highly aneuploid with tumor cells frequently being in early mitosis and showing mitotic abnormalities, including lagging and incorrectly segregating chromosomes. We further demonstrate in vitro that even though EMI1 overexpression may cause mitotic arrest and cell death, it also promotes chromosome instability (CIN) following delayed chromosome alignment and anaphase onset. In human solid tumors, EMI1 is co-expressed with many markers for CIN and EMI1 overexpression is a stronger marker for CIN than most well-established ones. The fact that Emi1 overexpression promotes CIN and the formation of solid cancers in vivo indicates that Emi1 overexpression actively drives solid tumorigenesis. These novel mechanistic insights have important clinical implications.

5-bp Classical Satellite DNA Loci from Chromosome-1 Instability in Cervical Neoplasia Detected by DNA Breakage Detection/Fluorescence in Situ Hybridization (DBD-FISH

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Jaime Gosálvez

2013-02-01

Full Text Available We aimed to evaluate the association between the progressive stages of cervical neoplasia and DNA damage in 5-bp classical satellite DNA sequences from chromosome-1 in cervical epithelium and in peripheral blood lymphocytes using DNA breakage detection/fluorescence in situ hybridization (DBD-FISH. A hospital-based unmatched case-control study was conducted in 2011 with a sample of 30 women grouped according to disease stage and selected according to histological diagnosis; 10 with low-grade squamous intraepithelial lesions (LG-SIL, 10 with high-grade SIL (HG-SIL, and 10 with no cervical lesions, from the Unidad Medica de Alta Especialidad of The Mexican Social Security Institute, IMSS, Mexico. Specific chromosome damage levels in 5-bp classical satellite DNA sequences from chromosome-1 were evaluated in cervical epithelium and peripheral blood lymphocytes using the DBD-FISH technique. Whole-genome DNA hybridization was used as a reference for the level of damage. Results of Kruskal-Wallis test showed a significant increase according to neoplastic development in both tissues. The instability of 5-bp classical satellite DNA sequences from chromosome-1 was evidenced using chromosome-orientation FISH. In conclusion, we suggest that the progression to malignant transformation involves an increase in the instability of 5-bp classical satellite DNA sequences from chromosome-1.

5-bp Classical Satellite DNA Loci from Chromosome-1 Instability in Cervical Neoplasia Detected by DNA Breakage Detection/Fluorescence in Situ Hybridization (DBD-FISH).

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Cortés-Gutiérrez, Elva I; Ortíz-Hernández, Brenda L; Dávila-Rodríguez, Martha I; Cerda-Flores, Ricardo M; Fernández, José Luis; López-Fernández, Carmen; Gosálvez, Jaime

2013-02-19

We aimed to evaluate the association between the progressive stages of cervical neoplasia and DNA damage in 5-bp classical satellite DNA sequences from chromosome-1 in cervical epithelium and in peripheral blood lymphocytes using DNA breakage detection/fluorescence in situ hybridization (DBD-FISH). A hospital-based unmatched case-control study was conducted in 2011 with a sample of 30 women grouped according to disease stage and selected according to histological diagnosis; 10 with low-grade squamous intraepithelial lesions (LG-SIL), 10 with high-grade SIL (HG-SIL), and 10 with no cervical lesions, from the Unidad Medica de Alta Especialidad of The Mexican Social Security Institute, IMSS, Mexico. Specific chromosome damage levels in 5-bp classical satellite DNA sequences from chromosome-1 were evaluated in cervical epithelium and peripheral blood lymphocytes using the DBD-FISH technique. Whole-genome DNA hybridization was used as a reference for the level of damage. Results of Kruskal-Wallis test showed a significant increase according to neoplastic development in both tissues. The instability of 5-bp classical satellite DNA sequences from chromosome-1 was evidenced using chromosome-orientation FISH. In conclusion, we suggest that the progression to malignant transformation involves an increase in the instability of 5-bp classical satellite DNA sequences from chromosome-1.

CCAT2, a novel noncoding RNA mapping to 8q24, underlies metastatic progression and chromosomal instability in colon cancer

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Ling, Hui; Spizzo, Riccardo; Atlasi, Yaser; Nicoloso, Milena; Shimizu, Masayoshi; Redis, Roxana S.; Nishida, Naohiro; Gafà, Roberta; Song, Jian; Guo, Zhiyi; Ivan, Cristina; Barbarotto, Elisa; De Vries, Ingrid; Zhang, Xinna; Ferracin, Manuela; Churchman, Mike; van Galen, Janneke F.; Beverloo, Berna H.; Shariati, Maryam; Haderk, Franziska; Estecio, Marcos R.; Garcia-Manero, Guillermo; Patijn, Gijs A.; Gotley, David C.; Bhardwaj, Vikas; Shureiqi, Imad; Sen, Subrata; Multani, Asha S.; Welsh, James; Yamamoto, Ken; Taniguchi, Itsuki; Song, Min-Ae; Gallinger, Steven; Casey, Graham; Thibodeau, Stephen N.; Le Marchand, Loïc; Tiirikainen, Maarit; Mani, Sendurai A.; Zhang, Wei; Davuluri, Ramana V.; Mimori, Koshi; Mori, Masaki; Sieuwerts, Anieta M.; Martens, John W.M.; Tomlinson, Ian; Negrini, Massimo; Berindan-Neagoe, Ioana; Foekens, John A.; Hamilton, Stanley R.; Lanza, Giovanni; Kopetz, Scott; Fodde, Riccardo; Calin, George A.

2013-01-01

The functional roles of SNPs within the 8q24 gene desert in the cancer phenotype are not yet well understood. Here, we report that CCAT2, a novel long noncoding RNA transcript (lncRNA) encompassing the rs6983267 SNP, is highly overexpressed in microsatellite-stable colorectal cancer and promotes tumor growth, metastasis, and chromosomal instability. We demonstrate that MYC, miR–17–5p, and miR–20a are up-regulated by CCAT2 through TCF7L2-mediated transcriptional regulation. We further identify the physical interaction between CCAT2 and TCF7L2 resulting in an enhancement of WNT signaling activity. We show that CCAT2 is itself a WNT downstream target, which suggests the existence of a feedback loop. Finally, we demonstrate that the SNP status affects CCAT2 expression and the risk allele G produces more CCAT2 transcript. Our results support a new mechanism of MYC and WNT regulation by the novel lncRNA CCAT2 in colorectal cancer pathogenesis, and provide an alternative explanation of the SNP-conferred cancer risk. PMID:23796952

Telomere dysfunction and chromosome structure modulate the contribution of individual chromosomes in abnormal nuclear morphologies

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Pampalona, J.; Soler, D.; Genesca, A. [Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Bellaterra E-08193 (Spain); Tusell, L., E-mail: laura.tusell@uab.es [Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Bellaterra E-08193 (Spain)

2010-01-05

The cytokinesis-block micronucleus assay has emerged as a biomarker of chromosome damage relevant to cancer. Although it was initially developed to measure micronuclei, it is also useful for measuring nucleoplasmic bridges and nuclear buds. Abnormal nuclear morphologies are frequently observed in malignant tissues and short-term tumour cell cultures. Changes in chromosome structure and number resulting from chromosome instability are important factors in oncogenesis. Telomeres have become key players in the initiation of chromosome instability related to carcinogenesis by means of breakage-fusion-bridge cycles. To better understand the connection between telomere dysfunction and the appearance of abnormal nuclear morphologies, we have characterised the presence of micronuclei, nucleoplasmic bridges and nuclear buds in human mammary primary epithelial cells. These cells can proliferate beyond the Hayflick limit by spontaneously losing expression of the p16{sup INK4a} protein. Progressive telomere shortening leads to the loss of the capping function, and the appearance of end-to-end chromosome fusions that can enter into breakage-fusion-bridge cycles generating massive chromosomal instability. In human mammary epithelial cells, different types of abnormal nuclear morphologies were observed, however only nucleoplasmatic bridges and buds increased significantly with population doublings. Fluorescent in situ hybridisation using centromeric and painting specific probes for chromosomes with eroded telomeres has revealed that these chromosomes are preferentially included in the different types of abnormal nuclear morphologies observed, thus reflecting their common origin. Accordingly, real-time imaging of cell divisions enabled us to determine that anaphase bridge resolution was mainly through chromatin breakage and the formation of symmetric buds in daughter nuclei. Few micronuclei emerged in this cell system thus validating the scoring of nucleoplasmic bridges and

Telomere dysfunction and chromosome structure modulate the contribution of individual chromosomes in abnormal nuclear morphologies

International Nuclear Information System (INIS)

Pampalona, J.; Soler, D.; Genesca, A.; Tusell, L.

2010-01-01

The cytokinesis-block micronucleus assay has emerged as a biomarker of chromosome damage relevant to cancer. Although it was initially developed to measure micronuclei, it is also useful for measuring nucleoplasmic bridges and nuclear buds. Abnormal nuclear morphologies are frequently observed in malignant tissues and short-term tumour cell cultures. Changes in chromosome structure and number resulting from chromosome instability are important factors in oncogenesis. Telomeres have become key players in the initiation of chromosome instability related to carcinogenesis by means of breakage-fusion-bridge cycles. To better understand the connection between telomere dysfunction and the appearance of abnormal nuclear morphologies, we have characterised the presence of micronuclei, nucleoplasmic bridges and nuclear buds in human mammary primary epithelial cells. These cells can proliferate beyond the Hayflick limit by spontaneously losing expression of the p16 INK4a protein. Progressive telomere shortening leads to the loss of the capping function, and the appearance of end-to-end chromosome fusions that can enter into breakage-fusion-bridge cycles generating massive chromosomal instability. In human mammary epithelial cells, different types of abnormal nuclear morphologies were observed, however only nucleoplasmatic bridges and buds increased significantly with population doublings. Fluorescent in situ hybridisation using centromeric and painting specific probes for chromosomes with eroded telomeres has revealed that these chromosomes are preferentially included in the different types of abnormal nuclear morphologies observed, thus reflecting their common origin. Accordingly, real-time imaging of cell divisions enabled us to determine that anaphase bridge resolution was mainly through chromatin breakage and the formation of symmetric buds in daughter nuclei. Few micronuclei emerged in this cell system thus validating the scoring of nucleoplasmic bridges and nuclear

Telomere dysfunction and chromosome structure modulate the contribution of individual chromosomes in abnormal nuclear morphologies.

Science.gov (United States)

Pampalona, J; Soler, D; Genescà, A; Tusell, L

2010-01-05

The cytokinesis-block micronucleus assay has emerged as a biomarker of chromosome damage relevant to cancer. Although it was initially developed to measure micronuclei, it is also useful for measuring nucleoplasmic bridges and nuclear buds. Abnormal nuclear morphologies are frequently observed in malignant tissues and short-term tumour cell cultures. Changes in chromosome structure and number resulting from chromosome instability are important factors in oncogenesis. Telomeres have become key players in the initiation of chromosome instability related to carcinogenesis by means of breakage-fusion-bridge cycles. To better understand the connection between telomere dysfunction and the appearance of abnormal nuclear morphologies, we have characterised the presence of micronuclei, nucleoplasmic bridges and nuclear buds in human mammary primary epithelial cells. These cells can proliferate beyond the Hayflick limit by spontaneously losing expression of the p16(INK4a) protein. Progressive telomere shortening leads to the loss of the capping function, and the appearance of end-to-end chromosome fusions that can enter into breakage-fusion-bridge cycles generating massive chromosomal instability. In human mammary epithelial cells, different types of abnormal nuclear morphologies were observed, however only nucleoplasmatic bridges and buds increased significantly with population doublings. Fluorescent in situ hybridisation using centromeric and painting specific probes for chromosomes with eroded telomeres has revealed that these chromosomes are preferentially included in the different types of abnormal nuclear morphologies observed, thus reflecting their common origin. Accordingly, real-time imaging of cell divisions enabled us to determine that anaphase bridge resolution was mainly through chromatin breakage and the formation of symmetric buds in daughter nuclei. Few micronuclei emerged in this cell system thus validating the scoring of nucleoplasmic bridges and nuclear

Telomere Shortening in Hematological Malignancies with Tetraploidization—A Mechanism for Chromosomal Instability?

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Eigil Kjeldsen

2017-11-01

Full Text Available Aneuploidy, the presence of an abnormal number of chromosomes in a cell, is one of the most obvious differences between normal and cancer cells. There is, however, debate on how aneuploid cells arise and whether or not they are a cause or a consequence of tumorigenesis. Further, it is important to distinguish aneuploidy (the “state” of the karyotype from chromosomal instability (CIN; the “rate” of karyotypic change. Although CIN leads to aneuploidy, not all aneuploid cells exhibit CIN. One proposed route to aneuploid cells is through an unstable tetraploid intermediate because tetraploidy promotes chromosomal aberrations and tumorigenesis. Tetraploidy or near-tetraploidy (T/NT (81–103 chromosomes karyotypes with or without additional structural abnormalities have been reported in acute leukemia, T-cell and B-cell lymphomas, and solid tumors. In solid tumors it has been shown that tetraploidization can occur in response to loss of telomere protection in the early stages of tumorigenesis in colon cancer, Barrett’s esophagus, and breast and cervical cancers. In hematological malignancies T/NT karyotypes are rare and the role of telomere dysfunction for the induction of tetraploidization is less well characterized. To further our understanding of possible telomere dysfunction as a mechanism for tetrapolydization in hematological cancers we here characterized the chromosomal complement and measured the telomere content by interphase nuclei quantitative fluorescence in situ hybridization (iQFISH in seven hematological cancer patients with T/NT karyotypes, and after cytogenetic remission. The patients were identified after a search in our local cytogenetic registry in the 5-year period between June 2012 and May 2017 among more than 12,000 analyzed adult patients in this period. One advantage of measuring telomere content by iQFISH is that it is a single-cell analysis so that the telomere content can be distinguished between normal karyotype

Genetics and epigenetics of small bowel adenocarcinoma: the interactions of CIN, MSI, and CIMP.

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Warth, Arne; Kloor, Matthias; Schirmacher, Peter; Bläker, Hendrik

2011-04-01

Characterization of tumor genetics and epigenetics allows to stratify a tumor entity according to molecular pathways and may shed light on the interactions of different types of DNA alterations during tumorigenesis. Small intestinal adenocarcinoma is rare, and to date the interrelation of genomic instability and epigenetics has not been investigated in this tumor type. We therefore analyzed 37 primary small bowel carcinomas with known microsatellite instability and KRAS status for chromosomal instability using comparative genomic hybridization, for the presence of aberrant methylation (CpG island methylation phenotype) by methylation-specific polymerase chain reaction, and for BRAF mutations. Chromosomal instability was detected in 22 of 37 (59%) tumors (3 of 9 microsatellite instable, and 19 of 28 microsatellite stable carcinomas). Nine carcinomas (24%) were microsatellite and chromosomally stable. High-level DNA methylation was found in 16% of chromosomal instable tumors and in 44% of both microsatellite instable and microsatellite and chromosomally stable carcinomas. KRAS was mutated in 55, 0, and 10% of chromosomal instable, microsatellite instable, and microsatellite and chromosomally stable tumors, respectively whereas the frequencies of BRAF mutations were 6% for chromosomal instable and 22% for both microsatellite instable and microsatellite and chromosomally stable carcinomas. In conclusion, in this study we show that chromosomal instable carcinomas of the small intestine are distinguished from microsatellite instable and microsatellite and chromosomally stable tumors by a high frequency of KRAS mutations, low frequencies of CpG island methylation phenotype, and BRAF mutations. In microsatellite instable and microsatellite and chromosomally stable cancers, CpG island methylation phenotype and BRAF/KRAS mutations are similarly distributed, indicating common mechanisms of tumor initiation or progression in their molecular pathogenesis.

Delayed cell death, giant cell formation and chromosome instability induced by X-irradiation in human embryo cells

International Nuclear Information System (INIS)

Roy, K.; Kodama, Seiji; Suzuki, Keiji; Watanabe, Masami

1999-01-01

We studied X-ray-induced delayed cell death, delayed giant cell formation and delayed chromosome aberrations in normal human embryo cells to explore the relationship between initial radiation damage and delayed effect appeared at 14 to 55 population doubling numbers (PDNs) after X-irradiation. The delayed effect was induced in the progeny of X-ray survivors in a dose-dependent manner and recovered with increasing PDNs after X-irradiation. Delayed plating for 24 h post-irradiation reduced both acute and delayed lethal damage, suggesting that potentially lethal damage repair (PLDR) can be effective for relieving the delayed cell death. The chromosome analysis revealed that most of the dicentrics (more than 90%) observed in the progeny of X-ray survivors were not accompanied with fragments, in contrast with those observed in the first mitosis after X-irradiation. The present results indicate that the potentiality of genetic instability is determined during the repair process of initial radiation damage and suggest that the mechanism for formation of delayed chromosome aberrations by radiation might be different from that of direct radiation-induced chromosome aberrations. (author)

Complex chromosome rearrangements related 15q14 microdeletion plays a relevant role in phenotype expression and delineates a novel recurrent syndrome

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Tomaiuolo Anna

2011-04-01

Full Text Available Abstract Complex chromosome rearrangements are constitutional structural rearrangements involving three or more chromosomes or having more than two breakpoints. These are rarely seen in the general population but their frequency should be much higher due to balanced states with no phenotypic presentation. These abnormalities preferentially occur de novo during spermatogenesis and are transmitted in families through oogenesis. Here, we report a de novo complex chromosome rearrangement that interests eight chromosomes in eighteen-year-old boy with an abnormal phenotype consisting in moderate developmental delay, cleft palate, and facial dysmorphisms. Standard G-banding revealed four apparently balanced traslocations involving the chromosomes 1;13, 3;19, 9;15 and 14;18 that appeared to be reciprocal. Array-based comparative genomic hybridization analysis showed no imbalances at all the breakpoints observed except for an interstitial microdeletion on chromosome 15. This deletion is 1.6 Mb in size and is located at chromosome band 15q14, distal to the Prader-Willi/Angelman region. Comparing the features of our patient with published reports of patients with 15q14 deletion this finding corresponds to the smallest genomic region of overlap. The deleted segment at 15q14 was investigated for gene content.

Knockdown of αII spectrin in normal human cells by siRNA leads to chromosomal instability and decreased DNA interstrand cross-link repair

International Nuclear Information System (INIS)

McMahon, Laura W.; Zhang Pan; Sridharan, Deepa M.; Lefferts, Joel A.; Lambert, Muriel W.

2009-01-01

Nonerythroid α-spectrin (αIISp) is a structural protein involved in repair of DNA interstrand cross-links and is deficient in cells from patients with Fanconi anemia (FA), which are defective in ability to repair cross-links. In order to further demonstrate the importance of the role that αIISp plays in normal human cells and in the repair defect in FA, αIISp was knocked down in normal cells using siRNA. Depletion of αIISp in normal cells by siRNA resulted in chromosomal instability and cellular hypersensitivity to DNA interstrand cross-linking agents. An increased number of chromosomal aberrations were observed and, following treatment with a DNA interstrand cross-linking agent, mitomycin C, cells showed decreased cell growth and survival and decreased formation of damage-induced αIISp and XPF nuclear foci. Thus depletion of αIISp in normal cells leads to a number of defects observed in FA cells, such as chromosome instability and a deficiency in cross-link repair.

Patients with an inherited syndrome characterized by immunodeficiency, microcephaly, and chromosomal instability: genetic relationship to ataxia telangiectasia

International Nuclear Information System (INIS)

Jaspers, N.G.; Taalman, R.D.; Baan, C.

1988-01-01

Fibroblast cultures from six unrelated patients having a familial type of immunodeficiency combined with microcephaly, developmental delay, and chromosomal instability were studied with respect to their response to ionizing radiation. The cells from five of them resembled those from individuals with ataxia telangiectasia (AT) in that they were two to three times more radiosensitive on the basis of clonogenic cell survival. In addition, after exposure to either X-rays or bleomycin, they showed an inhibition of DNA replication that was less pronounced than that in normal cells and characteristic of AT fibroblasts. However, the patients are clinically very different from AT patients, not showing any signs of neurocutaneous symptoms. Genetic complementation studies in fused cells, with the radioresistant DNA synthesis used as a marker, showed that the patients' cells could complement representatives of all presently known AT complementation groups. Furthermore, they were shown to constitute a genetically heterogeneous group as well. It is concluded that these patients are similar to AT patients with respect to cytological parameters. The clinical differences between these patients and AT patients are a reflection of genetic heterogeneity. The data indicate that the patients suffer from a chromosome-instability syndrome that is distinct from AT

Chromosomal instability in mouse embryonic fibroblasts null for the transcriptional co-repressor Ski.

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Marcelain, Katherine; Armisen, Ricardo; Aguirre, Adam; Ueki, Nobuhide; Toro, Jessica; Colmenares, Clemencia; Hayman, Michael J

2012-01-01

Ski is a transcriptional regulator that has been considered an oncoprotein given its ability to induce oncogenic transformation in avian model systems. However, studies in mouse and in some human tumor cells have also indicated a tumor suppressor activity for this protein. We found that Ski-/- mouse embryo fibroblasts exhibit high levels of genome instability, namely aneuploidy, consistent with a tumor suppressor function for Ski. Time-lapse microscopy revealed lagging chromosomes and chromatin/chromosome bridges as the major cause of micronuclei (MN) formation and the subsequent aneuploidy. Although these cells arrested in mitosis after treatment with spindle disrupting drugs and exhibited a delayed metaphase/anaphase transition, spindle assembly checkpoint (SAC) was not sufficient to prevent chromosome missegregation, consistent with a weakened SAC. Our in vivo analysis also showed dynamic metaphase plate rearrangements with switches in polarity in cells arrested in metaphase. Importantly, after ectopic expression of Ski the cells that displayed this metaphase arrest died directly during metaphase or after aberrant cell division, relating SAC activation and mitotic cell death. This increased susceptibility to undergo mitosis-associated cell death reduced the number of MN-containing cells. The presented data support a new role for Ski in the mitotic process and in maintenance of genetic stability, providing insights into the mechanism of tumor suppression mediated by this protein. Copyright © 2011 Wiley Periodicals, Inc.

Chromosomal instability mediated by non-B DNA: cruciform conformation and not DNA sequence is responsible for recurrent translocation in humans.

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Inagaki, Hidehito; Ohye, Tamae; Kogo, Hiroshi; Kato, Takema; Bolor, Hasbaira; Taniguchi, Mariko; Shaikh, Tamim H; Emanuel, Beverly S; Kurahashi, Hiroki

2009-02-01

Chromosomal aberrations have been thought to be random events. However, recent findings introduce a new paradigm in which certain DNA segments have the potential to adopt unusual conformations that lead to genomic instability and nonrandom chromosomal rearrangement. One of the best-studied examples is the palindromic AT-rich repeat (PATRR), which induces recurrent constitutional translocations in humans. Here, we established a plasmid-based model that promotes frequent intermolecular rearrangements between two PATRRs in HEK293 cells. In this model system, the proportion of PATRR plasmid that extrudes a cruciform structure correlates to the levels of rearrangement. Our data suggest that PATRR-mediated translocations are attributable to unusual DNA conformations that confer a common pathway for chromosomal rearrangements in humans.

Clonal heterogeneity and chromosomal instability at disease presentation in high hyperdiploid acute lymphoblastic leukemia.

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Talamo, Anna; Chalandon, Yves; Marazzi, Alfio; Jotterand, Martine

2010-12-01

Although aneuploidy has many possible causes, it often results from underlying chromosomal instability (CIN) leading to an unstable karyotype with cell-to-cell variation and multiple subclones. To test for the presence of CIN in high hyperdiploid acute lymphoblastic leukemia (HeH ALL) at diagnosis, we investigated 20 patients (10 HeH ALL and 10 non-HeH ALL), using automated four-color interphase fluorescence in situ hybridization (I-FISH) with centromeric probes for chromosomes 4, 6, 10, and 17. In HeH ALL, the proportion of abnormal cells ranged from 36.3% to 92.4%, and a variety of aneuploid populations were identified. Compared with conventional cytogenetics, I-FISH revealed numerous additional clones, some of them very small. To investigate the nature and origin of this clonal heterogeneity, we determined average numerical CIN values for all four chromosomes together and for each chromosome and patient group. The CIN values in HeH ALL were relatively high (range, 22.2-44.7%), compared with those in non-HeH ALL (3.2-6.4%), thus accounting for the presence of numerical CIN in HeH ALL at diagnosis. We conclude that numerical CIN may be at the origin of the high level of clonal heterogeneity revealed by I-FISH in HeH ALL at presentation, which would corroborate the potential role of CIN in tumor pathogenesis. Copyright © 2010 Elsevier Inc. All rights reserved.

Genome organization, instabilities, stem cells, and cancer

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Senthil Kumar Pazhanisamy

2009-01-01

Full Text Available It is now widely recognized that advances in exploring genome organization provide remarkable insights on the induction and progression of chromosome abnormalities. Much of what we know about how mutations evolve and consequently transform into genome instabilities has been characterized in the spatial organization context of chromatin. Nevertheless, many underlying concepts of impact of the chromatin organization on perpetuation of multiple mutations and on propagation of chromosomal aberrations remain to be investigated in detail. Genesis of genome instabilities from accumulation of multiple mutations that drive tumorigenesis is increasingly becoming a focal theme in cancer studies. This review focuses on structural alterations evolve to raise a variety of genome instabilities that are manifested at the nucleotide, gene or sub-chromosomal, and whole chromosome level of genome. Here we explore an underlying connection between genome instability and cancer in the light of genome architecture. This review is limited to studies directed towards spatial organizational aspects of origin and propagation of aberrations into genetically unstable tumors.

Mechanisms of ring chromosome formation in 11 cases of human ring chromosome 21

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McGinniss, M J; Kazazian, H H; Stetten, G

1992-01-01

We studied the mechanism of ring chromosome 21 (r(21)) formation in 13 patients (11 unique r(21)s), consisting of 7 from five families with familial r(21) and 6 with de novo r(21). The copy number of chromosome 21 sequences in the rings of these patients was determined by quantitative dosage......), resulting in deletion of varying amounts of 21q22.1 to 21qter. The data from one individual who had a Down syndrome phenotype were consistent with asymmetric breakage and reunion of 21q sequences from an intermediate isochromosome or Robertsonian translocation chromosome as reported by Wong et al. Another......). The phenotype of patients correlated well with the extent of deletion or duplication of chromosome 21 sequences. These data demonstrate three mechanisms of r(21) formation and show that the phenotype of r(21) patients varies with the extent of chromosome 21 monosomy or trisomy....

The Role of Chromosomal Instability and Epigenetics in Colorectal Cancers Lacking β-Catenin/TCF Regulated Transcription

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Wael M. Abdel-Rahman

2016-01-01

Full Text Available All colorectal cancer cell lines except RKO displayed active β-catenin/TCF regulated transcription. This feature of RKO was noted in familial colon cancers; hence our aim was to dissect its carcinogenic mechanism. MFISH and CGH revealed distinct instability of chromosome structure in RKO. Gene expression microarray of RKO versus 7 colon cancer lines (with active Wnt signaling and 3 normal specimens revealed 611 differentially expressed genes. The majority of the tested gene loci were susceptible to LOH in primary tumors with various β-catenin localizations as a surrogate marker for β-catenin activation. The immunohistochemistry of selected genes (IFI16, RGS4, MCTP1, DGKI, OBCAM/OPCML, and GLIPR1 confirmed that they were differentially expressed in clinical specimens. Since epigenetic mechanisms can contribute to expression changes, selected target genes were evaluated for promoter methylation in patient specimens from sporadic and hereditary colorectal cancers. CMTM3, DGKI, and OPCML were frequently hypermethylated in both groups, whereas KLK10, EPCAM, and DLC1 displayed subgroup specificity. The overall fraction of hypermethylated genes was higher in tumors with membranous β-catenin. We identified novel genes in colorectal carcinogenesis that might be useful in personalized tumor profiling. Tumors with inactive Wnt signaling are a heterogeneous group displaying interaction of chromosomal instability, Wnt signaling, and epigenetics.

Suppression of gross chromosomal rearrangements by a new alternative replication factor C complex

International Nuclear Information System (INIS)

Banerjee, Soma; Sikdar, Nilabja; Myung, Kyungjae

2007-01-01

Defects in DNA replication fidelity lead to genomic instability. Gross chromosomal rearrangement (GCR), a type of genomic instability, is highly enhanced by various initial mutations affecting DNA replication. Frequent observations of GCRs in many cancers strongly argue the importance of maintaining high fidelity of DNA replication to suppress carcinogenesis. Recent genome wide screens in Saccharomyces cerevisiae identified a new GCR suppressor gene, ELG1, enhanced level of genome instability gene 1. Its physical interaction with proliferating cell nuclear antigen (PCNA) and complex formation with Rfc2-5p proteins suggest that Elg1 functions to load/unload PCNA onto DNA during a certain DNA metabolism. High level of DNA damage accumulation and enhanced phenotypes with mutations in genes involved in cell cycle checkpoints, homologous recombination (HR), or chromatin assembly in the elg1 strain suggest that Elg1p-Rfc2-5p functions in a fundamental DNA metabolism to suppress genomic instability

Instability of chromosome number and DNA methylation variation induced by hybridization and amphidiploid formation between Raphanus sativus L. and Brassica alboglabra Bailey

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Wang Yanjie

2010-09-01

Full Text Available Abstract Background Distant hybridization can result genome duplication and allopolyploid formation which may play a significant role in the origin and evolution of many plant species. It is unclear how the two or more divergent genomes coordinate in one nucleus with a single parental cytoplasm within allopolyploids. We used cytological and molecular methods to investigate the genetic and epigenetic instabilities associated with the process of distant hybridization and allopolyploid formation, measuring changes in chromosome number and DNA methylation across multiple generations. Results F1 plants from intergeneric hybridization between Raphanus sativus L. (2n = 18, RR and Brassica alboglabra Bailey (2n = 18, CC were obtained by hand crosses and subsequent embryo rescue. Random amplification of polymorphic DNA (RAPD markers were used to identify the F1 hybrid plants. The RAPD data indicated that the hybrids produced specific bands similar to those of parents and new bands that were not present in either parent. Chromosome number variation of somatic cells from allotetraploids in the F4 to F10 generations showed that intensive genetic changes occurred in the early generations of distant hybridization, leading to the formation of mixopolyploids with different chromosome numbers. DNA methylation variation was revealed using MSAP (methylation-sensitive amplification polymorphism, which showed that cytosine methylation patterns changed markedly in the process of hybridization and amphidiploid formation. Differences in cytosine methylation levels demonstrated an epigenetic instability of the allopolyploid of Raphanobrassica between the genetically stable and unstable generations. Conclusions Our results showed that chromosome instability occurred in the early generations of allopolyploidy and then the plants were reverted to largely euploidy in later generations. During this process, DNA methylation changed markedly. These results suggest that

Radiation induced chromosomal instability in lymphocytes of cancer patients

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Sudo, H.; Sagara, M.; Ban, S.; Noda, S.; Iwakawa, M.; Harada, Y.; Imai, T.; Cologne, J.B.

2003-01-01

Full text: Cytokinesis-blocked micronucleus (CBMN) assay has been extensively used to evaluate the radiation sensitivity of human individuals. Using the CBMN assay, Scott et al (1998, 1999) demonstrated that a fraction of radiosensitive individuals in breast cancer case population was larger than in normal individual population. However, Vral et al were very skeptical about the Scott et al's findings (2002). Under the approval from the ethical committee of NIRS, peripheral blood was obtained from 46 normal healthy females, 131 breast cancer patients, 32 cervical cancer patients and 7 female head and neck cancer patients. Radiosensitivity of T-lymphocytes was assessed by using a CBMN assay. The frequencies of MN per binucleated cell in healthy donors were 0.031(±0.010) and 0.151(±0.066) for cells treated before and after X-ray-irradiation (2Gy), respectively. Spontaneous MN frequencies in cancer patients were significantly higher than healthy donors (p < 0.001). Radiation sensitivities of breast- and head and neck-cancer patients were significantly higher than normal individuals (p < 0.001). Cervical cancer patients were more resistant to irradiation than healthy donors, though the number of cases for statistical analysis was small. (p < 0.001). We are considering that the HPV infection affected the radiosensitivity of cervical cancer cases. Because it is widely believed that one key mechanism which leads to spontaneous micronucleus formation involves an imbalance of chromosomal segregation and a chromosomal instability in patients' lymphocytes might be greater than that in normal individuals' lymphocytes. Recently, Kuschel et al (2002) demonstrated that ratios in two SNPs on XRCC3 were significantly different between cancer patients and healthy females. Then, we can suppose that the radiation-related genes with low penetrance may be involved in tumorigenesis of mammary- and head and neck-cells, and also, in patients' radiation susceptibility

The Relationship between the (In-)Stability of NORs and Their Chromosomal Location: The Example of Cercopithecidae and a Short Review of Other Primates.

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Gerbault-Seureau, Michèle; Cacheux, Lauriane; Dutrillaux, Bernard

2017-01-01

Amongst Cercopithecidae, the species of the Cercopithecini tribe underwent a very active chromosome evolution, principally by fissions, which increased their chromosome number up to 72. In contrast, all the species of Papionini have fairly similar karyotypes with 42 chromosomes. In animals, nucleolus organizer regions (NORs) are generally considered as instable structures, which frequently vary in size, number, and location at both infra- and interspecific levels. Although in Cercopithecinae the NORs, involved in breaks, exchanges, and translocations, behave like fragile sites in somatic cells, their number and location appear to be very stable between species. Fluorescence in situ hybridization of a 28S rDNA probe on metaphase chromosomes displayed a unique interstitial location in either an acrocentric pair (in 12 species of Cercopithecini) or a metacentric pair (in 6 species of Papionini). A non-exhaustive survey of literature data on NOR location in other primates shows that numerical variations of the NORs principally depend on their location: most multiple NORs are in terminal positions, while almost all unique NORs are in interstitial positions. We propose that this correlation is the consequence of the selection against gametic imbalances involving the chromosomal material distal to the NORs, which is effective when they are interstitially, but not terminally, located. Thus, the consequences of the interstitial NOR instability for reproduction are essentially limited to their size variations, as observed in Cercopithecidae. © 2018 S. Karger AG, Basel.

Tumor progression: analysis of the instability of the metastatic phenotype, sensitivity to radiation and chemotherapy

International Nuclear Information System (INIS)

Welch, D.R.

1984-01-01

The major complications for tumor therapy are 1) tumor spread (metastasis); 2) the mixed nature of tumors (heterogeneity); and 3) the capacity of tumors to evolve (progress). To study these tumor characteristics, the rat 13762NF mammary adenocarcinoma was cloned and studied for metastatic properties and sensitivities to therapy (chemotherapy, radiation and hyperthermia). The cell clones were heterogeneous and no correlation between metastatic potential and therapeutic sensitivities was observed. Further, these phenotypes were unstable during pasage in vitro; yet, the changes were clone dependent and reproducible using different cryoprotected cell stocks. To understand the phenotypic instability, subclones were isolated from low and high passage cell clones. The results demonstrated that 1) tumor cells are heterogeneous for multiple phenotypes; 2) tumor cells are unstable for multiple phenotypes; 3) the magnitude, direction and time of occurrence of phenotypic drift is clone dependent; 4) the sensitivity of cell clones to ionizing radiation (γ or heat) and chemotherapy agents is independent of their metastatic potential; 5) shifts in metastatic potential and sensitivity to therapy may occur simultaneously but are not linked; and 6) tumor cells independently diverge to form several subpopulations with unique phenotypic profiles

Overexpression screens identify conserved dosage chromosome instability genes in yeast and human cancer

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Duffy, Supipi; Fam, Hok Khim; Wang, Yi Kan; Styles, Erin B.; Kim, Jung-Hyun; Ang, J. Sidney; Singh, Tejomayee; Larionov, Vladimir; Shah, Sohrab P.; Andrews, Brenda; Boerkoel, Cornelius F.; Hieter, Philip

2016-01-01

Somatic copy number amplification and gene overexpression are common features of many cancers. To determine the role of gene overexpression on chromosome instability (CIN), we performed genome-wide screens in the budding yeast for yeast genes that cause CIN when overexpressed, a phenotype we refer to as dosage CIN (dCIN), and identified 245 dCIN genes. This catalog of genes reveals human orthologs known to be recurrently overexpressed and/or amplified in tumors. We show that two genes, TDP1, a tyrosyl-DNA-phosphdiesterase, and TAF12, an RNA polymerase II TATA-box binding factor, cause CIN when overexpressed in human cells. Rhabdomyosarcoma lines with elevated human Tdp1 levels also exhibit CIN that can be partially rescued by siRNA-mediated knockdown of TDP1. Overexpression of dCIN genes represents a genetic vulnerability that could be leveraged for selective killing of cancer cells through targeting of an unlinked synthetic dosage lethal (SDL) partner. Using SDL screens in yeast, we identified a set of genes that when deleted specifically kill cells with high levels of Tdp1. One gene was the histone deacetylase RPD3, for which there are known inhibitors. Both HT1080 cells overexpressing hTDP1 and rhabdomyosarcoma cells with elevated levels of hTdp1 were more sensitive to histone deacetylase inhibitors valproic acid (VPA) and trichostatin A (TSA), recapitulating the SDL interaction in human cells and suggesting VPA and TSA as potential therapeutic agents for tumors with elevated levels of hTdp1. The catalog of dCIN genes presented here provides a candidate list to identify genes that cause CIN when overexpressed in cancer, which can then be leveraged through SDL to selectively target tumors. PMID:27551064

Molecular Mechanisms of Radiation-Induced Genomic Instability in Human Cells

Energy Technology Data Exchange (ETDEWEB)

Howard L. Liber; Jeffrey L. Schwartz

2005-10-31

There are many different model systems that have been used to study chromosome instability. What is clear from all these studies is that conclusions concerning chromosome instability depend greatly on the model system and instability endpoint that is studied. The model system for our studies was the human B-lymphoblastoid cell line TK6. TK6 was isolated from a spontaneously immortalized lymphoblast culture. Thus there was no outside genetic manipulation used to immortalize them. TK6 is a relatively stable p53-normal immortal cell line (37). It shows low gene and chromosome mutation frequencies (19;28;31). Our general approach to studying instability in TK6 cells has been to isolate individual clones and analyze gene and chromosome mutation frequencies in each. This approach maximizes the possibility of detecting low frequency events that might be selected against in mass cultures.

Increased chromosomal breakage in Tourette syndrome predicts the possibility of variable multiple gene involvement in spectrum phenotypes: Preliminary findings and hypothesis

Energy Technology Data Exchange (ETDEWEB)

Gericke, G.S.; Simonic, I.; Cloete, E.; Buckle, C. [Univ. of Pretoria (South Africa)] [and others

1995-10-09

Increased chromosomal breakage was found in 12 patients with DSM-IV Tourette syndrome (TS) as compared with 10 non-TS control individuals with respect to untreated, modified RPM1-, and BrdU treated lymphocyte cultures (P < 0.001 in each category). A hypothesis is proposed that a major TS gene is probably connected to genetic instability, and associated chromosomal marker sites may be indicative of the localization of secondary genes whose altered expression could be responsible for associated comorbid conditions. This concept implies that genes influencing higher brain functions may be situated at or near highly recombigenic areas allowing enhanced amplification, duplication and recombination following chromosomal strand breakage. Further studies on a larger sample size are required to confirm the findings relating to chromosomal breakage and to analyze the possible implications for a paradigmatic shift in linkage strategy for complex disorders by focusing on areas at or near unstable chromosomal marker sites. 32 refs., 1 tab.

Molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 8 or r(8(::p12→q13.1:: associated with phenotypic abnormalities

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Chih-Ping Chen

2016-12-01

Conclusion: Mosaic sSMC(8 derived from r(8(::p12→q13.1:: can present phenotypic abnormalities. Chromosome 8q12 duplication syndrome should be included in differential diagnosis when an sSMC(8 contains 8q12.2 and CHD7.

DNA-damage response during mitosis induces whole-chromosome missegregation.

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Bakhoum, Samuel F; Kabeche, Lilian; Murnane, John P; Zaki, Bassem I; Compton, Duane A

2014-11-01

Many cancers display both structural (s-CIN) and numerical (w-CIN) chromosomal instabilities. Defective chromosome segregation during mitosis has been shown to cause DNA damage that induces structural rearrangements of chromosomes (s-CIN). In contrast, whether DNA damage can disrupt mitotic processes to generate whole chromosomal instability (w-CIN) is unknown. Here, we show that activation of the DNA-damage response (DDR) during mitosis selectively stabilizes kinetochore-microtubule (k-MT) attachments to chromosomes through Aurora-A and PLK1 kinases, thereby increasing the frequency of lagging chromosomes during anaphase. Inhibition of DDR proteins, ATM or CHK2, abolishes the effect of DNA damage on k-MTs and chromosome segregation, whereas activation of the DDR in the absence of DNA damage is sufficient to induce chromosome segregation errors. Finally, inhibiting the DDR during mitosis in cancer cells with persistent DNA damage suppresses inherent chromosome segregation defects. Thus, the DDR during mitosis inappropriately stabilizes k-MTs, creating a link between s-CIN and w-CIN. The genome-protective role of the DDR depends on its ability to delay cell division until damaged DNA can be fully repaired. Here, we show that when DNA damage is induced during mitosis, the DDR unexpectedly induces errors in the segregation of entire chromosomes, thus linking structural and numerical chromosomal instabilities. ©2014 American Association for Cancer Research.

Induction of genomic instability and activation of autophagy in artificial human aneuploid cells

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Ariyoshi, Kentaro [Hirosaki University, Institute of Radiation Emergency Medicine, 66-1 Hon-cho, Hirosaki 036-8564 (Japan); Miura, Tomisato; Kasai, Kosuke; Fujishima, Yohei [Department of Biomedical Sciences, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki 036-8564 (Japan); Oshimura, Mitsuo [Chromosome Engineering Research Center (CERC), Tottori University, Nishicho 86, Yonago, Tottori 683-8503 (Japan); Yoshida, Mitsuaki A., E-mail: ariyoshi@hirosaki-u.ac.jp [Hirosaki University, Institute of Radiation Emergency Medicine, 66-1 Hon-cho, Hirosaki 036-8564 (Japan)

2016-08-15

Highlights: • Clones with artificial aneuploidy of chromosome 8 or chromosome 22 both show inhibited proliferation and genomic instability. • Increased autophagy was observed in the artificially aneuploid clones. • Inhibition of autophagy resulted in increased genomic instability and DNA damage. • Intracellular levels of reactive oxygen species were up-regulated in the artificially aneuploid clones. - Abstract: Chromosome missegregation can lead to a change in chromosome number known as aneuploidy. Although aneuploidy is a known hallmark of cancer cells, the various mechanisms by which altered gene and/or DNA copy number facilitate tumorigenesis remain unclear. To understand the effect of aneuploidy occurring in non-tumorigenic human breast epithelial cells, we generated clones harboring artificial aneuploidy using microcell-mediated chromosome transfer. Our results demonstrate that clones with artificial aneuploidy of chromosome 8 or chromosome 22 both show inhibited proliferation and genomic instability. Also, the increased autophagy was observed in the artificially aneuploidy clones, and inhibition of autophagy resulted in increased genomic instability and DNA damage. In addition, the intracellular levels of reactive oxygen species were up-regulated in the artificially aneuploid clones, and inhibition of autophagy further increased the production of reactive oxygen species. Together, these results suggest that even a single extraneous chromosome can induce genomic instability, and that autophagy triggered by aneuploidy-induced stress is a mechanism to protect cells bearing abnormal chromosome number.

Induction of genomic instability and activation of autophagy in artificial human aneuploid cells

International Nuclear Information System (INIS)

Ariyoshi, Kentaro; Miura, Tomisato; Kasai, Kosuke; Fujishima, Yohei; Oshimura, Mitsuo; Yoshida, Mitsuaki A.

2016-01-01

Highlights: • Clones with artificial aneuploidy of chromosome 8 or chromosome 22 both show inhibited proliferation and genomic instability. • Increased autophagy was observed in the artificially aneuploid clones. • Inhibition of autophagy resulted in increased genomic instability and DNA damage. • Intracellular levels of reactive oxygen species were up-regulated in the artificially aneuploid clones. - Abstract: Chromosome missegregation can lead to a change in chromosome number known as aneuploidy. Although aneuploidy is a known hallmark of cancer cells, the various mechanisms by which altered gene and/or DNA copy number facilitate tumorigenesis remain unclear. To understand the effect of aneuploidy occurring in non-tumorigenic human breast epithelial cells, we generated clones harboring artificial aneuploidy using microcell-mediated chromosome transfer. Our results demonstrate that clones with artificial aneuploidy of chromosome 8 or chromosome 22 both show inhibited proliferation and genomic instability. Also, the increased autophagy was observed in the artificially aneuploidy clones, and inhibition of autophagy resulted in increased genomic instability and DNA damage. In addition, the intracellular levels of reactive oxygen species were up-regulated in the artificially aneuploid clones, and inhibition of autophagy further increased the production of reactive oxygen species. Together, these results suggest that even a single extraneous chromosome can induce genomic instability, and that autophagy triggered by aneuploidy-induced stress is a mechanism to protect cells bearing abnormal chromosome number.

Trisomy 21 and facial developmental instability.

Science.gov (United States)

Starbuck, John M; Cole, Theodore M; Reeves, Roger H; Richtsmeier, Joan T

2013-05-01

The most common live-born human aneuploidy is trisomy 21, which causes Down syndrome (DS). Dosage imbalance of genes on chromosome 21 (Hsa21) affects complex gene-regulatory interactions and alters development to produce a wide range of phenotypes, including characteristic facial dysmorphology. Little is known about how trisomy 21 alters craniofacial morphogenesis to create this characteristic appearance. Proponents of the "amplified developmental instability" hypothesis argue that trisomy 21 causes a generalized genetic imbalance that disrupts evolutionarily conserved developmental pathways by decreasing developmental homeostasis and precision throughout development. Based on this model, we test the hypothesis that DS faces exhibit increased developmental instability relative to euploid individuals. Developmental instability was assessed by a statistical analysis of fluctuating asymmetry. We compared the magnitude and patterns of fluctuating asymmetry among siblings using three-dimensional coordinate locations of 20 anatomic landmarks collected from facial surface reconstructions in four age-matched samples ranging from 4 to 12 years: (1) DS individuals (n = 55); (2) biological siblings of DS individuals (n = 55); 3) and 4) two samples of typically developing individuals (n = 55 for each sample), who are euploid siblings and age-matched to the DS individuals and their euploid siblings (samples 1 and 2). Identification in the DS sample of facial prominences exhibiting increased fluctuating asymmetry during facial morphogenesis provides evidence for increased developmental instability in DS faces. We found the highest developmental instability in facial structures derived from the mandibular prominence and lowest in facial regions derived from the frontal prominence. Copyright © 2013 Wiley Periodicals, Inc.

Cell kinetics and genetic instabilities in differentiated type early gastric cancers with different mucin phenotype.

Science.gov (United States)

Shibata, Naomi; Watari, Jiro; Fujiya, Mikihiro; Tanno, Satoshi; Saitoh, Yusuke; Kohgo, Yutaka

2003-01-01

To clarify the biological impact and molecular pathogenesis of cellular phenotype in differentiated-type gastric cancers (DGCs), we investigated cell kinetics and genetic instabilities in early stage of DGCs. A total of 43 early gastric cancers (EGCs) were studied. EGCs were divided into 3 phenotypic categories: gastric (G type, n = 11), ordinary (O type, n = 20), and complete intestinal (CI type, n = 12) based on the combination of HGM, ConA, MUC2, and CD10. Proliferative index (PI), apoptotic index (AI), and p53 overexpression were investigated by immunohistochemical staining with anti-Ki-67, the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method, and p53 antibody, respectively. Using a high-resolution fluorescent microsatellite analysis system, microsatellite instability (MSI) and loss of heterozygosity (LOH) were examined. Frameshift mutation analysis of transforming growth factor-beta type II receptor (TGF-betaRII) and bcl-2-associated X (BAX) in cancers with MSI was also performed. The mean AI/PI ratio values were 0.04 for G-type, 0.10 for O-type, and 0.13 for CI-type cancers--significantly lower in G type than in O and CI types (P = 0.02 and P = 0.001, respectively). No difference in the incidence of MSI and LOH was seen among the 3 cellular phenotypes. However, the major pattern of MSI, which showed drastic and widely dispersed changes and is related to an increased risk for cancer, was significantly higher in G and O types than in CI type (P cancers. These results indicate that G-type cancers are likely to show more aggressive behaviors than CI-type cancers, and that O-type cancers show the intermediate characteristics of both types. However, the molecular pathogenesis of each phenotypic cancer is not associated with microsatellite alterations. Copyright 2003, Elsevier Science (USA). All rights reserved.

Cancers of unknown primary origin (CUP) are characterized by chromosomal instability (CIN) compared to metastasis of know origin

DEFF Research Database (Denmark)

Vikeså, Jonas; Møller, Anne Kirstine H; Kaczkowski, Bogumil

2015-01-01

BACKGROUND: Cancers of unknown primary (CUPs) constitute ~5% of all cancers. The tumors have an aggressive biological and clinical behavior. The aim of the present study has been to uncover whether CUPs exhibit distinct molecular features compared to metastases of known origin. METHODS: Employing......RNA signatures of chromosome instability (CIN), indicating that CUPs are chromosome unstable compared to metastases of known origin. CONCLUSIONS: CIN may account for the uncommon clinical presentation, chemoresistance and poor outcome in patients with CUP and warrant selective diagnostic strategies and treatment....... genome wide transcriptome analysis, Linear Discriminant Analysis (LDA) and Quadratic Discriminant Analysis (QDA), we defined the putative origins of a large series of CUP and how closely related a particular CUP was to corresponding metastases of known origin. LDA predictions were subsequently used...

Multipolar spindle pole coalescence is a major source of kinetochore mis-attachment and chromosome mis-segregation in cancer cells.

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William T Silkworth

Full Text Available Many cancer cells display a CIN (Chromosome Instability phenotype, by which they exhibit high rates of chromosome loss or gain at each cell cycle. Over the years, a number of different mechanisms, including mitotic spindle multipolarity, cytokinesis failure, and merotelic kinetochore orientation, have been proposed as causes of CIN. However, a comprehensive theory of how CIN is perpetuated is still lacking. We used CIN colorectal cancer cells as a model system to investigate the possible cellular mechanism(s underlying CIN. We found that CIN cells frequently assembled multipolar spindles in early mitosis. However, multipolar anaphase cells were very rare, and live-cell experiments showed that almost all CIN cells divided in a bipolar fashion. Moreover, fixed-cell analysis showed high frequencies of merotelically attached lagging chromosomes in bipolar anaphase CIN cells, and higher frequencies of merotelic attachments in multipolar vs. bipolar prometaphases. Finally, we found that multipolar CIN prometaphases typically possessed gamma-tubulin at all spindle poles, and that a significant fraction of bipolar metaphase/early anaphase CIN cells possessed more than one centrosome at a single spindle pole. Taken together, our data suggest a model by which merotelic kinetochore attachments can easily be established in multipolar prometaphases. Most of these multipolar prometaphase cells would then bi-polarize before anaphase onset, and the residual merotelic attachments would produce chromosome mis-segregation due to anaphase lagging chromosomes. We propose this spindle pole coalescence mechanism as a major contributor to chromosome instability in cancer cells.

Genomic instability and radiation effects

International Nuclear Information System (INIS)

Christian Streffer

2007-01-01

Complete text of publication follows. Cancer, genetic mutations and developmental abnormalities are apparently associated with an increased genomic instability. Such phenomena have been frequently shown in human cancer cells in vitro and in situ. It is also well-known that individuals with a genetic predisposition for cancer proneness, such as ataxia telangiectesia, Fanconi anaemia etc. demonstrate a general high genomic instability e.g. in peripheral lymphocytes before a cancer has developed. Analogous data have been found in mice which develop a specific congenital malformation which has a genetic background. Under these aspects it is of high interest that ionising radiation can increase the genomic instability of mammalian cells after exposures in vitro an in vivo. This phenomenon is expressed 20 to 40 cell cycles after the exposure e.g. by de novo chromosomal aberrations. Such effects have been observed with high and low LET radiation, high LET radiation is more efficient. With low LET radiation a good dose response is observed in the dose range 0.2 to 2.0 Gy, Recently it has been reported that senescence and genomic instability was induced in human fibroblasts after 1 mGy carbon ions (1 in 18 cells are hit), apparently bystander effects also occurred under these conditions. The instability has been shown with DNA damage, chromosomal aberrations, gene mutation and cell death. It is also transferred to the next generation of mice with respect to gene mutations, chromosomal aberrations and congenital malformations. Several mechanisms have been discussed. The involvement of telomeres has gained interest. Genomic instability seems to be induced by a general lesion to the whole genome. The transmission of one chromosome from an irradiated cell to an non-irradiated cell leads to genomic instability in the untreated cells. Genomic instability increases mutation rates in the affected cells in general. As radiation late effects (cancer, gene mutations and congenital

Genetic control of chromosome instability in Aspergillus nidulans as a means for gene amplification in eukaryotic microorganisms

International Nuclear Information System (INIS)

Parag, Y.; Roper, J.A.

1975-01-01

A haploid strain of Aspergillus nidulans carrying I-II duplication homozygous for the leaky mutation adE20 shows improved growth on minimal medium. The duplication, though more stable than disomics, still shows instability. Several methods were used for detecting genetic control of improved stability. a) visual selection, using a duplicated strain which is very unstable due to UV sensitivity, (adE20, biAl/dp yA2; uvsB). One stable strain showed a deletion (or a lethal mutation) distal to biA on the segment at the original position (on chromosome I). This deletion reduces crossing-over frequency detween the two homologous segments. As the deletion of the non-translated segment (yellow sectors) must be preceded by crossing-over, the above reduces the frequency of yellow sectors. A deletion of the translocated segment (green sectors) results in non-viability due to the deletion, and such sectors do not appear. The net result is a stable duplication involving only 12 C.O. units carrying the gene in concern. b) Suppressors of UV sensitivity (su-uvsB) were attempted using the above uvs duplicated strain. Phenotypic revertants were easily obtained, but all were back mutations at the uvsB locus. c) Mutations for UV resistance higher than that of the wild type were not obtained, in spite of the strong selective pressure inserted. d) Recombination deficient mutations (rec), six altogether, all uvs + , did not have any effect on stability. (orig.) [de

Loss of RMI2 Increases Genome Instability and Causes a Bloom-Like Syndrome.

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Damien F Hudson

2016-12-01

Full Text Available Bloom syndrome is a recessive human genetic disorder with features of genome instability, growth deficiency and predisposition to cancer. The only known causative gene is the BLM helicase that is a member of a protein complex along with topoisomerase III alpha, RMI1 and 2, which maintains replication fork stability and dissolves double Holliday junctions to prevent genome instability. Here we report the identification of a second gene, RMI2, that is deleted in affected siblings with Bloom-like features. Cells from homozygous individuals exhibit elevated rates of sister chromatid exchange, anaphase DNA bridges and micronuclei. Similar genome and chromosome instability phenotypes are observed in independently derived RMI2 knockout cells. In both patient and knockout cell lines reduced localisation of BLM to ultra fine DNA bridges and FANCD2 at foci linking bridges are observed. Overall, loss of RMI2 produces a partially active BLM complex with mild features of Bloom syndrome.

Chromosomal instability detected by interphase fluorescence in situ hybridization and its relation to p3 alteration in prostate carcinoma in Saudi patients

International Nuclear Information System (INIS)

Al-Maghrabi, Jaudah A.

2005-01-01

Chromosomal instability (CIN) is a feature of human neoplasm. The p53 mutation has been shown to be associated with CIN in many human dysplastic and neoplastic lesions. The objective of this study was to examine CIN and p53 mutations in prostate carcinoma (Pca) resected from Saudi patients. Testing of p53 alterations using immunohistochemistry was performed on 28 archived prostatic carcinoma specimens containing Pca foci from Saudi patients seen at King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia. Chrosomal instability was evaluated in the same tissues by interphase in situ hybridization (IFISH) using centromere probes for chromosomes 7 and 8. Immunochemistry and IFISH were performed at Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada in 2001. The p53 immunoreactivity was found in 29% in Pca and 0% in benign epithelium. Interphase in situ hybridization revealed numerical chromosomal alterations in keeping with CIN in 63% of p53 positive and 20% p53 negative Pca. No evidence of CIN was seen in non-neoplastic epithelium. We concluded that CIN as determined by IFISH is present in Pca from Saudi patients similarly to those reported in western countries. The p53 mutation occurs relatively infrequently in Pca and associated with the presence of CIN at least in a subset of Pca. (author)

The Social Behavioral Phenotype in Boys and Girls with an Extra X Chromosome (Klinefelter Syndrome and Trisomy X): A Comparison with Autism Spectrum Disorder

Science.gov (United States)

van Rijn, Sophie; Stockmann, Lex; Borghgraef, Martine; Bruining, Hilgo; van Ravenswaaij-Arts, Conny; Govaerts, Lutgarde; Hansson, Kerstin; Swaab, Hanna

2014-01-01

The present study aimed to gain more insight in the social behavioral phenotype, and related autistic symptomatology, of children with an extra X chromosome in comparison to children with ASD. Participants included 60 children with an extra X chromosome (34 boys with Klinefelter syndrome and 26 girls with Trisomy X), 58 children with ASD and 106…

Combined array-comparative genomic hybridization and single-nucleotide polymorphism-loss of heterozygosity analysis reveals complex changes and multiple forms of chromosomal instability in colorectal cancers

DEFF Research Database (Denmark)

Gaasenbeek, Michelle; Howarth, Kimberley; Rowan, Andrew J

2006-01-01

Cancers with chromosomal instability (CIN) are held to be aneuploid/polyploid with multiple large-scale gains/deletions, but the processes underlying CIN are unclear and different types of CIN might exist. We investigated colorectal cancer cell lines using array-comparative genomic hybridization...

Genomic regulatory landscapes and chromosomal rearrangements

DEFF Research Database (Denmark)

Ladegaard, Elisabete L Engenheiro

2008-01-01

The main objectives of the PhD study are to identify and characterise chromosomal rearrangements within evolutionarily conserved regulatory landscapes around genes involved in the regulation of transcription and/or development (trans-dev genes). A frequent feature of trans-dev genes is that they ......The main objectives of the PhD study are to identify and characterise chromosomal rearrangements within evolutionarily conserved regulatory landscapes around genes involved in the regulation of transcription and/or development (trans-dev genes). A frequent feature of trans-dev genes...... the complex spatio-temporal expression of the associated trans-dev gene. Rare chromosomal breakpoints that disrupt the integrity of these regulatory landscapes may be used as a tool, not only to make genotype-phenotype associations, but also to link the associated phenotype with the position and tissue...... specificity of the individual CNEs. In this PhD study I have studied several chromosomal rearrangements with breakpoints in the vicinity of trans-dev genes. This included chromosomal rearrangements compatible with known phenotype-genotype associations (Rieger syndrome-PITX2, Mowat-Wilson syndrome-ZEB2...

No significant effect of monosomy for distal 21q22. 3 on the Down syndrom phenotype in mirror' duplications of chromosome 21

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Pangalos, C.; Prieur, M.; Rethore, M.O.; Lejeune, J. (Institut de Progenese, Paris (France)); Theophile, D.; Sinet, P.M.; Chettouh, Z.; Delabar, J.M. (Hopital Necker Enfants Malades, Paris (France)); Marks, A. (Univ. of Toronto, Ontario (Canada)); Stamboulieh-Abazis, D. (Diagnostic Genetic Center, Athens (Greece)); Verellen, C. (Centre de Genetique Humaine, Brussels (Belgium))

1992-12-01

Three Down syndrome patients for whom karyotypic analysis showed a mirror' (reverse tandem) duplication of chromosome 21 were studied by phenotypic, cytogenetic, and molecular methods. On high-resolution R-banding analysis performed in two cases, the size of the fusion 21q22.3 band was apparently less than twice the size of the normal 21q22.3, suggesting a partial deletion of distal 21q. The evaluation of eight chromosome 21 single-copy sequences of the 21q22 region - namely, SOD1, D21S15, D21S42, CRYA1, PFKL, CD18, COL6A1, and S100B - by a slot blot method showed in all three cases a partial deletion of 21q22.3 and partial monosomy. The translocation breakpoints were different in each patient, and in two cases the rearranged chromosome was found to be asymmetrical. The molecular definition of the monosomy 21 in each patient was, respectively, COL6A1-S100B, CD18-S100B, and PFKL-S100B. DNA polymorphism analysis indicated in all cases a homozygosity of the duplicated material. The duplicated region was maternal in two patients and paternal in one patient. These data suggest that the reverse tandem chromosomes did not result from a telomeric fusion between chromosomes 21 but from a translocation between sister chromatids. The phenotypes of these patients did not differ significantly from that of individuals with full trisomy 21, except in one case with large ears with an unfolded helix. The fact that monosomy of distal 21q22.3 in these patients resulted in a phenotype very similar to Down syndrome suggests that the duplication of the genes located in this part of chromosome 21 is not necessary for the pathogenesis of the Down syndrome features observed in these patients, including most of the facial and hand features, muscular hypotonia, cardiopathy of the Fallot tetralogy type, and part of the mental retardation. 54 refs., 5 figs., 3 tabs.

Fanconi anemia: causes and consequences of genetic instability.

Science.gov (United States)

Kalb, R; Neveling, K; Nanda, I; Schindler, D; Hoehn, H

2006-01-01

Fanconi anemia (FA) is a rare recessive disease that reflects the cellular and phenotypic consequences of genetic instability: growth retardation, congenital malformations, bone marrow failure, high risk of neoplasia, and premature aging. At the cellular level, manifestations of genetic instability include chromosomal breakage, cell cycle disturbance, and increased somatic mutation rates. FA cells are exquisitely sensitive towards oxygen and alkylating drugs such as mitomycin C or diepoxybutane, pointing to a function of FA genes in the defense against reactive oxygen species and other DNA damaging agents. FA is caused by biallelic mutations in at least 12 different genes which appear to function in the maintenance of genomic stability. Eight of the FA proteins form a nuclear core complex with a catalytic function involving ubiquitination of the central FANCD2 protein. The posttranslational modification of FANCD2 promotes its accumulation in nuclear foci, together with known DNA maintenance proteins such as BRCA1, BRCA2, and the RAD51 recombinase. Biallelic mutations in BRCA2 cause a severe FA-like phenotype, as do biallelic mutations in FANCD2. In fact, only leaky or hypomorphic mutations in this central group of FA genes appear to be compatible with life birth and survival. The newly discovered FANCJ (= BRIP1) and FANCM (= Hef ) genes correspond to known DNA-maintenance genes (helicase resp. helicase-associated endonuclease for fork-structured DNA). These genes provide the most convincing evidence to date of a direct involvement of FA genes in DNA repair functions associated with the resolution of DNA crosslinks and stalled replication forks. Even though genetic instability caused by mutational inactivation of the FANC genes has detrimental effects for the majority of FA patients, around 20% of patients appear to benefit from genetic instability since genetic instability also increases the chance of somatic reversion of their constitutional mutations. Intragenic

Mirror-symmetric duplicated chromosome 21q with minor proximal deletion, and with neocentromere in a child without the classical Down syndrome phenotype.

Science.gov (United States)

Barbi, G; Kennerknecht, I; Wöhr, G; Avramopoulos, D; Karadima, G; Petersen, M B

2000-03-13

We report on a mentally retarded child with multiple minor anomalies and an unusually rearranged chromosome 21. This der(21) chromosome has a deletion of 21p and of proximal 21q, whereas the main portion of 21q is duplicated leading to a mirror-symmetric appearance with the mirror axis at the breakpoint. The centromere is only characterized by a secondary constriction (with a centromeric index of a G chromosome) at an unexpected distal position, but fluorescence in situ hybridization (FISH) with either chromosome specific or with all human centromeres alpha satellite DNA shows no cross hybridization. Thus, the marker chromosome represents a further example of an "analphoid marker with neocentromere." Molecular analysis using polymorphic markers on chromosome 21 verified a very small monosomic segment of the proximal long arm of chromosome 21, and additionally trisomy of the remaining distal segment. Although trisomic for almost the entire 21q arm, our patient shows no classical Down syndrome phenotype, but only a few minor anomalies found in trisomy 21 and in monosomy of proximal 21q, respectively. Copyright 2000 Wiley-Liss, Inc.

Unsupervised Analysis of Array Comparative Genomic Hybridization Data from Early-Onset Colorectal Cancer Reveals Equivalence with Molecular Classification and Phenotypes

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María Arriba

2017-01-01

Full Text Available AIM: To investigate whether chromosomal instability (CIN is associated with tumor phenotypes and/or with global genomic status based on MSI (microsatellite instability and CIMP (CpG island methylator phenotype in early-onset colorectal cancer (EOCRC. METHODS: Taking as a starting point our previous work in which tumors from 60 EOCRC cases (≤45 years at the time of diagnosis were analyzed by array comparative genomic hybridization (aCGH, in the present study we performed an unsupervised hierarchical clustering analysis of those aCGH data in order to unveil possible associations between the CIN profile and the clinical features of the tumors. In addition, we evaluated the MSI and the CIMP statuses of the samples with the aim of investigating a possible relationship between copy number alterations (CNAs and the MSI/CIMP condition in EOCRC. RESULTS: Based on the similarity of the CNAs detected, the unsupervised analysis stratified samples into two main clusters (A, B and four secondary clusters (A1, A2, B3, B4. The different subgroups showed a certain correspondence with the molecular classification of colorectal cancer (CRC, which enabled us to outline an algorithm to categorize tumors according to their CIMP status. Interestingly, each subcluster showed some distinctive clinicopathological features. But more interestingly, the CIN of each subcluster mainly affected particular chromosomes, allowing us to define chromosomal regions more specifically affected depending on the CIMP/MSI status of the samples. CONCLUSIONS: Our findings may provide a basis for a new form of classifying EOCRC according to the genomic status of the tumors.

A breast cancer meta-analysis of two expression measures of chromosomal instability reveals a relationship with younger age at diagnosis and high risk histopathological variables

DEFF Research Database (Denmark)

Endesfelder, David; McGranahan, Nicholas; Birkbak, Nicolai Juul

2011-01-01

Breast cancer in younger patients often presents with adverse histopathological features, including increased frequency of estrogen receptor negative and lymph node positive disease status. Chromosomal instability (CIN) is increasingly recognised as an important prognostic variable in solid tumours...... may be a defining feature of breast cancer biology and clinical outcome....

The pathological phenotype of colon cancer with microsatellite instability

DEFF Research Database (Denmark)

Andersen, Helene Schou; Bertelsen, Claus Anders; Henriksen, Rikke

2016-01-01

proteins: pMLH1, pMSH2, pMSH6 and pPMS2 for the determination of microsatellite instability. Microsatellite instability was defined as deficient expression of one or more of these proteins. RESULTS: Of the 833 patients, 177 had microsatellite instable tumours (21%). Using multivariable logistic regression...

Chromosomal instability and the abrogated G2/M arrest in x-irradiated myelodysplastic syndrome cells

International Nuclear Information System (INIS)

Ban, S.; Sudo, H.; Saegusa, K.; Sagara, M.; Imai, T.; Kimura, A.

2003-01-01

A preliminary epidemiological study demonstrated that myelodysplastic syndrome (MDS) has an excess relative risk per sievert of 13 in atomic bomb survivors in Hiroshima. MDS is the only other radiogenic blood disease apart from leukemia. Clinically, MDS involves dysplastic hematopoiesis and an increased risk of leukemic transformation. Because it is uncertain whether MDS pathogenesis affects lymphoid progenitor cells as well as myeloid progenitor cells, we investigated the karyotypes of bone marrow cells and the micronucleus (MN) frequency in peripheral T lymphocytes of twenty- three atomic bomb survivors with MDS and five normal individuals. Aneuploidy was observed in 10 of 23 patients. Chromosome aberrations were observed in 3 of 12 patients with mild symptoms, and six of 11 patients of severe symptoms. The spontaneous- and X-ray-induced-MN frequencies were significantly higher in MDS patients than in normal individuals. Interestingly, radiation sensitivity increased along with the severity of MDS clinical subtypes. Because many of the patients in this study had not been exposed to chemo- or radiation- therapy, their unusual radiosensitivity may be related to their chromosomal or genomic instability. Immortalized lymphoid cell lines were established from B-lymphocytes infected with Epstein-Barr virus in vitro. The abrogation of radiation-induced-G2/M arrest was observed in 10 of 12 MDS-B lymphoid cell lines, but not in the normal B lymphoid cell lines. Our data suggest that the control of chromosomal stability is impaired in pluripotent stem cells of MDS patients, and that the abrogated G2/M arrest may be involved in the pathophysiology of disease progression and the high radiation sensitivity of patients

Variations in dysfunction of sister chromatid cohesion in esco2 mutant zebrafish reflect the phenotypic diversity of Roberts syndrome

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Stefanie M. Percival

2015-08-01

Full Text Available Mutations in ESCO2, one of two establishment of cohesion factors necessary for proper sister chromatid cohesion (SCC, cause a spectrum of developmental defects in the autosomal-recessive disorder Roberts syndrome (RBS, warranting in vivo analysis of the consequence of cohesion dysfunction. Through a genetic screen in zebrafish targeting embryonic-lethal mutants that have increased genomic instability, we have identified an esco2 mutant zebrafish. Utilizing the natural transparency of zebrafish embryos, we have developed a novel technique to observe chromosome dynamics within a single cell during mitosis in a live vertebrate embryo. Within esco2 mutant embryos, we observed premature chromatid separation, a unique chromosome scattering, prolonged mitotic delay, and genomic instability in the form of anaphase bridges and micronuclei formation. Cytogenetic studies indicated complete chromatid separation and high levels of aneuploidy within mutant embryos. Amongst aneuploid spreads, we predominantly observed decreases in chromosome number, suggesting that either cells with micronuclei or micronuclei themselves are eliminated. We also demonstrated that the genomic instability leads to p53-dependent neural tube apoptosis. Surprisingly, although many cells required Esco2 to establish cohesion, 10-20% of cells had only weakened cohesion in the absence of Esco2, suggesting that compensatory cohesion mechanisms exist in these cells that undergo a normal mitotic division. These studies provide a unique in vivo vertebrate view of the mitotic defects and consequences of cohesion establishment loss, and they provide a compensation-based model to explain the RBS phenotypes.

Human hereditary diseases associated with elevated frequency of chromosome aberrations

International Nuclear Information System (INIS)

Ejima, Yosuke

1988-01-01

Human recessive diseases collectively known as chromosome breakage syndromes include Fanconi's anemia, Bloom's syndrome and ataxia telangiectasia. Cells from these patients show chromosome instabilities both spontaneously and following treatments with radiations or certain chemicals, where defects in DNA metabolisms are supposed to be involved. Cells from patients with ataxia telangiectasia are hypersensitive to ionizing radiations, though DNA replication is less affected than in normal cells. Chromatid-type as well as chromosom-type aberrations are induced in cells irradiated in G 0 or G 1 phases. These unusual responses to radiations may provide clues for understanding the link between DNA replicative response and cellular radiosensitivity. Alterations in cellular radiosensitivity or spontaneous chromosome instabilities are observed in some patients with congenital chromosome anomalies or dominant diseases, where underlying defects may be different from those in recessive diseases. (author)

Human hereditary diseases associated with elevated frequency of chromosome aberrations

Energy Technology Data Exchange (ETDEWEB)

Ejima, Yosuke; Ikushima, Takaji (ed.)

1988-07-01

Human recessive diseases collectively known as chromosome breakage syndromes include Fanconi's anemia, Bloom's syndrome and ataxia telangiectasia. Cells from these patients show chromosome instabilities both spontaneously and following treatments with radiations or certain chemicals, where defects in DNA metabolisms are supposed to be involved. Cells from patients with ataxia telangiectasia are hypersensitive to ionizing radiations, though DNA replication is less affected than in normal cells. Chromatid-type as well as chromosom-type aberrations are induced in cells irradiated in G/sub 0/ or G/sub 1/ phases. These unusual responses to radiations may provide clues for understanding the link between DNA replicative response and cellular radiosensitivity. Alterations in cellular radiosensitivity or spontaneous chromosome instabilities are observed in some patients with congenital chromosome anomalies or dominant diseases, where underlying defects may be different from those in recessive diseases.

Leaf phenotypic variation and developmental instability in relation to different light regimes

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Henrique Venâncio

2016-06-01

Full Text Available ABSTRACT For pioneer plants, shaded habitats represent a stressful condition, where sunlight exposure is below the optimum level and so leaves expand in order to intercept a greater amount of light. We investigated changes in both phenotypic variation and stress of Bauhinia brevipes in sunny and shaded microhabitats. Leaf area was used as a measure of phenotypic variation, whereas leaf asymmetry (difference between right and left sides of leaves, was used as a measure of stress. We hypothesized an increase in leaf area and stress in shaded locations, which might indicate that B. brevipes was compensating for low light absorption, and elevated levels of stress, respectively. Plants in the sun fitted a fluctuating asymmetry pattern (normal distribution of right minus left sides, while shaded plants were clearly antisymmetric (bimodal distribution of leaf side differences. Leaf asymmetry and area were 5% and 26.8% higher in plants in the shade compared to plants in the sun, respectively. These results were expected since B. brevipes is found predominantly in open areas; so sunlight exposure is important for its development. The presence of antisymmetry is rare in studies of developmental instability, and here it might indicate higher stress compared to plants with fluctuating asymmetry.

Warburg effect and translocation-induced genomic instability: two yeast models for cancer cells

International Nuclear Information System (INIS)

Tosato, Valentina; Grüning, Nana-Maria; Breitenbach, Michael; Arnak, Remigiusz; Ralser, Markus; Bruschi, Carlo V.

2013-01-01

Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression (i) the activity of pyruvate kinase (PK), which recapitulates metabolic features of cancer cells, including the Warburg effect, and (ii) chromosome bridge-induced translocation (BIT) mimiking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect), and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, PK, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and post-translational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (“translocants”), between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the BIT system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

Warburg effect and translocation-induced genomic instability: two yeast models for cancer cells

Energy Technology Data Exchange (ETDEWEB)

Tosato, Valentina [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy); Grüning, Nana-Maria [Cambridge System Biology Center, Department of Biochemistry, University of Cambridge, Cambridge (United Kingdom); Breitenbach, Michael [Division of Genetics, Department of Cell Biology, University of Salzburg, Salzburg (Austria); Arnak, Remigiusz [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy); Ralser, Markus [Cambridge System Biology Center, Department of Biochemistry, University of Cambridge, Cambridge (United Kingdom); Bruschi, Carlo V., E-mail: bruschi@icgeb.org [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy)

2013-01-18

Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression (i) the activity of pyruvate kinase (PK), which recapitulates metabolic features of cancer cells, including the Warburg effect, and (ii) chromosome bridge-induced translocation (BIT) mimiking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect), and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, PK, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and post-translational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (“translocants”), between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the BIT system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

WARBURG EFFECT AND TRANSLOCATION-INDUCED GENOMIC INSTABILITY: TWO YEAST MODELS FOR CANCER CELLS

Directory of Open Access Journals (Sweden)

Valentina eTosato

2013-01-01

Full Text Available Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression i the activity of pyruvate kinase (PK, which recapitulates metabolic features of cancer cells, including the Warburg effect, and ii Bridge-Induced chromosome Translocation (BIT mimicking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect, and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, pyruvate kinase, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and posttranslational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (translocants, between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the Bridge-Induced Translocation system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

A ring D chromosome in association with Down's syndrome-like phenotype

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A. Wajntal

1973-03-01

Full Text Available The case of a ten-years-old mentally retarded girl with Down's syndrome-like features whose chromosome analysis revealed an unusual mosaicism including 10% mitosis with a ring chromosome replacing a D chromosome is reported. The clinical features of the patient were considered similar to those described by Jacobsen (1966 and Emberger et al. (1971 who interpreted the ring chromosome present in their patients as being chromosome 15.

The CRO-1 gene of Saccharomyces cerevisiae controls mitotic crossing over, chromosomal stability and sporulation

International Nuclear Information System (INIS)

Esposito, M.S.; Maleas, D.T.; Bjornstad, K.A.; Holbrook, L.L.

1987-01-01

The properties of a novel temperature-sensitive recombination-defective mutant of Saccharomyces cerevisiae, cro1-1 is described. The cro1-1 mutant is the first instance of a rec mutation that reduces drastically the rates of spontaneous mitotic crossing-over events but not those of gene conversional events. The cro1-1 mutation thus provides evidence that mitotic crossing-over is dependent upon gene products that are not essential for gene conversional events. The cro1-1 mutation also results in enhanced mitotic-chromosomal instability and MATa/MATα cro1-1/cro1-1 mutants are sporulation deficient. These phenotypes indicate that the CRO1 gene modulates mitotic chromosomal integrity and is essential for normal meiosis. The cro1-1 mutant possesses Holliday junction resolvase activity, hence its recombinational defect does not involve failure to execute this putative final recombinational step. 7 refs., 1 fig., 5 tabs

Characterization of chromosome instability in interspecific somatic hybrids obtained by X-ray fusion between potato (Solanum tuberosum L.) and S. brevidens Phil

International Nuclear Information System (INIS)

Fehér, A.; Preiszner, J.; Litkey, Z.; Csanádi, G; Dudits, D.

1992-01-01

Asymmetric somatic hybrids between Solanum tuberosum L. and S. brevidens Phil. have been obtained via the fusion of protoplasts from potato leaves and from cell suspension culture of S. brevidens. The wild Solanum species served as donor after irradiation of its protoplasts with a lethal X-ray dose (200 Gy). Selection of the putative hybrids was based on the kanamycin-resistance marker gene previously introduced into the genome of Solanum brevidens by Agrobacterium-mediated gene transfer. Thirteen out of the 45 selected clones exhibited reduced morphogenic potential. The morphological abnormalities of the regenerated plantlets were gradually eliminated during the extended in vitro culture period. Cytological investigations revealed that the number of chromosomes in the cultured S. brevidens cells used as protoplast source ranged between 28-40 instead of the basic 2n=24 value. There was a high degree of aneuploidy in all of the investigated hybrid clones, and at least 12 extra chromosomes were observed in addition to the potato chromosomes (2n=48). Interand intraclonal variation and segregation during vegetative propagation indicated the genetic instability of the hybrids, which can be ascribed to the pre-existing and X-ray irradiation-induced chromosomal abnormalities in the donor S. brevidens cells. The detection of centromeric chromosome fragments and long, poly-constrictional chromosomes in cytological preparations as well as non-parental bands in Southern hybridizations with restriction fragment length polymorphism (RFLP) markers revealed extensive chromosome rearrangements in most of the regenerated clones. On the basis of the limited number of RFLP probes used, preferential loss of S. brevidens specific markers with a non-random elimination pattern could be detected in hybrid regenerants

The Consequences of Chromosome Segregation Errors in Mitosis and Meiosis

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Tamara Potapova

2017-02-01

Full Text Available Mistakes during cell division frequently generate changes in chromosome content, producing aneuploid or polyploid progeny cells. Polyploid cells may then undergo abnormal division to generate aneuploid cells. Chromosome segregation errors may also involve fragments of whole chromosomes. A major consequence of segregation defects is change in the relative dosage of products from genes located on the missegregated chromosomes. Abnormal expression of transcriptional regulators can also impact genes on the properly segregated chromosomes. The consequences of these perturbations in gene expression depend on the specific chromosomes affected and on the interplay of the aneuploid phenotype with the environment. Most often, these novel chromosome distributions are detrimental to the health and survival of the organism. However, in a changed environment, alterations in gene copy number may generate a more highly adapted phenotype. Chromosome segregation errors also have important implications in human health. They may promote drug resistance in pathogenic microorganisms. In cancer cells, they are a source for genetic and phenotypic variability that may select for populations with increased malignance and resistance to therapy. Lastly, chromosome segregation errors during gamete formation in meiosis are a primary cause of human birth defects and infertility. This review describes the consequences of mitotic and meiotic errors focusing on novel concepts and human health.

Statistics for X-chromosome associations.

Science.gov (United States)

Özbek, Umut; Lin, Hui-Min; Lin, Yan; Weeks, Daniel E; Chen, Wei; Shaffer, John R; Purcell, Shaun M; Feingold, Eleanor

2018-06-13

In a genome-wide association study (GWAS), association between genotype and phenotype at autosomal loci is generally tested by regression models. However, X-chromosome data are often excluded from published analyses of autosomes because of the difference between males and females in number of X chromosomes. Failure to analyze X-chromosome data at all is obviously less than ideal, and can lead to missed discoveries. Even when X-chromosome data are included, they are often analyzed with suboptimal statistics. Several mathematically sensible statistics for X-chromosome association have been proposed. The optimality of these statistics, however, is based on very specific simple genetic models. In addition, while previous simulation studies of these statistics have been informative, they have focused on single-marker tests and have not considered the types of error that occur even under the null hypothesis when the entire X chromosome is scanned. In this study, we comprehensively tested several X-chromosome association statistics using simulation studies that include the entire chromosome. We also considered a wide range of trait models for sex differences and phenotypic effects of X inactivation. We found that models that do not incorporate a sex effect can have large type I error in some cases. We also found that many of the best statistics perform well even when there are modest deviations, such as trait variance differences between the sexes or small sex differences in allele frequencies, from assumptions. © 2018 WILEY PERIODICALS, INC.

Polymorphisms, Chromosomal Rearrangements, and Mutator Phenotype Development during Experimental Evolution of Lactobacillus rhamnosus GG.

Science.gov (United States)

Douillard, François P; Ribbera, Angela; Xiao, Kun; Ritari, Jarmo; Rasinkangas, Pia; Paulin, Lars; Palva, Airi; Hao, Yanling; de Vos, Willem M

2016-07-01

Lactobacillus rhamnosus GG is a lactic acid bacterium widely marketed by the food industry. Its genomic analysis led to the identification of a gene cluster encoding mucus-binding SpaCBA pili, which is located in a genomic island enriched in insertion sequence (IS) elements. In the present study, we analyzed by genome-wide resequencing the genomic integrity of L. rhamnosus GG in four distinct evolutionary experiments conducted for approximately 1,000 generations under conditions of no stress or salt, bile, and repetitive-shearing stress. Under both stress-free and salt-induced stress conditions, the GG population (excluding the mutator lineage in the stress-free series [see below]) accumulated only a few single nucleotide polymorphisms (SNPs) and no frequent chromosomal rearrangements. In contrast, in the presence of bile salts or repetitive shearing stress, some IS elements were found to be activated, resulting in the deletion of large chromosomal segments that include the spaCBA-srtC1 pilus gene cluster. Remarkably, a high number of SNPs were found in three strains obtained after 900 generations of stress-free growth. Detailed analysis showed that these three strains derived from a founder mutant with an altered DNA polymerase subunit that resulted in a mutator phenotype. The present work confirms the stability of the pilus production phenotype in L. rhamnosus GG under stress-free conditions, highlights the possible evolutionary scenarios that may occur when this probiotic strain is extensively cultured, and identifies external factors that affect the chromosomal integrity of GG. The results provide mechanistic insights into the stability of GG in regard to its extensive use in probiotic and other functional food products. Lactobacillus rhamnosus GG is a widely marketed probiotic strain that has been used in numerous clinical studies to assess its health-promoting properties. Hence, the stability of the probiotic functions of L. rhamnosus GG is of importance, and

Role of Ku80-dependent end-joining in delayed genomic instability in mammalian cells surviving ionizing radiation

International Nuclear Information System (INIS)

Suzuki, Keiji; Kodama, Seiji; Watanabe, Masami

2010-01-01

Ionizing radiation induces delayed destabilization of the genome in the progenies of surviving cells. This phenomenon, which is called radiation-induced genomic instability, is manifested by delayed induction of radiation effects, such as cell death, chromosome aberration, and mutation in the progeny of cells surviving radiation exposure. Previously, there was a report showing that delayed cell death was absent in Ku80-deficient Chinese hamster ovary (CHO) cells, however, the mechanism of their defect has not been determined. We found that delayed induction of DNA double strand breaks and chromosomal breaks were intact in Ku80-deficient cells surviving X-irradiation, whereas there was no sign for the production of chromosome bridges between divided daughter cells. Moreover, delayed induction of dicentric chromosomes was significantly compromised in those cells compared to the wild-type CHO cells. Reintroduction of the human Ku86 gene complimented the defective DNA repair and recovered delayed induction of dicentric chromosomes and delayed cell death, indicating that defective Ku80-dependent dicentric induction was the cause of the absence of delayed cell death. Since DNA-PKcs-defective cells showed delayed phenotypes, Ku80-dependent illegitimate rejoining is involved in delayed impairment of the integrity of the genome in radiation-survived cells.

Role of Ku80-dependent end-joining in delayed genomic instability in mammalian cells surviving ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Keiji, E-mail: kzsuzuki@nagasaki-u.ac.jp [Course of Life Sciences and Radiation Research, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Kodama, Seiji [Research Institute for Advanced Science and Technology, Osaka Prefecture University, 1-2 Gakuen-machi, Sakai 599-8570 (Japan); Watanabe, Masami [Kyoto University Research Reactor Institute, Kumatori-cho Sennan-gun, Osaka 590-0494 (Japan)

2010-01-05

Ionizing radiation induces delayed destabilization of the genome in the progenies of surviving cells. This phenomenon, which is called radiation-induced genomic instability, is manifested by delayed induction of radiation effects, such as cell death, chromosome aberration, and mutation in the progeny of cells surviving radiation exposure. Previously, there was a report showing that delayed cell death was absent in Ku80-deficient Chinese hamster ovary (CHO) cells, however, the mechanism of their defect has not been determined. We found that delayed induction of DNA double strand breaks and chromosomal breaks were intact in Ku80-deficient cells surviving X-irradiation, whereas there was no sign for the production of chromosome bridges between divided daughter cells. Moreover, delayed induction of dicentric chromosomes was significantly compromised in those cells compared to the wild-type CHO cells. Reintroduction of the human Ku86 gene complimented the defective DNA repair and recovered delayed induction of dicentric chromosomes and delayed cell death, indicating that defective Ku80-dependent dicentric induction was the cause of the absence of delayed cell death. Since DNA-PKcs-defective cells showed delayed phenotypes, Ku80-dependent illegitimate rejoining is involved in delayed impairment of the integrity of the genome in radiation-survived cells.

Genetics, Cytogenetics, and Epigenetics of Colorectal Cancer

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Lucia Migliore

2011-01-01

Full Text Available Most of the colorectal cancer (CRC cases are sporadic, only 25% of the patients have a family history of the disease, and major genes causing syndromes predisposing to CRC only account for 5-6% of the total cases. The following subtypes can be recognized: MIN (microsatellite instability, CIN (chromosomal instability, and CIMP (CpG island methylator phenotype. CIN occurs in 80–85% of CRC. Chromosomal instability proceeds through two major mechanisms, missegregation that results in aneuploidy through the gain or loss of whole chromosomes, and unbalanced structural rearrangements that lead to the loss and/or gain of chromosomal regions. The loss of heterozygosity that occur in the first phases of the CRC cancerogenesis (in particular for the genes on 18q as well as the alteration of methylation pattern of multiple key genes can drive the development of colorectal cancer by facilitating the acquisition of multiple tumor-associated mutations and the instability phenotype.

Mitochondrial ribosomal protein S18-2 evokes chromosomal instability and transforms primary rat skin fibroblasts

KAUST Repository

Kashuba, Elena

2015-05-12

We have shown earlier that overexpression of the human mitochondrial ribosomal protein MRPS18-2 (S18-2) led to immortalization of primary rat embryonic fibroblasts. The derived cells expressed the embryonic stem cell markers, and cellular pathways that control cell proliferation, oxidative phosphorylation, cellular respiration, and other redox reactions were activated in the immortalized cells. Here we report that, upon overexpression of S18-2 protein, primary rat skin fibroblasts underwent cell transformation. Cells passed more than 300 population doublings, and two out of three tested clones gave rise to tumors in experimental animals. Transformed cells showed anchorage-independent growth and loss of contact inhibition; they expressed epithelial markers, such as E-cadherin and β-catenin. Transformed cells showed increased telomerase activity, disturbance of the cell cycle, and chromosomal instability. Taken together, our data suggest that S18-2 is a newly identified oncoprotein that may be involved in cancerogenesis.

Microsatellite instability in bladder cancer

DEFF Research Database (Denmark)

Gonzalez-Zulueta, M; Ruppert, J M; Tokino, K

1993-01-01

Somatic instability at microsatellite repeats was detected in 6 of 200 transitional cell carcinomas of the bladder. Instabilities were apparent as changes in (GT)n repeat lengths on human chromosome 9 for four tumors and as alterations in a (CAG)n repeat in the androgen receptor gene on the X...... or larger (> 2 base pairs) alterations in repeat length. All six tumors were low stage (Ta-T1), suggesting that these alterations can occur early in bladder tumorigenesis....

Causes of genome instability: the effect of low dose chemical exposures in modern society

Science.gov (United States)

Langie, Sabine A.S.; Koppen, Gudrun; Desaulniers, Daniel; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Azqueta, Amaya; Bisson, William H.; Brown, Dustin; Brunborg, Gunnar; Charles, Amelia K.; Chen, Tao; Colacci, Annamaria; Darroudi, Firouz; Forte, Stefano; Gonzalez, Laetitia; Hamid, Roslida A.; Knudsen, Lisbeth E.; Leyns, Luc; Lopez de Cerain Salsamendi, Adela; Memeo, Lorenzo; Mondello, Chiara; Mothersill, Carmel; Olsen, Ann-Karin; Pavanello, Sofia; Raju, Jayadev; Rojas, Emilio; Roy, Rabindra; Ryan, Elizabeth; Ostrosky-Wegman, Patricia; Salem, Hosni K.; Scovassi, Ivana; Singh, Neetu; Vaccari, Monica; Van Schooten, Frederik J.; Valverde, Mahara; Woodrick, Jordan; Zhang, Luoping; van Larebeke, Nik; Kirsch-Volders, Micheline; Collins, Andrew R.

2015-01-01

Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome’s integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus, genome instability can be defined as an enhanced tendency for the genome to acquire mutations; ranging from changes to the nucleotide sequence to chromosomal gain, rearrangements or loss. This review raises the hypothesis that in addition to known human carcinogens, exposure to low dose of other chemicals present in our modern society could contribute to carcinogenesis by indirectly affecting genome stability. The selected chemicals with their mechanisms of action proposed to indirectly contribute to genome instability are: heavy metals (DNA repair, epigenetic modification, DNA damage signaling, telomere length), acrylamide (DNA repair, chromosome segregation), bisphenol A (epigenetic modification, DNA damage signaling, mitochondrial function, chromosome segregation), benomyl (chromosome segregation), quinones (epigenetic modification) and nano-sized particles (epigenetic pathways, mitochondrial function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make scientists aware of the increasing need to unravel the underlying mechanisms via which chemicals at low doses can induce genome instability and thus promote carcinogenesis. PMID:26106144

35-Year Follow-Up of a Case of Ring Chromosome 2

DEFF Research Database (Denmark)

Sarri, Catherine; Douzgou, Sofia; Kontos, Haris

2015-01-01

Côté et al. [1981] suggested that ring chromosomes with or without deletions share a common pattern of phenotypic anomalies, regardless of which chromosome is involved. The phenotype of this 'general ring syndrome' consists of growth failure without malformations, few or no minor anomalies, and m...

Causes of genome instability

DEFF Research Database (Denmark)

Langie, Sabine A S; Koppen, Gudrun; Desaulniers, Daniel

2015-01-01

function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make......Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus...

Molecular characterization of a rice mutator-phenotype derived from an incompatible cross-pollination reveals transgenerational mobilization of multiple transposable elements and extensive epigenetic instability

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Xu Chunming

2009-05-01

Full Text Available Abstract Background Inter-specific hybridization occurs frequently in plants, which may induce genetic and epigenetic instabilities in the resultant hybrids, allopolyploids and introgressants. It remains unclear however whether pollination by alien pollens of an incompatible species may impose a "biological stress" even in the absence of genome-merger or genetic introgression, whereby genetic and/or epigenetic instability of the maternal recipient genome might be provoked. Results We report here the identification of a rice mutator-phenotype from a set of rice plants derived from a crossing experiment involving two remote and apparently incompatible species, Oryza sativa L. and Oenothera biennis L. The mutator-phenotype (named Tong211-LP showed distinct alteration in several traits, with the most striking being substantially enlarged panicles. Expectably, gel-blotting by total genomic DNA of the pollen-donor showed no evidence for introgression. Characterization of Tong211-LP (S0 and its selfed progenies (S1 ruled out contamination (via seed or pollen or polyploidy as a cause for its dramatic phenotypic changes, but revealed transgenerational mobilization of several previously characterized transposable elements (TEs, including a MITE (mPing, and three LTR retrotransposons (Osr7, Osr23 and Tos17. AFLP and MSAP fingerprinting revealed extensive, transgenerational alterations in cytosine methylation and to a less extent also genetic variation in Tong211-LP and its immediate progenies. mPing mobility was found to correlate with cytosine methylation alteration detected by MSAP but not with genetic variation detected by AFLP. Assay by q-RT-PCR of the steady-state transcript abundance of a set of genes encoding for the various putative DNA methyltransferases, 5-methylcytosine DNA glycosylases, and small interference RNA (siRNA pathway-related proteins showed that, relative to the rice parental line, heritable perturbation in expression of 12 out of

Gtl2lacZ, an insertional mutation on mouse chromosome 12 with parental origin-dependent phenotype.

Science.gov (United States)

Schuster-Gossler, K; Simon-Chazottes, D; Guenet, J L; Zachgo, J; Gossler, A

1996-01-01

We have produced a transgenic mouse line, Gtl2lacZ (Gene trap locus 2), that carries an insertional mutation with a dominant modified pattern of inheritance:heterozygous Gtl2lacZ mice that inherited the transgene from the father show a proportionate dwarfism phenotype, whereas the penetrance and expressivity of the phenotype is strongly reduced in Gtl2lacZ mice that inherited the transgene from the mother. On a mixed genetic background this pattern of inheritance was reversible upon transmission of the transgene through the germ line of the opposite sex. On a predominantly 129/Sv genetic background, however, transgene passage through the female germ line modified the transgene effect, such that the penetrance of the mutation was drastically reduced and the phenotype was no longer obvious after subsequent male germ line transmission. Expression of the transgene, however, was neither affected by genetic background nor by parental legacy. Gtl2lacZ maps to mouse Chromosome 12 in a region that displays imprinting effects associated with maternal and paternal disomy. Our results suggest that the transgene insertion in Gtl2lacZ mice affects an endogenous gene(s) required for fetal and postnatal growth and that this gene(s) is predominantly paternally expressed.

Helicobacter pylori infection generates genetic instability in gastric cells

DEFF Research Database (Denmark)

Machado, Ana Manuel Dantas; Figueiredo, Céu; Seruca, Raquel

2010-01-01

The discovery that Helicobacter pylori is associated with gastric cancer has led to numerous studies that investigate the mechanisms by which H. pylori induces carcinogenesis. Gastric cancer shows genetic instability both in nuclear and mitochondrial DNA, besides impairment of important DNA repair...... of the host, such as oxidative damage, methylation, chromosomal instability, microsatellite instability, and mutations. Interestingly, H. pylori infection generates genetic instability in nuclear and mitochondrial DNA. Based on the reviewed literature we conclude that H. pylori infection promotes gastric...

Assessment of chromosomal imbalances in CIMP-high and CIMP-low/CIMP-0 colorectal cancers.

Science.gov (United States)

Kozlowska, Joanna; Karpinski, Pawel; Szmida, Elzbieta; Laczmanska, Izabela; Misiak, Blazej; Ramsey, David; Bebenek, Marek; Kielan, Wojciech; Pesz, Karolina A; Sasiadek, Maria M

2012-08-01

Data presented in a number of recent studies have revealed a negative correlation between CpG island methylator phenotype (CIMP) and chromosomal instability (CIN) measured by a loss of heterozygosity (LOH) of selected loci, suggesting that CIN and CIMP represent two independent mechanisms in sporadic colorectal cancer (CRC) carcinogenesis. However, CIN is a heterogeneous phenomenon, which may be studied not only by employing LOH analysis but also by observing chromosomal imbalances (gains and deletions). The current study aimed to investigate the relationship between CIMP and chromosomal gains and deletions (assessed by comparative genomic hybridization) in a group of 20 CIMP-high and 79 CIMP-low/CIMP-0 CRCs. Our results revealed that the mean numbers of gains and of total chromosomal imbalances were significantly greater (p = 0.004 and p = 0.007, respectively) in the CIMP-low/CIMP-0 group compared to the CIMP-high group, while no significant difference was observed between the mean numbers of losses (p = 0.056). The analysis of copy number changes of 41 cancer-related genes by multiplex ligation-dependent probe amplification showed that CRK gene was exclusively deleted in CIMP-low/CIMP-0 tumors (p = 0.02). Given that chromosomal losses play an important role in tumor suppressor inactivation and chromosomal gains, in the activation of proto-oncogenes, we hypothesize that tumor suppressor inactivation plays similar roles in both CIMP-high and CIMP-low/CIMP-0 CRCs, while the predominance of chromosomal gains in CIMP-low/CIMP-0 tumors may suggest that the activation of proto-oncogenes is the underlying mechanism of CIMP-low/CIMP-0 CRC progression.

Mixed Phenotype Acute Leukemia with Two Immunophenotypically Distinct B and T Blasts Populations, Double Chromosome and Complex Karyotype: Report of an Unusual Case

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Samah A. Kohla

2015-01-01

Full Text Available Mixed phenotype acute leukemia (MPAL is considered as a rare type of leukemia with an incidence of less than 4% of all acute leukemia based on the most recent 2008 WHO classification. Common subtypes are the B/myeloid and T/myeloid; B/T and trilineage MPAL being extremely rare. We present a case of a male in his 20s, whose peripheral blood smears showed 34% blast cells and bone marrow with 70% blasts. Immunophenotyping by multiparametric flow cytometry showed two populations of blasts, the major one with B-lineage and the minor one with T-lineage. Conventional karyotyping revealed complex karyotype with the presence of double Philadelphia chromosome ( Ph + . BCR/ABL1 rearrangement was confirmed by fluorescent in situ hybridization (FISH analysis. The BCR/ABL1 ES probe on interphase cells indicated pl90 minor m-BCR/ABL fusion in 46% and a second abnormal clone with double Ph + in 16% of the cells analyzed confirmed by reverse transcription-PCR (RT-PCR. The case was diagnosed as MPAL with double Philadelphia chromosome Ph + . The patient was treated with dasatinib, four cycle hyper CVAD/methotrexate cytarabin protocol, and allogeneic transplant. He is still alive in complete hematological, cytogenetic, and molecular remission. Mixed phenotype B/T acute leukemia is an extremely rare disease, particularly those with double Philadelphia chromosomes and clinically presents challenges in diagnosis and treatment.

Genomic instability and telomere fusion of canine osteosarcoma cells.

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Junko Maeda

Full Text Available Canine osteosarcoma (OSA is known to present with highly variable and chaotic karyotypes, including hypodiploidy, hyperdiploidy, and increased numbers of metacentric chromosomes. The spectrum of genomic instabilities in canine OSA has significantly augmented the difficulty in clearly defining the biological and clinical significance of the observed cytogenetic abnormalities. In this study, eight canine OSA cell lines were used to investigate telomere fusions by fluorescence in situ hybridization (FISH using a peptide nucleotide acid probe. We characterized each cell line by classical cytogenetic studies and cellular phenotypes including telomere associated factors and then evaluated correlations from this data. All eight canine OSA cell lines displayed increased abnormal metacentric chromosomes and exhibited numerous telomere fusions and interstitial telomeric signals. Also, as evidence of unstable telomeres, colocalization of γ-H2AX and telomere signals in interphase cells was observed. Each cell line was characterized by a combination of data representing cellular doubling time, DNA content, chromosome number, metacentric chromosome frequency, telomere signal level, cellular radiosensitivity, and DNA-PKcs protein expression level. We have also studied primary cultures from 10 spontaneous canine OSAs. Based on the observation of telomere aberrations in those primary cell cultures, we are reasonably certain that our observations in cell lines are not an artifact of prolonged culture. A correlation between telomere fusions and the other characteristics analyzed in our study could not be identified. However, it is important to note that all of the canine OSA samples exhibiting telomere fusion utilized in our study were telomerase positive. Pending further research regarding telomerase negative canine OSA cell lines, our findings may suggest telomere fusions can potentially serve as a novel marker for canine OSA.

Inherited phenotype instability of inflorescence and floral organ development in homeotic barley double mutants and its specific modification by auxin inhibitors and 2,4-D.

Science.gov (United States)

Šiukšta, Raimondas; Vaitkūnienė, Virginija; Kaselytė, Greta; Okockytė, Vaiva; Žukauskaitė, Justina; Žvingila, Donatas; Rančelis, Vytautas

2015-03-01

Barley (Hordeum vulgare) double mutants Hv-Hd/tw2, formed by hybridization, are characterized by inherited phenotypic instability and by several new features, such as bract/leaf-like structures, long naked gaps in the spike, and a wide spectrum of variations in the basic and ectopic flowers, which are absent in single mutants. Several of these features resemble those of mutations in auxin distribution, and thus the aim of this study was to determine whether auxin imbalances are related to phenotypic variations and instability. The effects of auxin inhibitors and 2,4-D (2,4-dichlorophenoxyacetic acid) on variation in basic and ectopic flowers were therefore examined, together with the effects of 2,4-D on spike structure. The character of phenotypic instability and the effects of auxin inhibitors and 2,4-D were compared in callus cultures and intact plants of single homeotic Hv-tw2 and Hv-Hooded/Kap (in the BKn3 gene) mutants and alternative double mutant lines: offspring from individual plants in distal hybrid generations (F9-F10) that all had the same BKn3 allele as determined by DNA sequencing. For intact plants, two auxin inhibitors, 9-hydroxyfluorene-9-carboxylic acid (HFCA) and p-chlorophenoxyisobutyric acid (PCIB), were used. Callus growth and flower/spike structures of the Hv-tw2 mutant differed in their responses to HFCA and PCIB. An increase in normal basic flowers after exposure to auxin inhibitors and a decrease in their frequencies caused by 2,4-D were observed, and there were also modifications in the spectra of ectopic flowers, especially those with sexual organs, but the effects depended on the genotype. Exposure to 2,4-D decreased the frequency of short gaps and lodicule transformations in Hv-tw2 and of long naked gaps in double mutants. The effects of auxin inhibitors and 2,4-D suggest that ectopic auxin maxima or deficiencies arise in various regions of the inflorescence/flower primordia. Based on the phenotypic instability observed, definite

Prognostic utility of chromosomal instability detected by fluorescence in situ hybridization in fine-needle aspirates from oral squamous cell carcinomas

International Nuclear Information System (INIS)

Sato, Hiroaki; Uzawa, Narikazu; Takahashi, Ken-Ichiro; Myo, Kunihiro; Ohyama, Yoshio; Amagasa, Teruo

2010-01-01

Although chromosomal instability (CIN) has been detected in many kinds of human malignancies by means of various methods, there is no practical assessment for small clinical specimens. In this study, we evaluated CIN in fine-needle aspiration (FNA) biopsied oral squamous cell carcinomas (SCCs) using fluorescence in situ hybridization (FISH) analysis, and investigated its prognostic significance. To evaluate CIN status of tumors, FISH with genomic probes for the centromeres of chromosomes 7, 9, and 11 was performed on specimens obtained by FNA from 77 patients with primary oral SCCs. High-grade CIN (CIN3) was observed in 11.7% (9/77) of patients with oral SCCs and was associated significantly with reduced disease-free survival (p = .008) and overall survival (p = .003). Multivariate Cox proportional hazards analysis showed that CIN status was significantly correlated with disease-free survival (p = .035) and overall survival (p = .041). Analysis of CIN status using FISH on FNA biopsy specimens may be useful in predicting of recurrence and poor prognosis in patients with oral SCCs

Identification of supernumerary ring chromosome 1 mosaicism using fluorescence in situ hybridization.

Science.gov (United States)

Chen, H; Tuck-Muller, C M; Batista, D A; Wertelecki, W

1995-03-27

We report on a 15-year-old black boy with severe mental retardation, multiple congenital anomalies, and a supernumerary ring chromosome mosaicism. Fluorescence in situ hybridization with a chromosome 1 painting probe (pBS1) identified the ring as derived from chromosome 1. The karyotype was 46,XY/47,XY,+r(1)(p13q23). A review showed 8 reports of ring chromosome 1. In 5 cases, the patients had a non-supernumerary ring chromosome 1 resulting in partial monosomies of the short and/or long arm of chromosome 1. In 3 cases, the presence of a supernumerary ring resulted in partial trisomy of different segments of chromosome 1. In one of these cases the supernumerary ring was composed primarily of the centromere and the heterochromatic region of chromosome 1, resulting in normal phenotype. Our patient represents the third report of a supernumerary ring chromosome 1 resulting in abnormal phenotype.

Persistent genetic instability induced by synergistic interaction between x-irradiation and 6-thioguanine

International Nuclear Information System (INIS)

Grosovsky, A.J.; Nelson, S.L.; Smith, L.E.

1995-01-01

Clonal karyotypic analysis was performed using G-banding on four groups of clones derived from TK6 human lymphoblasts: 25 HPRT - total gene deletion mutants induced by exposure to 2 Gy of x-rays; 8 spontaneous HPRT - total gene deletion mutants; 25 clones irradiated with 2 Gy, not selected with 6-thioguanine. Ten to twenty metaphases were examined for each clone. Extensive karyotypic heterogeneity was observed among x-ray induced HPRT - mutants involving translocations, deletions, duplications and aneuploidy; recovery of chromosomal aberrations and karyotypic heterogeneity was greater than the additive effects of clones treated with x-irradiation or 6-thioguanine alone. This synergistic interaction between x-irradiation and 6-thioguanine was observed despite a 7 day phenotypic expression interval between exposure to the two agents. Thus, x-irradiated TK6 cells appear to be persistently hypersensitive to the induction of genetic instability. Several mutants appeared to exhibit evidence of clonal evolution since aberrant chromosomes observed in one metaphase, were found to be further modified in other metaphases. In order to determine if genetic instability, identified by clonal karyotypic heterogeneity, affected specific locus mutation rates, we utilized the heterozygous thymidine kinase (tk) locus as a genetic marker. Four x-ray induced HPRT - mutants with extensive karyotypic heterogeneity, exhibited mutation rates at tk ranging from 5 to 8 fold higher than the parental TK6 cells. Further analysis, using fractionated low dose radiation exposure, is currently in progress

Genomic instability and radiation

Energy Technology Data Exchange (ETDEWEB)

Little, John B [Harvard School of Public Health, Boston, MA 02115 (United States)

2003-06-01

Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)

Genomic instability and radiation

International Nuclear Information System (INIS)

Little, John B

2003-01-01

Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)

Small supernumerary marker chromosome derived from proximal p-arm of chromosome 2: identification by fluorescent in situ hybridization.

Science.gov (United States)

Lasan Trcić, Ruzica; Hitrec, Vlasta; Letica, Ljiljana; Cuk, Mario; Begović, Davor

2003-08-01

Conventional cytogenetics detected an interstitial deletion of proximal region of p-arm of chromosome 2 in a 6-month-old boy with a phenotype slightly resembling Down's syndrome. The deletion was inherited from the father, whose karyotype revealed a small ring-shaped marker chromosome, in addition to interstitial deletion. Fluorescence in situ hybridization identified the marker, which consisted of the proximal region of the p-arm of chromosome 2, including a part of its centromere. This case shows that molecular cytogenetic analysis can reveal the mechanism of the formation of the marker chromosome.

Fenotipo turneriano asociado al cromosoma Y en anillo TURNER'S PHENOTYPE ASSOCIATED WITH RING Y CHROMOSOME

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Estela Morales Peralta

2005-03-01

Full Text Available El síndrome de Turner es una enfermedad que típicamente afecta a las hembras. En nuestro trabajo describimos un paciente con los signos principales de esta. Su cariotipo fue 46, X r(Y /45, X. Este mosaicismo se explica por la inestabilidad del anillo cromosómico que conduce a su pérdida luego de la mitosis. Mediante pruebas moleculares, que incluyeron la identificación de los genes SRY y AM-XY, obtuvimos los resultados habituales encontrados en varones. De estos hallazgos podemos concluir que el material genético perdido, como parte del proceso de formación del anillo cromosómico, es distal a Y p11.3. Esto demuestra que los genes anti-Turner se encuentran localizados en esta región pseudoautosómica.Turner's syndrome is a disease typically affecting females. In our paper, we describe a patient with its main signs. His karyotype was 46, Xr(Y/45,X. This mosaicism is explained by the instability of the chromosomic ring leading to its loss after mitosis. By molecular tests, including the identification of SRY and AM-XY genes, we obtained the usual results found in males. According to these findings, we can conclude that the genetical material lost as part of the process of formation of the chromosomic ring is distal to Y p 11.3. This shows that the anti-Turner genes are located in this pseudoautosomal region.

Sex chromosome turnover contributes to genomic divergence between incipient stickleback species.

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Kohta Yoshida

2014-03-01

Full Text Available Sex chromosomes turn over rapidly in some taxonomic groups, where closely related species have different sex chromosomes. Although there are many examples of sex chromosome turnover, we know little about the functional roles of sex chromosome turnover in phenotypic diversification and genomic evolution. The sympatric pair of Japanese threespine stickleback (Gasterosteus aculeatus provides an excellent system to address these questions: the Japan Sea species has a neo-sex chromosome system resulting from a fusion between an ancestral Y chromosome and an autosome, while the sympatric Pacific Ocean species has a simple XY sex chromosome system. Furthermore, previous quantitative trait locus (QTL mapping demonstrated that the Japan Sea neo-X chromosome contributes to phenotypic divergence and reproductive isolation between these sympatric species. To investigate the genomic basis for the accumulation of genes important for speciation on the neo-X chromosome, we conducted whole genome sequencing of males and females of both the Japan Sea and the Pacific Ocean species. No substantial degeneration has yet occurred on the neo-Y chromosome, but the nucleotide sequence of the neo-X and the neo-Y has started to diverge, particularly at regions near the fusion. The neo-sex chromosomes also harbor an excess of genes with sex-biased expression. Furthermore, genes on the neo-X chromosome showed higher non-synonymous substitution rates than autosomal genes in the Japan Sea lineage. Genomic regions of higher sequence divergence between species, genes with divergent expression between species, and QTL for inter-species phenotypic differences were found not only at the regions near the fusion site, but also at other regions along the neo-X chromosome. Neo-sex chromosomes can therefore accumulate substitutions causing species differences even in the absence of substantial neo-Y degeneration.

Multiple roles of the Y chromosome in the biology of Drosophila melanogaster.

Science.gov (United States)

Piergentili, Roberto

2010-09-01

The X and Y chromosomes of Drosophila melanogaster were the first examples of chromosomes associated with genetic information. Thanks to the serendipitous discovery of a male with white eyes in 1910, T.H. Morgan was able to associate the X chromosome of the fruit fly with a phenotypic character (the eye color) for the first time. A few years later, his student, C.B. Bridges, demonstrated that X0 males, although phenotypically normal, are completely sterile. This means that the X chromosome, like the autosomes, harbors genes that control several phenotypic traits, while the Y chromosome is important for male fertility only. Notwithstanding its long history--almost 100 years in terms of genetic studies--most of the features of the Y chromosome are still a mystery. This is due to the intrinsic nature of this genetic element, namely, (1) its molecular composition (mainly transposable elements and satellite DNA), (2) its genetic inertia (lack of recombination due to its heterochromatic nature), (3) the absence of homology with the X (with the only exception of the nucleolar organizer), (4) the lack of visible phenotypes when it is missing (indeed, except for their sterility, X0 flies are normal males), and (5) its low density as for protein-coding sequences (to date, only 13 genes out of approximately 14,000 have been mapped on this chromosome in D. melanogaster, i.e., ~0.1% of the total). Nonetheless, a more accurate analysis reveals that this chromosome can influence several complex phenotypes: (1) it has a role in the fertility of both sexes and viability of males when over-represented; (2) it can unbalance the intracellular nucleotide pool; (3) it can interfere with the gene expression either by recruiting proteins involved in chromatin remodeling (PEV) or, to a higher extent, by influencing the expression of up to 1,000 different genes, probably by changing the availability of transcription factors; (4) it plays a major role (up to 50%) in the resistance to heat

Characterization of genomic instability in Saccharomyces cerevisiae and engaging teaching strategies described in two curricula

Science.gov (United States)

Keller, Alexandra P.

Cancer arises through an accumulation of mutations in the genome. In cancer cells, mutations are frequently caused by DNA rearrangements, which include chromosomal breakages, deletions, insertions, and translocations. Such events contribute to genomic instability, a known hallmark of cancer. To study cycles of chromosomal instability, we are using baker's yeast as a model organism. In yeast, a ChrVII system was previously developed (Admire et al., 2006), in which a disomic yeast strain was used to identify regions of instability on ChrVII. Using this system, a fragile site on the left arm of ChrVII (Admire et al., 2006) was identified and characterized. This study led to insight into mechanisms involved in chromosomal rearrangements and mutations that arise from them as well as to an understanding of mechanisms involved in genomic instability. To further our understanding of genomic instability, I devised a strategy to study instability on a different chromosome (ChrV) (Figure 3), so that we could determine whether lessons learned from the ChrVII system are applicable to other chromosomes, and/or whether other mechanisms of instability could be identified. A suitable strain was generated and analyzed, and our findings suggest that frequencies of instability on the right arm of ChrV are similar to those found in ChrVII. The results from the work in ChrV described in this paper support the idea that the instability found on ChrVII is not an isolated occurrence. My research was supported by an NSF GK-12 grant. The aim of this grant is to improve science education in middle schools, and as part of my participation in this program, I studied and practiced effective science communication methodologies. In attempts to explain my research to middle school students, I collaborated with others to develop methods for explaining genetics and the most important techniques I used in my research. While developing these methods, I learned more about what motivates people to learn

Partial trisomy 5q resulting from chromosome 7 insertion: An expansion of the phenotype

Energy Technology Data Exchange (ETDEWEB)

Fries, M.H.; Reilly, P.A.; Williams, T.C. [Keesler Medical Center, MS (United States)] [and others

1994-09-01

Partial trisomy 5q has been categorized into three separate phenotypes; however, a distinctive phenotype has not been described for duplications spanning 5q23-q35. We report a case of partial trisomy 5q for this region as a result of a ins(7,5)(q31.3;q23.2q35.1)mat. The liveborn male infant was delivered by emergency cesarean section at 37 weeks after a pregnancy notable for oligohydramnios, with birth weight 1792 g (<3%). Postnatal course was marked by psychomotor delay, failure to thrive, and biopsy demonstrated neonatal giant cell hepatitis with a paucity of intrahepatic bile ducts. His appearance was remarkable for lack of subcutaneous fat, midline displaced hair whorl, bitemporal narrowing with frontal bossing, wide anterior fontanel, widow`s peak, protuberant eyes with periorbital and lid edema, short flat nasal bridge with broad flattened nasal tip, long smooth philtrum, wide mouth with thin lips, wide gingival ridges, micrognathia, posteriorly rotated low-set ears, hepatomegaly, flexion contractions of elbows, and generalized hypertonicity. Urine organic acids, oligosaccharide/mucopolysaccharide screen, and plasma amino acids were negative. GTG-banding on prometaphase chromosomes showed an unbalanced translocation involving chr. 7. This was identified as an insertion of chr. 5 (q23.2q35.1) into distal 7q after FISH using chr. 5 and chr. 7 painting probes. The infant`s mother carries the balanced insertional rearrangement: 46,XX,dir ins(7,5)(q31.3;q23.2q35.1). This phenotype overlaps that of previously described duplications with the addition of giant cell hepatitis, coarsened facial features, gingival thickening, and flexion contractures, suggestive of a yet undiagnosed storage disorder.

Instability of isochromosome 4p in a child with pure trisomy 4p syndrome features and entire 4q-arm translocation.

Science.gov (United States)

Pota, Pruthvi; Grammatopoulou, Vasiliki; Torti, Erin; Braddock, Stephen; Batanian, Jacqueline R

2014-01-01

Constitutional chromosome instability so far has mainly been associated with ring formation. In addition, isochromosome formation involving the short arm with translocation of the entire long arm is rarely observed. This type of rearrangement has been reported for chromosomes 4, 5, 7, 9, 10, 12, and 20. Here, we present the third patient having an isochromosome 4p with 4q translocation, but showing for the first time chromosome instability detected by FISH following chromosome microarray analysis.

Cytogenetic and molecular analysis of inv dup(15) chromosomes observed in two patients with autistic disorder and mental retardation

Energy Technology Data Exchange (ETDEWEB)

Flejter, W.L. [Univ. of Utah, Salt Lake City, UT (United States); Bennett-Baker, P.E.; Gorski, J.L. [Univ. of Michigan, Ann Arbor, MI (United States)] [and other

1996-01-11

A variety of distinct phenotypes has been associated with supernumerary inv dup(15) chromosomes. Although different cytogenetic rearrangements have been associated with distinguishable clinical syndromes, precise genotype-phenotype correlations have not been determined. However, the availability of chromosome 15 DNA markers provides a means to characterize inv dup(15) chromosomes in detail to facilitate the determination of specific genotype-phenotype associations. We describe 2 patients with an autistic disorder, mental retardation, developmental delay, seizures, and supernumerary inv dup(15) chromosomes. Conventional and molecular cytogenetic studies confirmed the chromosomal origin of the supernumerary chromosomes and showed that the duplicated region extended to at least band 15q13. An analysis of chromosome 15 microsatellite CA polymorphisms suggested a maternal origin of the inv dup(15) chromosomes and biparental inheritance of the two intact chromosome 15 homologs. The results of this study add to the existing literature which suggests that the clinical phenotype of patients with a supernumerary inv dup(15) chromosome is determined not only by the extent of the duplicated region, but by the dosage of genes located within band 15q13 and the origin of the normal chromosomes 15. 21 refs., 2 figs., 1 tab.

Blepharophimosis and mental retardation (BMR) phenotypes caused by chromosomal rearrangements: description in a boy with partial trisomy 10q and monosomy 4q and review of the literature.

Science.gov (United States)

Bartholdi, Deborah; Toelle, Sandra P; Steiner, Bernhard; Boltshauser, Eugen; Schinzel, Albert; Riegel, Mariluce

2008-01-01

Blepharophimosis is a rare congenital anomaly of the palpebral fissure which is often associated with mental retardation and additional malformations. We report on a boy with blepharophimosis, ptosis and severe mental retardation carrying an unbalanced 4;10 translocation with terminal duplication of 10q [dup(10)(q25.1-->qter)] and monosomy of a small terminal segment of chromosome 4q [del(4)(34.3-->qter)]. Detailed clinical examination and review of the literature showed that the phenotype of the patient was mainly determined by the dup(10q). This paper reviews the chromosomal aberrations associated with BMR (blepharophimosis mental retardation) phenotypes. Searching different databases and reviewing the literature revealed 14 microscopically visible aberrations (among them UPD(14)pat) and two submicroscopic rearrangements causing blepharophimosis and mental retardation (BMR) syndrome. Some of these rearrangements-like the terminal dup(10q) identified in our patient or interstitial del(2q)-are associated with clearly defined phenotypes and can be well distinguished from each other on basis of clinical examination. This paper should assist clinicians and cytogeneticists when evaluating patients with BMR syndrome.

Evaluation of chromosome aberration frequency instable in individual groups residents at the municipality of Monte Alegre, Para, Brazil, exposed to radon

International Nuclear Information System (INIS)

Yunes, Samira Nogarol

2010-01-01

The municipality of Monte Alegre is a region that presents natural radiation high due to the presence of the radionuclide uranium ( 238 U) in its soil, which through its decay gives rise to element Rn, a gas. The radioactivity of the rocks has become a problem for the population of Monte Alegre, from the moment when the radioactive material began to be used in the construction of houses and paving of streets. Among all bio markers related to environmental exposures and its biological effects, the chromosomal aberrations are considered good bio markers as predictors of the risk of cancer. Studies suggest that the frequency of chromosomal aberrations may be related to the genetic instability individual and/or exposure to ionizing radiation. Our work aimed to evaluate the frequency of chromosomal aberrations in individuals in the region of high natural radioactivity in Monte Alegre-PA. As well as to correlate the cytogenetic analysis made in this study with the results of analysis of frequency of polymorphisms of genes of DNA repair carried out in another study that resulted in other dissertation. In accordance with the distribution of the data obtained in characterizing environmental radiological and in the calculation of dose, were chosen residents of homes with more and less exposure to radiation. The samples of peripheral blood of 85 individuals of the resident population of the region of Monte Alegre - PA were collected and examine provided two slides for individual was performed to verify the quality of the sample. Through this evaluation we decide that 33% of the material collected, or is, samples of 28 individuals were in suitable conditions for analysis of the frequency of chromosomal aberrations. After the collections lymphocytes present in the sample were cultivated in accordance with the methodology proposed for obtaining of cells in metaphase. were analyzed 6,177 metaphases of 28 individuals among which were found dicentric chromosomes 4 and 19 fragments

Knockdown of αII spectrin in normal human cells by siRNA leads to chromosomal instability and decreased DNA interstrand cross-link repair

OpenAIRE

McMahon, Laura W.; Zhang, Pan; Sridharan, Deepa M.; Lefferts, Joel A.; Lambert, Muriel W.

2009-01-01

Nonerythroid α-spectrin (αIISp) is a structural protein involved in repair of DNA interstrand cross-links and is deficient in cells from patients with Fanconi anemia (FA), which are defective in ability to repair cross-links. In order to further demonstrate the importance of the role that αIISp plays in normal human cells and in the repair defect in FA, αIISp was knocked down in normal cells using siRNA. Depletion of αIISp in normal cells by siRNA resulted in chromosomal instability and cellu...

Asymmetry in dentition and shape of pharyngeal arches in the clonal fish Chrosomus eos-neogaeus: Phenotypic plasticity and developmental instability.

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Christelle Leung

Full Text Available The effect of the environment may result in different developmental outcomes. Extrinsic signals can modify developmental pathways and result in alternative phenotypes (phenotypic plasticity. The environment can also be interpreted as a stressor and increase developmental instability (developmental noise. Directional and fluctuating asymmetry provide a conceptual background to discriminate between these results. This study aims at assessing whether variation in dentition and shape of pharyngeal arches of the clonal fish Chrosomus eos-neogaeus results from developmental instability or environmentally induced changes. A total of 262 specimens of the Chrosomus eos-neogaeus complex from 12 natural sites were analysed. X-ray microcomputed tomography (X-ray micro-CT was used to visualize the pharyngeal arches in situ with high resolution. Variation in the number of pharyngeal teeth is high in hybrids in contrast to the relative stability observed in both parental species. The basal dental formula is symmetric while the most frequent alternative dental formula is asymmetric. Within one lineage, large variation in the proportion of individuals bearing basal or alternative dental formulae was observed among sites in the absence of genetic difference. Both dentition and arch shape of this hybrid lineage were explained significantly by environmental differences. Only individuals bearing asymmetric dental formula displayed fluctuating asymmetry as well as directional left-right asymmetry for the arches. The hybrids appeared sensitive to environmental signals and intraspecific variation on pharyngeal teeth was not random but reflects phenotypic plasticity. Altogether, these results support the influence of the environment as a trigger for an alternative developmental pathway resulting in left-right asymmetry in dentition and shape of pharyngeal arches.

Chromosomal imbalance in the progression of high-risk non-muscle invasive bladder cancer

International Nuclear Information System (INIS)

Zieger, Karsten; Wiuf, Carsten; Jensen, Klaus Møller-Ernst; Ørntoft, Torben Falck; Dyrskjøt, Lars

2009-01-01

Non-muscle invasive bladder neoplasms with invasion of the lamina propria (stage T1) or high grade of dysplasia are at 'high risk' of progression to life-threatening cancer. However, the individual course is difficult to predict. Chromosomal instability (CI) is associated with high tumor stage and grade, and possibly with the risk of progression. To investigate the relationship between CI and subsequent disease progression, we performed a case-control-study of 125 patients with 'high-risk' non-muscle invasive bladder neoplasms, 67 with later disease progression, and 58 with no progression. Selection criteria were conservative (non-radical) resections and full prospective clinical follow-up (> 5 years). We investigated primary lesions in 59, and recurrent lesions in 66 cases. We used Affymetrix GeneChip ® Mapping 10 K and 50 K SNP microarrays to evaluate genome wide chromosomal imbalance (loss-of-heterozygosity and DNA copy number changes) in 48 representative tumors. DNA copy number changes of 15 key instability regions were further investigated using QPCR in 101 tumors (including 25 tumors also analysed on 50 K SNP microarrays). Chromosomal instability did not predict any higher risk of subsequent progression. Stage T1 and high-grade tumors had generally more unstable genomes than tumors of lower stage and grade (mostly non-primary tumors following a 'high-risk' tumor). However, about 25% of the 'high-risk' tumors had very few alterations. This was independent of subsequent progression. Recurrent lesions represent underlying field disease. A separate analysis of these lesions did neither reflect any difference in the risk of progression. Of specific chromosomal alterations, a possible association between loss of chromosome 8p11 and the risk of progression was found. However, the predictive value was limited by the heterogeneity of the changes. Chromosomal instability (CI) was associated with 'high risk' tumors

Genomic instability following irradiation

International Nuclear Information System (INIS)

Hacker-Klom, U.B.; Goehde, W.

2001-01-01

Ionising irradiation may induce genomic instability. The broad spectrum of stress reactions in eukaryontic cells to irradiation complicates the discovery of cellular targets and pathways inducing genomic instability. Irradiation may initiate genomic instability by deletion of genes controlling stability, by induction of genes stimulating instability and/or by activating endogeneous cellular viruses. Alternatively or additionally it is discussed that the initiation of genomic instability may be a consequence of radiation or other agents independently of DNA damage implying non nuclear targets, e.g. signal cascades. As a further mechanism possibly involved our own results may suggest radiation-induced changes in chromatin structure. Once initiated the process of genomic instability probably is perpetuated by endogeneous processes necessary for proliferation. Genomic instability may be a cause or a consequence of the neoplastic phenotype. As a conclusion from the data available up to now a new interpretation of low level radiation effects for radiation protection and in radiotherapy appears useful. The detection of the molecular mechanisms of genomic instability will be important in this context and may contribute to a better understanding of phenomenons occurring at low doses <10 cSv which are not well understood up to now. (orig.)

Genetic instability of T-lymphocytes grown clonally in vitro of A-bomb survivors

International Nuclear Information System (INIS)

Hamasaki, Kanya; Kusunoki, Yoichiro; Nakajima, Eiji; Takahashi, Norio; Nakachi, Kei; Nakamura, Nori; Kodama, Yoshiaki

2009-01-01

Authors have reported their studies on genetic instability of A-bomb survivors' peripheral T-lymphocytes in vivo that chromosomal instability is not observed in the cells. This paper reports their further studies to see genetic instability that may occur in clones of T-cells cultured long, for the purpose of data collection at chromosome level. Subjects were the T-cells of 2 female A-bomb survivors (Case 1: age 65 y, exposed at age 20 y with marrow estimated dose DS02 (Dosimetry system 2002) of 1950 mGy; and Case 2: 72 y, 13 y, 1150 mGy, respectively) and age / sex matched 2 control females (Case 3: 63 y, 19 y, 1.3 mGy; and Case 4: 70 y, 13 y, 1.7 mGy, respectively). T-cells were those freeze-stored (Case 1, 3, and 4) and freshly prepared (Case 2). Monocytes were isolated by Ficoll procedure and cloned in 96-hole plate as previously described. Colonies formed were cultured in 24-hole plate with CD3/CD28 T-cell proliferation beads for 4 weeks in average (Case 2, 3 and 4; ave. cell cycles 23-25) and cells of Case 1 (cloned and freeze-stored previously) were cultured similarly. Chromosome specimens were prepared routinely, and 100 cells of each clone were subjected to mFISH observation for image analysis with CytoVision (Applied Imaging) to detect the aberrations like translocation, derived and dicentric chromosomes. No significant difference in stable chromosome aberrations yielded during the long culture in vitro was found between exposed and control groups, suggesting that genetic instability due to radiation exposure had not occurred in this experiment. (K.T)

A dominant negative mutant of TLK1 causes chromosome missegregation and aneuploidy in normal breast epithelial cells

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Williams Briana

2003-10-01

Full Text Available Abstract Background In Arabidopsis thaliana, the gene Tousled encodes a protein kinase of unknown function, but mutations in the gene lead to flowering and leaf morphology defects. We have recently cloned a mammalian Tousled-Like Kinase (TLK1B and found that it phosphorylates specifically histone H3, in vitro and in vivo. We now report the effects that overexpression of a kinase-dead mutant of TLK1B mediates in a normal diploid cell line. Results Expression of a kinase-dead mutant resulted in reduction of phosphorylated histone H3, which could have consequences in mitotic segregation of chromosomes. When analyzed by FACS and microscopy, these cells displayed high chromosome number instability and aneuploidy. This phenomenon was accompanied by less condensed chromosomes at mitosis; failure of a number of chromosomes to align properly on the metaphase plate; failure of some chromosomes to attach to microtubules; and the occasional presentation of two bipolar spindles. We also used a different method (siRNA to reduce the level of endogenous TLK1, but in this case, the main result was a strong block of cell cycle progression suggesting that TLK1 may also play a role in progression from G1. This block in S phase progression could also offer a different explanation of some of the later mitotic defects. Conclusions TLK1 has a function important for proper chromosome segregation and maintenance of diploid cells at mitosis in mammalian cells that could be mediated by reduced phosphorylation of histone H3 and condensation of chromosomes, although other explanations to the phenotype are possible.

Small chromosomes among Danish Candida glabrata isolates originated through different mechanisms

DEFF Research Database (Denmark)

Ahmad, Khadija Mohamed; Ishchuk, Olena P.; Hellborg, Linda

2013-01-01

chromosomes, which were smaller than 0.5 Mb. Regarding the year, patient and hospital, these C. glabrata strains had independent origin and the analyzed small chromosomes were structurally not related to each other (i.e. they contained different sets of genes). We suggest that at least two mechanisms could...... exhibited mitotic instability, while the second type, which contained the corresponding genes in only one copy in the genome, was mitotically stable. Apparently, in patients C. glabrata chromosomes are frequently reshuffled resulting in new genetic configurations, including appearance of small chromosomes...

Detection of genomic instability in hypospadias patients by random ...

African Journals Online (AJOL)

DIRECTOR

2011-05-16

May 16, 2011 ... organism including bacteria (Sahoo et al., 2010), fungi. (Motlagh and Anvari ... technique that detects genomic alteration correlated with human tumor is .... chromosomal instability among hypospadias patients. REFERENCES.

Niacin deficiency delays DNA excision repair and increases spontaneous and nitrosourea-induced chromosomal instability in rat bone marrow.

Science.gov (United States)

Kostecki, Lisa M; Thomas, Megan; Linford, Geordie; Lizotte, Matthew; Toxopeus, Lori; Bartleman, Anne-Pascale; Kirkland, James B

2007-12-01

We have shown that niacin deficiency impairs poly(ADP-ribose) formation and enhances sister chromatid exchanges and micronuclei formation in rat bone marrow. We designed the current study to investigate the effects of niacin deficiency on the kinetics of DNA repair following ethylation, and the accumulation of double strand breaks, micronuclei (MN) and chromosomal aberrations (CA). Weanling male Long-Evans rats were fed niacin deficient (ND), or pair fed (PF) control diets for 3 weeks. We examined repair kinetics by comet assay in the 36h following a single dose of ethylnitrosourea (ENU) (30mg/kg bw). There was no effect of ND on mean tail moment (MTM) before ENU treatment, or on the development of strand breaks between 0 and 8h after ENU. Repair kinetics between 12 and 30h were significantly delayed by ND, with a doubling of area under the MTM curve during this period. O(6)-ethylation of guanine peaked by 1.5h, was largely repaired by 15h, and was also delayed in bone marrow cells from ND rats. ND significantly enhanced double strand break accumulation at 24h after ENU. ND alone increased chromosome and chromatid breaks (four- and two-fold). ND alone caused a large increase in MN, and this was amplified by ENU treatment. While repair kinetics suggest that ND may be acting by creating catalytically inactive PARP molecules with a dominant-negative effect on repair processes, the effect of ND alone on O(6)-ethylation, MN and CA, in the absence of altered comet results, suggests additional mechanisms are also leading to chromosomal instability. These data support the idea that the bone marrow cells of niacin deficient cancer patients may be more sensitive to the side effects of genotoxic chemotherapy, resulting in acute bone marrow suppression and chronic development of secondary leukemias.

Ring 2 chromosome associated with failure to thrive, microcephaly and dysmorphic facial features.

Science.gov (United States)

López-Uriarte, Arelí; Quintero-Rivera, Fabiola; de la Fuente Cortez, Beatriz; Puente, Viviana Gómez; Campos, María Del Roble Velazco; de Villarreal, Laura E Martínez

2013-10-15

We report here a child with a ring chromosome 2 [r(2)] associated with failure to thrive, microcephaly and dysmorphic features. The chromosomal aberration was defined by chromosome microarray analysis, revealing two small deletions of 2p25.3 (139 kb) and 2q37.3 (147 kb). We show the clinical phenotype of the patient, using a conventional approach and the molecular cytogenetics of a male with a history of prenatal intrauterine growth restriction (IUGR), failure to thrive, microcephaly and dysmorphic facial features. The phenotype is very similar to that reported in other clinical cases with ring chromosome 2. © 2013 Elsevier B.V. All rights reserved.

Coordinated phenotype switching with large-scale chromosome flip-flop inversion observed in bacteria.

Science.gov (United States)

Cui, Longzhu; Neoh, Hui-min; Iwamoto, Akira; Hiramatsu, Keiichi

2012-06-19

Genome inversions are ubiquitous in organisms ranging from prokaryotes to eukaryotes. Typical examples can be identified by comparing the genomes of two or more closely related organisms, where genome inversion footprints are clearly visible. Although the evolutionary implications of this phenomenon are huge, little is known about the function and biological meaning of this process. Here, we report our findings on a bacterium that generates a reversible, large-scale inversion of its chromosome (about half of its total genome) at high frequencies of up to once every four generations. This inversion switches on or off bacterial phenotypes, including colony morphology, antibiotic susceptibility, hemolytic activity, and expression of dozens of genes. Quantitative measurements and mathematical analyses indicate that this reversible switching is stochastic but self-organized so as to maintain two forms of stable cell populations (i.e., small colony variant, normal colony variant) as a bet-hedging strategy. Thus, this heritable and reversible genome fluctuation seems to govern the bacterial life cycle; it has a profound impact on the course and outcomes of bacterial infections.

Chromosome mosaicism in hypomelanosis of Ito.

Science.gov (United States)

Ritter, C L; Steele, M W; Wenger, S L; Cohen, B A

1990-01-01

Our finding of chromosome mosaicism with a ring 22 in a retarded black boy with hypomelanosis of Ito prompted a review of this "syndrome." Most patients have a variety of non-dermal defects, particularly those affecting CNS function. Among karyotyped patients, most are chromosome mosaics of one sort or another. Hypomelanosis of Ito turns out to be a causable non-specific phenotype, i.e., a clinical marker for chromosome mosaicism of all different types in individuals with a dark enough skin to show lighter patches. Consequently, cytogenetic evaluation is indicated in all patients with this skin finding.

Profiles of Genomic Instability in High-Grade Serous Ovarian Cancer Predict Treatment Outcome

DEFF Research Database (Denmark)

Wang, Zhigang C.; Birkbak, Nicolai Juul; Culhane, Aedín C.

2012-01-01

Purpose: High-grade serous cancer (HGSC) is the most common cancer of the ovary and is characterized by chromosomal instability. Defects in homologous recombination repair (HRR) are associated with genomic instability in HGSC, and are exploited by therapy targeting DNA repair. Defective HRR cause...

High level of chromosomal instability in circulating tumor cells of ROS1-rearranged non-small-cell lung cancer.

Science.gov (United States)

Pailler, E; Auger, N; Lindsay, C R; Vielh, P; Islas-Morris-Hernandez, A; Borget, I; Ngo-Camus, M; Planchard, D; Soria, J-C; Besse, B; Farace, F

2015-07-01

Genetic aberrations affecting the c-ros oncogene 1 (ROS1) tyrosine kinase gene have been reported in a small subset of patients with non-small-cell lung cancer (NSCLC). We evaluated whether ROS1-chromosomal rearrangements could be detected in circulating tumor cells (CTCs) and examined tumor heterogeneity of CTCs and tumor biopsies in ROS1-rearranged NSCLC patients. Using isolation by size of epithelial tumor cells (ISET) filtration and filter-adapted-fluorescence in situ hybridization (FA-FISH), ROS1 rearrangement was examined in CTCs from four ROS1-rearranged patients treated with the ROS1-inhibitor, crizotinib, and four ROS1-negative patients. ROS1-gene alterations observed in CTCs at baseline from ROS1-rearranged patients were compared with those present in tumor biopsies and in CTCs during crizotinib treatment. Numerical chromosomal instability (CIN) of CTCs was assessed by DNA content quantification and chromosome enumeration. ROS1 rearrangement was detected in the CTCs of all four patients with ROS1 rearrangement previously confirmed by tumor biopsy. In ROS1-rearranged patients, median number of ROS1-rearranged CTCs at baseline was 34.5 per 3 ml blood (range, 24-55). In ROS1-negative patients, median background hybridization of ROS1-rearranged CTCs was 7.5 per 3 ml blood (range, 7-11). Tumor heterogeneity, assessed by ROS1 copy number, was significantly higher in baseline CTCs compared with paired tumor biopsies in the three patients experiencing PR or SD (P < 0.0001). Copy number in ROS1-rearranged CTCs increased significantly in two patients who progressed during crizotinib treatment (P < 0.02). CTCs from ROS1-rearranged patients had a high DNA content and gain of chromosomes, indicating high levels of aneuploidy and numerical CIN. We provide the first proof-of-concept that CTCs can be used for noninvasive and sensitive detection of ROS1 rearrangement in NSCLC patients. CTCs from ROS1-rearranged patients show considerable heterogeneity of ROS1-gene

Aneuploidy in immortalized human mesenchymal stem cells with non-random loss of chromosome 13 in culture.

Science.gov (United States)

Takeuchi, Masao; Takeuchi, Kikuko; Ozawa, Yutaka; Kohara, Akihiro; Mizusawa, Hiroshi

2009-01-01

Aneuploidy (an abnormal number of chromosomes) is commonly observed in most human cancer cells, highlighting the need to examine chromosomal instability in tumorigenesis. Previously, the immortalized human mesenchymal stem cell line UE6E7T-3 was shown to undergo a preferential loss of one copy of chromosome 13 after prolonged culture. Here, the loss of chromosome 13 was found to be caused by chromosome missegregation during mitosis, which involved unequal segregation, exclusion of the misaligned chromosome 13 on the metaphase plate, and trapping of chromosome 13 in the midbody region, as observed by fluorescence in situ hybridization. Near-diploid aneuploidy, not tetraploidy, was the direct result. The loss of chromosome 13 was non-random, and was detected by analysis of microsatellites and single nucleotide polymorphism-based loss of heterozygosity (LOH). Of the five microsatellite loci on chromosome 13, four loci showed microsatellite instability at an early stage in culture, and LOH was apparent at a late stage in culture. These results suggest that the microsatellite mutations cause changes in centromere integrity provoking loss of this chromosome in the UE6E7T-3 cell line. Thus, these results support the use of this cell line as a useful model for understanding the mechanism of aneuploid formation in cell cultures.

The impact of physical activity on the level of chromosome aberrations

Directory of Open Access Journals (Sweden)

Šošić Gordana M.

2015-01-01

Full Text Available During the lifetime, people are constantly exposed to the chemicals and agents of exogenic and endogenic sources, which through reaction with a molecule of DNA can cause the damage of genomes and their instability. The formation of micronuclei is a consequence of chromosomal aberrations caused by the influence of different genetic and environmental factors. Micronuclei are cytoplasmic chromatin masses that look like small nuclei and can originate from whole or parts of chromosomes. Micronucleus test ( MN test is used to detect genotoxic effects of various chemical , physical or biological mutagens, as well as the test for determination of chromosomal instability in a variety of cell types. Micronucleus frequency is directly proportional to the degree of chromosomal aberrations. It has been shown that genome damage may occur as a result of environmental exposure to genotoxins and medical procedures, due to deficiency of micronutrients and under the influence of various lifestyles and genetic factors. Unbalanced diet, lack of physical exercise, lack of sleep and overwork contribute significantly to increased frequency of micronuclei. It was also shown that strenuous exercise causes DNA damage, which results in the formation of micronuclei. As a professional athlete conduct highly Intensive physical training, these populations are at risk for the development of genomic instability and carcinogenesis. A healthy lifestyle, the optimal intake of antioxidants and regular moderate physical activity significantly reduced the frequency of micronuclei, and contribute to the stability of the genome.

BCL9L Dysfunction Impairs Caspase-2 Expression Permitting Aneuploidy Tolerance in Colorectal Cancer

DEFF Research Database (Denmark)

López-García, Carlos; Sansregret, Laurent; Domingo, Enric

2016-01-01

Chromosomal instability (CIN) contributes to cancer evolution, intratumor heterogeneity, and drug resistance. CIN is driven by chromosome segregation errors and a tolerance phenotype that permits the propagation of aneuploid genomes. Through genomic analysis of colorectal cancers and cell lines, ...

Recurrent RECQL4 Imbalance and Increased Gene Expression Levels Are Associated with Structural Chromosomal Instability in Sporadic Osteosarcoma

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Georges Maire

2009-03-01

Full Text Available Osteosarcoma (OS is an aggressive bone tumor with complex abnormal karyotypes and a highly unstable genome, exhibiting both numerical- and structural-chromosomal instability (N- and S-CIN. Chromosomal rearrangements and genomic imbalances affecting 8q24 are frequent in OS. RECQL4 gene maps to this cytoband and encodes a putative helicase involved in the fidelity of DNA replication and repair. This protective genomic function of the protein is relevant because often patients with Rothmund-Thomson syndrome have constitutional mutations of RECQL4 and carry a very high risk of developing OS. To determine the relative level of expression of RECQL4 in OS, 18 sporadic tumors were studied by reverse transcription–polymerase chain reaction. All tumors overexpressed RECQL4 in comparison to control osteoblasts, and fluorescence in situ hybridization analysis of tumor DNA showed that expression levels were strongly copy number–dependent. Relative N- and S-CIN levels were determined by classifying copy number transitions within array comparative genomic hybridization profiles and by enumerating the frequency of break-apart fluorescence in situ hybridization within 8q24 using region-specific and control probes. Although there was no evidence that disruption of 8q24 in OS led to an elevated expression of RECQL4, there was a marked association between increased overall levels of S-CIN, determined by copy number transition frequency and higher levels of RECQL4.

Early embryonic chromosome instability results in stable mosaic pattern in human tissues.

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Hasmik Mkrtchyan

Full Text Available The discovery of copy number variations (CNV in the human genome opened new perspectives on the study of the genetic causes of inherited disorders and the aetiology of common diseases. Here, a single-cell-level investigation of CNV in different human tissues led us to uncover the phenomenon of mitotically derived genomic mosaicism, which is stable in different cell types of one individual. The CNV mosaic ratios were different between the 10 individuals studied. However, they were stable in the T lymphocytes, immortalized B lymphoblastoid cells, and skin fibroblasts analyzed in each individual. Because these cell types have a common origin in the connective tissues, we suggest that mitotic changes in CNV regions may happen early during embryonic development and occur only once, after which the stable mosaic ratio is maintained throughout the differentiated tissues. This concept is further supported by a unique study of immortalized B lymphoblastoid cell lines obtained with 20 year difference from two subjects. We provide the first evidence of somatic mosaicism for CNV, with stable variation ratios in different cell types of one individual leading to the hypothesis of early embryonic chromosome instability resulting in stable mosaic pattern in human tissues. This concept has the potential to open new perspectives in personalized genetic diagnostics and can explain genetic phenomena like diminished penetrance in autosomal dominant diseases. We propose that further genomic studies should focus on the single-cell level, to better understand the aetiology of aging and diseases mediated by somatic mutations.

Overexpression of the E2F target gene CENPI promotes chromosome instability and predicts poor prognosis in estrogen receptor-positive breast cancer.

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Thangavelu, Pulari U; Lin, Cheng-Yu; Vaidyanathan, Srividya; Nguyen, Thu H M; Dray, Eloise; Duijf, Pascal H G

2017-09-22

During cell division, chromosome segregation is facilitated by the mitotic checkpoint, or spindle assembly checkpoint (SAC), which ensures correct kinetochore-microtubule attachments and prevents premature sister-chromatid separation. It is well established that misexpression of SAC components on the outer kinetochores promotes chromosome instability (CIN) and tumorigenesis. Here, we study the expression of CENP-I, a key component of the HIKM complex at the inner kinetochores, in breast cancer, including ductal, lobular, medullary and male breast carcinomas. CENPI mRNA and protein levels are significantly elevated in estrogen receptor-positive (ER+) but not in estrogen receptor-negative (ER-) breast carcinoma. Well-established prognostic tests indicate that CENPI overexpression constitutes a powerful independent marker for poor patient prognosis and survival in ER+ breast cancer. We further demonstrate that CENPI is an E2F target gene. Consistently, it is overexpressed in RB1 -deficient breast cancers. However, CENP-I overexpression is not purely due to cell cycle-associated expression. In ER+ breast cancer cells, CENP-I overexpression promotes CIN, especially chromosome gains. In addition, in ER+ breast carcinomas the degree of CENPI overexpression is proportional to the level of aneuploidy and CENPI overexpression is one of the strongest markers for CIN identified to date. Our results indicate that overexpression of the inner kinetochore protein CENP-I promotes CIN and forecasts poor prognosis for ER+ breast cancer patients. These observations provide novel mechanistic insights and have important implications for breast cancer diagnostics and potentially therapeutic targeting.

A familial Cri-du-Chat/5p deletion syndrome resulted from rare maternal complex chromosomal rearrangements (CCRs and/or possible chromosome 5p chromothripsis.

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Heng Gu

Full Text Available Cri-du-Chat syndrome (MIM 123450 is a chromosomal syndrome characterized by the characteristic features, including cat-like cry and chromosome 5p deletions. We report a family with five individuals showing chromosomal rearrangements involving 5p, resulting from rare maternal complex chromosomal rearrangements (CCRs, diagnosed post- and pre-natally by comprehensive molecular and cytogenetic analyses. Two probands, including a 4½-year-old brother and his 2½-year- old sister, showed no diagnostic cat cry during infancy, but presented with developmental delay, dysmorphic and autistic features. Both patients had an interstitial deletion del(5(p13.3p15.33 spanning ≈ 26.22 Mb. The phenotypically normal mother had de novo CCRs involving 11 breakpoints and three chromosomes: ins(11;5 (q23;p14.1p15.31,ins(21;5(q21;p13.3p14.1,ins(21;5(q21;p15.31p15.33,inv(7(p22q32dn. In addition to these two children, she had three first-trimester miscarriages, two terminations due to the identification of the 5p deletion and one delivery of a phenotypically normal daughter. The unaffected daughter had the maternal ins(11;5 identified prenatally and an identical maternal allele haplotype of 5p. Array CGH did not detect any copy number changes in the mother, and revealed three interstitial deletions within 5p15.33-p13.3, in the unaffected daughter, likely products of the maternal insertions ins(21;5. Chromothripsis has been recently reported as a mechanism drives germline CCRs in pediatric patients with congenital defects. We postulate that the unique CCRs in the phenotypically normal mother could resulted from chromosome 5p chromothripsis, that further resulted in the interstitial 5p deletions in the unaffected daughter. Further high resolution sequencing based analysis is needed to determine whether chromothripsis is also present as a germline structural variation in phenotypically normal individuals in this family.

Molecular and cellular pathways associated with chromosome 1p deletions during colon carcinogenesis

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Payne CM

2011-05-01

Full Text Available Claire M Payne, Cheray Crowley-Skillicorn, Carol Bernstein, Hana Holubec, Harris BernsteinDepartment of Cell Biology and Anatomy, College of Medicine, University of Arizona Tucson, AZ, USAAbstract: Chromosomal instability is a major pathway of sporadic colon carcinogenesis. Chromosome arm 1p appears to be one of the “hot spots” in the non-neoplastic mucosa that, when deleted, is associated with the initiation of carcinogenesis. Chromosome arm 1p contains genes associated with DNA repair, spindle checkpoint function, apoptosis, multiple microRNAs, the Wnt signaling pathway, tumor suppression, antioxidant activities, and defense against environmental toxins. Loss of 1p is dangerous since it would likely contribute to genomic instability leading to tumorigenesis. The 1p deletion-associated colon carcinogenesis pathways are reviewed at the molecular and cellular levels. Sporadic colon cancer is strongly linked to a high-fat/low-vegetable/low-micronutrient, Western-style diet. We also consider how selected dietary-related compounds (eg, excess hydrophobic bile acids, and low levels of folic acid, niacin, plant-derived antioxidants, and other modulatory compounds might affect processes leading to chromosomal deletions, and to the molecular and cellular pathways specifically altered by chromosome 1p loss.Keywords: chromosome 1p, colon carcinogenesis, molecular pathways, cellular pathways

Loss of CDX2 Expression and Microsatellite Instability Are Prominent Features of Large Cell Minimally Differentiated Carcinomas of the Colon

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Hinoi, Takao; Tani, Masachika; Lucas, Peter C.; Caca, Karel; Dunn, Rodney L.; Macri¶, Ettore; Loda¶, Massimo; Appelman, Henry D.; Cho, Kathleen R.; Fearon, Eric R.

2001-01-01

Most large bowel cancers are moderately to well-differentiated adenocarcinomas comprised chiefly or entirely of glands lined by tall columnar cells. We have identified a subset of poorly differentiated colon carcinomas with a distinctive histopathological appearance that we term large cell minimally differentiated carcinomas (LCMDCs). These tumors likely include a group of poorly differentiated carcinomas previously described by others as medullary adenocarcinomas. To better understand the pathogenesis of these uncommon neoplasms, we compared molecular features of 15 LCMDCs to those present in 25 differentiated adenocarcinomas (DACs) of the colon. Tumors were examined for alterations commonly seen in typical colorectal carcinomas, including increased p53 and β-catenin immunoreactivity, K-ras gene mutations, microsatellite instability, and loss of heterozygosity of markers on chromosomes 5q, 17p, and 18q. In addition, tumors were evaluated by immunohistochemistry for CDX2, a homeobox protein whose expression in normal adult tissues is restricted to intestinal and colonic epithelium. Markedly reduced or absent CDX2 expression was noted in 13 of 15 (87%) LCMDCs, whereas only 1 of the 25 (4%) DACs showed reduced CDX2 expression (P < 0.001). Nine of 15 (60%) LCMDCs had the high-frequency microsatellite instability phenotype, but only 2 of 25 (8%) DACs had the high-frequency microsatellite instability phenotype (P = 0.002). Our findings provide support for the hypothesis that the molecular pathogenesis of LCMDCs is distinct from that of most DACs. CDX2 alterations and DNA mismatch repair defects have particularly prominent roles in the development of LCMDCs. PMID:11733373

Role of oxidative DNA damage in genome instability and cancer

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Bignami, M.; Kunkel, T.

2009-01-01

Inactivation of mismatch repair (MMR) is associated with a dramatic genomic instability that is observed experimentally as a mutator phenotype and micro satellite instability (MSI). It has been implicit that the massive genetic instability in MMR defective cells simply reflects the accumulation of spontaneous DNA polymerase errors during DNA replication. We recently identified oxidation damage, a common threat to DNA integrity to which purines are very susceptible, as an important cofactor in this genetic instability

Ring Chromosome 4 in a Child with Multiple Congenital Abnormalities: A Case Report and Review of the Literature

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C. S. Paththinige

2016-01-01

Full Text Available A female child born preterm with intrauterine growth retardation and presenting with facial dysmorphism with clefts, microcephaly, limb deformities, and congenital abnormalities involving cardiovascular and urinary systems is described. Chromosomal analysis showed a de novo 46,XX,r(4(p15.3q35 karyotype. The clinical features of the patient were compared with the phenotypic characteristics of 17 previously reported cases with ring chromosome 4 and those with Wolf-Hirschhorn syndrome (4p-. Clinical features observed in this case are consistent with the consensus phenotype in ring chromosome 4. Patent ductus arteriosus and bilateral talipes equinovarus observed in this baby widen the phenotypic spectrum associated with ring chromosome 4.

The Role of Dicentric Chromosome Formation and Secondary Centromere Deletion in the Evolution of Myeloid Malignancy

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MacKinnon, Ruth N.; Campbell, Lynda J.

2011-01-01

Dicentric chromosomes have been identified as instigators of the genome instability associated with cancer, but this instability is often resolved by one of a number of different secondary events. These include centromere inactivation, inversion, and intercentromeric deletion. Deletion or excision of one of the centromeres may be a significant occurrence in myeloid malignancy and other malignancies but has not previously been widely recognized, and our reports are the first describing centromere deletion in cancer cells. We review what is known about dicentric chromosomes and the mechanisms by which they can undergo stabilization in both constitutional and cancer genomes. The failure to identify centromere deletion in cancer cells until recently can be partly explained by the standard approaches to routine diagnostic cancer genome analysis, which do not identify centromeres in the context of chromosome organization. This hitherto hidden group of primary dicentric, secondary monocentric chromosomes, together with other unrecognized dicentric chromosomes, points to a greater role for dicentric chromosomes in cancer initiation and progression than is generally acknowledged. We present a model that predicts and explains a significant role for dicentric chromosomes in the formation of unbalanced translocations in malignancy. PMID:22567363

The Role of Dicentric Chromosome Formation and Secondary Centromere Deletion in the Evolution of Myeloid Malignancy

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Ruth N. MacKinnon

2011-01-01

Full Text Available Dicentric chromosomes have been identified as instigators of the genome instability associated with cancer, but this instability is often resolved by one of a number of different secondary events. These include centromere inactivation, inversion, and intercentromeric deletion. Deletion or excision of one of the centromeres may be a significant occurrence in myeloid malignancy and other malignancies but has not previously been widely recognized, and our reports are the first describing centromere deletion in cancer cells. We review what is known about dicentric chromosomes and the mechanisms by which they can undergo stabilization in both constitutional and cancer genomes. The failure to identify centromere deletion in cancer cells until recently can be partly explained by the standard approaches to routine diagnostic cancer genome analysis, which do not identify centromeres in the context of chromosome organization. This hitherto hidden group of primary dicentric, secondary monocentric chromosomes, together with other unrecognized dicentric chromosomes, points to a greater role for dicentric chromosomes in cancer initiation and progression than is generally acknowledged. We present a model that predicts and explains a significant role for dicentric chromosomes in the formation of unbalanced translocations in malignancy.

Genome instabilities arising from ribonucleotides in DNA.

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Klein, Hannah L

2017-08-01

Genomic DNA is transiently contaminated with ribonucleotide residues during the process of DNA replication through misincorporation by the replicative DNA polymerases α, δ and ε, and by the normal replication process on the lagging strand, which uses RNA primers. These ribonucleotides are efficiently removed during replication by RNase H enzymes and the lagging strand synthesis machinery. However, when ribonucleotides remain in DNA they can distort the DNA helix, affect machineries for DNA replication, transcription and repair, and can stimulate genomic instabilities which are manifest as increased mutation, recombination and chromosome alterations. The genomic instabilities associated with embedded ribonucleotides are considered here, along with a discussion of the origin of the lesions that stimulate particular classes of instabilities. Copyright © 2017 Elsevier B.V. All rights reserved.

Is there a genetic instability in A-bomb survivors' lymphocytes?

International Nuclear Information System (INIS)

Nakamura, Nori; Kodama, Yoshiaki; Awa, Akio

1997-01-01

Based on the reports that the genetic instability can be induced even by low LET radiation and that the instability can be essentially the cause of radiation carcinogenicity, data accumulated hitherto on the chromosome aberrations in A-bomb survivors were re-evaluated since it can be conceivable that there is still remaining a genetic instability in them. For a measure of biological radiation dose, translocation frequency was used and for genetic instability, dicentrics frequency. The relationship between those frequencies was analyzed in about 2500 survivors and showed either a saturable or linear one. For clear conclusion, additional studies on dicentrics frequency occurring in cultured lymphocytes from subjects who received various radiation doses would be necessary. (K.H.)

Selective cognitive impairment and tall stature due to chromosome 19 supernumerary ring.

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Melis, Daniela; Genesio, Rita; Del Giudice, Ennio; Taurisano, Roberta; Mormile, Angela; D'Elia, Federica; Conti, Anna; Imperati, Floriana; Andria, Generoso; Nitsch, Lucio

2012-01-01

Small supernumerary marker chromosomes (sSMC) occur with a frequency of approximately 0.4 per 1000 newborns and are more frequent in the population with mental retardation and/or with dysmorphic signs. Small supernumerary chromosome rings (sSCR) usually occur as apart of a mosaic karyotype (Liehr et al., 2004). Chromosome 19 supernumerary rings are very rare. Almost all cases of sSMC19 have been reported on Thomas Liehr's website (http://www.med.uni-jena.de/fish/sSMC/19.htm#Start19). Of these cases, 14 were with phenotypic abnormalities and a clear characterization of the sSMC; two cases were suitable for comparison with our case with regard to their genetic content, but not with regard to the structure ofthe sSMC (Manvelyan et al., 2008). The phenotype, associated with partial trisomy 19q, includes facial dysmorphism, growth and mental retardation, macrocephaly, heart malformation and anomalies of the genitourinary and gastrointestinal tracts. The phenotype associated with partial trisomy 19p is characterized by dysmorphic features, severe mental retardation, abnormalities of brain morphology and anomalies of the fingers (Tercanli et al., 2000; Qorri et al., 2002; Novelli et al., 2005; Vraneković et al., 2008). Herein, we report the phenotype and molecular cytogenetic analysis in a patient with the smallest de-novo constitutional ring extended from the p12 to q12 region of chromosome 19.

Genomic instability after targeted irradiation of human lymphocytes: Evidence for inter-individual differences under bystander conditions

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Kadhim, Munira A.; Lee, Ryonfa; Moore, Stephen R.; Macdonald, Denise A.; Chapman, Kim L.; Patel, Gaurang; Prise, Kevin M.

2010-01-01

Environmental 222 radon exposure is a human health concern, and many studies demonstrate that very low doses of high LET α-particle irradiation initiate deleterious genetic consequences in both irradiated and non-irradiated bystander cells. One consequence, radiation-induced genomic instability (RIGI), is a hallmark of tumorigenesis and is often assessed by measuring delayed chromosomal aberrations. We utilised a technique that facilitates transient immobilization of primary lymphocytes for targeted microbeam irradiation and have reported that environmentally relevant doses, e.g. a single 3 He 2+ particle traversal to a single cell, are sufficient to induce RIGI. Herein we sought to determine differences in radiation response in lymphocytes isolated from five healthy male donors. Primary lymphocytes were irradiated with a single particle per cell nucleus. We found evidence for inter-individual variation in radiation response (RIGI, measured as delayed chromosome aberrations). Although this was not highly significant, it was possibly masked by high levels of intra-individual variation. While there are many studies showing a link between genetic predisposition and RIGI, there are few studies linking genetic background with bystander effects in normal human lymphocytes. In an attempt to investigate inter-individual variation in the induction of bystander effects, primary lymphocytes were irradiated with a single particle under conditions where fractions of the population were traversed. We showed a marked genotype-dependent bystander response in one donor after exposure to 15% of the population. The findings may also be regarded as a radiation-induced genotype-dependent bystander effect triggering an instability phenotype.

Genomic instability after targeted irradiation of human lymphocytes: Evidence for inter-individual differences under bystander conditions

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Kadhim, Munira A., E-mail: mkadhim@brookes.ac.uk [School of Life Sciences, Oxford Brookes University, Oxford OX3 0BP (United Kingdom); Lee, Ryonfa [Biophysics, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, D-64291 Darmstadt (Germany); Moore, Stephen R.; Macdonald, Denise A. [Radiation and Genome Stability Unit, Medical Research Council, Harwell, Oxfordshire OX11 0RD (United Kingdom); Chapman, Kim L. [School of Life Sciences, Oxford Brookes University, Oxford OX3 0BP (United Kingdom); Patel, Gaurang; Prise, Kevin M. [Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Belfast BT9 7BL (United Kingdom)

2010-06-01

Environmental {sup 222}radon exposure is a human health concern, and many studies demonstrate that very low doses of high LET {alpha}-particle irradiation initiate deleterious genetic consequences in both irradiated and non-irradiated bystander cells. One consequence, radiation-induced genomic instability (RIGI), is a hallmark of tumorigenesis and is often assessed by measuring delayed chromosomal aberrations. We utilised a technique that facilitates transient immobilization of primary lymphocytes for targeted microbeam irradiation and have reported that environmentally relevant doses, e.g. a single {sup 3}He{sup 2+} particle traversal to a single cell, are sufficient to induce RIGI. Herein we sought to determine differences in radiation response in lymphocytes isolated from five healthy male donors. Primary lymphocytes were irradiated with a single particle per cell nucleus. We found evidence for inter-individual variation in radiation response (RIGI, measured as delayed chromosome aberrations). Although this was not highly significant, it was possibly masked by high levels of intra-individual variation. While there are many studies showing a link between genetic predisposition and RIGI, there are few studies linking genetic background with bystander effects in normal human lymphocytes. In an attempt to investigate inter-individual variation in the induction of bystander effects, primary lymphocytes were irradiated with a single particle under conditions where fractions of the population were traversed. We showed a marked genotype-dependent bystander response in one donor after exposure to 15% of the population. The findings may also be regarded as a radiation-induced genotype-dependent bystander effect triggering an instability phenotype.

Centromere Destiny in Dicentric Chromosomes: New Insights from the Evolution of Human Chromosome 2 Ancestral Centromeric Region.

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Chiatante, Giorgia; Giannuzzi, Giuliana; Calabrese, Francesco Maria; Eichler, Evan E; Ventura, Mario

2017-07-01

Dicentric chromosomes are products of genomic rearrangements that place two centromeres on the same chromosome. Due to the presence of two primary constrictions, they are inherently unstable and overcome their instability by epigenetically inactivating and/or deleting one of the two centromeres, thus resulting in functionally monocentric chromosomes that segregate normally during cell division. Our understanding to date of dicentric chromosome formation, behavior and fate has been largely inferred from observational studies in plants and humans as well as artificially produced de novo dicentrics in yeast and in human cells. We investigate the most recent product of a chromosome fusion event fixed in the human lineage, human chromosome 2, whose stability was acquired by the suppression of one centromere, resulting in a unique difference in chromosome number between humans (46 chromosomes) and our most closely related ape relatives (48 chromosomes). Using molecular cytogenetics, sequencing, and comparative sequence data, we deeply characterize the relicts of the chromosome 2q ancestral centromere and its flanking regions, gaining insight into the ancestral organization that can be easily broadened to all acrocentric chromosome centromeres. Moreover, our analyses offered the opportunity to trace the evolutionary history of rDNA and satellite III sequences among great apes, thus suggesting a new hypothesis for the preferential inactivation of some human centromeres, including IIq. Our results suggest two possible centromere inactivation models to explain the evolutionarily stabilization of human chromosome 2 over the last 5-6 million years. Our results strongly favor centromere excision through a one-step process. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Is early-onset microsatellite and chromosomally stable colorectal cancer a hallmark of a genetic susceptibility syndrome?

NARCIS (Netherlands)

Kets, C.M.; Krieken, J.H.J.M. van; Erp, P.E.J. van; Feuth, T.; Jacobs, Y.H.A.; Brunner, H.G.; Ligtenberg, M.J.L.; Hoogerbrugge, N.

2008-01-01

Most colorectal cancers show either microsatellite or chromosomal instability. A subset of colorectal cancers, especially those diagnosed at young age, is known to show neither of these forms of genetic instability and thus might have a distinct pathogenesis. Colorectal cancers diagnosed at young

Research for genetic instability of human genome

International Nuclear Information System (INIS)

Hori, T.; Takahashi, E.; Tsuji, H.; Yamauchi, M.; Murata, M.

1992-01-01

In the present review paper, the potential relevance of chromosomal fragile sites to carcinogenesis and mutagenesis is discussed based on our own and other's studies. Recent evidence indicate that fragile sites may act as predisposition factors involved in chromosomal instability of the human genome and that the sites may be preferential targets for various DNA damaging agents including ionizing radiation. It is also demonstrated that some critical genomic rearrangements at the fragile sites may contribute towards oncogenesis and that individuals carrying heritable form of fragile site may be at the risk. Although clinical significance of autosomal fragile sites has been a matter of discussion, a fragile site of the X chromosome is known to be associated with an X-linked genetic diseases, called fragile X syndrome. Molecular events leading to the fragile X syndrome have recently been elucidated. The fragile X genotype can be characterized by an increased amount of p(CCG)n repeat DNA sequence in the FMR-1 gene and the repeated sequences are shown to be unstable in both meiosis and mitosis. These repeats might exhibit higher mutation rate than is generally seen in the human genome. Further studies on the fragile sites in molecular biology and radiation biology will yield relevant data to the molecular mechanisms of genetic instability of the human genome as well as to better assessment of genetic effect of ionizing radiation. (author)

The inactive X chromosome is epigenetically unstable and transcriptionally labile in breast cancer.

Science.gov (United States)

Chaligné, Ronan; Popova, Tatiana; Mendoza-Parra, Marco-Antonio; Saleem, Mohamed-Ashick M; Gentien, David; Ban, Kristen; Piolot, Tristan; Leroy, Olivier; Mariani, Odette; Gronemeyer, Hinrich; Vincent-Salomon, Anne; Stern, Marc-Henri; Heard, Edith

2015-04-01

Disappearance of the Barr body is considered a hallmark of cancer, although whether this corresponds to genetic loss or to epigenetic instability and transcriptional reactivation is unclear. Here we show that breast tumors and cell lines frequently display major epigenetic instability of the inactive X chromosome, with highly abnormal 3D nuclear organization and global perturbations of heterochromatin, including gain of euchromatic marks and aberrant distributions of repressive marks such as H3K27me3 and promoter DNA methylation. Genome-wide profiling of chromatin and transcription reveal modified epigenomic landscapes in cancer cells and a significant degree of aberrant gene activity from the inactive X chromosome, including several genes involved in cancer promotion. We demonstrate that many of these genes are aberrantly reactivated in primary breast tumors, and we further demonstrate that epigenetic instability of the inactive X can lead to perturbed dosage of X-linked factors. Taken together, our study provides the first integrated analysis of the inactive X chromosome in the context of breast cancer and establishes that epigenetic erosion of the inactive X can lead to the disappearance of the Barr body in breast cancer cells. This work offers new insights and opens up the possibility of exploiting the inactive X chromosome as an epigenetic biomarker at the molecular and cytological levels in cancer. © 2015 Chaligné et al.; Published by Cold Spring Harbor Laboratory Press.

Protein kinase C zeta suppresses low- or high-grade colorectal cancer (CRC) phenotypes by interphase centrosome anchoring.

Science.gov (United States)

Deevi, Ravi Kiran; Javadi, Arman; McClements, Jane; Vohhodina, Jekaterina; Savage, Kienan; Loughrey, Maurice Bernard; Evergren, Emma; Campbell, Frederick Charles

2018-04-01

Histological grading provides prognostic stratification of colorectal cancer (CRC) by scoring heterogeneous phenotypes. Features of aggressiveness include aberrant mitotic spindle configurations, chromosomal breakage, and bizarre multicellular morphology, but pathobiology is poorly understood. Protein kinase C zeta (PKCz) controls mitotic spindle dynamics, chromosome segregation, and multicellular patterns, but its role in CRC phenotype evolution remains unclear. Here, we show that PKCz couples genome segregation to multicellular morphology through control of interphase centrosome anchoring. PKCz regulates interdependent processes that control centrosome positioning. Among these, interaction between the cytoskeletal linker protein ezrin and its binding partner NHERF1 promotes the formation of a localized cue for anchoring interphase centrosomes to the cell cortex. Perturbation of these phenomena induced different outcomes in cells with single or extra centrosomes. Defective anchoring of a single centrosome promoted bipolar spindle misorientation, multi-lumen formation, and aberrant epithelial stratification. Collectively, these disturbances induce cribriform multicellular morphology that is typical of some categories of low-grade CRC. By contrast, defective anchoring of extra centrosomes promoted multipolar spindle formation, chromosomal instability (CIN), disruption of glandular morphology, and cell outgrowth across the extracellular matrix interface characteristic of aggressive, high-grade CRC. Because PKCz enhances apical NHERF1 intensity in 3D epithelial cultures, we used an immunohistochemical (IHC) assay of apical NHERF1 intensity as an indirect readout of PKCz activity in translational studies. We show that apical NHERF1 IHC intensity is inversely associated with multipolar spindle frequency and high-grade morphology in formalin-fixed human CRC samples. To conclude, defective PKCz control of interphase centrosome anchoring may underlie distinct categories of

A Turner Syndrome Patient Carrying a Mosaic Distal X Chromosome Marker

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Roberto L. P. Mazzaschi

2014-01-01

Full Text Available A skin sample from a 17-year-old female was received for routine karyotyping with a set of clinical features including clonic seizures, cardiomyopathy, hepatic adenomas, and skeletal dysplasia. Conventional karyotyping revealed a mosaic Turner syndrome karyotype with a cell line containing a small marker of X chromosome origin. This was later confirmed on peripheral blood cultures by conventional G-banding, fluorescence in situ hybridisation and microarray analysis. Similar Turner mosaic marker chromosome cases have been previously reported in the literature, with a variable phenotype ranging from the mild “classic” Turner syndrome to anencephaly, agenesis of the corpus callosum, complex heart malformation, and syndactyly of the fingers and toes. This case report has a phenotype that is largely discordant with previously published cases as it lies at the severe end of the Turner variant phenotype scale. The observed cytogenetic abnormalities in this study may represent a coincidental finding, but we cannot exclude the possibility that the marker has a nonfunctioning X chromosome inactivation locus, leading to functional disomy of those genes carried by the marker.

Initiation of genome instability and preneoplastic processes through loss of Fhit expression.

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Joshua C Saldivar

Full Text Available Genomic instability drives tumorigenesis, but how it is initiated in sporadic neoplasias is unknown. In early preneoplasias, alterations at chromosome fragile sites arise due to DNA replication stress. A frequent, perhaps earliest, genetic alteration in preneoplasias is deletion within the fragile FRA3B/FHIT locus, leading to loss of Fhit protein expression. Because common chromosome fragile sites are exquisitely sensitive to replication stress, it has been proposed that their clonal alterations in cancer cells are due to stress sensitivity rather than to a selective advantage imparted by loss of expression of fragile gene products. Here, we show in normal, transformed, and cancer-derived cell lines that Fhit-depletion causes replication stress-induced DNA double-strand breaks. Using DNA combing, we observed a defect in replication fork progression in Fhit-deficient cells that stemmed primarily from fork stalling and collapse. The likely mechanism for the role of Fhit in replication fork progression is through regulation of Thymidine kinase 1 expression and thymidine triphosphate pool levels; notably, restoration of nucleotide balance rescued DNA replication defects and suppressed DNA breakage in Fhit-deficient cells. Depletion of Fhit did not activate the DNA damage response nor cause cell cycle arrest, allowing continued cell proliferation and ongoing chromosomal instability. This finding was in accord with in vivo studies, as Fhit knockout mouse tissue showed no evidence of cell cycle arrest or senescence yet exhibited numerous somatic DNA copy number aberrations at replication stress-sensitive loci. Furthermore, cells established from Fhit knockout tissue showed rapid immortalization and selection of DNA deletions and amplifications, including amplification of the Mdm2 gene, suggesting that Fhit loss-induced genome instability facilitates transformation. We propose that loss of Fhit expression in precancerous lesions is the first step in the

Human MLH1 suppresses the insertion of telomeric sequences at intra-chromosomal sites in telomerase-expressing cells

Science.gov (United States)

Jia, Pingping; Chastain, Megan; Zou, Ying; Her, Chengtao

2017-01-01

Abstract Aberrant formation of interstitial telomeric sequences (ITSs) promotes genome instabilities. However, it is unclear how aberrant ITS formation is suppressed in human cells. Here, we report that MLH1, a key protein involved in mismatch repair (MMR), suppresses telomeric sequence insertion (TSI) at intra-chromosomal regions. The frequency of TSI can be elevated by double-strand break (DSB) inducer and abolished by ATM/ATR inhibition. Suppression of TSI requires MLH1 recruitment to DSBs, indicating that MLH1's role in DSB response/repair is important for suppressing TSI. Moreover, TSI requires telomerase activity but is independent of the functional status of p53 and Rb. Lastly, we show that TSI is associated with chromosome instabilities including chromosome loss, micronuclei formation and chromosome breakage that are further elevated by replication stress. Our studies uncover a novel link between MLH1, telomerase, telomere and genome stability. PMID:28180301

Exceptional Complex Chromosomal Rearrangements in Three Generations

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Hannie Kartapradja

2015-01-01

Full Text Available We report an exceptional complex chromosomal rearrangement (CCR found in three individuals in a family that involves 4 chromosomes with 5 breakpoints. The CCR was ascertained in a phenotypically abnormal newborn with additional chromosomal material on the short arm of chromosome 4. Maternal karyotyping indicated that the mother carried an apparently balanced CCR involving chromosomes 4, 6, 11, and 18. Maternal transmission of the derivative chromosome 4 resulted in partial trisomy for chromosomes 6q and 18q and a partial monosomy of chromosome 4p in the proband. Further family studies found that the maternal grandmother carried the same apparently balanced CCR as the proband’s mother, which was confirmed using the whole chromosome painting (WCP FISH. High resolution whole genome microarray analysis of DNA from the proband’s mother found no evidence for copy number imbalance in the vicinity of the CCR translocation breakpoints, or elsewhere in the genome, providing evidence that the mother’s and grandmother’s CCRs were balanced at a molecular level. This structural rearrangement can be categorized as an exceptional CCR due to its complexity and is a rare example of an exceptional CCR being transmitted in balanced and/or unbalanced form across three generations.

Knockdown of μ-calpain in Fanconi Anemia, FA-A, cells by siRNA Restores αII Spectrin levels and Corrects Chromosomal Instability and Defective DNA Interstrand Cross-link Repair†

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Zhang, Pan; Sridharan, Deepa; Lambert, Muriel W.

2010-01-01

We have previously shown that there is a deficiency in the structural protein, nonerythroid α spectrin (αIISp), in cells from patients with Fanconi anemia (FA). These studies indicate that this deficiency is due to reduced stability of αIISp and correlates with decreased repair of DNA interstrand cross-links and chromosomal instability in FA cells. An important factor in the stability of αIISp is its susceptibility to cleavage by the protease, μ-calpain. We hypothesized that increased μ-calpa...

A unique mosaic Turner syndrome patient with androgen receptor gene derived marker chromosome.

Science.gov (United States)

Kalkan, Rasime; Özdağ, Nermin; Bundak, Rüveyde; Çirakoğlu, Ayşe; Serakinci, Nedime

2016-01-01

Patients with Turner syndrome are generally characterized by having short stature with no secondary sexual characteristics. Some abnormalities, such as webbed neck, renal malformations (>50%) and cardiac defects (10%) are less common. The intelligence of these patients is considered normal. Non-mosaic monosomy X is observed in approximately 45% of postnatal patients with Turner syndrome and the rest of the patients have structural abnormalities or mosaicism involving 46,X,i(Xq), 45,X/46,XX, 45,X and other variants. The phenotype of 45,X/46,X,+mar individuals varies by the genetic continent and degree of the mosaicism. The gene content of the marker chromosome is the most important when correlating the phenotype with the genotype. Here we present an 11-year-old female who was referred for evaluation of her short stature and learning disabilities. Conventional cytogenetic investigation showed a mosaic 45,X/46,X,+mar karyotype. Fluorescence in situ hybridization showed that the marker chromosome originated from the X chromosome within the androgen receptor (AR) and X-inactive specific transcript (XIST) genes. Therefore, it is possible that aberrant activation of the marker chromosome, compromising the AR and XIST genes, may modify the Turner syndrome phenotype.

Model selection emphasises the importance of non-chromosomal information in genetic studies.

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Reda Rawi

Full Text Available Ever since the case of the missing heritability was highlighted some years ago, scientists have been investigating various possible explanations for the issue. However, none of these explanations include non-chromosomal genetic information. Here we describe explicitly how chromosomal and non-chromosomal modifiers collectively influence the heritability of a trait, in this case, the growth rate of yeast. Our results show that the non-chromosomal contribution can be large, adding another dimension to the estimation of heritability. We also discovered, combining the strength of LASSO with model selection, that the interaction of chromosomal and non-chromosomal information is essential in describing phenotypes.

Phenotypic and genetic heterogeneity in a genome-wide linkage study of asthma families

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Schuster Antje

2005-01-01

Full Text Available Abstract Background Asthma is a complex genetic disease with more than 20 genome-wide scans conducted so far. Regions on almost every chromosome have been linked to asthma and several genes have been associated. However, most of these associations are weak and are still awaiting replication. Methods In this study, we conducted a second-stage genome-wide scan with 408 microsatellite markers on 201 asthma-affected sib pair families and defined clinical subgroups to identify phenotype-genotype relations. Results The lowest P value for asthma in the total sample was 0.003 on chromosome 11, while several of the clinical subsets reached lower significance levels than in the overall sample. Suggestive evidence for linkage (p = 0.0007 was found for total IgE on chromosomes 1, 7 and again on chromosome 11, as well as for HDM asthma on chromosome 12. Weaker linkage signals could be found on chromosomes 4 and 5 for early onset and HDM, and, newly described, on chromosome 2 for severe asthma and on chromosome 9 for hay fever. Conclusions This phenotypic dissection underlines the importance of detailed clinical characterisations and the extreme genetic heterogeneity of asthma.

[Diagnosis of a case with Williams-Beuren syndrome with nephrocalcinosis using chromosome microarray analysis].

Science.gov (United States)

Jin, S J; Liu, M; Long, W J; Luo, X P

2016-12-02

Objective: To explore the clinical phenotypes and the genetic cause for a boy with unexplained growth retardation, nephrocalcinosis, auditory anomalies and multi-organ/system developmental disorders. Method: Routine G-banding and chromosome microarray analysis were applied to a child with unexplained growth retardation, nephrocalcinosis, auditory anomalies and multi-organ/system developmental disorders treated in the Department of Pediatrics of Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology in September 2015 and his parents to conduct the chromosomal karyotype analysis and the whole genome scanning. Deleted genes were searched in the Decipher and NCBI databases, and their relationships with the clinical phenotypes were analyzed. Result: A six-month-old boy was refered to us because of unexplained growth retardation and feeding intolerance.The affected child presented with abnormal manifestation such as special face, umbilical hernia, growth retardation, hypothyroidism, congenital heart disease, right ear sensorineural deafness, hypercalcemia and nephrocalcinosis. The child's karyotype was 46, XY, 16qh + , and his parents' karyotypes were normal. Chromosome microarray analysis revealed a 1 436 kb deletion on the 7q11.23(72701098_74136633) region of the child. This region included 23 protein-coding genes, which were reported to be corresponding to Williams-Beuren syndrome and its certain clinical phenotypes. His parents' results of chromosome microarray analysis were normal. Conclusion: A boy with characteristic manifestation of Williams-Beuren syndrome and rare nephrocalcinosis was diagnosed using chromosome microarray analysis. The deletion on the 7q11.23 might be related to the clinical phenotypes of Williams-Beuren syndrome, yet further studies are needed.

Research for genetic instability of human genome

Energy Technology Data Exchange (ETDEWEB)

Hori, T.; Takahashi, E.; Tsuji, H.; Yamauchi, M. (National Inst. of Radiological Sciences, Chiba (Japan)); Murata, M.

1992-01-01

In the present review paper, the potential relevance of chromosomal fragile sites to carcinogenesis and mutagenesis is discussed based on our own and other's studies. Recent evidence indicate that fragile sites may act as predisposition factors involved in chromosomal instability of the human genome and that the sites may be preferential targets for various DNA damaging agents including ionizing radiation. It is also demonstrated that some critical genomic rearrangements at the fragile sites may contribute towards oncogenesis and that individuals carrying heritable form of fragile site may be at the risk. Although clinical significance of autosomal fragile sites has been a matter of discussion, a fragile site of the X chromosome is known to be associated with an X-linked genetic diseases, called fragile X syndrome. Molecular events leading to the fragile X syndrome have recently been elucidated. The fragile X genotype can be characterized by an increased amount of p(CCG)n repeat DNA sequence in the FMR-1 gene and the repeated sequences are shown to be unstable in both meiosis and mitosis. These repeats might exhibit higher mutation rate than is generally seen in the human genome. Further studies on the fragile sites in molecular biology and radiation biology will yield relevant data to the molecular mechanisms of genetic instability of the human genome as well as to better assessment of genetic effect of ionizing radiation. (author).

Asymmetric Centriole Numbers at Spindle Poles Cause Chromosome Missegregation in Cancer

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Marco R. Cosenza

2017-08-01

Full Text Available Chromosomal instability is a hallmark of cancer and correlates with the presence of extra centrosomes, which originate from centriole overduplication. Overduplicated centrioles lead to the formation of centriole rosettes, which mature into supernumerary centrosomes in the subsequent cell cycle. While extra centrosomes promote chromosome missegregation by clustering into pseudo-bipolar spindles, the contribution of centriole rosettes to chromosome missegregation is unknown. We used multi-modal imaging of cells with conditional centriole overduplication to show that mitotic rosettes in bipolar spindles frequently harbor unequal centriole numbers, leading to biased chromosome capture that favors binding to the prominent pole. This results in chromosome missegregation and aneuploidy. Rosette mitoses lead to viable offspring and significantly contribute to progeny production. We further show that centrosome abnormalities in primary human malignancies frequently consist of centriole rosettes. As asymmetric centriole rosettes generate mitotic errors that can be propagated, rosette mitoses are sufficient to cause chromosome missegregation in cancer.

Chromosomal islands of Streptococcus pyogenes and related streptococci: molecular switches for survival and virulence.

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Nguyen, Scott V; McShan, William M

2014-01-01

Streptococcus pyogenes is a significant pathogen of humans, annually causing over 700,000,000 infections and 500,000 deaths. Virulence in S. pyogenes is closely linked to mobile genetic elements like phages and chromosomal islands (CI). S. pyogenes phage-like chromosomal islands (SpyCI) confer a complex mutator phenotype on their host. SpyCI integrate into the 5' end of DNA mismatch repair (MMR) gene mutL, which also disrupts downstream operon genes lmrP, ruvA, and tag. During early logarithmic growth, SpyCI excise from the bacterial chromosome and replicate as episomes, relieving the mutator phenotype. As growth slows and the cells enter stationary phase, SpyCI reintegrate into the chromosome, again silencing the MMR operon. This system creates a unique growth-dependent and reversible mutator phenotype. Additional CI using the identical attachment site in mutL have been identified in related species, including Streptococcus dysgalactiae subsp. equisimilis, Streptococcus anginosus, Streptococcus intermedius, Streptococcus parauberis, and Streptococcus canis. These CI have small genomes, which range from 13 to 20 kB, conserved integrase and DNA replication genes, and no identifiable genes encoding capsid proteins. SpyCI may employ a helper phage for packaging and dissemination in a fashion similar to the Staphylococcus aureus pathogenicity islands (SaPI). Outside of the core replication and integration genes, SpyCI and related CI show considerable diversity with the presence of many indels that may contribute to the host cell phenotype or fitness. SpyCI are a subset of a larger family of streptococcal CI who potentially regulate the expression of other host genes. The biological and phylogenetic analysis of streptococcal chromosomal islands provides important clues as to how these chromosomal islands help S. pyogenes and other streptococcal species persist in human populations in spite of antibiotic therapy and immune challenges.

Is early-onset microsatellite and chromosomally stable colorectal cancer a hallmark of a genetic susceptibility syndrome?

Science.gov (United States)

Kets, C M; van Krieken, J H J M; van Erp, P E J; Feuth, T; Jacobs, Y H A; Brunner, H G; Ligtenberg, M J L; Hoogerbrugge, N

2008-02-15

Most colorectal cancers show either microsatellite or chromosomal instability. A subset of colorectal cancers, especially those diagnosed at young age, is known to show neither of these forms of genetic instability and thus might have a distinct pathogenesis. Colorectal cancers diagnosed at young age are suggestive for hereditary predisposition. We investigate whether such early-onset microsatellite and chromosomally stable colorectal cancers are a hallmark of a genetic susceptibility syndrome. The ploidy status of microsatellite stable (familial) colorectal cancers of patients diagnosed before age 50 (n = 127) was analyzed in relation to the histopathological characteristics and family history. As a control the ploidy status of sporadic colorectal cancer, with normal staining of mismatch repair proteins, diagnosed at the age of 69 years or above (n = 70) was determined. A diploid DNA content was used as a marker for chromosomal stability. Within the group of patients with (familial) early onset microsatellite stable colorectal cancer the chromosomally stable tumors did not differ from chromosomally unstable tumors with respect to mean age at diagnosis, fulfillment of Amsterdam criteria or pathological characteristics. Segregation analysis did not reveal any family with microsatellite and chromosomally stable colorectal cancer in 2 relatives. The prevalence of microsatellite and chromosomally stable colorectal cancer was not significantly different for the early and late onset group (28 and 21%, respectively). We find no evidence that early-onset microsatellite and chromosomally stable colorectal cancer is a hallmark of a hereditary colorectal cancer syndrome. (c) 2007 Wiley-Liss, Inc.

Clinical spectrum of immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome).

NARCIS (Netherlands)

Hagleitner, M.M.; Lankester, A.; Maraschio, P.; Hulten, M.; Fryns, J.P.; Schuetz, C.; Gimelli, G.; Davies, E.G.; Gennery, A.R.; Belohradsky, B.H.; Groot, R. de; Gerritsen, E.J.; Mattina, T.; Howard, P.J.; Fasth, A.; Reisli, I.; Furthner, D.; Slatter, M.A.; Cant, A.J.; Cazzola, G.; Dijken, P.J. van; Deuren, M. van; Greef, J.C. de; Maarel, S.M. van der; Weemaes, C.M.R.

2008-01-01

BACKGROUND: Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a

Widespread over-expression of the X chromosome in sterile F₁hybrid mice.

Directory of Open Access Journals (Sweden)

Jeffrey M Good

2010-09-01

Full Text Available The X chromosome often plays a central role in hybrid male sterility between species, but it is unclear if this reflects underlying regulatory incompatibilities. Here we combine phenotypic data with genome-wide expression data to directly associate aberrant expression patterns with hybrid male sterility between two species of mice. We used a reciprocal cross in which F₁ males are sterile in one direction and fertile in the other direction, allowing us to associate expression differences with sterility rather than with other hybrid phenotypes. We found evidence of extensive over-expression of the X chromosome during spermatogenesis in sterile but not in fertile F₁ hybrid males. Over-expression was most pronounced in genes that are normally expressed after meiosis, consistent with an X chromosome-wide disruption of expression during the later stages of spermatogenesis. This pattern was not a simple consequence of faster evolutionary divergence on the X chromosome, because X-linked expression was highly conserved between the two species. Thus, transcriptional regulation of the X chromosome during spermatogenesis appears particularly sensitive to evolutionary divergence between species. Overall, these data provide evidence for an underlying regulatory basis to reproductive isolation in house mice and underscore the importance of transcriptional regulation of the X chromosome to the evolution of hybrid male sterility.

Widespread over-expression of the X chromosome in sterile F₁hybrid mice.

Science.gov (United States)

Good, Jeffrey M; Giger, Thomas; Dean, Matthew D; Nachman, Michael W

2010-09-30

The X chromosome often plays a central role in hybrid male sterility between species, but it is unclear if this reflects underlying regulatory incompatibilities. Here we combine phenotypic data with genome-wide expression data to directly associate aberrant expression patterns with hybrid male sterility between two species of mice. We used a reciprocal cross in which F₁ males are sterile in one direction and fertile in the other direction, allowing us to associate expression differences with sterility rather than with other hybrid phenotypes. We found evidence of extensive over-expression of the X chromosome during spermatogenesis in sterile but not in fertile F₁ hybrid males. Over-expression was most pronounced in genes that are normally expressed after meiosis, consistent with an X chromosome-wide disruption of expression during the later stages of spermatogenesis. This pattern was not a simple consequence of faster evolutionary divergence on the X chromosome, because X-linked expression was highly conserved between the two species. Thus, transcriptional regulation of the X chromosome during spermatogenesis appears particularly sensitive to evolutionary divergence between species. Overall, these data provide evidence for an underlying regulatory basis to reproductive isolation in house mice and underscore the importance of transcriptional regulation of the X chromosome to the evolution of hybrid male sterility.

Characterization of the chromosomal inversion associated with the Koa mutation in the mouse revealed the cause of skeletal abnormalities

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Suzuki Hiroetsu

2009-09-01

Full Text Available Abstract Background Koala (Koa is a dominant mutation in mice causing bushy muzzle and pinna, and is associated with a chromosomal inversion on the distal half of chromosome 15. To identify the gene responsible for the Koa phenotypes, we investigated phenotypes of Koa homozygous mice and determined the breakpoints of the inversion with a genetic method using recombination between two different chromosomal inversions. Results Skeletal preparation of Koa homozygotes showed marked deformity of the ribs and a wider skull with extended zygomatic arches, in addition to a general reduction in the lengths of long bones. They also had open eyelids at birth caused by a defect in the extension of eyelid anlagen during the embryonic stages. The proximal and distal breakpoints of the Koa inversion were determined to be 0.8-Mb distal to the Trsps1 gene and to 0.1-Mb distal to the Hoxc4 gene, respectively, as previously reported. The phenotypes of mice with the recombinant inverted chromosomes revealed the localization of the gene responsible the Koa phenotype in the vicinity of the proximal recombinant breakpoint. Expression of the Trsps1 gene in this region was significantly reduced in the Koa homozygous and heterozygous embryos. Conclusion While no gene was disrupted by the chromosomal inversion, an association between the Koa phenotype and the proximal recombinant breakpoint, phenotypic similarities with Trps1-deficient mice or human patients with TRSP1 mutations, and the reduced expression of the Trsps1 gene in Koa mice, indicated that the phenotypes of the Koa mice are caused by the altered expression of the Trps1 gene.

The FANC pathway and BLM collaborate during mitosis to prevent micro-nucleation and chromosome abnormalities.

Science.gov (United States)

Naim, Valeria; Rosselli, Filippo

2009-06-01

Loss-of-function of caretaker genes characterizes a group of cancer predisposition diseases that feature cellular hypersensitivity to DNA damage and chromosome fragility; this group includes Fanconi anaemia and Bloom syndrome. The products of the 13 FANC genes (mutated in Fanconi anaemia), which constitute the 'FANC' pathway, and BLM (the RecQ helicase mutated in Bloom syndrome) are thought to collaborate during the S phase of the cell cycle, preventing chromosome instability. Recently, BLM has been implicated in the completion of sister chromatid separation during mitosis, a complex process in which precise regulation and execution is crucial to preserve genomic stability. Here we show for the first time a role for the FANC pathway in chromosome segregation during mitotic cell division. FANCD2, a key component of the pathway, localizes to discrete spots on mitotic chromosomes. FANCD2 chromosomal localization is responsive to replicative stress and specifically targets aphidicolin (APH)-induced chromatid gaps and breaks. Our data indicate that the FANC pathway is involved in rescuing abnormal anaphase and telophase (ana-telophase) cells, limiting aneuploidy and reducing chromosome instability in daughter cells. We further address a cooperative role for the FANC pathway and BLM in preventing micronucleation, through FANC-dependent targeting of BLM to non-centromeric abnormal structures induced by replicative stress. We reveal new crosstalk between FANC and BLM proteins, extending their interaction beyond the S-phase rescue of damaged DNA to the safeguarding of chromosome stability during mitosis.

Predictable Phenotypes of Antibiotic Resistance Mutations.

Science.gov (United States)

Knopp, M; Andersson, D I

2018-05-15

Antibiotic-resistant bacteria represent a major threat to our ability to treat bacterial infections. Two factors that determine the evolutionary success of antibiotic resistance mutations are their impact on resistance level and the fitness cost. Recent studies suggest that resistance mutations commonly show epistatic interactions, which would complicate predictions of their stability in bacterial populations. We analyzed 13 different chromosomal resistance mutations and 10 host strains of Salmonella enterica and Escherichia coli to address two main questions. (i) Are there epistatic interactions between different chromosomal resistance mutations? (ii) How does the strain background and genetic distance influence the effect of chromosomal resistance mutations on resistance and fitness? Our results show that the effects of combined resistance mutations on resistance and fitness are largely predictable and that epistasis remains rare even when up to four mutations were combined. Furthermore, a majority of the mutations, especially target alteration mutations, demonstrate strain-independent phenotypes across different species. This study extends our understanding of epistasis among resistance mutations and shows that interactions between different resistance mutations are often predictable from the characteristics of the individual mutations. IMPORTANCE The spread of antibiotic-resistant bacteria imposes an urgent threat to public health. The ability to forecast the evolutionary success of resistant mutants would help to combat dissemination of antibiotic resistance. Previous studies have shown that the phenotypic effects (fitness and resistance level) of resistance mutations can vary substantially depending on the genetic context in which they occur. We conducted a broad screen using many different resistance mutations and host strains to identify potential epistatic interactions between various types of resistance mutations and to determine the effect of strain

The inactive X chromosome is epigenetically unstable and transcriptionally labile in breast cancer

OpenAIRE

Chaligné, Ronan; Popova, Tatiana; Mendoza-Parra, Marco-Antonio; Saleem, Mohamed-Ashick M.; Gentien, David; Ban, Kristen; Piolot, Tristan; Leroy, Olivier; Mariani, Odette; Gronemeyer, Hinrich; Vincent-Salomon, Anne; Stern, Marc-Henri; Heard, Edith

2015-01-01

Disappearance of the Barr body is considered a hallmark of cancer, although whether this corresponds to genetic loss or to epigenetic instability and transcriptional reactivation is unclear. Here we show that breast tumors and cell lines frequently display major epigenetic instability of the inactive X chromosome, with highly abnormal 3D nuclear organization and global perturbations of heterochromatin, including gain of euchromatic marks and aberrant distributions of repressive marks such as ...

Comparative genomics reveals mobile pathogenicity chromosomes in Fusarium

Energy Technology Data Exchange (ETDEWEB)

Ma, Li Jun; van der Does, H. C.; Borkovich, Katherine A.; Coleman, Jeffrey J.; Daboussi, Marie-Jose; Di Pietro, Antonio; Dufresne, Marie; Freitag, Michael; Grabherr, Manfred; Henrissat, Bernard; Houterman, Petra M.; Kang, Seogchan; Shim, Won-Bo; Wolochuk, Charles; Xie, Xiaohui; Xu, Jin Rong; Antoniw, John; Baker, Scott E.; Bluhm, Burton H.; Breakspear, Andrew; Brown, Daren W.; Butchko, Robert A.; Chapman, Sinead; Coulson, Richard; Coutinho, Pedro M.; Danchin, Etienne G.; Diener, Andrew; Gale, Liane R.; Gardiner, Donald; Goff, Steven; Hammond-Kossack, Kim; Hilburn, Karen; Hua-Van, Aurelie; Jonkers, Wilfried; Kazan, Kemal; Kodira, Chinnappa D.; Koehrsen, Michael; Kumar, Lokesh; Lee, Yong Hwan; Li, Liande; Manners, John M.; Miranda-Saavedra, Diego; Mukherjee, Mala; Park, Gyungsoon; Park, Jongsun; Park, Sook Young; Proctor, Robert H.; Regev, Aviv; Ruiz-Roldan, M. C.; Sain, Divya; Sakthikumar, Sharadha; Sykes, Sean; Schwartz, David C.; Turgeon, Barbara G.; Wapinski, Ilan; Yoder, Olen; Young, Sarah; Zeng, Qiandong; Zhou, Shiguo; Galagan, James; Cuomo, Christina A.; Kistler, H. Corby; Rep, Martijn

2010-03-18

Fusarium species are among the most important phytopathogenic and toxigenic fungi, having significant impact on crop production and animal health. Distinctively, members of the F. oxysporum species complex exhibit wide host range but discontinuously distributed host specificity, reflecting remarkable genetic adaptability. To understand the molecular underpinnings of diverse phenotypic traits and their evolution in Fusarium, we compared the genomes of three economically important and phylogenetically related, yet phenotypically diverse plant-pathogenic species, F. graminearum, F. verticillioides and F. oxysporum f. sp. lycopersici. Our analysis revealed greatly expanded lineage-specific (LS) genomic regions in F. oxysporum that include four entire chromosomes, accounting for more than one-quarter of the genome. LS regions are rich in transposons and genes with distinct evolutionary profiles but related to pathogenicity. Experimentally, we demonstrate for the first time the transfer of two LS chromosomes between strains of F. oxysporum, resulting in the conversion of a non-pathogenic strain into a pathogen. Transfer of LS chromosomes between otherwise genetically isolated strains explains the polyphyletic origin of host specificity and the emergence of new pathogenic lineages in the F. oxysporum species complex, putting the evolution of fungal pathogenicity into a new perspective.

Aplastic Anemia in Two Patients with Sex Chromosome Aneuploidies.

Science.gov (United States)

Rush, Eric T; Schaefer, G Bradley; Sanger, Warren G; Coccia, Peter F

2015-01-01

Sex chromosome aneuploidies range in incidence from rather common to exceedingly rare and have a variable phenotype. We report 2 patients with sex chromosome aneuploidies who developed severe aplastic anemia requiring treatment. The first patient had tetrasomy X (48,XXXX) and presented at 9 years of age, and the second patient had trisomy X (47,XXX) and presented at 5 years of age. Although aplastic anemia has been associated with other chromosomal abnormalities, sex chromosome abnormalities have not been traditionally considered a risk factor for this condition. A review of the literature reveals that at least one other patient with a sex chromosome aneuploidy (45,X) has suffered from aplastic anemia and that other autosomal chromosomal anomalies have been described. Despite the uncommon nature of each condition, it is possible that the apparent association is coincidental. A better understanding of the genetic causes of aplastic anemia remains important. © 2015 S. Karger AG, Basel.

Chromosomal localization of microsatellite loci in Drosophila mediopunctata

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Renato Cavasini

2015-03-01

Full Text Available Drosophila mediopunctata has been used as a model organism for genetics and evolutionary studies in the last three decades. A linkage map with 48 microsatellite loci recently published for this species showed five syntenic groups, which had their homology determined to Drosophila melanogaster chromosomes. Then, by inference, each of the groups was associated with one of the five major chromosomes of D. mediopunctata. Our objective was to carry out a genetic (chromosomal analysis to increase the number of available loci with known chromosomal location. We made a simultaneous analysis of visible mutant phenotypes and microsatellite genotypes in a backcross of a standard strain and a mutant strain, which had each major autosome marked. Hence, we could establish the chromosomal location of seventeen loci; including one from each of the five major linkage groups previously published, and twelve new loci. Our results were congruent with the previous location and they open new possibilities to future work integrating microsatellites, chromosomal inversions, and genetic determinants of physiological and morphological variation.

Determination of chromosomes that control physiological traits ...

African Journals Online (AJOL)

Determination of chromosomes that control physiological traits associated with salt tolerance in barley at the seedling stage. ... The phenotypic traits under study included: chlorophyll contents, chlorophyll fluorescence (Fo, Fv, Fv/Fm), proline and carbohydrate rates, relative water content (RWC) and dry and wet weight of ...

Chromosome polymorphism in a population of ceratitis capitata

International Nuclear Information System (INIS)

Lifschitz, E.

1987-08-01

A morphological chromosomal polymorphism along with the observation of B chromosomes in a natural population of Ceratitis capitata is reported. A variability affecting the centromere size of chromosome 3 is described. The observed B chromosome is minute, heterochromatic and telocentric. The B chromosome was found in the male and female germ cells and it exhibited, in the males, intra-individual numerical variation with OB and IB cells, which suggested a mitotic instability. It was also found, in both sexes, in somatic cells (cerebral ganglia tissue). Only males transmitted the B chromosomes to the progeny. The high rate of transmission suggested a differential utilization of the sperm carrying the B chromosomes or a preferential segregation into secondary spermatocytes. Previously reported linkage relationship between a pupal esterase gene (Est-1) and a pupa colour mutant (nig) has been extended to a line carrying a Y-chromosome (Y,B) shorter than the one previously studied (Y,A). Furthermore, an elaborate crossing scheme has been devised in order to estimate the recombination distances between these two genes and a third one affecting pupal length (lp-1). It is concluded that all three genes are in the same linkage group but Est-1 is far from the other two. In turn, nig and lp-1 are separated by 14.9 map units. It is confirmed that genetic recombination does not regularly occur at high frequency in the male and this frequency is not increased by the varying length of the Y-chromosome. Refs, figs, tabs

Reproductive history of a healthy woman with mosaic duplication of chromosome 4p.

Science.gov (United States)

Bernardini, Laura; Sinibaldi, Lorenzo; Ceccarini, Caterina; Novelli, Antonio; Dallapiccola, Bruno

2005-04-01

Mosaic autosomal duplications are rare and often result in mental retardation and congenital anomalies. Phenotype is not predictable depending on the chromosomal imbalance involved and the percentage and tissues distribution of unbalanced cells. We report on a young woman carrying a mosaic duplication of chromosome 4p, evaluated because of three abortions due to IUGR and fetal malformation. Mosaic dup(4p) was detected by standard and molecular cytogenetics. Unbalanced cells accounted for about 20 to 30% of nuclei in four examined tissues and did not cause any obvious phenotypic effect. It is likely that mosaic duplications are underascertained because they are not associated with obvious clinical effects in some individuals. Prenatal diagnosis is the method of choice to predict the karyotype in the offspring of subjects carrying mosaic chromosome imbalances.

Constitutional chromosome anomalies in patients with cerebral gigantism (Sotos syndrome).

Science.gov (United States)

Haeusler, G; Guchev, Z; Köhler, I; Schober, E; Haas, O; Frisch, H

1993-01-01

Two boys are presented with the clinical features of cerebral gigantism and chromosomal variants which have not been described so far in this syndrome. In the first boy a de novo pericentric inversion of chromosome Y was found, the karyotypes of all other investigated family members were normal. The patient had an obstructive hypertrophic cardiomyopathy and atrial septal defect type II. The second boy had inherited pericentric inversion of the heterochromatic region of chromosome 9 from his mother. This chromosome 9 variant was also found in his sister who had a similar phenotype but without gigantism. Endocrine evaluation demonstrated normal results in both boys. The intellectual achievement in both cases was average.

Widespread Over-Expression of the X Chromosome in Sterile F1 Hybrid Mice

Science.gov (United States)

Good, Jeffrey M.; Giger, Thomas; Dean, Matthew D.; Nachman, Michael W.

2010-01-01

The X chromosome often plays a central role in hybrid male sterility between species, but it is unclear if this reflects underlying regulatory incompatibilities. Here we combine phenotypic data with genome-wide expression data to directly associate aberrant expression patterns with hybrid male sterility between two species of mice. We used a reciprocal cross in which F1 males are sterile in one direction and fertile in the other direction, allowing us to associate expression differences with sterility rather than with other hybrid phenotypes. We found evidence of extensive over-expression of the X chromosome during spermatogenesis in sterile but not in fertile F1 hybrid males. Over-expression was most pronounced in genes that are normally expressed after meiosis, consistent with an X chromosome-wide disruption of expression during the later stages of spermatogenesis. This pattern was not a simple consequence of faster evolutionary divergence on the X chromosome, because X-linked expression was highly conserved between the two species. Thus, transcriptional regulation of the X chromosome during spermatogenesis appears particularly sensitive to evolutionary divergence between species. Overall, these data provide evidence for an underlying regulatory basis to reproductive isolation in house mice and underscore the importance of transcriptional regulation of the X chromosome to the evolution of hybrid male sterility. PMID:20941395

[Molecular cytogenetic analysis of a case with ring chromosome 3 syndrome].

Science.gov (United States)

Zhang, Kaihui; Song, Fengling; Zhang, Dongdong; Zhang, Haiyan; Wang, Ying; Dong, Rui; Zhang, Yufeng; Liu, Yi; Gai, Zhongtao

2016-12-10

To investigate the genetic cause for a child with developmental delay and congenital heart disease through molecular cytogenetic analysis. G-banded karyotyping and chromosomal microarray analysis (CMA) were performed for the patient and his parents. The proband's karyotype was detected as ring chromosome 3, and a 3q26.3-25.3 deletion encompassing 45 genes has been found with CMA. Testing of both parents was normal. Clinical phenotype of the patient with ring chromosome 3 mainly depends on the involved genes. It is necessary to combine CMA and karyotyping for the diagnosis of ring chromosome, as CMA can provide more accurate information for variations of the genome.

Construction of an Unstable Ring-X Chromosome Bearing the Autosomal Dopa Decarboxylase Gene in Drosophila melanogaster and Analysis of Ddc Mosaics

OpenAIRE

Gailey, Donald A.; Bordne, Deborah L.; Vallés, Ana Maria; Hall, Jeffrey C.; White, Kalpana

1987-01-01

An unstable Ring-X chromosome, Ddc+- Ring-X carrying a cloned Dopa decarboxylase (Ddc) encoding segment was constructed. The construction involved a double recombination event between the unstable Ring-X, R(1)wvC and a Rod-X chromosome which contained a P-element mediated Ddc + insert. The resulting Ddc+-Ring-X chromosome behaves similarly to the parent chromosome with respect to somatic instability. The Ddc+-Ring-X chromosome was used to generate Ddc mosaics. Analyses of Ddc mosaics reveal...

Engineering of Systematic Elimination of a Targeted Chromosome in Human Cells.

Science.gov (United States)

Sato, Hiroshi; Kato, Hiroki; Yamaza, Haruyoshi; Masuda, Keiji; Nguyen, Huong Thi Nguyen; Pham, Thanh Thi Mai; Han, Xu; Hirofuji, Yuta; Nonaka, Kazuaki

2017-01-01

Embryonic trisomy leads to abortion or congenital genetic disorders in humans. The most common autosomal chromosome abnormalities are trisomy of chromosomes 13, 18, and 21. Although alteration of gene dosage is thought to contribute to disorders caused by extra copies of chromosomes, genes associated with specific disease phenotypes remain unclear. To generate a normal cell from a trisomic cell as a means of etiological analysis or candidate therapy for trisomy syndromes, we developed a system to eliminate a targeted chromosome from human cells. Chromosome 21 was targeted by integration of a DNA cassette in HeLa cells that harbored three copies of chromosome 21. The DNA cassette included two inverted loxP sites and a herpes simplex virus thymidine kinase (HSV-tk) gene. This system causes missegregation of chromosome 21 after expression of Cre recombinase and subsequently enables the selection of cells lacking the chromosome by culturing in a medium that includes ganciclovir (GCV). Cells harboring only two copies of chromosome 21 were efficiently induced by transfection of a Cre expression vector, indicating that this approach is useful for eliminating a targeted chromosome.

Absence of Wip1 partially rescues Atm deficiency phenotypes in mice

Science.gov (United States)

Darlington, Yolanda; Nguyen, Thuy-Ai; Moon, Sung-Hwan; Herron, Alan; Rao, Pulivarthi; Zhu, Chengming; Lu, Xiongbin; Donehower, Lawrence A.

2011-01-01

Wildtype p53-Induced Phosphatase 1 (WIP1) is a serine/threonine phosphatase that dephosphorylates proteins in the ataxia telangiectasia mutated (ATM)-initiated DNA damage response pathway. WIP1 may play a homeostatic role in ATM signaling by returning the cell to a normal pre-stress state following completion of DNA repair. To better understand the effects of WIP1 on ATM signaling, we crossed Atm-deficient mice to Wip1-deficient mice and characterized phenotypes of the double knockout progeny. We hypothesized that the absence of Wip1 might rescue Atm deficiency phenotypes. Atm null mice, like ATM-deficient humans with the inherited syndrome ataxia telangiectasia, exhibit radiation sensitivity, fertility defects, and are T-cell lymphoma prone. Most double knockout mice were largely protected from lymphoma development and had a greatly extended lifespan compared to Atm null mice. Double knockout mice had increased p53 and H2AX phosphorylation and p21 expression compared to their Atm null counterparts, indicating enhanced p53 and DNA damage responses. Additionally, double knockout splenocytes displayed reduced chromosomal instability compared to Atm null mice. Finally, doubly null mice were partially rescued from infertility defects observed in Atm null mice. These results indicate that inhibition of WIP1 may represent a useful strategy for cancer treatment in general and A-T patients in particular. PMID:21765465

Identification of a basic helix-loop-helix-type transcription regulator gene in Aspergillus oryzae by systematically deleting large chromosomal segments.

Science.gov (United States)

Jin, Feng Jie; Takahashi, Tadashi; Machida, Masayuki; Koyama, Yasuji

2009-09-01

We previously developed two methods (loop-out and replacement-type recombination) for generating large-scale chromosomal deletions that can be applied to more effective chromosomal engineering in Aspergillus oryzae. In this study, the replacement-type method is used to systematically delete large chromosomal DNA segments to identify essential and nonessential regions in chromosome 7 (2.93 Mb), which is the smallest A. oryzae chromosome and contains a large number of nonsyntenic blocks. We constructed 12 mutants harboring deletions that spanned 16- to 150-kb segments of chromosome 7 and scored phenotypic changes in the resulting mutants. Among the deletion mutants, strains designated Delta5 and Delta7 displayed clear phenotypic changes involving growth and conidiation. In particular, the Delta5 mutant exhibited vigorous growth and conidiation, potentially beneficial characteristics for certain industrial applications. Further deletion analysis allowed identification of the AO090011000215 gene as the gene responsible for the Delta5 mutant phenotype. The AO090011000215 gene was predicted to encode a helix-loop-helix binding protein belonging to the bHLH family of transcription factors. These results illustrate the potential of the approach for identifying novel functional genes.

Production and repair of chromosome damage in an X-ray sensitive CHO mutant visualized and analysed in interphase using the technique of premature chromosome condensation

International Nuclear Information System (INIS)

Iliakis, G.E.; Pantelias, G.E.

1990-01-01

Production of chromosome damage per unit of absorbed radiation dose was in xrs-5 cells larger by a factor of 2.6 than in CHO cells (5.2 breaks per cell per Gy). Changes in chromatin structure, associated with the radiation-sensitive pheno-type of xrs-5 cells, that increase the probability of conversion of a DNA double-strand break (dsb) to a chromosome break are invoked to explain this. Repair of chromosome breaks as measured in plateau-phase G 1 cells was deficient in xrs-5 cells and the number of residual chromosome breaks practically identical to the number of lethal lesions calculated from survival data, suggesting that non-repaired chromosome breaks are likely to be manifestations of lethal events in the cell. The yield of ring chromosomes scored after a few hours of repair was higher by a factor of three in xrs-5 compared with CHO cells. (author)

Unmasking of a hemizygous WFS1 gene mutation by a chromosome 4p deletion of 8.3 Mb in a patient with Wolf-Hirschhorn syndrome.

Science.gov (United States)

Flipsen-ten Berg, Klara; van Hasselt, Peter M; Eleveld, Marc J; van der Wijst, Suzanne E; Hol, Frans A; de Vroede, Monique A M; Beemer, Frits A; Hochstenbach, P F Ron; Poot, Martin

2007-11-01

The Wolf-Hirschhorn syndrome (WHS (MIM 194190)), which is characterized by growth delay, mental retardation, epilepsy, facial dysmorphisms, and midline fusion defects, shows extensive phenotypic variability. Several of the proposed mutational and epigenetic mechanisms in this and other chromosomal deletion syndromes fail to explain the observed phenotypic variability. To explain the complex phenotype of a patient with WHS and features reminiscent of Wolfram syndrome (WFS (MIM 222300)), we performed extensive clinical evaluation and classical and molecular cytogenetic (GTG banding, FISH and array-CGH) and WFS1 gene mutation analyses. We detected an 8.3 Mb terminal deletion and an adjacent 2.6 Mb inverted duplication in the short arm of chromosome 4, which encompasses a gene associated with WFS (WFS1). In addition, a nonsense mutation in exon 8 of the WFS1 gene was found on the structurally normal chromosome 4. The combination of the 4p deletion with the WFS1 point mutation explains the complex phenotype presented by our patient. This case further illustrates that unmasking of hemizygous recessive mutations by chromosomal deletions represents an additional explanation for the phenotypic variability observed in chromosomal deletion disorders.

Is there a yet unreported unbalanced chromosomal abnormality without phenotypic consequences in proximal 4p?

Science.gov (United States)

Liehr, T; Bartels, I; Zoll, B; Ewers, E; Mrasek, K; Kosyakova, N; Merkas, M; Hamid, A B; von Eggeling, F; Posorski, N; Weise, A

2011-01-01

Unbalanced chromosomal abnormalities (UBCA) are reported for >50 euchromatic regions of almost all human autosomes. UBCA are comprised of a few megabases of DNA, and carriers are in many cases clinically healthy. Here we report on a partial trisomy of chromosome 4 of the centromere-near region of the short arm of chromosome 4 present as a small supernumerary marker chromosome (sSMC). The sSMC was present in >70% of amnion cells and in 60% of placenta. Further delineation of the size of the duplicated region was done by molecular cytogenetics and array comparative genomic hybridization. Even though the sSMC lead to a partial trisomy of ~9 megabase pairs, a healthy child was born, developing normally at 1 year of age. No comparable cases are available in the literature. Thus, we discuss here the possibility of having found a yet unrecognized chromosomal region subject to UBCA. Copyright © 2010 S. Karger AG, Basel.

Genetic and phenotypic intra-species variation in Candida albicans.

Science.gov (United States)

Hirakawa, Matthew P; Martinez, Diego A; Sakthikumar, Sharadha; Anderson, Matthew Z; Berlin, Aaron; Gujja, Sharvari; Zeng, Qiandong; Zisson, Ethan; Wang, Joshua M; Greenberg, Joshua M; Berman, Judith; Bennett, Richard J; Cuomo, Christina A

2015-03-01

Candida albicans is a commensal fungus of the human gastrointestinal tract and a prevalent opportunistic pathogen. To examine diversity within this species, extensive genomic and phenotypic analyses were performed on 21 clinical C. albicans isolates. Genomic variation was evident in the form of polymorphisms, copy number variations, chromosomal inversions, subtelomeric hypervariation, loss of heterozygosity (LOH), and whole or partial chromosome aneuploidies. All 21 strains were diploid, although karyotypic changes were present in eight of the 21 isolates, with multiple strains being trisomic for Chromosome 4 or Chromosome 7. Aneuploid strains exhibited a general fitness defect relative to euploid strains when grown under replete conditions. All strains were also heterozygous, yet multiple, distinct LOH tracts were present in each isolate. Higher overall levels of genome heterozygosity correlated with faster growth rates, consistent with increased overall fitness. Genes with the highest rates of amino acid substitutions included many cell wall proteins, implicating fast evolving changes in cell adhesion and host interactions. One clinical isolate, P94015, presented several striking properties including a novel cellular phenotype, an inability to filament, drug resistance, and decreased virulence. Several of these properties were shown to be due to a homozygous nonsense mutation in the EFG1 gene. Furthermore, loss of EFG1 function resulted in increased fitness of P94015 in a commensal model of infection. Our analysis therefore reveals intra-species genetic and phenotypic differences in C. albicans and delineates a natural mutation that alters the balance between commensalism and pathogenicity. © 2015 Hirakawa et al.; Published by Cold Spring Harbor Laboratory Press.

Mlh1 deficiency in normal mouse colon mucosa associates with chromosomally unstable colon cancer

Science.gov (United States)

Pussila, Marjaana; Törönen, Petri; Einarsdottir, Elisabet; Katayama, Shintaro; Krjutškov, Kaarel; Holm, Liisa; Kere, Juha; Peltomäki, Päivi; Mäkinen, Markus J; Linden, Jere; Nyström, Minna

2018-01-01

Abstract Colorectal cancer (CRC) genome is unstable and different types of instabilities, such as chromosomal instability (CIN) and microsatellite instability (MSI) are thought to reflect distinct cancer initiating mechanisms. Although 85% of sporadic CRC reveal CIN, 15% reveal mismatch repair (MMR) malfunction and MSI, the hallmarks of Lynch syndrome with inherited heterozygous germline mutations in MMR genes. Our study was designed to comprehensively follow genome-wide expression changes and their implications during colon tumorigenesis. We conducted a long-term feeding experiment in the mouse to address expression changes arising in histologically normal colonic mucosa as putative cancer preceding events, and the effect of inherited predisposition (Mlh1+/−) and Western-style diet (WD) on those. During the 21-month experiment, carcinomas developed mainly in WD-fed mice and were evenly distributed between genotypes. Unexpectedly, the heterozygote (B6.129-Mlh1tm1Rak) mice did not show MSI in their CRCs. Instead, both wildtype and heterozygote CRC mice showed a distinct mRNA expression profile and shortage of several chromosomal segregation gene-specific transcripts (Mlh1, Bub1, Mis18a, Tpx2, Rad9a, Pms2, Cenpe, Ncapd3, Odf2 and Dclre1b) in their colon mucosa, as well as an increased mitotic activity and abundant numbers of unbalanced/atypical mitoses in tumours. Our genome-wide expression profiling experiment demonstrates that cancer preceding changes are already seen in histologically normal colon mucosa and that decreased expressions of Mlh1 and other chromosomal segregation genes may form a field-defect in mucosa, which trigger MMR-proficient, chromosomally unstable CRC. PMID:29701748

Genomic instability in mice is greater in Fanconi anemia caused by deficiency of Fancd2 than Fancg.

Science.gov (United States)

Reliene, Ramune; Yamamoto, Mitsuko L; Rao, P Nagesh; Schiestl, Robert H

2010-12-01

Fanconi anemia (FA) results from mutations in the FANC genes and is characterized by bone marrow failure, birth defects, and a high incidence of cancer. FANCG is a part of the FA core complex that is responsible for monoubiquitination of FANCD2 and FANCI. The precise role of the FA pathway is not well understood, although it may be involved in homologous recombination (HR), nonhomologous end joining, and translesion synthesis (TLS). Fancd2(-/-) mice have a more severe phenotype than Fancg(-/-), and other FA core complex-deficient mice, although both Fancg and Fancd2 belong to the same FA pathway. We hypothesized that Fancd2 deficiency results in a more severe phenotype because Fancd2 also has a FA pathway-independent function in the maintenance of genomic integrity. To test this hypothesis, we determined the level of DNA damage and genomic instability in Fancd2(-/-), Fancg(-/-), and wild-type controls. Fancd2(-/-) mice displayed a higher magnitude of chromosomal breakage and micronucleus formation than the wild-type or Fancg(-/-) mice. Also, DNA strand breaks were increased in Fancd2(-/-) but not in Fancg(-/-) mice. In addition, Fancd2(-/-) mice displayed an elevated frequency of DNA deletions, resulting from HR at the endogenous p(un) locus. In contrast, in Fancg(-/-) mice, the frequency of DNA deletions was decreased. Thus, Fancd2 but not Fancg deficiency results in elevated chromosomal/DNA breakage and permanent genome rearrangements. This provides evidence that Fancd2 plays an additional role in the maintenance of genomic stability than Fancg, which might explain the higher predisposition to cancer seen in the Fancd2(-/-) mice.

[Chromosomal instability parameters in the population affected by nuclear explosions at the Semipalatinsk nuclear test site].

Science.gov (United States)

Abil'dinova, G Zh; Kuleshov, N P; Sviatova, G S

2003-08-01

A population genetic survey of 149 persons who were born and have permanently lived in the contaminated zones of the Semipalatinsk region has been performed. A cytogenetic study has demonstrated that the frequency of aberrant cells is 1.7-3 times higher than control parameters. The total frequencies of chromosome aberrations are 3.43 +/- 0.48, 3.1 +/- 0.3, 1.8 +/- 0.2, and 1.15 +/- 0.17 aberrations per 100 cells in the populations of the extreme radiation risk (ERR), maximum radiation risk (MaxRR), minimum radiation risk (MinRR), and control zones, respectively. The high chromosome aberration rate in all three zones of radiation risk has been detected mainly due to radiation-induced chromosome markers, including paired fragments (1.2 +/- 0.2, 0.94 +/- 0.13, and 0.43 +/- 0.06 per 100 cells, respectively), dicentric and ring chromosomes (0.44 +/- 0.04, 0.45 +/- 0.07, and 0.11 +/- 0.02 per 100 cells, respectively), and stable chromosome aberrations (0.74 +/- 0.16, 0.8 +/- 0.1, and 0.63 +/- 0.13 per 100 cells, respectively). The qualitative spectra of the cytogenetic lesions observed in these groups indicate a mutagenic effect of ionizing radiation on chromosomes in the populations studied.

New MCM8 mutation associated with premature ovarian insufficiency and chromosomal instability in a highly consanguineous Tunisian family.

Science.gov (United States)

Bouali, Nouha; Francou, Bruno; Bouligand, Jérôme; Imanci, Dilek; Dimassi, Sarra; Tosca, Lucie; Zaouali, Monia; Mougou, Soumaya; Young, Jacques; Saad, Ali; Guiochon-Mantel, Anne

2017-10-01

To identify the gene(s) involved in the etiology of premature ovarian insufficiency in a highly consanguineous Tunisian family. Genetic analysis of a large consanguineous family with several affected siblings. University hospital-based cytogenetics and molecular genetics laboratories. A highly consanguineous Tunisian family with several affected siblings born to healthy second-degree cousins. None. Targeted exome sequencing was performed by next-generation sequencing for affected family members. Mutations were validated by Sanger sequencing. Functional experiments were performed to explore the deleterious effects of the identified mutation. DNA damage was induced by increasing mitomycin C (MMC) concentrations on cultured peripheral lymphocytes. Analysis of the next-generation sequencing data revealed a new homozygous missense mutation in the minichromosome maintenance 8 gene (MCM8).This homozygous mutation (c. 482A>C; p.His161Pro) was predicted to be deleterious and segregated with the disease in the family. MCM8 participates in homologous recombination during meiosis and DNA double-stranded break repair by dimerizing with MCM9. Mcm8 knock out results in an early block in follicle development and small gonads. Given this, we tested the chromosomal breakage repair capacity of homozygous and heterozygous MCM8 p.His161Pro mutation on cultured peripheral lymphocytes exposed to increasing MMC concentrations. We found that chromosomal breakage after MMC exposure was significantly higher in cells from homozygously affected individuals than in those from a healthy control. Our findings provide additional support to the view that MCM8 mutations are involved in the primary ovarian insufficiency phenotype. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Siblings with opposite chromosome constitutions, dup(2q)/del(7q) and del(2q)/dup(7q).

Science.gov (United States)

Shim, Sung Han; Shim, Jae Sun; Min, Kyunghoon; Lee, Hee Song; Park, Ji Eun; Park, Sang Hee; Hwang, Euna; Kim, Minyoung

2014-01-15

Chromosome 7q36 microdeletion syndrome is a rare genomic disorder characterized by underdevelopment of the brain, microcephaly, anomalies of the sex organs, and language problems. Developmental delay, intellectual disability, autistic spectrum disorders, BDMR syndrome, and unusual facial morphology are the key features of the chromosome 2q37 microdeletion syndrome. A genetic screening for two brothers with global developmental delay using high-resolution chromosomal analysis and subtelomeric multiplex ligation-dependent probe amplification revealed subtelomeric rearrangements on the same sites of 2q37.2 and 7q35, with reversed deletion and duplication. Both of them showed dysmorphic facial features, severe disability of physical and intellectual development, and abnormal genitalia with differential abnormalities in their phenotypes. The family did not have abnormal genetic phenotypes. According to the genetic analysis of their parents, adjacent-1 segregation from their mother's was suggested as a mechanism of their gene mutation. By comparing the phenotypes of our patients with previous reports on similar patients, we tried to obtain the information of related genes and their chromosomal locations. © 2013.

B chromosomes in the species Prochilodus argenteus (Characiformes, Prochilodontidae: morphologicalidentity and dispersion

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Manolo Penitente

2015-03-01

Full Text Available B chromosomes have attracted the attention of Neotropical fish cytogeneticists in recent years, both for their remarkable occurrence in this group and also because of the interest in studies of the genetic structure and role played in the genome of these organisms. The aim of this study was to report the first occurrence of supernumerary chromosomes in Prochilodus argenteus (Agassiz, 1829, this being the fifth carrier species among thirteen within the genus Prochilodus (Agassiz, 1829. The extra elements identified in this species are small sized heterochromatic chromosomes characterized by a low mitotic instability index, being very similar to other supernumerary chromosomes described in the species of the genus Prochilodus. Morphology, structure and dispersion of the supernumerary genomic elements which occur in species of this genus are discussed aiming to better understand aspects involved the origin of supernumerary chromosomes and the differentiation process and relationships among species of this family.

Dynamics of Tumor Heterogeneity Derived from Clonal Karyotypic Evolution

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Ashley M. Laughney

2015-08-01

Full Text Available Numerical chromosomal instability is a ubiquitous feature of human neoplasms. Due to experimental limitations, fundamental characteristics of karyotypic changes in cancer are poorly understood. Using an experimentally inspired stochastic model, based on the potency and chromosomal distribution of oncogenes and tumor suppressor genes, we show that cancer cells have evolved to exist within a narrow range of chromosome missegregation rates that optimizes phenotypic heterogeneity and clonal survival. Departure from this range reduces clonal fitness and limits subclonal diversity. Mapping of the aneuploid fitness landscape reveals a highly favorable, commonly observed, near-triploid state onto which evolving diploid- and tetraploid-derived populations spontaneously converge, albeit at a much lower fitness cost for the latter. Finally, by analyzing 1,368 chromosomal translocation events in five human cancers, we find that karyotypic evolution also shapes chromosomal translocation patterns by selecting for more oncogenic derivative chromosomes. Thus, chromosomal instability can generate the heterogeneity required for Darwinian tumor evolution.

Step-wise and punctuated genome evolution drive phenotype changes of tumor cells

International Nuclear Information System (INIS)

Stepanenko, Aleksei; Andreieva, Svitlana; Korets, Kateryna; Mykytenko, Dmytro; Huleyuk, Nataliya; Vassetzky, Yegor; Kavsan, Vadym

2015-01-01

Highlights: • There are the step-wise continuous and punctuated phases of cancer genome evolution. • The system stresses during the different phases may lead to very different responses. • Stable transfection of an empty vector can result in genome and phenotype changes. • Functions of a (trans)gene can be opposite/versatile in cells with different genomes. • Contextually, temozolomide can both promote and suppress tumor cell aggressiveness. - Abstract: The pattern of genome evolution can be divided into two phases: the step-wise continuous phase (step-wise clonal evolution, stable dominant clonal chromosome aberrations (CCAs), and low frequency of non-CCAs, NCCAs) and punctuated phase (marked by elevated NCCAs and transitional CCAs). Depending on the phase, system stresses (the diverse CIN promoting factors) may lead to the very different phenotype responses. To address the contribution of chromosome instability (CIN) to phenotype changes of tumor cells, we characterized CCAs/NCCAs of HeLa and HEK293 cells, and their derivatives after genotoxic stresses (a stable plasmid transfection, ectopic expression of cancer-associated CHI3L1 gene or treatment with temozolomide) by conventional cytogenetics, copy number alterations (CNAs) by array comparative genome hybridization, and phenotype changes by cell viability and soft agar assays. Transfection of either the empty vector pcDNA3.1 or pcDNA3.1-CHI3L1 into 293 cells initiated the punctuated genome changes. In contrast, HeLa-CHI3L1 cells demonstrated the step-wise genome changes. Increased CIN correlated with lower viability of 293-pcDNA3.1 cells but higher colony formation efficiency (CFE). Artificial CHI3L1 production in 293-CHI3L1 cells increased viability and further contributed to CFE. The opposite growth characteristics of 293-CHI3L1 and HeLa-CHI3L1 cells were revealed. The effect and function of a (trans)gene can be opposite and versatile in cells with different genetic network, which is defined by

Step-wise and punctuated genome evolution drive phenotype changes of tumor cells

Energy Technology Data Exchange (ETDEWEB)

Stepanenko, Aleksei, E-mail: a.a.stepanenko@gmail.com [Department of Biosynthesis of Nucleic Acids, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv 03680 (Ukraine); Andreieva, Svitlana; Korets, Kateryna; Mykytenko, Dmytro [Department of Biosynthesis of Nucleic Acids, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv 03680 (Ukraine); Huleyuk, Nataliya [Institute of Hereditary Pathology, National Academy of Medical Sciences of Ukraine, Lviv 79008 (Ukraine); Vassetzky, Yegor [CNRS UMR8126, Université Paris-Sud 11, Institut de Cancérologie Gustave Roussy, Villejuif 94805 (France); Kavsan, Vadym [Department of Biosynthesis of Nucleic Acids, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv 03680 (Ukraine)

2015-01-15

Highlights: • There are the step-wise continuous and punctuated phases of cancer genome evolution. • The system stresses during the different phases may lead to very different responses. • Stable transfection of an empty vector can result in genome and phenotype changes. • Functions of a (trans)gene can be opposite/versatile in cells with different genomes. • Contextually, temozolomide can both promote and suppress tumor cell aggressiveness. - Abstract: The pattern of genome evolution can be divided into two phases: the step-wise continuous phase (step-wise clonal evolution, stable dominant clonal chromosome aberrations (CCAs), and low frequency of non-CCAs, NCCAs) and punctuated phase (marked by elevated NCCAs and transitional CCAs). Depending on the phase, system stresses (the diverse CIN promoting factors) may lead to the very different phenotype responses. To address the contribution of chromosome instability (CIN) to phenotype changes of tumor cells, we characterized CCAs/NCCAs of HeLa and HEK293 cells, and their derivatives after genotoxic stresses (a stable plasmid transfection, ectopic expression of cancer-associated CHI3L1 gene or treatment with temozolomide) by conventional cytogenetics, copy number alterations (CNAs) by array comparative genome hybridization, and phenotype changes by cell viability and soft agar assays. Transfection of either the empty vector pcDNA3.1 or pcDNA3.1-CHI3L1 into 293 cells initiated the punctuated genome changes. In contrast, HeLa-CHI3L1 cells demonstrated the step-wise genome changes. Increased CIN correlated with lower viability of 293-pcDNA3.1 cells but higher colony formation efficiency (CFE). Artificial CHI3L1 production in 293-CHI3L1 cells increased viability and further contributed to CFE. The opposite growth characteristics of 293-CHI3L1 and HeLa-CHI3L1 cells were revealed. The effect and function of a (trans)gene can be opposite and versatile in cells with different genetic network, which is defined by

The duplication 17p13.3 phenotype

DEFF Research Database (Denmark)

Curry, Cynthia J; Rosenfeld, Jill A; Grant, Erica

2013-01-01

. Older patients were often overweight. Three variant phenotypes included cleft lip/palate (CLP), split hand/foot with long bone deficiency (SHFLD), and a connective tissue phenotype resembling Marfan syndrome. The duplications in patients with clefts appear to disrupt ABR, while the SHFLD phenotype......Chromosome 17p13.3 is a gene rich region that when deleted is associated with the well-known Miller-Dieker syndrome. A recently described duplication syndrome involving this region has been associated with intellectual impairment, autism and occasional brain MRI abnormalities. We report 34...... was associated with duplication of BHLHA9 as noted in two recent reports. The connective tissue phenotype did not have a convincing critical region. Our experience with this large cohort expands knowledge of this diverse duplication syndrome....

Engineering of Systematic Elimination of a Targeted Chromosome in Human Cells

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Hiroshi Sato

2017-01-01

Full Text Available Embryonic trisomy leads to abortion or congenital genetic disorders in humans. The most common autosomal chromosome abnormalities are trisomy of chromosomes 13, 18, and 21. Although alteration of gene dosage is thought to contribute to disorders caused by extra copies of chromosomes, genes associated with specific disease phenotypes remain unclear. To generate a normal cell from a trisomic cell as a means of etiological analysis or candidate therapy for trisomy syndromes, we developed a system to eliminate a targeted chromosome from human cells. Chromosome 21 was targeted by integration of a DNA cassette in HeLa cells that harbored three copies of chromosome 21. The DNA cassette included two inverted loxP sites and a herpes simplex virus thymidine kinase (HSV-tk gene. This system causes missegregation of chromosome 21 after expression of Cre recombinase and subsequently enables the selection of cells lacking the chromosome by culturing in a medium that includes ganciclovir (GCV. Cells harboring only two copies of chromosome 21 were efficiently induced by transfection of a Cre expression vector, indicating that this approach is useful for eliminating a targeted chromosome.

Ring Chromosome 17 Not Involving the Miller-Dieker Region: A Case with Drug-Resistant Epilepsy.

Science.gov (United States)

Coppola, Antonietta; Morrogh, Deborah; Farrell, Fiona; Balestrini, Simona; Hernandez-Hernandez, Laura; Krithika, S; Sander, Josemir W; Waters, Jonathan J; Sisodiya, Sanjay M

2017-12-01

Chromosomal abnormalities are often identified in people with neurodevelopmental disorders including intellectual disability, autism, and epilepsy. Ring chromosomes, which usually involve gene copy number loss, are formed by fusion of subtelomeric or telomeric chromosomal regions. Some ring chromosomes, including ring 14, 17, and 20, are strongly associated with seizure disorders. We report an individual with a ring chromosome 17, r(17)(p13.3q25.3), with a terminal 17q25.3 deletion and no short arm copy number loss, and with a phenotype characterized by intellectual disability and drug-resistant epilepsy, including a propensity for nonconvulsive status epilepticus.

Empirical evidence for son-killing X chromosomes and the operation of SA-zygotic drive.

Science.gov (United States)

Friberg, Urban; Stewart, Andrew D; Rice, William R

2011-01-01

Diploid organisms have two copies of all genes, but only one is carried by each haploid gamete and diploid offspring. This causes a fundamental genetic conflict over transmission rate between alternative alleles. Single genes, or gene clusters, only rarely code for the complex phenotypes needed to give them a transmission advantage (drive phenotype). However, all genes on a male's X and Y chromosomes co-segregate, allowing different sex-linked genes to code for different parts of the drive phenotype. Correspondingly, the well-characterized phenomenon of male gametic drive, occurring during haploid gametogenesis, is especially common on sex chromosomes. The new theory of sexually antagonistic zygotic drive of the sex chromosomes (SA-zygotic drive) extends the logic of gametic drive into the diploid phase of the lifecycle, whenever there is competition among siblings or harmful sib-sib mating. The X and Y are predicted to gain a transmission advantage by harming offspring of the sex that does not carry them. Here we analyzed a mutant X-chromosome in Drosophila simulans that produced an excess of daughters when transmitted from males. We developed a series of tests to differentiate between gametic and SA-zygotic drive, and provide multiple lines of evidence that SA-zygotic drive is responsible for the sex ratio bias. Driving sires produce about 50% more surviving daughters than sons. Sex-ratio distortion due to genetic conflict has evolved via gametic drive and maternally transmitted endosymbionts. Our data indicate that sex chromosomes can also drive by harming the non-carrier sex of offspring.

Empirical evidence for son-killing X chromosomes and the operation of SA-zygotic drive.

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Urban Friberg

Full Text Available Diploid organisms have two copies of all genes, but only one is carried by each haploid gamete and diploid offspring. This causes a fundamental genetic conflict over transmission rate between alternative alleles. Single genes, or gene clusters, only rarely code for the complex phenotypes needed to give them a transmission advantage (drive phenotype. However, all genes on a male's X and Y chromosomes co-segregate, allowing different sex-linked genes to code for different parts of the drive phenotype. Correspondingly, the well-characterized phenomenon of male gametic drive, occurring during haploid gametogenesis, is especially common on sex chromosomes. The new theory of sexually antagonistic zygotic drive of the sex chromosomes (SA-zygotic drive extends the logic of gametic drive into the diploid phase of the lifecycle, whenever there is competition among siblings or harmful sib-sib mating. The X and Y are predicted to gain a transmission advantage by harming offspring of the sex that does not carry them.Here we analyzed a mutant X-chromosome in Drosophila simulans that produced an excess of daughters when transmitted from males. We developed a series of tests to differentiate between gametic and SA-zygotic drive, and provide multiple lines of evidence that SA-zygotic drive is responsible for the sex ratio bias. Driving sires produce about 50% more surviving daughters than sons.Sex-ratio distortion due to genetic conflict has evolved via gametic drive and maternally transmitted endosymbionts. Our data indicate that sex chromosomes can also drive by harming the non-carrier sex of offspring.

Genome-wide mapping of susceptibility to coronary artery disease identifies a novel replicated locus on chromosome 17.

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Martin Farrall

2006-05-01

Full Text Available Coronary artery disease (CAD is a leading cause of death world-wide, and most cases have a complex, multifactorial aetiology that includes a substantial heritable component. Identification of new genes involved in CAD may inform pathogenesis and provide new therapeutic targets. The PROCARDIS study recruited 2,658 affected sibling pairs (ASPs with onset of CAD before age 66 y from four European countries to map susceptibility loci for CAD. ASPs were defined as having CAD phenotype if both had CAD, or myocardial infarction (MI phenotype if both had a MI. In a first study, involving a genome-wide linkage screen, tentative loci were mapped to Chromosomes 3 and 11 with the CAD phenotype (1,464 ASPs, and to Chromosome 17 with the MI phenotype (739 ASPs. In a second study, these loci were examined with a dense panel of grid-tightening markers in an independent set of families (1,194 CAD and 344 MI ASPs. This replication study showed a significant result on Chromosome 17 (MI phenotype; p = 0.009 after adjustment for three independent replication tests. An exclusion analysis suggests that further genes of effect size lambda(sib > 1.24 are unlikely to exist in these populations of European ancestry. To our knowledge, this is the first genome-wide linkage analysis to map, and replicate, a CAD locus. The region on Chromosome 17 provides a compelling target within which to identify novel genes underlying CAD. Understanding the genetic aetiology of CAD may lead to novel preventative and/or therapeutic strategies.

Integrating chromosomal aberrations and gene expression profiles to dissect rectal tumorigenesis

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Eilers Paul HC

2008-10-01

Full Text Available Abstract Background Accurate staging of rectal tumors is essential for making the correct treatment choice. In a previous study, we found that loss of 17p, 18q and gain of 8q, 13q and 20q could distinguish adenoma from carcinoma tissue and that gain of 1q was related to lymph node metastasis. In order to find markers for tumor staging, we searched for candidate genes on these specific chromosomes. Methods We performed gene expression microarray analysis on 79 rectal tumors and integrated these data with genomic data from the same sample series. We performed supervised analysis to find candidate genes on affected chromosomes and validated the results with qRT-PCR and immunohistochemistry. Results Integration of gene expression and chromosomal instability data revealed similarity between these two data types. Supervised analysis identified up-regulation of EFNA1 in cases with 1q gain, and EFNA1 expression was correlated with the expression of a target gene (VEGF. The BOP1 gene, involved in ribosome biogenesis and related to chromosomal instability, was over-expressed in cases with 8q gain. SMAD2 was the most down-regulated gene on 18q, and on 20q, STMN3 and TGIF2 were highly up-regulated. Immunohistochemistry for SMAD4 correlated with SMAD2 gene expression and 18q loss. Conclusion On basis of integrative analysis this study identified one well known CRC gene (SMAD2 and several other genes (EFNA1, BOP1, TGIF2 and STMN3 that possibly could be used for rectal cancer characterization.

On the nosology and pathogenesis of Wolf-Hirschhorn syndrome: genotype-phenotype correlation analysis of 80 patients and literature review.

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Zollino, Marcella; Murdolo, Marina; Marangi, Giuseppe; Pecile, Vanna; Galasso, Cinzia; Mazzanti, Laura; Neri, Giovanni

2008-11-15

Based on genotype-phenotype correlation analysis of 80 Wolf-Hirschhorn syndrome (WHS) patients, as well as on review of relevant literature, we add further insights to the following aspects of WHS: (1) clinical delineation and phenotypic categories; (2) characterization of the basic genomic defect, mechanisms of origin and familiarity; (3) identification of prognostic factors for mental retardation; (4) chromosome mapping of the distinctive clinical signs, in an effort to identify pathogenic genes. Clinically, we consider that minimal diagnostic criteria for WHS, defining a "core" phenotype, are typical facial appearance, mental retardation, growth delay and seizures (or EEG anomalies). Three different categories of the WHS phenotype were defined, generally correlating with the extent of the 4p deletion. The first one comprises a small deletion not exceeding 3.5 Mb, that is usually associated with a mild phenotype, lacking major malformations. This category is likely under-diagnosed. The second and by far the more frequent category is identified by large deletions, averaging between 5 and 18 Mb, and causes the widely recognizable WHS phenotype. The third clinical category results from a very large deletion exceeding 22-25 Mb causing a severe phenotype, that can hardly be defined as typical WHS. Genetically, de novo chromosome abnormalities in WHS include pure deletions but also complex rearrangements, mainly unbalanced translocations. With the exception of t(4p;8p), WHS-associated chromosome abnormalities are neither mediated by segmental duplications, nor associated with a parental inversion polymorphism on 4p16.3. Factors involved in prediction of prognosis include the extent of the deletion, the occurrence of complex chromosome anomalies, and the severity of seizures. We found that the core phenotype maps within the terminal 1.9 Mb region of chromosome 4p. Therefore, WHSCR-2 should be considered the critical region for this condition. We also confirmed that the

CENPA overexpression promotes genome instability in pRb-depleted human cells

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Lentini Laura

2009-12-01

Full Text Available Abstract Background Aneuploidy is a hallmark of most human cancers that arises as a consequence of chromosomal instability and it is frequently associated with centrosome amplification. Functional inactivation of the Retinoblastoma protein (pRb has been indicated as a cause promoting chromosomal instability as well centrosome amplification. However, the underlying molecular mechanism still remains to be clarified. Results Here we show that pRb depletion both in wild type and p53 knockout HCT116 cells was associated with the presence of multipolar spindles, anaphase bridges, lagging chromosomes and micronuclei harbouring whole chromosomes. In addition aneuploidy caused by pRb acute loss was not affected by p53 loss. Quantitative real-time RT-PCR showed that pRB depletion altered expression of genes involved in centrosome duplication, kinetochore assembly and in the Spindle Assembly Checkpoint (SAC. However, despite MAD2 up-regulation pRb-depleted cells seemed to have a functional SAC since they arrested in mitosis after treatments with mitotic poisons. Moreover pRb-depleted HCT116 cells showed BRCA1 overexpression that seemed responsible for MAD2 up-regulation. Post-transcriptional silencing of CENPA by RNA interference, resulting in CENP-A protein levels similar to those present in control cells greatly reduced aneuploid cell numbers in pRb-depleted cells. Conclusion Altogether our findings indicate a novel aspect of pRb acute loss that promotes aneuploidy mainly by inducing CENPA overexpression that in turn might induce micronuclei by affecting the correct attachment of spindle microtubules to kinetochores.

Molecular Classification and Correlates in Colorectal Cancer

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Ogino, Shuji; Goel, Ajay

2008-01-01

Molecular classification of colorectal cancer is evolving. As our understanding of colorectal carcinogenesis improves, we are incorporating new knowledge into the classification system. In particular, global genomic status [microsatellite instability (MSI) status and chromosomal instability (CIN) status] and epigenomic status [CpG island methylator phenotype (CIMP) status] play a significant role in determining clinical, pathological and biological characteristics of colorectal cancer. In thi...

Avian sex, sex chromosomes, and dosage compensation in the age of genomics.

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Graves, Jennifer A Marshall

2014-04-01

Comparisons of the sex chromosome systems in birds and mammals are widening our view and deepening our understanding of vertebrate sex chromosome organization, function, and evolution. Birds have a very conserved ZW system of sex determination in which males have two copies of a large, gene-rich Z chromosome, and females have a single Z and a female-specific W chromosome. The avian ZW system is quite the reverse of the well-studied mammalian XY chromosome system, and evolved independently from different autosomal blocs. Despite the different gene content of mammal and bird sex chromosomes, there are many parallels. Genes on the bird Z and the mammal X have both undergone selection for male-advantage functions, and there has been amplification of male-advantage genes and accumulation of LINEs. The bird W and mammal Y have both undergone extensive degradation, but some birds retain early stages and some mammals terminal stages of the process, suggesting that the process is more advanced in mammals. Different sex-determining genes, DMRT1 and SRY, define the ZW and XY systems, but DMRT1 is involved in downstream events in mammals. Birds show strong cell autonomous specification of somatic sex differences in ZZ and ZW tissue, but there is growing evidence for direct X chromosome effects on sexual phenotype in mammals. Dosage compensation in birds appears to be phenotypically and molecularly quite different from X inactivation, being partial and gene-specific, but both systems use tools from the same molecular toolbox and there are some signs that galliform birds represent an early stage in the evolution of a coordinated system.

Molecular cytogenetic analysis of Inv Dup(15) chromosomes, using probes specific for the Pradar-Willi/Angelman syndrome region: Clinical implications

Energy Technology Data Exchange (ETDEWEB)

Leana-Cox, J. (Univ. of Maryland School of Medicine, Baltimore, MD (United States)); Jenkins, L. (Kaiser Permanente Medical Group, San Jose, CA (United States)); Palmer, C.G.; Plattner, R. (Indiana School of Medicine, Indianapolis, IN (United States)); Sheppard, L. (Palo Verde Laboratory, Inc., Chandler, AZ (United States)); Flejter, W.L. (Univ. of Michigan, Ann Arbor, MI (United States)); Zackowski, J. (Univ. of Florida Health Science Center, Gainsville, FL (United States)); Tsien, F. (Tulane Univ. School of Medicine, New Orleans, LA (United States)); Schwartz, S. (Case Western Reserve Univ., Cleveland, OH (United States))

1994-05-01

Twenty-seven cases of inverted duplications of chromosome 15 (inv dup[15]) were investigated by FISH with two DNA probes specific for the Prader-Willi syndrome/Angelman syndrome (PWS/AS) region on proximal 15q. Sixteen of the marker chromosomes displayed two copies of each probe, while in the remaining 11 markers no hybridization was observed. A significant association was found between the presence of this region and an abnormal phenotype (P<.01). This is the largest study to date of inv dup(15) chromosomes, that uses molecular cytogenetic methods and is the first to report a significant association between the presence of a specific chromosomal region in such markers and an abnormal phenotype. 30 refs., 1 fig., 4 tabs.

Dynamic chromosomal rearrangements in Hodgkin's lymphoma are due to ongoing three-dimensional nuclear remodeling and breakage-bridge-fusion cycles.

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Guffei, Amanda; Sarkar, Rahul; Klewes, Ludger; Righolt, Christiaan; Knecht, Hans; Mai, Sabine

2010-12-01

Hodgkin's lymphoma is characterized by the presence of mono-nucleated Hodgkin cells and bi- to multi-nucleated Reed-Sternberg cells. We have recently shown telomere dysfunction and aberrant synchronous/asynchronous cell divisions during the transition of Hodgkin cells to Reed-Sternberg cells.1 To determine whether overall changes in nuclear architecture affect genomic instability during the transition of Hodgkin cells to Reed-Sternberg cells, we investigated the nuclear organization of chromosomes in these cells. Three-dimensional fluorescent in situ hybridization revealed irregular nuclear positioning of individual chromosomes in Hodgkin cells and, more so, in Reed-Sternberg cells. We characterized an increasingly unequal distribution of chromosomes as mono-nucleated cells became multi-nucleated cells, some of which also contained chromosome-poor 'ghost' cell nuclei. Measurements of nuclear chromosome positions suggested chromosome overlaps in both types of cells. Spectral karyotyping then revealed both aneuploidy and complex chromosomal rearrangements: multiple breakage-bridge-fusion cycles were at the origin of the multiple rearranged chromosomes. This conclusion was challenged by super resolution three-dimensional structured illumination imaging of Hodgkin and Reed-Sternberg nuclei. Three-dimensional super resolution microscopy data documented inter-nuclear DNA bridges in multi-nucleated cells but not in mono-nucleated cells. These bridges consisted of chromatids and chromosomes shared by two Reed-Sternberg nuclei. The complexity of chromosomal rearrangements increased as Hodgkin cells developed into multi-nucleated cells, thus indicating tumor progression and evolution in Hodgkin's lymphoma, with Reed-Sternberg cells representing the highest complexity in chromosomal rearrangements in this disease. This is the first study to demonstrate nuclear remodeling and associated genomic instability leading to the generation of Reed-Sternberg cells of Hodgkin's lymphoma

Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice.

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Sasada, Tatsunari; Hinoi, Takao; Saito, Yasufumi; Adachi, Tomohiro; Takakura, Yuji; Kawaguchi, Yasuo; Sotomaru, Yusuke; Sentani, Kazuhiro; Oue, Naohide; Yasui, Wataru; Ohdan, Hideki

2015-01-01

The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc) knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma--caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc(+/flox), abbreviated to CPC;Apc) or microsatellite (CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox)) instability, respectively--were administered chlorinated (10.0 mg/L chlorine) or tap (0.7 mg/L chlorine) water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox) mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to differences

Trisomy 12p and monosomy 4p: phenotype-genotype correlation.

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Benussi, Daniela Gambel; Costa, Paola; Zollino, Marcella; Murdolo, Marina; Petix, Vincenzo; Carrozzi, Marco; Pecile, Vanna

2009-04-01

4p Monosomy and 12p trisomy have been discussed and redefined along with recently reviewed chromosomal syndromes. 12p Trisomy syndrome is characterized by normal or increased birth weight, developmental delay with early hypotonia, psychomotor delay, and typical facial appearance. Most likely, the observed phenotypic variability depends on the type and extent of the associated partial monosomy. Partial deletions of the short arm of one chromosome 4 cause the Wolf-Hirschhorn syndrome (WHS). Affected patients present Greek helmet face, growth and mental retardation, hypotonia, and seizures. The combination of these characteristics constitutes the phenotypic core of WHS. We present a clinical and molecular cytogenetic characterization of a 4-year old mentally retarded girl with macrosomy, facial dysmorphisms, and epilepsy, in whom an unbalanced t(4;12)(p16.3;p13.3) translocation was detected, giving rise to partial 4p monosomy and partial 12p trisomy. Because the patient shows most of the phenotypic characteristics of 12p trisomy, this case could contribute to a better definition of the duplicate critical region that determines the phenotype of the 12p trisomy syndrome.

Cell-autonomous correction of ring chromosomes in human induced pluripotent stem cells

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Bershteyn, Marina; Hayashi, Yohei; Desachy, Guillaume; Hsiao, Edward C.; Sami, Salma; Tsang, Kathryn M.; Weiss, Lauren A.; Kriegstein, Arnold R.; Yamanaka, Shinya; Wynshaw-Boris, Anthony

2014-03-01

Ring chromosomes are structural aberrations commonly associated with birth defects, mental disabilities and growth retardation. Rings form after fusion of the long and short arms of a chromosome, and are sometimes associated with large terminal deletions. Owing to the severity of these large aberrations that can affect multiple contiguous genes, no possible therapeutic strategies for ring chromosome disorders have been proposed. During cell division, ring chromosomes can exhibit unstable behaviour leading to continuous production of aneuploid progeny with low viability and high cellular death rate. The overall consequences of this chromosomal instability have been largely unexplored in experimental model systems. Here we generated human induced pluripotent stem cells (iPSCs) from patient fibroblasts containing ring chromosomes with large deletions and found that reprogrammed cells lost the abnormal chromosome and duplicated the wild-type homologue through the compensatory uniparental disomy (UPD) mechanism. The karyotypically normal iPSCs with isodisomy for the corrected chromosome outgrew co-existing aneuploid populations, enabling rapid and efficient isolation of patient-derived iPSCs devoid of the original chromosomal aberration. Our results suggest a fundamentally different function for cellular reprogramming as a means of `chromosome therapy' to reverse combined loss-of-function across many genes in cells with large-scale aberrations involving ring structures. In addition, our work provides an experimentally tractable human cellular system for studying mechanisms of chromosomal number control, which is of critical relevance to human development and disease.

An update on the mechanisms and pathophysiological consequences of genomic instability with a focus on ionizing radiation

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Streffer C

2015-12-01

Full Text Available Christian Streffer Institute for Medical Radiobiology, University Clinics Essen, Essen, Germany Abstract: The genome of eukaryotic cells is generally instable. DNA damage occurs by endogenous processes and exogenous toxic agents. The efficient DNA repair pathways conserve the genetic information to a large extent throughout the life. However, exposure to genotoxic agents can increase the genomic instability. This phenomenon develops in a delayed manner after approximately 20 and more cell generations. It is comparatively thoroughly investigated after the exposure to ionizing radiation. The increase of genomic instability has been observed after exposures to ionizing radiation in vitro and in vivo as well as with many different types of radiation. The effect is induced over a wide dose range, and it has been found with cell death, chromosomal damage, cell transformations, mutations, double-strand breaks, malformations, and cancers. No specific chromosomes or genomic sites have been observed for such events. The increased genomic instability can be transmitted to the next generation. Possible mechanisms such as oxidative stress (mitochondria may be involved, reduced DNA repair, changes in telomeres, epigenetic effects are discussed. A second wave of oxidative stress has been observed after radiation exposures with considerably high doses as well as with cytotoxic agents at time periods when an increased genomic instability was seen. However, the increase of genomic instability also happens to much lower radiation doses. Hypoxia induces an increase of genomic instability. This effect is apparently connected with a reduction of DNA repair. Changes of telomeres appear as the most probable mechanisms for the increase of genomic instability. Syndromes have been described with a genetic predisposition for high radiosensitivity. These individuals show an increase of cancer, a deficient DNA repair, a disturbed regulation of the cell cycle, and an

Reproductive outcome in 3 families with a satellited chromosome 4 with review of the literature.

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Arn, P H; Younie, L; Russo, S; Zackowski, J L; Mankinen, C; Estabrooks, L

1995-07-03

We describe 3 families segregating for a translocation of the nucleolus organizer region (NOR) onto chromosome 4. Review of previously reported cases of translocations involving NOR and chromosome 4 shows that these translocations may be associated with variable reproductive outcomes. We provide evidence that imprinting is not the mechanism responsible for the variable reproductive outcomes in the case of satellited 4p chromosomes; this may offer indirect support for a ribosomal gene position effect. Translocated ribosomal genes may influence the expression of neighboring genes and could explain the variable phenotypes in individuals with satellited nonacrocentric chromosomes. We recommend that prenatal counseling of individuals with satellited nonacrocentric chromosomes should be cautious.

Amplification of HER2 is a marker for global genomic instability

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Love Brad

2008-10-01

Full Text Available Abstract Background Genomic alterations of the proto-oncogene c-erbB-2 (HER-2/neu are associated with aggressive behavior and poor prognosis in patients with breast cancer. The variable clinical outcomes seen in patients with similar HER2 status, given similar treatments, suggests that the effects of amplification of HER2 can be influenced by other genetic changes. To assess the broader genomic implications of structural changes at the HER2 locus, we investigated relationships between genomic instability and HER2 status in patients with invasive breast cancer. Methods HER2 status was determined using the PathVysion® assay. DNA was extracted after laser microdissection from the 181 paraffin-embedded HER2 amplified (n = 39 or HER2 negative (n = 142 tumor specimens with sufficient tumor available to perform molecular analysis. Allelic imbalance (AI was assessed using a panel of microsatellite markers representing 26 chromosomal regions commonly altered in breast cancer. Student t-tests and partial correlations were used to investigate relationships between genomic instability and HER2 status. Results The frequency of AI was significantly higher (P P Conclusion The poor prognosis associated with HER2 amplification may be attributed to global genomic instability as cells with high frequencies of chromosomal alterations have been associated with increased cellular proliferation and aggressive behavior. In addition, high levels of DNA damage may render tumor cells refractory to treatment. In addition, specific alterations at chromosomes 11q13, 16q22-q24, and 18q21, all of which have been associated with aggressive tumor behavior, may serve as genetic modifiers to HER2 amplification. These data not only improve our understanding of HER in breast pathogenesis but may allow more accurate risk profiles and better treatment options to be developed.

Induction of genetic instability by ionizing radiation

International Nuclear Information System (INIS)

Little, J.B.

1999-01-01

Evidence is presented to support the hypothesis that radiation may induce a heritable, genome-wide process of instability that leads to an enhanced frequency of genetic changes occurring among the progeny of the original irradiated cell. This instability is transmissible over many generations of cell replication. Mutational instability is induced in a relatively large fraction (approximately 10 %) of the cell population, and may be modulated by factors acting in vivo. Thus, it cannot be a targeted event involving a specific gene or set of genes. There is no dose-response relationship in the range 2-12 Gy, suggesting that the instability phenotype may be induced by quite low radiation doses. The molecular mechanisms associated with the genesis of mutations in unstable populations differ from those for direct X-ray-induced mutations. These results suggest that it may not be possible to predict the nature of the dose-response relationship for the ultimate genetic effects of radiation based on a qualitative or quantitative analysis of the original DNA lesions. (author)

Uniparental isodisomy of chromosome 14 in two cases: An abnormal child and a normal adult

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Papenhausen, P.R.; Mueller, O.T.; Sutcliffe, M.; Diamond, T.M.; Kousseff, B.G. [Univ. of South Florida College of Medicine, Tampa, FL (United States); Johnson, V.P. [Univ. of South Dakota, Sioux Falls, SD (United States)

1995-11-20

Uniparental disomy (UPD) of a number of different chromosomes has been found in association with abnormal phenotypes. A growing body of evidence for an imprinting effect involving chromosome 14 has been accumulating. We report on a case of paternal UPD of chromosome 14 studied in late gestation due to polyhydramnios and a ventral wall hernia. A prenatal karyotype documented a balanced Robertsonian 14:14 translocation. The baby was born prematurely with hairy forehead, retrognathia, mild puckering of the lips and finger contractures. Hypotonia has persisted since birth and at age one year, a tracheostomy for laryngomalacia and gastrostomy for feeding remain necessary. Absence of maternal VNTR polymorphisms and homozygosity of paternal polymorphisms using chromosome 14 specific probes at D14S22 and D14S13 loci indicated paternal uniparental isodisomy (pUPID). Parental chromosomes were normal. We also report on a case of maternal LTPD in a normal patient with a balanced Robertsonian 14:14 translocation and a history of multiple miscarriages. Five previous reports of chromosome 14 UPD suggest that an adverse developmental effect may be more severe whenever the UPD is paternal in origin. This is the second reported patient with paternal UPD and the fifth reported with maternal UPD, and only few phenotypic similarities are apparent. Examination of these chromosome 14 UPD cases of maternal and paternal origin suggests that there are syndromic imprinting effects. 30 refs., 3 figs.

Condensin II mutation causes T-cell lymphoma through tissue-specific genome instability

Science.gov (United States)

Woodward, Jessica; Taylor, Gillian C.; Soares, Dinesh C.; Boyle, Shelagh; Sie, Daoud; Read, David; Chathoth, Keerthi; Vukovic, Milica; Tarrats, Nuria; Jamieson, David; Campbell, Kirsteen J.; Blyth, Karen; Acosta, Juan Carlos; Ylstra, Bauke; Arends, Mark J.; Kranc, Kamil R.; Jackson, Andrew P.; Bickmore, Wendy A.

2016-01-01

Chromosomal instability is a hallmark of cancer, but mitotic regulators are rarely mutated in tumors. Mutations in the condensin complexes, which restructure chromosomes to facilitate segregation during mitosis, are significantly enriched in cancer genomes, but experimental evidence implicating condensin dysfunction in tumorigenesis is lacking. We report that mice inheriting missense mutations in a condensin II subunit (Caph2nes) develop T-cell lymphoma. Before tumors develop, we found that the same Caph2 mutation impairs ploidy maintenance to a different extent in different hematopoietic cell types, with ploidy most severely perturbed at the CD4+CD8+ T-cell stage from which tumors initiate. Premalignant CD4+CD8+ T cells show persistent catenations during chromosome segregation, triggering DNA damage in diploid daughter cells and elevated ploidy. Genome sequencing revealed that Caph2 single-mutant tumors are near diploid but carry deletions spanning tumor suppressor genes, whereas P53 inactivation allowed Caph2 mutant cells with whole-chromosome gains and structural rearrangements to form highly aggressive disease. Together, our data challenge the view that mitotic chromosome formation is an invariant process during development and provide evidence that defective mitotic chromosome structure can promote tumorigenesis. PMID:27737961

Nitric oxide coordinates development of genomic instability in realization of combined effect with ionizing radiation.

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Mikhailenko, V M; Diomina, E A; Muzalov, I I; Gerashchenko, B I

2013-03-01

The aim of this study was to investigate the ability of environmental nitrogen oxides or natural nitric oxide (NO) donors to modify free radicals ba-lance and development of genomic instability alone or in combination with ionizing radiation. Genotoxicity and cytogenetic abnormalities were assessed in vitro in peripheral blood lymphocytes (PBL) isolated from healthy humans or in vivo in rats PBL. Human PBL were treated with physiologically relevant NO donor - S-Nitrosoglutathione and X-ray irradiation. The inhalation treatment of animals with NO was carried out in chamber with purified gaseous NO mixed inside with air. Levels of S-Nitrosohemoglobin and methemoglobin in the blood were assessed with electron paramagnetic resonance. The total level of reactive oxygen and nitrogen species in PBL was determined fluorometrically, and serum levels of reactive oxygen species was determined by spectrophotometric assay. DNA damages were assessed by alkaline single-cell gel electrophoresis. The frequency of chromosomal aberrations in human PBL measured with the conventional cytogenetic assay in metaphase cells on short-term (52 h) and long-term (72 h) cultures. Environmental nitrogen oxides or release of NO from stable complexes with biomolecules (such as S-Nitrosothiols) intensified generation of free radicals, DNA damage and development of genomic instability alone or in combination with ionizing radiation. Treatment of PBL by S-Nitrosoglutathione caused prevalent induction of chromatid type but irradiation - chromosome aberrations. The dose dependence of chromatid-type aberrations observed in human PBL after combined influence of S-Nitrosoglutathione and ionizing radiation indicates a crucial role of NO in the formation of chromosomal instability. NO can deregulate free radicals balance resulted in genotoxic effect, posttranslational modification of repair enzymes and thus coordinated development of genomic instability and increase of cancer risk.

Chromosomal Copy Number Variation in Saccharomyces pastorianus Is Evidence for Extensive Genome Dynamics in Industrial Lager Brewing Strains.

Science.gov (United States)

van den Broek, M; Bolat, I; Nijkamp, J F; Ramos, E; Luttik, M A H; Koopman, F; Geertman, J M; de Ridder, D; Pronk, J T; Daran, J-M

2015-09-01

Lager brewing strains of Saccharomyces pastorianus are natural interspecific hybrids originating from the spontaneous hybridization of Saccharomyces cerevisiae and Saccharomyces eubayanus. Over the past 500 years, S. pastorianus has been domesticated to become one of the most important industrial microorganisms. Production of lager-type beers requires a set of essential phenotypes, including the ability to ferment maltose and maltotriose at low temperature, the production of flavors and aromas, and the ability to flocculate. Understanding of the molecular basis of complex brewing-related phenotypic traits is a prerequisite for rational strain improvement. While genome sequences have been reported, the variability and dynamics of S. pastorianus genomes have not been investigated in detail. Here, using deep sequencing and chromosome copy number analysis, we showed that S. pastorianus strain CBS1483 exhibited extensive aneuploidy. This was confirmed by quantitative PCR and by flow cytometry. As a direct consequence of this aneuploidy, a massive number of sequence variants was identified, leading to at least 1,800 additional protein variants in S. pastorianus CBS1483. Analysis of eight additional S. pastorianus strains revealed that the previously defined group I strains showed comparable karyotypes, while group II strains showed large interstrain karyotypic variability. Comparison of three strains with nearly identical genome sequences revealed substantial chromosome copy number variation, which may contribute to strain-specific phenotypic traits. The observed variability of lager yeast genomes demonstrates that systematic linking of genotype to phenotype requires a three-dimensional genome analysis encompassing physical chromosomal structures, the copy number of individual chromosomes or chromosomal regions, and the allelic variation of copies of individual genes. Copyright © 2015, van den Broek et al.

The phenotypic variance gradient - a novel concept.

Science.gov (United States)

Pertoldi, Cino; Bundgaard, Jørgen; Loeschcke, Volker; Barker, James Stuart Flinton

2014-11-01

Evolutionary ecologists commonly use reaction norms, which show the range of phenotypes produced by a set of genotypes exposed to different environments, to quantify the degree of phenotypic variance and the magnitude of plasticity of morphometric and life-history traits. Significant differences among the values of the slopes of the reaction norms are interpreted as significant differences in phenotypic plasticity, whereas significant differences among phenotypic variances (variance or coefficient of variation) are interpreted as differences in the degree of developmental instability or canalization. We highlight some potential problems with this approach to quantifying phenotypic variance and suggest a novel and more informative way to plot reaction norms: namely "a plot of log (variance) on the y-axis versus log (mean) on the x-axis, with a reference line added". This approach gives an immediate impression of how the degree of phenotypic variance varies across an environmental gradient, taking into account the consequences of the scaling effect of the variance with the mean. The evolutionary implications of the variation in the degree of phenotypic variance, which we call a "phenotypic variance gradient", are discussed together with its potential interactions with variation in the degree of phenotypic plasticity and canalization.

Structural Chromosomal Alterations Induced by Dietary Bioflavonoids in Fanconi Anemia Lymphocytes

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Gonzalo Guevara

2007-06-01

Full Text Available IntroductionFanconi anemia is an autosomal recessive diseasecharacterized by a variety of congenital abnormalities,progressive bone marrow failure,increased chromosomal instability and higherrisk to acute myeloid leukemia, solid tumors. Thisentity can be considered an appropriate biologicalmodel to analyze natural substances with possiblegenotoxic effect. The aims of this study wereto describe and quantify structural chromosomalaberrations induced by 5 flavones, 2 isoflavonesand a topoisomerase II chemotherapeutic inhibitorin Fanconi anemia lymphocytes in order todetermine chromosomal numbers changes and/or type of chromosomal damage.Materials and methodsChromosomes stimulated by phytohaemagglutininM, from Fanconi anemia lymphocytes,were analysed by conventional cytogenetic culture.For each chemical substance and controls,one hundred metaphases were evaluated. Chromosomalalterations were documented by photographyand imaging analyzer. To statisticalanalysis was used chi square test to identify significantdifferences between frequencies of chromosomaldamage of basal and exposed cellcultured a P value less than 0.05.ResultsThere were 431 chromosomal alterations in1000 metaphases analysed; genistein was themore genotoxic bioflavonoid, followed in descendentorder by genistin, fisetin, kaempferol,quercetin, baicalein and miricetin. Chromosomalaberrations observed were: chromatidbreaks, chromosomal breaks, cromatid andchromosomal gaps, quadriratials exchanges,dicentrics chromosome and complex rearrangements.ConclusionBioflavonoids as genistein, genistin and fisetin,which are commonly present in the human diet,showed statistical significance in the number ofchromosomal aberrations in Fanconi anemialymphocytes, regarding the basal damage.

Schizophrenia and chromosomal deletions

Energy Technology Data Exchange (ETDEWEB)

Lindsay, E.A.; Baldini, A. [Baylor College of Medicine, Houston, TX (United States); Morris, M. A. [Univ. of Geneva School of Medicine, NY (United States)] [and others

1995-06-01

Recent genetic linkage analysis studies have suggested the presence of a schizophrenia locus on the chromosomal region 22q11-q13. Schizophrenia has also been frequently observed in patients affected with velo-cardio-facial syndrome (VCFS), a disorder frequently associated with deletions within 22q11.1. It has been hypothesized that psychosis in VCFS may be due to deletion of the catechol-o-methyl transferase gene. Prompted by these observations, we screened for 22q11 deletions in a population of 100 schizophrenics selected from the Maryland Epidemiological Sample. Our results show that there are schizophrenic patients carrying a deletion of 22q11.1 and a mild VCFS phenotype that might remain unrecognized. These findings should encourage a search for a schizophrenia-susceptibility gene within the deleted region and alert those in clinical practice to the possible presence of a mild VCFS phenotype associated with schizophrenia. 9 refs.

Amplification of HER2 is a marker for global genomic instability

International Nuclear Information System (INIS)

Ellsworth, Rachel E; Ellsworth, Darrell L; Patney, Heather L; Deyarmin, Brenda; Love, Brad; Hooke, Jeffrey A; Shriver, Craig D

2008-01-01

Genomic alterations of the proto-oncogene c-erbB-2 (HER-2/neu) are associated with aggressive behavior and poor prognosis in patients with breast cancer. The variable clinical outcomes seen in patients with similar HER2 status, given similar treatments, suggests that the effects of amplification of HER2 can be influenced by other genetic changes. To assess the broader genomic implications of structural changes at the HER2 locus, we investigated relationships between genomic instability and HER2 status in patients with invasive breast cancer. HER2 status was determined using the PathVysion ® assay. DNA was extracted after laser microdissection from the 181 paraffin-embedded HER2 amplified (n = 39) or HER2 negative (n = 142) tumor specimens with sufficient tumor available to perform molecular analysis. Allelic imbalance (AI) was assessed using a panel of microsatellite markers representing 26 chromosomal regions commonly altered in breast cancer. Student t-tests and partial correlations were used to investigate relationships between genomic instability and HER2 status. The frequency of AI was significantly higher (P < 0.005) in HER2 amplified (27%) compared to HER2 negative tumors (19%). Samples with HER2 amplification showed significantly higher levels of AI (P < 0.05) at chromosomes 11q23, 16q22-q24 and 18q21. Partial correlations including ER status and tumor grade supported associations between HER2 status and alterations at 11q13.1, 16q22-q24 and 18q21. The poor prognosis associated with HER2 amplification may be attributed to global genomic instability as cells with high frequencies of chromosomal alterations have been associated with increased cellular proliferation and aggressive behavior. In addition, high levels of DNA damage may render tumor cells refractory to treatment. In addition, specific alterations at chromosomes 11q13, 16q22-q24, and 18q21, all of which have been associated with aggressive tumor behavior, may serve as genetic modifiers to HER2

Phenotypic variation within European carriers of the Y-chromosomal gr/gr deletion is independent of Y-chromosomal background

DEFF Research Database (Denmark)

Krausz, C; Giachini, C; Xue, Y

2008-01-01

of duplications and the Y-chromosomal haplogroup were characterised. Although the study had good power to detect factors that accounted for >or=5.5% of the variation in sperm concentration, no such factor was found. A negative effect of gr/gr deletions followed by b2/b4 duplication was found within...

Preferential retrotransposition in aging yeast mother cells is correlated with increased genome instability.

Science.gov (United States)

Patterson, Melissa N; Scannapieco, Alison E; Au, Pak Ho; Dorsey, Savanna; Royer, Catherine A; Maxwell, Patrick H

2015-10-01

Retrotransposon expression or mobility is increased with age in multiple species and could promote genome instability or altered gene expression during aging. However, it is unclear whether activation of retrotransposons during aging is an indirect result of global changes in chromatin and gene regulation or a result of retrotransposon-specific mechanisms. Retromobility of a marked chromosomal Ty1 retrotransposon in Saccharomyces cerevisiae was elevated in mother cells relative to their daughter cells, as determined by magnetic cell sorting of mothers and daughters. Retromobility frequencies in aging mother cells were significantly higher than those predicted by cell age and the rate of mobility in young populations, beginning when mother cells were only several generations old. New Ty1 insertions in aging mothers were more strongly correlated with gross chromosome rearrangements than in young cells and were more often at non-preferred target sites. Mother cells were more likely to have high concentrations and bright foci of Ty1 Gag-GFP than their daughter cells. Levels of extrachromosomal Ty1 cDNA were also significantly higher in aged mother cell populations than their daughter cell populations. These observations are consistent with a retrotransposon-specific mechanism that causes retrotransposition to occur preferentially in yeast mother cells as they begin to age, as opposed to activation by phenotypic changes associated with very old age. These findings will likely be relevant for understanding retrotransposons and aging in many organisms, based on similarities in regulation and consequences of retrotransposition in diverse species. Copyright © 2015 Elsevier B.V. All rights reserved.

Reproductive outcome in 3 families with a satellited chromosome 4 with review of the literature

Energy Technology Data Exchange (ETDEWEB)

Arn, P.H.; Younie, L.; Russo, S. [Nemours Children`s Clinic, Jacksonville, FL (United States)] [and others

1995-07-03

We describe 3 families segregating for a translocation of the nucleolus organizer region (NOR) onto chromosome 4. Review of previously reported cases of translocations involving NOR and chromosome 4 shows that these translocations may be associated with variable reproductive outcomes. We provide evidence that imprinting is not the mechanism responsible for the variable reproductive outcomes in the case of satellited 4p chromosomes; this may offer indirect support for a ribosomal gene position effect. Translocated ribosomal genes may influence the expression of neighboring genes and could explain the variable phenotypes in individuals with satellited nonacrocentric chromosomes. We recommend that prenatal counseling of individuals with satellited nonacrocentric chromosomes should be cautious. 23 refs., 2 figs., 1 tab.

Is auxin involved in the induction of genetic instability in barley homeotic double mutants?

Science.gov (United States)

Šiukšta, Raimondas; Vaitkūnienė, Virginija; Rančelis, Vytautas

2018-02-01

The triggers of genetic instability in barley homeotic double mutants are tweaky spike -type mutations associated with an auxin imbalance in separate spike phytomeres. Barley homeotic tweaky spike;Hooded (tw;Hd) double mutants are characterized by an inherited instability of spike and flower development, which is absent in the single parental constituents. The aim of the present study was to show that the trigger of genetic instability in the double mutants is the tw mutations, which are associated with an auxin imbalance in the developing spikes. Their pleiotropic effects on genes related to spike/flower development may cause the genetic instability of double mutants. The study of four double-mutant groups composed of different mutant alleles showed that the instability arose only if the mutant allele tw was a constituent of the double mutants. Application of auxin inhibitors and 2,4-dichlorophenoxyacetic acid (2,4-D) demonstrated the relationship of the instability of the double mutants and the phenotype of the tw mutants to auxin imbalance. 2,4-D induced phenocopies of the tw mutation in wild-type plants and rescued the phenotypes of three allelic tw mutants. The differential display (dd-PCR) method allowed the identification of several putative candidate genes in tw that may be responsible for the initiation of instability in the double mutants by pleiotropic variations of their expression in the tw mutant associated with auxin imbalance in the developing spikes. The results of the present study linked the genetic instability of homeotic double mutants with an auxin imbalance caused by one of the constituents (tw). The genetic instability of the double mutants in relation to auxin imbalance was studied for the first time. A matrocliny on instability expression was also observed.

Delayed changes in gene expression in human fibroblasts after alpha irradiation

International Nuclear Information System (INIS)

Salo, A.; Peraelae, M.; Mustonen, R.; Kadhim, M.; Marsden, S.; Sabatier, L.; Martins, L.

2003-01-01

It has been commonly accepted that the biological consequences following radiation exposure are attributable to DNA damage and expressed within one or two cell generations. Recent evidence, however, has now been emerged to challenge this classical paradigm. Changes in non-irradiated bystander cells may lead to transmissible genomic instability. This phenomenon has been termed 'non-targeted' and in addition to genomic instability, includes also radiation-induced bystander effects. Various types of genomic damage can be observed in affected cells for many generations after irradiation. After alphaparticle irradiation, delayed non-clonal chromosomal aberrations were seen in surviving cells of cultured haematopoietic stem cells from CBA/H mice. These aberrations were mostly of non-identical chromatid type, showing that they had arisen for many generations after the irradiation. Although radiation-induced genomic instability has been observed in several in vitro and in vivo experiments, the mechanisms involved in the induction and transmission of genomic instability remain unknown. The purpose of this work was to provide new information about the delayed or persistent effects of radiation on expression of genes associated with chromosomal instability phenotype. It has been assumed that this phenotype is linked to sustained alterations in gene expression rather than to specific gene mutations. The delayed gene expression changes in cells after irradiation have not been extensively studied. Human syndromes expressing chromosomal instability have been demonstrated to have a role in the evolution of malignancy. Thus, the role of radiation-induced genomic instability in radiation oncogenesis is of importance. The work is part of the joint EU-funded project called 'Genomic instability and radiation-induced cancer' (RADINSTAB). The aim of the RADINSTAB project was to investigate health effects of genomic damage, predisposition to cancer and correlation of genomic instability

Chromosomal Aneuploidy Improves the Brewing Characteristics of Sake Yeast.

Science.gov (United States)

Kadowaki, Masafumi; Fujimaru, Yuki; Taguchi, Seiga; Ferdouse, Jannatul; Sawada, Kazutaka; Kimura, Yuta; Terasawa, Yohei; Agrimi, Gennaro; Anai, Toyoaki; Noguchi, Hideki; Toyoda, Atsushi; Fujiyama, Asao; Akao, Takeshi; Kitagaki, Hiroshi

2017-12-15

The effect of chromosomal aneuploidy on the brewing characteristics of brewery yeasts has not been studied. Here we report that chromosomal aneuploidy in sake brewery yeast ( Saccharomyces cerevisiae ) leads to the development of favorable brewing characteristics. We found that pyruvate-underproducing sake yeast, which produces less off-flavor diacetyl, is aneuploid and trisomic for chromosomes XI and XIV. To confirm that this phenotype is due to aneuploidy, we obtained 45 haploids with various chromosomal additions and investigated their brewing profiles. A greater number of chromosomes correlated with a decrease in pyruvate production. Especially, sake yeast haploids with extra chromosomes in addition to chromosome XI produced less pyruvate than euploids. Mitochondrion-related metabolites and intracellular oxygen species in chromosome XI aneuploids were higher than those in euploids, and this effect was canceled in their "petite" strains, suggesting that an increase in chromosomes upregulated mitochondrial activity and decreased pyruvate levels. These findings suggested that an increase in chromosome number, including chromosome XI, in sake yeast haploids leads to pyruvate underproduction through the augmentation of mitochondrial activity. This is the first report proposing that aneuploidy in brewery yeasts improves their brewing profile. IMPORTANCE Chromosomal aneuploidy has not been evaluated in development of sake brewing yeast strains. This study shows the relationship between chromosomal aneuploidy and brewing characteristics of brewery yeast strains. High concentrations of pyruvate during sake storage give rise to α-acetolactate and, in turn, to high concentrations of diacetyl, which is considered an off-flavor. It was demonstrated that pyruvate-underproducing sake yeast is trisomic for chromosome XI and XIV. Furthermore, sake yeast haploids with extra chromosomes produced reduced levels of pyruvate and showed metabolic processes characteristic of

Tumor Cell-Free DNA Copy Number Instability Predicts Therapeutic Response to Immunotherapy.

Science.gov (United States)

Weiss, Glen J; Beck, Julia; Braun, Donald P; Bornemann-Kolatzki, Kristen; Barilla, Heather; Cubello, Rhiannon; Quan, Walter; Sangal, Ashish; Khemka, Vivek; Waypa, Jordan; Mitchell, William M; Urnovitz, Howard; Schütz, Ekkehard

2017-09-01

Purpose: Chromosomal instability is a fundamental property of cancer, which can be quantified by next-generation sequencing (NGS) from plasma/serum-derived cell-free DNA (cfDNA). We hypothesized that cfDNA could be used as a real-time surrogate for imaging analysis of disease status as a function of response to immunotherapy and as a more reliable tool than tumor biomarkers. Experimental Design: Plasma cfDNA sequences from 56 patients with diverse advanced cancers were prospectively collected and analyzed in a single-blind study for copy number variations, expressed as a quantitative chromosomal number instability (CNI) score versus 126 noncancer controls in a training set of 23 and a blinded validation set of 33. Tumor biomarker concentrations and a surrogate marker for T regulatory cells (Tregs) were comparatively analyzed. Results: Elevated CNI scores were observed in 51 of 56 patients prior to therapy. The blinded validation cohort provided an overall prediction accuracy of 83% (25/30) and a positive predictive value of CNI score for progression of 92% (11/12). The combination of CNI score before cycle (Cy) 2 and 3 yielded a correct prediction for progression in all 13 patients. The CNI score also correctly identified cases of pseudo-tumor progression from hyperprogression. Before Cy2 and Cy3, there was no significant correlation for protein tumor markers, total cfDNA, or surrogate Tregs. Conclusions: Chromosomal instability quantification in plasma cfDNA can serve as an early indicator of response to immunotherapy. The method has the potential to reduce health care costs and disease burden for cancer patients following further validation. Clin Cancer Res; 23(17); 5074-81. ©2017 AACR . ©2017 American Association for Cancer Research.

Csm4, in collaboration with Ndj1, mediates telomere-led chromosome dynamics and recombination during yeast meiosis.

Directory of Open Access Journals (Sweden)

Jennifer J Wanat

2008-09-01

Full Text Available Chromosome movements are a general feature of mid-prophase of meiosis. In budding yeast, meiotic chromosomes exhibit dynamic movements, led by nuclear envelope (NE-associated telomeres, throughout the zygotene and pachytene stages. Zygotene motion underlies the global tendency for colocalization of NE-associated chromosome ends in a "bouquet." In this study, we identify Csm4 as a new molecular participant in these processes and show that, unlike the two previously identified components, Ndj1 and Mps3, Csm4 is not required for meiosis-specific telomere/NE association. Instead, it acts to couple telomere/NE ensembles to a force generation mechanism. Mutants lacking Csm4 and/or Ndj1 display the following closely related phenotypes: (i elevated crossover (CO frequencies and decreased CO interference without abrogation of normal pathways; (ii delayed progression of recombination, and recombination-coupled chromosome morphogenesis, with resulting delays in the MI division; and (iii nondisjunction of homologs at the MI division for some reason other than absence of (the obligatory CO(s. The recombination effects are discussed in the context of a model where the underlying defect is chromosome movement, the absence of which results in persistence of inappropriate chromosome relationships that, in turn, results in the observed mutant phenotypes.

Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster

OpenAIRE

He, Bing; Caudy, Amy; Parsons, Lance; Rosebrock, Adam; Pane, Attilio; Raj, Sandeep; Wieschaus, Eric

2012-01-01

Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions. By excluding seque...

Molecular evolution of colorectal cancer: from multistep carcinogenesis to the big bang.

Science.gov (United States)

Amaro, Adriana; Chiara, Silvana; Pfeffer, Ulrich

2016-03-01

Colorectal cancer is characterized by exquisite genomic instability either in the form of microsatellite instability or chromosomal instability. Microsatellite instability is the result of mutation of mismatch repair genes or their silencing through promoter methylation as a consequence of the CpG island methylator phenotype. The molecular causes of chromosomal instability are less well characterized. Genomic instability and field cancerization lead to a high degree of intratumoral heterogeneity and determine the formation of cancer stem cells and epithelial-mesenchymal transition mediated by the TGF-β and APC pathways. Recent analyses using integrated genomics reveal different phases of colorectal cancer evolution. An initial phase of genomic instability that yields many clones with different mutations (big bang) is followed by an important, previously not detected phase of cancer evolution that consists in the stabilization of several clones and a relatively flat outgrowth. The big bang model can best explain the coexistence of several stable clones and is compatible with the fact that the analysis of the bulk of the primary tumor yields prognostic information.

Genomic changes in Fanconi anemia: implications for diagnosis, pathogenesis and prognosis

OpenAIRE

Groß, Michaela

2003-01-01

Fanconi anemia (FA) is a genetically and phenotypically heterogenous autoso- mal recessive disease associated with chromosomal instability, progressive bone marrow failure, typical birth defects and predisposition to neoplasia. The clinical phenotype is similar in all known complementation groups (FA-A, FA-B, FA-C,FA-D1, FA-D2, FA-E, FA-F and FA-G). The cellular phenotype is characterized by hypersensitivity to DNA crosslinking agents (MMC,DEB), which is exploited as a diagnostic tool. Alltog...

Genomic instability in rat: Breakpoints induced by ionising radiation and interstitial telomeric-like sequences

International Nuclear Information System (INIS)

Camats, Nuria; Ruiz-Herrera, Aurora; Parrilla, Juan Jose; Acien, Maribel; Paya, Pilar; Giulotto, Elena; Egozcue, Josep; Garcia, Francisca; Garcia, Montserrat

2006-01-01

The Norwegian rat (Rattus norvegicus) is the most widely studied experimental species in biomedical research although little is known about its chromosomal structure. The characterisation of possible unstable regions of the karyotype of this species would contribute to the better understanding of its genomic architecture. The cytogenetic effects of ionising radiation have been widely used for the study of genomic instability, and the importance of interstitial telomeric-like sequences (ITSs) in instability of the genome has also been reported in previous studies in vertebrates. In order to describe the unstable chromosomal regions of R. norvegicus, the distribution of breakpoints induced by X-irradiation and ITSs in its karyotype were analysed in this work. For the X-irradiation analysis, 52 foetuses (from 14 irradiated rats) were studied, 4803 metaphases were analysed, and a total of 456 breakpoints induced by X-rays were detected, located in 114 chromosomal bands, with 25 of them significantly affected by X-irradiation (hot spots). For the analysis of ITSs, three foetuses (from three rats) were studied, 305 metaphases were analysed and 121 ITSs were detected, widely distributed in the karyotype of this species. Seventy-six percent of all hot spots analysed in this study were co-localised with ITSs

Genomic instability in rat: Breakpoints induced by ionising radiation and interstitial telomeric-like sequences

Energy Technology Data Exchange (ETDEWEB)

Camats, Nuria [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Departament de Biologia Cel.lular, Fisiologia i Immunologia Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Ruiz-Herrera, Aurora [Departament de Biologia Cel.lular, Fisiologia i Immunologia Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Parrilla, Juan Jose [Servicio de Ginecologia y Obstetricia, Hospital Universitario Virgen de la Arrixaca, Ctra, Madrid-Cartagena, s/n, El Palmar, 30120 Murcia (Spain); Acien, Maribel [Servicio de Ginecologia y Obstetricia, Hospital Universitario Virgen de la Arrixaca, Ctra, Madrid-Cartagena, s/n, El Palmar, 30120 Murcia (Spain); Paya, Pilar [Servicio de Ginecologia y Obstetricia, Hospital Universitario Virgen de la Arrixaca, Ctra, Madrid-Cartagena, s/n, El Palmar, 30120 Murcia (Spain); Giulotto, Elena [Dipartimento di Genetica e Microbiologia Adriano Buzzati Traverso, Universita degli Studi di Pavia, 27100 Pavia (Italy); Egozcue, Josep [Departament de Biologia Cel.lular, Fisiologia i Immunologia Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Garcia, Francisca [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Garcia, Montserrat [Institut de Biotecnologia i Biomedicina (IBB), Universitat Autonoma de Barcelona, 08193 Barcelona (Spain) and Departament de Biologia Cellular, Fisiologia i Immunologia Universitat Autonoma de Barcelona, 08193 Barcelona (Spain)]. E-mail: Montserrat.Garcia.Caldes@uab.es

2006-03-20

The Norwegian rat (Rattus norvegicus) is the most widely studied experimental species in biomedical research although little is known about its chromosomal structure. The characterisation of possible unstable regions of the karyotype of this species would contribute to the better understanding of its genomic architecture. The cytogenetic effects of ionising radiation have been widely used for the study of genomic instability, and the importance of interstitial telomeric-like sequences (ITSs) in instability of the genome has also been reported in previous studies in vertebrates. In order to describe the unstable chromosomal regions of R. norvegicus, the distribution of breakpoints induced by X-irradiation and ITSs in its karyotype were analysed in this work. For the X-irradiation analysis, 52 foetuses (from 14 irradiated rats) were studied, 4803 metaphases were analysed, and a total of 456 breakpoints induced by X-rays were detected, located in 114 chromosomal bands, with 25 of them significantly affected by X-irradiation (hot spots). For the analysis of ITSs, three foetuses (from three rats) were studied, 305 metaphases were analysed and 121 ITSs were detected, widely distributed in the karyotype of this species. Seventy-six percent of all hot spots analysed in this study were co-localised with ITSs.

Chromosome aberrations and oncogene alterations in atomic bomb related leukemias - different mechanisms from de novo leukemias

International Nuclear Information System (INIS)

Tanaka, K.; Tanaka, H.; Kamada, N.

2003-01-01

It is well known that leukemia occurred more frequently among atomic bomb survivors. In 132 atomic bomb related ( AB- related) leukemia patients during 1978-1999, 33 acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) patients had their exposure doses of more than 1Gy (DS86). Chromosome aberrations of the 33 patients were compared with those from 588 de novo AML/MDS patients who had been bone before August 1945 as control. No FAB M3 patient was observed in the exposed group. Most AB-related AML preceded a long term of MDS stage. Twenty seven of the 33 patients showed complex types of chromosome aberrations with more than three chromosomes involving chromosomes 5,7 and 11. The number of chromosomes abnormality per cell in the AB-related leukemia was 3.78 while 0.92 in de novo leukemia. Only one of the 33 patients had normal karyotype, while 44.1% in de novo leukemia patients. Translocations of chromosome 11 at 11q13 to 11q23 and deletion/ loss of chromosome 20 were frequently observed in AB-related leukemia. No leukemia-type specific translocations such as t(8;21),t(15;17) and 11q23 were found in the 33 AB-related leukemia patients. Furthermore, molecular analyses using FISH and PCR-SSCP revealed the presence of breakpoint located outside of MLL gene in the patients with translocations at 11q22-23 and DNA base derangements of RUNT domain of AML1(CBF β 2)gene with AML/MDS patients without t(8;21) and with a high dose of exposure. These results suggest that AB-related leukemia derives from an exposed pluripotent hematopoietic stem cell which has been preserved for a long time in the bone marrow, expressing high genetic instability such as microsatellite instability. On the other hand, de novo leukemia develops from a committed hematopoietic stem cell and shows simple and leukemia-type specific chromosome aberrations. These findings are important for understanding mechanisms for radiation-induced leukemia

A mitosis-specific and R loop-driven ATR pathway promotes faithful chromosome segregation.

Science.gov (United States)

Kabeche, Lilian; Nguyen, Hai Dang; Buisson, Rémi; Zou, Lee

2018-01-05

The ataxia telangiectasia mutated and Rad3-related (ATR) kinase is crucial for DNA damage and replication stress responses. Here, we describe an unexpected role of ATR in mitosis. Acute inhibition or degradation of ATR in mitosis induces whole-chromosome missegregation. The effect of ATR ablation is not due to altered cyclin-dependent kinase 1 (CDK1) activity, DNA damage responses, or unscheduled DNA synthesis but to loss of an ATR function at centromeres. In mitosis, ATR localizes to centromeres through Aurora A-regulated association with centromere protein F (CENP-F), allowing ATR to engage replication protein A (RPA)-coated centromeric R loops. As ATR is activated at centromeres, it stimulates Aurora B through Chk1, preventing formation of lagging chromosomes. Thus, a mitosis-specific and R loop-driven ATR pathway acts at centromeres to promote faithful chromosome segregation, revealing functions of R loops and ATR in suppressing chromosome instability. Copyright © 2018, American Association for the Advancement of Science.

Pericentric inversion of chromosome 18 in parents leading to a phenotypically normal child with segmental uniparental disomy 18.

Science.gov (United States)

Kariminejad, Ariana; Kariminejad, Roxana; Moshtagh, Azadeh; Zanganeh, Maryam; Kariminejad, Mohammad Hassan; Neuenschwander, Stefan; Okoniewski, Michal; Wey, Eva; Schinzel, Albert; Baumer, Alessandra

2011-05-01

In this study, we report a familial inversion of chromosome 18, inv(18)(p11.31q21.33), in both members of a consanguineous couple. Their first child had inherited one balanced pericentric inversion along with a recombinant chromosome 18 resulting in dup(18q)/del(18p), and had mild dysmorphic features in the absence of mental and developmental retardation. The second child had received two recombinant chromosomes 18, from the mother a derivative chromosome 18 with dup(18p)/del(18q) and from the father a derivative chromosome 18 with dup(18q)/del(18p). The aberration was prenatally detected; however, as the two opposite aneuploidies were thought to compensate each other, the family decided to carry on with the pregnancy, knowing that uniparental disomy for the segments outside the inversion could have an adverse influence on the development of the child. Uniparental disomy was confirmed by SNP arrays. The child, who has been followed up until the age of 20 months, is healthy and normal. It seems to be the first reported case with two opposite recombinant chromosomes that compensate each other and lead to segmental uniparental disomy for two segments on the chromosome, one maternal and the other paternal.

Mouse Chromosome Engineering for Modeling Human Disease

OpenAIRE

van der Weyden, Louise; Bradley, Allan

2006-01-01

Chromosomal rearrangements occur frequently in humans and can be disease-associated or phenotypically neutral. Recent technological advances have led to the discovery of copy-number changes previously undetected by cytogenetic techniques. To understand the genetic consequences of such genomic changes, these mutations need to be modeled in experimentally tractable systems. The mouse is an excellent organism for this analysis because of its biological and genetic similarity to humans, and the e...

New type of genome instability in Drosophila melanogaster

International Nuclear Information System (INIS)

Georgiev, P.G.; Simonova, O.B.; Gerasimova, T.I.

1988-01-01

During crossing of two stable laboratory lines, y 2 sc 1w aG and Df(1)Pgd-kz/FM4, y 31d sc 8 dm B, consistent instability originated reproducibly in progeny containing a y 2 sc 1 w aG chromosome and autosomes of both lines. It is expressed in active mutagenesis observed over the course of several tens of generations. Destabilization occurs independently of direction of crossing. Mutagenesis occurs both in somatic and in sex cells of males and females. It displays high locus specificity. A transpositional nature was shown for at least some of the mutations. Results of the experiments concerning hybridization in situ with different mobile elements indicates an absence or low frequency of tranpositional bursts in the system. Possible mechanisms of induction of genetic instability in the system described are discussed

Radiation induced genomic instability

International Nuclear Information System (INIS)

Morgan, W.

2003-01-01

This presentation will focus on delayed genetic effects occurring in the progeny of cells after exposure to ionizing radiation. We have developed a model system for investigating those genetic effects occurring multiple generations after radiation exposure. The presentation will describe some of the delayed effects observed after radiation exposures including delayed chromosomal rearrangements, and recombination events as determined by a plasmid based assay system. We will present new data on how changes in gene expression as measured by differential display and DNA microarray analysis provides a mechanism by which cells display a memory of irradiation, and introduce candidate genes that may play a role in initiating and perpetuation the unstable phenotype. These results will be discussed in terms of the recently described non-targeted Death Inducing Effect (DIE) where by secreted factors from clones of unstable cells can elicit effects in non irradiated cells and may serve to perpetuate the unstable phenotype in cells that themselves were not irradiated

Chromosomes of older humans are more prone to aminopterine-induced breakage

International Nuclear Information System (INIS)

Esposito, D.; Fassina, G.; Szabo, P.; Weksler, M.; De Angelis, P.; Siniscalco, M.; Rodgers, L.

1989-01-01

The authors have adopted a simplified version of the cell hybrid cotransfer method to test the hypothesis that human lymphocytes derived from elderly individuals have a higher chromosome instability. Peripheral blood lymphocytes from old male individuals and young controls were fused with a Chinese hamster cell line (CHO-YH21), yielding 10 HAT-resistant rodent-human clones from the old propositi and 22 from the young controls. Both series of hybrid clones were analyzed with respect to the retention of the enzyme glucose-6-phosphate dehydrogenase and the surface antigen MIC2 identified by monoclonal antibody 12E7, two human X chromosome-linked markers located at opposite ends of the X chromosome. Cell hybrid clones with an X chromosome from a young control retained both markers in about 70% of the cells. In contrast, cell hybrid clones with an X chromosome from an old donor retained the MIC2 marker in only 30% of their cells. Slot-blot hybridization studies have established that the observed loss of the MIC2 marker is due to loss of the coding gene, not to suppression of its expression. T lymphocytes from old donors were also found to have an LD 50 for aminopterine significantly lower than the concentration of this drug in the HAT medium used to grow the hybrids. They speculate that the higher rate of chromosomal breakage and of marker loss observed along the old-age X chromosomes could be the result of molecular scars accumulated with aging at sites of constitutive chromosomal fragility

TMAP/CKAP2 is essential for proper chromosome segregation.

Science.gov (United States)

Hong, Kyung Uk; Kim, Eunhee; Bae, Chang-Dae; Park, Joobae

2009-01-15

Tumor-associated microtubule-associated protein (TMAP), also known as cytoskeleton associated protein 2 (CKAP2), is a novel mitotic spindle-associated protein which is frequently up-regulated in various malignances. However, its cellular functions remain unknown. Previous reports suggested that the cellular functions of TMAP/CKAP2 pertain to regulation of the dynamics and assembly of the mitotic spindle. To investigate its role in mitosis, we studied the effects of siRNA-mediated depletion of TMAP/CKAP2 in cultured mammalian cells. Unexpectedly, TMAP/CKAP2 knockdown did not result in significant alterations of the spindle apparatus. However, TMAP/CKAP2-depleted cells often exhibited abnormal nuclear morphologies, which were accompanied by abnormal organization of the nuclear lamina, and chromatin bridge formation between two daughter cell nuclei. Time lapse video microscopy revealed that the changes in nuclear morphology and chromatin bridge formations observed in TMAP/CKAP2-depleted cells are the result of defects in chromosome segregation. Consistent with this, the spindle checkpoint activity was significantly reduced in TMAP/CKAP2-depleted cells. Moreover, chromosome missegregation induced by depletion of TMAP/CKAP2 ultimately resulted in reduced cell viability and increased chromosomal instability. Our present findings demonstrate that TMAP/CKAP2 is essential for proper chromosome segregation and for maintaining genomic stability.

Chromosome r(10(p15.3q26.12 in a newborn child: case report

Directory of Open Access Journals (Sweden)

Jonasson Jon

2009-12-01

Full Text Available Abstract Background Ring chromosome 10 is a rare cytogenetic finding. Of the less than 10 reported cases we have found in the literature, none was characterized using high-resolution microarray analysis. Ring chromosomes are frequently unstable due to sister chromatid exchanges and mitotic failures. When mosaicism is present, the interpretation of genotype-phenotype correlations becomes extremely difficult. Results We report on a newborn girl with growth retardation, microcephaly, congenital heart defects, dysmorphic features and psychomotor retardation. Karyotyping revealed a non-mosaic apparently stable ring chromosome 10 replacing one of the normal homologues in all analyzed metaphases. High-resolution oligonucleotide microarray analysis showed a de novo approximately 12.5 Mb terminal deletion 10q26.12 -> qter and a corresponding 285 kb terminal deletion of 10pter -> p15.3. Conclusion This case demonstrates that an increased nuchal translucency thickness detected by early ultrasonography should preferably lead to not only QF-PCR for the diagnosis of Down syndrome but also karyotyping. In the future, microarray analysis, which needs further evaluation, might become the method of choice. The clinical phenotype of our patient was in agreement with that of patients with a terminal 10q deletion. For the purpose of genotype-phenotype analysis, there seems to be no need for a "ring syndrome" concept.

Identification of 2nd chromosome region translocated onto the W chromosome by RFLP with EST-cDNA clones in the Gensei-kouken strains of the mulberry silkworm, Bombyx mori L

Directory of Open Access Journals (Sweden)

Sivaramakurup Sreekumar

2010-01-01

Full Text Available In silkworms, sex-limited strains are either obtained spontaneously or induced by X-rays or gamma rays. When a fragment of an autosome carrying a dominant allele of those genes responsible for certain characters is translocated onto a W chromosome, the female of the successive generations will express these phenotypic characters and sex discrimination can be facilitated. Gensei-kouken strains are sex-limited strains of silkworms developed by irradiating the pupae with gamma rays, by which a portion of the second chromosome is translocated onto the W chromosome. In these improved strains, the females are yellow-blooded and spin yellow cocoons. By using the EST-cDNA clones mapped on the Z chromosome, we identified the sex according to the polymorphic banding pattern or intensity of the signals. Furthermore, by using the clones on the second chromosome, the region of the second chromosome translocated onto the W chromosome was also defined. In both the A95 and A 96 strains selected for the present study, only the mid-portion of the second chromosome was translocated. The differences in length of the fragments translocated in these strains are discussed.

Demarcation of informative chromosomes in tropical sweet corn inbred lines using microsatellite DNA markers

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Pedram Kashiani

2012-01-01

Full Text Available A study of genetic variation among 10 pairs of chromosomes extracted from 13 tropical sweet corn inbred lines, using 99 microsatellite markers, revealed a wide range of genetic diversity. Allelic richness and the number of effective alleles per chromosome ranged from 2.78 to 4.33 and 1.96 to 3.47, respectively, with respective mean values of 3.62 and 2.73. According to the Shannon's information index (I and Nei's gene diversity coefficient (Nei, Chromosome 10 was the most informative chromosome (I = 1.311 and Nei = 0.703, while Chromosome 2 possessed the least (I = 0.762 and Nei = 0.456. Based on linkage disequilibrium (LD measurements for loci less than 50 cM apart on the same chromosome, all loci on Chromosomes 1, 6 and 7 were in equilibrium. Even so, there was a high proportion of genetic variation in Chromosomes 4, 5, 8, 9 and 10, thereby revealing their appropriateness for use in the genetic diversity investigations among tropical sweet corn lines. Chromosome 4, with the highest number of loci in linkage disequilibrium, was considered the best for marker-phenotype association and QTL mapping, followed by Chromosomes 5, 8, 9 and 10.

Genomic instability: potential contributions to tumour and normal tissue response, and second tumours, after radiotherapy

International Nuclear Information System (INIS)

Hendry, Jolyon H.

2001-01-01

Purpose: Induced genomic instability generally refers to a type of damage which is transmissible down cell generations, and which results in a persistently enhanced frequency of de novo mutations, chromosomal abnormalities or lethality in a significant fraction of the descendant cell population. The potential contribution of induced genomic instability to tumour and normal tissue response, and second tumours, after radiotherapy, is explored. Results: The phenomenon of spontaneous genomic instability is well known in some rare genetic diseases (e.g. Gorlin's syndrome), and there is evidence in such cases that it can lead to a greater propensity for carcinogenesis (with shortened latency) which is enhanced after irradiation. It is unclear what role induced genomic instability plays in the response of normal individuals, but persistent chromosomal instability has been detected in vivo in lymphocytes and keratinocytes from irradiated normal individuals. Such induced genomic instability might play some role in tumour response in a subset of tumours with specific defects in damage response genes, but again its contribution to radiocurability in the majority of cancer patients is unclear. In normal tissues, genomic instability induced in wild-type cells leading to delayed cell death might contribute to more severe or prolonged early reactions as a consequence of increased cell loss, a longer time required for recovery, and greater residual injury. In tumours, induced genomic instability reflected in delayed reductions in clonogenic capacity might contribute to the radiosensitivity of primary tumours, and also to a lower incidence, longer latency and slower growth rate of recurrences and metastases. Conclusions: The evidence which is reviewed shows that there is little information at present to support these propositions, but what exists is consistent with their expectations. Also, it is not yet clear to what extent mutations associated with genomic instability

Fluorescence in situ hybridisation in chromosome aberration detection in subjects occupationally exposed to ionising radiation

International Nuclear Information System (INIS)

Zeljezic, D.; Garaj-Vrhovac, V.

2005-01-01

For more than two decades, chromosomal aberration analysis has been used to detect structural chromosomal aberrations as sensitive biodosimeters of occupational exposure to ionising radiation. Its use is also recommended by the World Health Organisation. Changes in chromosome structure detected by that method are considered to be early biomarkers of a possible malignant disease. Aberrations detected by the method are unstable and can be found in the lymphocytes of irradiated personnel only within a limited time after exposure. To detect stable chromosomal aberrations, which persist after exposure, multicolour fluorescent in situ hybridisation has to be used. Using DNA probes labelled with different fluorochromes, it dyes each pair of chromosomes with different colour. Due to the dynamic of unstable aberration formation, chromosomal aberration analysis is more suitable in genome damage assessment of recent exposures. On the other hand, fluorescence in situ hybridisation gives the information on chromosome instability caused by long-term occupational exposure to ionising radiation. Considering the high costs of fluorescence in situ hybridisation and the uncertainty of the result, it should be used in biodosimetry only when it is absolutely necessary.(author)

Chromosomal Aberrations in Normal and AT Cells Exposed to High Dose of Low Dose Rate Irradiation

Science.gov (United States)

Kawata, T.; Shigematsu, N.; Kawaguchi, O.; Liu, C.; Furusawa, Y.; Hirayama, R.; George, K.; Cucinotta, F.

2011-01-01

Ataxia telangiectasia (A-T) is a human autosomally recessive syndrome characterized by cerebellar ataxia, telangiectases, immune dysfunction, and genomic instability, and high rate of cancer incidence. A-T cell lines are abnormally sensitive to agents that induce DNA double strand breaks, including ionizing radiation. The diverse clinical features in individuals affected by A-T and the complex cellular phenotypes are all linked to the functional inactivation of a single gene (AT mutated). It is well known that cells deficient in ATM show increased yields of both simple and complex chromosomal aberrations after high-dose-rate irradiation, but, less is known on how cells respond to low-dose-rate irradiation. It has been shown that AT cells contain a large number of unrejoined breaks after both low-dose-rate irradiation and high-dose-rate irradiation, however sensitivity for chromosomal aberrations at low-dose-rate are less often studied. To study how AT cells respond to low-dose-rate irradiation, we exposed confluent normal and AT fibroblast cells to up to 3 Gy of gamma-irradiation at a dose rate of 0.5 Gy/day and analyzed chromosomal aberrations in G0 using fusion PCC (Premature Chromosomal Condensation) technique. Giemsa staining showed that 1 Gy induces around 0.36 unrejoined fragments per cell in normal cells and around 1.35 fragments in AT cells, whereas 3Gy induces around 0.65 fragments in normal cells and around 3.3 fragments in AT cells. This result indicates that AT cells can rejoin breaks less effectively in G0 phase of the cell cycle? compared to normal cells. We also analyzed chromosomal exchanges in normal and AT cells after exposure to 3 Gy of low-dose-rate rays using a combination of G0 PCC and FISH techniques. Misrejoining was detected in the AT cells only? When cells irradiated with 3 Gy were subcultured and G2 chromosomal aberrations were analyzed using calyculin-A induced PCC technique, the yield of unrejoined breaks decreased in both normal and AT

Involvement of DNA repair in telomere maintenance and chromosomal instability in human cells

International Nuclear Information System (INIS)

Ayouaz, Ali

2008-01-01

Telomeres are a major actor of cell immortalization, precursor of a carcinogenesis process. Thus, it appears that the maintenance of telomeres is crucial in the implementation of carcinogenesis process. Due to their structures and under some conditions, telomeres can be assimilated in some respects to chromosomal breakages. Within this perspective, this research thesis aims at determining under which circumstances telomeres can be taken as targets by DNA repair mechanisms. More precisely, the author addressed the respective contributions of two repair mechanisms (the Non-Homologous End-Joining or NHEJ, and Homologous Recombination or HR) in the maintenance of telomere integrity. The author first discusses knowledge related to the interaction between chromosomal extremities and repair mechanisms. Then, he defines the behaviour of these mechanisms with respect to telomeres. He shows that, in absence of recombination mechanisms, the integrity of telomeres is not affected. Finally, he reports the attempt to determine their respective contributions in telomeric homeostasis [fr

Ectopic Expression of Testis Germ Cell Proteins in Cancer and Its Potential Role in Genomic Instability

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Aaraby Yoheswaran Nielsen

2016-06-01

Full Text Available Genomic instability is a hallmark of human cancer and an enabling factor for the genetic alterations that drive cancer development. The processes involved in genomic instability resemble those of meiosis, where genetic material is interchanged between homologous chromosomes. In most types of human cancer, epigenetic changes, including hypomethylation of gene promoters, lead to the ectopic expression of a large number of proteins normally restricted to the germ cells of the testis. Due to the similarities between meiosis and genomic instability, it has been proposed that activation of meiotic programs may drive genomic instability in cancer cells. Some germ cell proteins with ectopic expression in cancer cells indeed seem to promote genomic instability, while others reduce polyploidy and maintain mitotic fidelity. Furthermore, oncogenic germ cell proteins may indirectly contribute to genomic instability through induction of replication stress, similar to classic oncogenes. Thus, current evidence suggests that testis germ cell proteins are implicated in cancer development by regulating genomic instability during tumorigenesis, and these proteins therefore represent promising targets for novel therapeutic strategies.

APC gene mutations and extraintestinal phenotype of familial adenomatous polyposis

NARCIS (Netherlands)

Giardiello, F. M.; Petersen, G. M.; Piantadosi, S.; Gruber, S. B.; Traboulsi, E. I.; Offerhaus, G. J.; Muro, K.; Krush, A. J.; Booker, S. V.; Luce, M. C.; Laken, S. J.; Kinzler, K. W.; Vogelstein, B.; Hamilton, S. R.

1997-01-01

Familial adenomatous polyposis (FAP) is caused by germline mutation of the adenomatous polyposis coli (APC) gene on chromosome 5q. This study assessed genotype-phenotype correlations for extraintestinal lesions in FAP. Mutations of the APC gene were compared with the occurrence of seven

Phenotypic instability of Saos-2 cells in long-term culture

International Nuclear Information System (INIS)

Hausser, Heinz-Juergen; Brenner, Rolf E.

2005-01-01

The human osteosarcoma cell line Saos-2 is widely used as a model system for human osteoblastic cells, though its phenotypic stability has not been ascertained. We therefore propagated these cells over 100 passages and compared relevant phenotypic properties. In general, higher passage cells exhibited higher proliferation rates and lower specific alkaline phosphatase activities, though mineralization was significantly more pronounced in cultures of late passage cells. Whereas expression of most genes investigated did not vary profoundly, some genes exhibited remarkable differences. Decorin, for instance, that has been discussed as a regulator of proliferation and mineralization, is strongly expressed only in early passage cells, and two receptors for pleiotrophin and midkine exhibited an almost mutually exclusive expression pattern in early and late passage cells, respectively. Our observations indicate that special care is required when results obtained with Saos-2 cells with different culture history are to be compared

A case-control study identifying chromosomal polymorphic variations as forms of epigenetic alterations associated with the infertility phenotype

DEFF Research Database (Denmark)

Minocherhomji, Sheroy; Athalye, Arundhati S; Madon, Prochi F

2009-01-01

To study the association of chromosomal polymorphic variations with infertility and subfertility.......To study the association of chromosomal polymorphic variations with infertility and subfertility....

Haploids in Conifer Species: Characterization and Chromosomal Integrity of a Maritime Pine Cell Line

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José Antonio Cabezas

2016-11-01

Full Text Available Haploids are a valuable tool for genomic studies in higher plants, especially those with huge genome size and long juvenile periods, such as conifers. In these species, megagametophyte cultures have been widely used to obtain haploid callus and somatic embryogenic lines. One of the main problems associated with tissue culture is the potential genetic instability of the regenerants. Because of this, chromosomal stability of the callus and/or somatic embryos should also be assessed. To this end, chromosome counting, flow cytometry and genotyping using microsatellites have been reported. Here, we present an overview of the work done in conifers, with special emphasis on the production of a haploid cell line in maritime pine (Pinus pinaster L. and the use of a set of molecular markers, which includes Single Nucleotide Polymorphisms (SNPs and microsatellites or Single Sequence Repeats (SSRs, to validate chromosomal integrity confirming the presence of all chromosomic arms.

Machado-Joseph disease in pedigrees of Azorean descent is linked to chromosome 14.

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St George-Hyslop, P; Rogaeva, E; Huterer, J; Tsuda, T; Santos, J; Haines, J L; Schlumpf, K; Rogaev, E I; Liang, Y; McLachlan, D R

1994-07-01

A locus for Machado-Joseph disease (MJD) has recently been mapped to a 30-cM region of chromosome 14q in five pedigrees of Japanese descent. MJD is a clinically pleomorphic neurodegenerative disease that was originally described in subjects of Azorean descent. In light of the nonallelic heterogeneity in other inherited spinocerebellar ataxias, we were interested to determine if the MJD phenotype in Japanese and Azorean pedigrees arose from mutations at the same locus. We provide evidence that MJD in five pedigrees of Azorean descent is also linked to chromosome 14q in an 18-cM region between the markers D14S67 and AACT (multipoint lod score +7.00 near D14S81). We also report molecular evidence for homozygosity at the MJD locus in an MJD-affected subject with severe, early-onset symptoms. These observations confirm the initial report of linkage of MJD to chromosome 14; suggest that MJD in Japanese and Azorean subjects may represent allelic or identical mutations at the same locus; and provide one possible explanation (MJD gene dosage) for the observed phenotypic heterogeneity in this disease.

Detection of genomic instability in normal human bronchial epithelial cells exposed to 238Pu

International Nuclear Information System (INIS)

Kennedy, C.H.; Fukushima, N.H.; Neft, R.E.; Lechner, J.F.

1994-01-01

Alpha particle-emitting radon daughters constitute a risk for development of lung cancer in humans. The development of this disease involves multiple genetic alterations. These changes and the time course they follow are not yet defined despite numerous in vitro endeavors to transform human lung cells with various physical or chemical agents. However, genomic instability, characterized both by structural and numerical chromosomal aberrations and by elevated rates of point mutations, is a common feature of tumor cells. Further, both types of genomic instability have been reported in the noncancerous progeny of normal murine hemopoietic cells exposed in vitro to α-particles. The purpose of this investigation was to determine if genomic instability is also a prominent feature of normal human bronchial epithelial cells exposed to α-particle irradiation from the decay of inhaled radon daughters

Dependence of Early and Late Chromosomal Aberrations on Radiation Quality and Cell Types

Science.gov (United States)

Lu, Tao; Zhang, Ye; Krieger, Stephanie; Yeshitla, Samrawit; Goss, Rosalin; Bowler, Deborah; Kadhim, Munira; Wilson, Bobby; Rohde, Larry; Wu, Honglu

2017-01-01

Exposure to radiation induces different types of DNA damage, increases mutation and chromosome aberration rates, and increases cellular transformation in vitro and in vivo. The susceptibility of cells to radiation depends on genetic background and growth condition of cells, as well as types of radiation. Mammalian cells of different tissue types and with different genetic background are known to have different survival rate and different mutation rate after cytogenetic insults. Genomic instability, induced by various genetic, metabolic, and environmental factors including radiation, is the driving force of tumorigenesis. Accurate measurements of the relative biological effectiveness (RBE) is important for estimating radiation-related risks. To further understand genomic instability induced by charged particles and their RBE, we exposed human lymphocytes ex vivo, human fibroblast AG1522, human mammary epithelial cells (CH184B5F5/M10), and bone marrow cells isolated from CBA/CaH(CBA) and C57BL/6 (C57) mice to high energy protons and Fe ions. Normal human fibroblasts AG1522 have apparently normal DNA damage response and repair mechanisms, while mammary epithelial cells (M10) are deficient in the repair of DNA DSBs. Mouse strain CBA is radio-sensitive while C57 is radio-resistant. Metaphase chromosomes at different cell divisions after radiation exposure were collected and chromosome aberrations were analyzed as RBE for different cell lines exposed to different radiations at various time points up to one month post irradiation.

Delayed manifestation and transmission bias of de novo chromosome mutations. Their relevance for radiation health effect

International Nuclear Information System (INIS)

Sasaki, Masao S.

2006-01-01

The origin and transmission of de novo chromosome mutations were reviewed on the basis of our chromosome studies in retinoblastoma patients and male infertility. In a series of 264 sporadic retinoblastoma families, gross chromosome rearrangements involving the RB1 locus were identified in 23 cases (8.7%), of which 16 were non-mosaic and 7 were mosaic mutations. The newly formed chromosome mutations, whether they were non-mosaic or mosaic, had a strong bias towards paternally derived chromosome, indicating that they shared a common mechanism where a pre-mutational event or instability is carried over to zygote by sperm and manifested as gross chromosome mutation at the early stages of development. The de novo chromosome mutations are preferentially transmitted through female carriers. This transmission bias is consistent with the finding of higher frequencies of translocation carriers in infertile men (7.69% versus 0.27% in general populations) in whom meiotic progression is severely suppressed, possibly through activation of meiotic checkpoints. Such a meiotic surveillance mechanism may minimize the spreading of newly-arisen chromosome mutations in populations. A quantitative model of meiotic surveillance mechanism is proposed and successfully applied to the published data on ''humped'' dose-response curves for radiation-induced spermatogonial reciprocal translocations in several mammalian species. (author)

Chromosomal damages and mutagenesis in mammalian and human cells induced by ionizing radiations with different LET

International Nuclear Information System (INIS)

Govorun, R.D.

1997-01-01

On the basis of literature and proper data the inference was made about essential role of structural chromosomal (and gene) damages in spontaneous and radiation-induced mutagenesis of mammalian and human cells on HPRT-loci. The evidences of increasing role of these damages in the mutagenesis after the influence of ionizing radiations with high LET are adduced. The consequences of HPRT-gene damages have been examined hypothetically. The geterogeneity of mutant subclones on their cytogenetical properties were revealed experimentally. The data reflect a phenomenon of the reproductive chromosomal instability in many generations of mutant cell. The mutagenesis of mammalian cells is also accompanied by the impairment of chromosome integrity with high probability as a stage of appropriate genome reorganization because of changed vital conditions

Chromosome abnormalities and the genetics of congenital corneal opacification.

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Mataftsi, A; Islam, L; Kelberman, D; Sowden, J C; Nischal, K K

2011-01-01

Congenital corneal opacification (CCO) encompasses a broad spectrum of disorders that have different etiologies, including genetic and environmental. Terminology used in clinical phenotyping is commonly not specific enough to describe separate entities, for example both the terms Peters anomaly and sclerocornea have been ascribed to a clinical picture of total CCO, without investigating the presence or absence of iridocorneal adhesions. This is not only confusing but also unhelpful in determining valid genotype-phenotype correlations, and thereby revealing clues for pathogenesis. We undertook a systematic review of the literature focusing on CCO as part of anterior segment developmental anomalies (ASDA), and analyzed its association specifically with chromosomal abnormalities. Genes previously identified as being associated with CCO are also summarized. All reports were critically appraised to classify phenotypes according to described features, rather than the given diagnosis. Some interesting associations were found, and are discussed.

Sexual dimorphism in white campion: deletion on the Y chromosome results in a floral asexual phenotype

International Nuclear Information System (INIS)

Farbos, I.; Veuskens, J.; Vyskot, B.; Oliveira, M.; Hinnisdaels, S.; Aghmir, A.; Mouras, A.; Negrutiu, I.

1999-01-01

White campion is a dioecious plant with heteromorphic X and Y sex chromosomes. In male plants, a filamentous structure replaces the pistil, while in female plants the stamens degenerate early in flower development. Asexual (asx) mutants, cumulating the two developmental defects that characterize the sexual dimorphism in this species, were produced by gamma ray irradiation of pollen and screening in the M1 generation. The mutants harbor a novel type of mutation affecting an early function in sporogenous/parietal cell differentiation within the anther. The function is called stamen-promoting function (SPF). The mutants are shown to result from interstitial deletions on the Y chromosome. We present evidence that such deletions tentatively cover the central domain on the (p)-arm of the Y chromosome (Y2 region). By comparing stamen development in wild-type female and asx mutant flowers we show that they share the same block in anther development, which results in the production of vestigial anthers. The data suggest that the SPF, a key function(s) controlling the sporogenous/parietal specialization in premeiotic anthers, is genuinely missing in females (XX constitution). We argue that this is the earliest function in the male program that is Y-linked and is likely responsible for ''male dimorphism'' (sexual dimorphism in the third floral whorl) in white campion. More generally, the reported results improve our knowledge of the structural and functional organization of the Y chromosome and favor the view that sex determination in this species results primarily from a trigger signal on the Y chromosome (Y1 region) that suppresses female development. The default state is therefore the ancestral hermaphroditic state

A major QTL controlling deep rooting on rice chromosome 4.

Science.gov (United States)

Uga, Yusaku; Yamamoto, Eiji; Kanno, Noriko; Kawai, Sawako; Mizubayashi, Tatsumi; Fukuoka, Shuichi

2013-10-24

Drought is the most serious abiotic stress that hinders rice production under rainfed conditions. Breeding for deep rooting is a promising strategy to improve the root system architecture in shallow-rooting rice cultivars to avoid drought stress. We analysed the quantitative trait loci (QTLs) for the ratio of deep rooting (RDR) in three F₂ mapping populations derived from crosses between each of three shallow-rooting varieties ('ARC5955', 'Pinulupot1', and 'Tupa729') and a deep-rooting variety, 'Kinandang Patong'. In total, we detected five RDR QTLs on chromosomes 2, 4, and 6. In all three populations, QTLs on chromosome 4 were found to be located at similar positions; they explained from 32.0% to 56.6% of the total RDR phenotypic variance. This suggests that one or more key genetic factors controlling the root growth angle in rice is located in this region of chromosome 4.

Complementation of a DNA repair defect in xeroderma pigmentosum cells by transfer of human chromosome 9

International Nuclear Information System (INIS)

Kaur, G.P.; Athwal, R.S.

1989-01-01

Complementation of the repair defect in xeroderma pigmentosum cells of complementation group A was achieved by the transfer of human chromosome 9. A set of mouse-human hybrid cell lines, each containing a single Ecogpt-marked human chromosome, was used as a source of donor chromosomes. Chromosome transfer to XPTG-1 cells, a hypoxanthine/guanine phosphoribosyltransferase-deficient mutant of simian virus 40-transformed complementation group A cells, was achieved by microcell fusion and selection for Ecogpt. Chromosome-transfer clones of XPTG-1 cells, each containing a different human donor chromosome, were analyzed for complementation of sensitivity to UV irradiation. Among all the clones, increased levels of resistance to UV was observed only in clones containing chromosome 9. Since our recipient cell line XPTG-1 is hypoxanthine/guanine phosphoribosyltransferase deficient, cultivation of Ecogpt+ clones in medium containing 6-thioguanine permits selection of cells for loss of the marker and, by inference, transferred chromosome 9. Clones isolated for growth in 6-thioguanine, which have lost the Ecogpt-marked chromosome, exhibited a UV-sensitive phenotype, confirming the presence of the repair gene(s) for complementation group A on chromosome 9

Upregulation of FOXM1 induces genomic instability in human epidermal keratinocytes

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Philpott Michael P

2010-02-01

Full Text Available Abstract Background The human cell cycle transcription factor FOXM1 is known to play a key role in regulating timely mitotic progression and accurate chromosomal segregation during cell division. Deregulation of FOXM1 has been linked to a majority of human cancers. We previously showed that FOXM1 was upregulated in basal cell carcinoma and recently reported that upregulation of FOXM1 precedes malignancy in a number of solid human cancer types including oral, oesophagus, lung, breast, kidney, bladder and uterus. This indicates that upregulation of FOXM1 may be an early molecular signal required for aberrant cell cycle and cancer initiation. Results The present study investigated the putative early mechanism of UVB and FOXM1 in skin cancer initiation. We have demonstrated that UVB dose-dependently increased FOXM1 protein levels through protein stabilisation and accumulation rather than de novo mRNA expression in human epidermal keratinocytes. FOXM1 upregulation in primary human keratinocytes triggered pro-apoptotic/DNA-damage checkpoint response genes such as p21, p38 MAPK, p53 and PARP, however, without causing significant cell cycle arrest or cell death. Using a high-resolution Affymetrix genome-wide single nucleotide polymorphism (SNP mapping technique, we provided the evidence that FOXM1 upregulation in epidermal keratinocytes is sufficient to induce genomic instability, in the form of loss of heterozygosity (LOH and copy number variations (CNV. FOXM1-induced genomic instability was significantly enhanced and accumulated with increasing cell passage and this instability was increased even further upon exposure to UVB resulting in whole chromosomal gain (7p21.3-7q36.3 and segmental LOH (6q25.1-6q25.3. Conclusion We hypothesise that prolonged and repeated UVB exposure selects for skin cells bearing stable FOXM1 protein causes aberrant cell cycle checkpoint thereby allowing ectopic cell cycle entry and subsequent genomic instability. The aberrant

Heterochromatin position effects on circularized sex chromosomes cause filicidal embryonic lethality in Drosophila melanogaster.

Science.gov (United States)

Ferree, Patrick M; Gomez, Karina; Rominger, Peter; Howard, Dagnie; Kornfeld, Hannah; Barbash, Daniel A

2014-04-01

Some circularized X-Y chromosomes in Drosophila melanogaster are mitotically unstable and induce early embryonic lethality, but the genetic basis is unknown. Our experiments suggest that a large region of X-linked satellite DNA causes anaphase bridges and lethality when placed into a new heterochromatic environment within certain circularized X-Y chromosomes. These results reveal that repetitive sequences can be incompatible with one another in cis. The lethal phenotype also bears a remarkable resemblance to a case of interspecific hybrid lethality.

Complex distal 10q rearrangement in a girl with mild intellectual disability: follow up of the patient and review of the literature of non-acrocentric satellited chromosomes.

Science.gov (United States)

Sarri, Catherine; Douzgou, Sofia; Gyftodimou, Yolanda; Tümer, Zeynep; Ravn, Kirstine; Pasparaki, Angela; Sarafidou, Theologia; Kontos, Harry; Kokotas, Haris; Karadima, Georgia; Grigoriadou, Maria; Pandelia, Effie; Theodorou, Virginia; Moschonas, Nicholas K; Petersen, Michael B

2011-11-01

We report on an intellectually disabled girl with a de novo satellited chromosome 10 (10qs) and performed a review of the literature of the non-acrocentric satellited chromosomes (NASC). Satellites and stalks normally occur on the short arms of acrocentric chromosomes; however, the literature cites several reports of satellited non-acrocentric chromosomes, which presumably result from a translocation with an acrocentric chromosome. This is, to our knowledge, the third report of a 10qs chromosome. The phenotype observed in the proband prompted a search for a structural rearrangement of chromosome 10q. By microsatellite analysis we observed a 4 Mb deletion on the long arm of chromosome 10, approximately 145 kb from the telomere. FISH and array CGH analyses revealed a complex rearrangement involving in range from the centromere to the telomere: A 9.64 Mb 10q26.11-q26.2 duplication, a 1.3 Mb region with no copy number change, followed by a 5.62 Mb 10q26.2-q26.3 deletion and a translocation of satellite material. The homology between the repeat sequences at 10q subtelomere region and the sequences on the acrocentric short arms may explain the origin of the rearrangement and it is likely that the submicroscopic microdeletion and microduplication are responsible for the abnormal phenotype in our patient. The patient presented here, with a 15-year follow-up, manifests a distinct phenotype different from the 10q26 pure distal monosomy and trisomy syndromes. Copyright © 2011 Wiley Periodicals, Inc.

Chromosome-wise dissection of the genome of the extremely big mouse line DU6i.

Science.gov (United States)

Bevova, Marianna R; Aulchenko, Yurii S; Aksu, Soner; Renne, Ulla; Brockmann, Gudrun A

2006-01-01

The extreme high-body-weight-selected mouse line DU6i is a polygenic model for growth research, harboring many small-effect QTL. We dissected the genome of this line into 19 autosomes and the Y chromosome by the construction of a new panel of chromosome substitution strains (CSS). The DU6i chromosomes were transferred to a DBA/2 mice genetic background by marker-assisted recurrent backcrossing. Mitochondria and the X chromosome were of DBA/2 origin in the backcross. During the construction of these novel strains, >4000 animals were generated, phenotyped, and genotyped. Using these data, we studied the genetic control of variation in body weight and weight gain at 21, 42, and 63 days. The unique data set facilitated the analysis of chromosomal interaction with sex and parent-of-origin effects. All analyzed chromosomes affected body weight and weight gain either directly or in interaction with sex or parent of origin. The effects were age specific, with some chromosomes showing opposite effects at different stages of development.

Alternative Lengthening of Telomeres: Recurrent Cytogenetic Aberrations and Chromosome Stability under Extreme Telomere Dysfunction

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Despoina Sakellariou

2013-11-01

Full Text Available Human tumors using the alternative lengthening of telomeres (ALT exert high rates of telomere dysfunction. Numerical chromosomal aberrations are very frequent, and structural rearrangements are widely scattered among the genome. This challenging context allows the study of telomere dysfunction-driven chromosomal instability in neoplasia (CIN in a massive scale. We used molecular cytogenetics to achieve detailed karyotyping in 10 human ALT neoplastic cell lines.We identified 518 clonal recombinant chromosomes affected by 649 structural rearrangements. While all human chromosomes were involved in random or clonal, terminal, or pericentromeric rearrangements and were capable to undergo telomere healing at broken ends, a differential recombinatorial propensity of specific genomic regions was noted.We show that ALT cells undergo epigenetic modifications rendering polycentric chromosomes functionally monocentric, and because of increased terminal recombinogenicity, they generate clonal recombinant chromosomes with interstitial telomeric repeats. Losses of chromosomes 13, X, and 22, gains of 2, 3, 5, and 20, and translocation/deletion events involving several common chromosomal fragile sites (CFSs were recurrent. Long-term reconstitution of telomerase activity in ALT cells reduced significantly the rates of random ongoing telomeric and pericentromeric CIN. However, the contribution of CFS in overall CIN remained unaffected, suggesting that in ALT cells whole-genome replication stress is not suppressed by telomerase activation. Our results provide novel insights into ALT-driven CIN, unveiling in parallel specific genomic sites that may harbor genes critical for ALT cancerous cell growth.

The elevation of radiation load on ecosystems and genome instability of organisms

International Nuclear Information System (INIS)

Gaziyev, A. I.; Bezlepkin, V.Q.

2002-01-01

prophylaxis of human disorders. Thus, it was found that the action of low-dose ionizing radiation on living organisms might induce an adaptive repair response in them aimed at decreasing the genetic consequences of the exposure. However, the potentialities of defense and repair systems of an organism are limited, so an increase in genome lesions may cause inheritable mutations, cancer and other pathologies, and death. DNA lesions caused by ionizing radiation in small and sublethal doses can essentially be repaired, whereas unrepaired lesions and errors of repair, replication, and recombination systems lead to formation of mutational changes in DNA sequences. These changes may be transmitted to daughter cells and induce genome instability in the progeny. Induced genome instability in survived somatic cells is characterized by persistence of a high level of acquired variability in many generations of these cells. Genome instability manifests itself as an increased frequency of karyotypic anomalies, chromosome and gene mutations, clonal heterogeneity, and malignant transformation in the progeny of cells exposed to DNA-damaging agents. Besides, cells with genome instability show increased amplification of genes and changes in their expression, as well as disturbances in their differentiation, delays in reproductive death and other phenotypic characters of abnormal development. Whereas some progress has been made towards knowledge of genome instability in the somatic cells of mammals, the radiation-induced genome instability in germ cells transmitted to individuals of the next generation is still not clearly understood. At the same time, evidence has been obtained which suggests that the transmission of genome instability to the somatic cells of the progeny from the germ cells of gamma - radiation-exposed parents is possible. This conclusion is based on the data on mutation frequency in the progeny of parents exposed to DNA-damaging agents. For instance, a significant increase in

Bi-allelic silencing of the Fanconi anaemia gene FANCF in acute myeloid leukaemia.

NARCIS (Netherlands)

Tischkowitz, M; Ameziane, N.; Waisfisz, Q.; Winter, de J.P.; Harris, R; Taniguchi, T; Andrea, d' A; Hodgson, SV; Mathew, C.G.; Joenje, H.

2003-01-01

Fanconi anaemia (FA) is a chromosomal instability disorder associated with a high risk of acute myeloid leukaemia (AML). Previous work has shown that the AML cell line CHRF-288, derived from a sporadic AML-M7 patient, does not express FANCF protein and exhibits a cellular FA phenotype. We show that

Chromosomal Bands Affected by Acute Oil Exposure and DNA Repair Errors

Science.gov (United States)

Zock, Jan-Paul; Giraldo, Jesús; Pozo-Rodríguez, Francisco; Espinosa, Ana; Rodríguez-Trigo, Gema; Verea, Hector; Castaño-Vinyals, Gemma; Gómez, Federico P.; Antó, Josep M.; Coll, Maria Dolors; Barberà, Joan Albert; Fuster, Carme

2013-01-01

Background In a previous study, we showed that individuals who had participated in oil clean-up tasks after the wreckage of the Prestige presented an increase of structural chromosomal alterations two years after the acute exposure had occurred. Other studies have also reported the presence of DNA damage during acute oil exposure, but little is known about the long term persistence of chromosomal alterations, which can be considered as a marker of cancer risk. Objectives We analyzed whether the breakpoints involved in chromosomal damage can help to assess the risk of cancer as well as to investigate their possible association with DNA repair efficiency. Methods Cytogenetic analyses were carried out on the same individuals of our previous study and DNA repair errors were assessed in cultures with aphidicolin. Results Three chromosomal bands, 2q21, 3q27 and 5q31, were most affected by acute oil exposure. The dysfunction in DNA repair mechanisms, expressed as chromosomal damage, was significantly higher in exposed-oil participants than in those not exposed (p= 0.016). Conclusion The present study shows that breaks in 2q21, 3q27 and 5q31 chromosomal bands, which are commonly involved in hematological cancer, could be considered useful genotoxic oil biomarkers. Moreover, breakages in these bands could induce chromosomal instability, which can explain the increased risk of cancer (leukemia and lymphomas) reported in chronically benzene-exposed individuals. In addition, it has been determined that the individuals who participated in clean-up of the oil spill presented an alteration of their DNA repair mechanisms two years after exposure. PMID:24303039

Establishment of a mouse model with misregulated chromosome condensation due to defective Mcph1 function.

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Marc Trimborn

Full Text Available Mutations in the human gene MCPH1 cause primary microcephaly associated with a unique cellular phenotype with premature chromosome condensation (PCC in early G2 phase and delayed decondensation post-mitosis (PCC syndrome. The gene encodes the BRCT-domain containing protein microcephalin/BRIT1. Apart from its role in the regulation of chromosome condensation, the protein is involved in the cellular response to DNA damage. We report here on the first mouse model of impaired Mcph1-function. The model was established based on an embryonic stem cell line from BayGenomics (RR0608 containing a gene trap in intron 12 of the Mcph1 gene deleting the C-terminal BRCT-domain of the protein. Although residual wild type allele can be detected by quantitative real-time PCR cell cultures generated from mouse tissues bearing the homozygous gene trap mutation display the cellular phenotype of misregulated chromosome condensation that is characteristic for the human disorder, confirming defective Mcph1 function due to the gene trap mutation. While surprisingly the DNA damage response (formation of repair foci, chromosomal breakage, and G2/M checkpoint function after irradiation appears to be largely normal in cell cultures derived from Mcph1(gt/gt mice, the overall survival rates of the Mcph1(gt/gt animals are significantly reduced compared to wild type and heterozygous mice. However, we could not detect clear signs of premature malignant disease development due to the perturbed Mcph1 function. Moreover, the animals show no obvious physical phenotype and no reduced fertility. Body and brain size are within the range of wild type controls. Gene expression on RNA and protein level did not reveal any specific pattern of differentially regulated genes. To the best of our knowledge this represents the first mammalian transgenic model displaying a defect in mitotic chromosome condensation and is also the first mouse model for impaired Mcph1-function.

Establishment of a mouse model with misregulated chromosome condensation due to defective Mcph1 function.

Science.gov (United States)

Trimborn, Marc; Ghani, Mahdi; Walther, Diego J; Dopatka, Monika; Dutrannoy, Véronique; Busche, Andreas; Meyer, Franziska; Nowak, Stefanie; Nowak, Jean; Zabel, Claus; Klose, Joachim; Esquitino, Veronica; Garshasbi, Masoud; Kuss, Andreas W; Ropers, Hans-Hilger; Mueller, Susanne; Poehlmann, Charlotte; Gavvovidis, Ioannis; Schindler, Detlev; Sperling, Karl; Neitzel, Heidemarie

2010-02-16

Mutations in the human gene MCPH1 cause primary microcephaly associated with a unique cellular phenotype with premature chromosome condensation (PCC) in early G2 phase and delayed decondensation post-mitosis (PCC syndrome). The gene encodes the BRCT-domain containing protein microcephalin/BRIT1. Apart from its role in the regulation of chromosome condensation, the protein is involved in the cellular response to DNA damage. We report here on the first mouse model of impaired Mcph1-function. The model was established based on an embryonic stem cell line from BayGenomics (RR0608) containing a gene trap in intron 12 of the Mcph1 gene deleting the C-terminal BRCT-domain of the protein. Although residual wild type allele can be detected by quantitative real-time PCR cell cultures generated from mouse tissues bearing the homozygous gene trap mutation display the cellular phenotype of misregulated chromosome condensation that is characteristic for the human disorder, confirming defective Mcph1 function due to the gene trap mutation. While surprisingly the DNA damage response (formation of repair foci, chromosomal breakage, and G2/M checkpoint function after irradiation) appears to be largely normal in cell cultures derived from Mcph1(gt/gt) mice, the overall survival rates of the Mcph1(gt/gt) animals are significantly reduced compared to wild type and heterozygous mice. However, we could not detect clear signs of premature malignant disease development due to the perturbed Mcph1 function. Moreover, the animals show no obvious physical phenotype and no reduced fertility. Body and brain size are within the range of wild type controls. Gene expression on RNA and protein level did not reveal any specific pattern of differentially regulated genes. To the best of our knowledge this represents the first mammalian transgenic model displaying a defect in mitotic chromosome condensation and is also the first mouse model for impaired Mcph1-function.

Fragile sites, dysfunctional telomere and chromosome fusions: What is 5S rDNA role?

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Barros, Alain Victor; Wolski, Michele Andressa Vier; Nogaroto, Viviane; Almeida, Mara Cristina; Moreira-Filho, Orlando; Vicari, Marcelo Ricardo

2017-04-15

Repetitive DNA regions are known as fragile chromosomal sites which present a high flexibility and low stability. Our focus was characterize fragile sites in 5S rDNA regions. The Ancistrus sp. species shows a diploid number of 50 and an indicative Robertsonian fusion at chromosomal pair 1. Two sequences of 5S rDNA were identified: 5S.1 rDNA and 5S.2 rDNA. The first sequence gathers the necessary structures to gene expression and shows a functional secondary structure prediction. Otherwise, the 5S.2 rDNA sequence does not contain the upstream sequences that are required to expression, furthermore its structure prediction reveals a nonfunctional ribosomal RNA. The chromosomal mapping revealed several 5S.1 and 5S.2 rDNA clusters. In addition, the 5S.2 rDNA clusters were found in acrocentric and metacentric chromosomes proximal regions. The pair 1 5S.2 rDNA cluster is co-located with interstitial telomeric sites (ITS). Our results indicate that its clusters are hotspots to chromosomal breaks. During the meiotic prophase bouquet arrangement, double strand breaks (DSBs) at proximal 5S.2 rDNA of acrocentric chromosomes could lead to homologous and non-homologous repair mechanisms as Robertsonian fusions. Still, ITS sites provides chromosomal instability, resulting in telomeric recombination via TRF2 shelterin protein and a series of breakage-fusion-bridge cycles. Our proposal is that 5S rDNA derived sequences, act as chromosomal fragile sites in association with some chromosomal rearrangements of Loricariidae. Copyright © 2017 Elsevier B.V. All rights reserved.

Chromosomal Behavior during Meiosis in the Progeny of Triticum timopheevii × Hexaploid Wild Oat.

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Hongzhou An

Full Text Available The meiotic behavior of pollen mother cells (PMCs of the F2 and F3 progeny from Triticum timopheevii × hexaploid wild oat was investigated by cytological analysis and sequential C-banding-genomic in situ hybridization (GISH in the present study. A cytological analysis showed that the chromosome numbers of the F2 and F3 progeny ranged from 28 to 41. A large number of univalents, lagging chromosomes, chromosome bridges and micronuclei were found at the metaphase I, anaphase I, anaphase II and tetrad stages in the F2 and F3 progeny. The averages of univalents were 3.50 and 2.73 per cell, and those of lagging chromosomes were 3.37 and 1.87 in the F2 and F3 progeny, respectively. The PMC meiotic indices of the F2 and F3 progeny were 12.22 and 20.34, respectively, indicating considerable genetic instability. A sequential C-banding-GISH analysis revealed that some chromosomes and fragments from the hexaploid wild oat were detected at metaphase I and anaphase I in the progeny, showing that the progeny were of true intergeneric hybrid origin. The alien chromosomes 6A, 7A, 3C and 2D were lost during transmission from F2 to F3. In addition, partial T. timopheevii chromosomes appeared in the form of univalents or lagging chromosomes, which might result from large genome differences between the parents, and the wild oat chromosome introgression interfered with the wheat homologues' normally pairing.

Tet Enzymes Regulate Telomere Maintenance and Chromosomal Stability of Mouse ESCs

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Jiao Yang

2016-05-01

Full Text Available Ten-eleven translocation (Tet family proteins convert 5-methylcytosine to 5-hydroxymethylcytosine. We show that mouse embryonic stem cells (ESCs depleted of Tet1 and/or Tet2 by RNAi exhibit short telomeres and chromosomal instability, concomitant with reduced telomere recombination. Tet1 and Tet2 double-knockout ESCs also display short telomeres but to a lesser extent. Notably, Tet1/2/3 triple-knockout ESCs show heterogeneous telomere lengths and increased frequency of telomere loss and chromosomal fusion. Mechanistically, Tets depletion or deficiency increases Dnmt3b and decreases 5hmC levels, resulting in elevated methylation levels at sub-telomeres. Consistently, knockdown of Dnmt3b or addition of 2i (MAPK and GSK3β inhibitors, which also inhibits Dnmt3b, reduces telomere shortening, partially rescuing Tet1/2 deficiency. Interestingly, Tet1/2 double or Tet1/2/3 triple knockout in ESCs consistently upregulates Zscan4, which may counteract telomere shortening. Together, Tet enzymes play important roles in telomere maintenance and chromosomal stability of ESCs by modulating sub-telomeric methylation levels.

Chromosome-wise Protein Interaction Patterns and Their Impact on Functional Implications of Large-Scale Genomic Aberrations

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Kirk, Isa Kristina; Weinhold, Nils; Belling, Kirstine González-Izarzugaza

2017-01-01

Gene copy-number changes influence phenotypes through gene-dosage alteration and subsequent changes of protein complex stoichiometry. Human trisomies where gene copy numbers are increased uniformly over entire chromosomes provide generic cases for studying these relationships. In most trisomies......, gene and protein level alterations have fatal consequences. We used genome-wide protein-protein interaction data to identify chromosome-specific patterns of protein interactions. We found that some chromosomes encode proteins that interact infrequently with each other, chromosome 21 in particular. We...... combined the protein interaction data with transcriptome data from human brain tissue to investigate how this pattern of global interactions may affect cellular function. We identified highly connected proteins that also had coordinated gene expression. These proteins were associated with important...

Refinement of genotype-phenotype correlation in 18 patients carrying a 1q24q25 deletion

DEFF Research Database (Denmark)

Chatron, Nicolas; Haddad, Véronique; Andrieux, Joris

2015-01-01

of different sizes (490 kb to 20.95 Mb) localized within chromosome bands 1q23.3-q31.2 (chr1:160797550-192912120, hg19). The 490 kb deletion is the smallest deletion reported to date associated with this phenotype. We delineated three regions that may contribute to the phenotype: a proximal one (chr1...

Human chromosome 9 can complement UV sensitivity of xeroderma pigmentosum group A cells

International Nuclear Information System (INIS)

Ishizaki, Kanji; Sasaki, Masao S.; Ikenaga, Mituo; Nakamura, Yusuke

1990-01-01

A single human chromosome derived from normal human fibroblasts and tagged with the G418 resistance gene was transferred into SV40-transformed xeroderma pigmentosum group A (XP-A) cells via microcell fusion. When chromosome 1 or 12 was transferred, UV sensitivity of microcell hybrid cells was not changed. By contrast, after transferring chromosome 9,7 of 11 reipient clones were as UV-resistant as normal human cells. Four other clones were still as UV-sensitive as the parental XP-A cells. Southern hybridization analysis using a polymorphic probe, pEKZ19.3, which is homologous to a sequence of the D9S17 locus on chromosome 9, has confirmed that at least a part of normal human chromosome 9 was transferred into the recipient clones. However, amounts iof UV-induced unscheduled DNA synthesis in the UV-resistant clones were only one-third of those in normal human cells. These results indicate that a gene on chromosome 9 can confer complementation of high UV sensitivity of XP-A cells although it is still possible that 2 or more genes might be involved in the defective-repair phenotypes of XP-A. (author). 20 refs.; 3 figs.; 1 tab

B chromosomes have a functional effect on female sex determination in Lake Victoria cichlid fishes.

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Kohta Yoshida

2011-08-01

Full Text Available The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of the sex-determination system may also play a role in speciation, little is known about the sex-determination system of Lake Victoria cichlids. To understand the evolution of the sex-determination system in these fish, we performed cytogenetic analysis in 11 cichlid species from Lake Victoria. B chromosomes, which are present in addition to standard chromosomes, were found at a high prevalence rate (85% in these cichlids. In one species, B chromosomes were female-specific. Cross-breeding using females with and without the B chromosomes demonstrated that the presence of the B chromosomes leads to a female-biased sex ratio in this species. Although B chromosomes were believed to be selfish genetic elements with little effect on phenotype and to lack protein-coding genes, the present study provides evidence that B chromosomes have a functional effect on female sex determination. FISH analysis using a BAC clone containing B chromosome DNA suggested that the B chromosomes are derived from sex chromosomes. Determination of the nucleotide sequences of this clone (104.5 kb revealed the presence of several protein-coding genes in the B chromosome, suggesting that B chromosomes have the potential to contain functional genes. Because some sex chromosomes in amphibians and arthropods are thought to be derived from B chromosomes, the B chromosomes in Lake Victoria cichlids may represent an evolutionary transition toward the generation of sex chromosomes.

The Human Proteome Organization Chromosome 6 Consortium: integrating chromosome-centric and biology/disease driven strategies.

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Borchers, C H; Kast, J; Foster, L J; Siu, K W M; Overall, C M; Binkowski, T A; Hildebrand, W H; Scherer, A; Mansoor, M; Keown, P A

2014-04-04

diseases have a high population prevalence, devastating clinical impact and profound societal consequences. As a result, they impose a multi-billion dollar economic burden on Canada and on all advanced societies through direct costs of patient care, the loss of health and productivity, and extensive caregiver burden. There is no definitive treatment at the present time for any of these disorders. The manuscript outlines the research which will involve a systematic assessment of all chromosome 6 genes, development of a knowledge base, and development of assays and reagents for all chromosome 6 proteins. We feel that the informatic infrastructure and MRM assays developed will place the chromosome 6 consortium in an excellent position to be a leading player in this major international research initiative. This article is part of a Special Issue: Can Proteomics Fill the Gap Between Genomics and Phenotypes? © 2013.

High Y-chromosomal differentiation among ethnic groups of Dir and Swat districts, Pakistan

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Ullah, Inam; Olofsson, Jill K.; Margaryan, Ashot

2017-01-01

The ethnic groups that inhabit the mountainous Dir and Swat districts of northern Pakistan are marked by high levels of cultural and phenotypic diversity. To obtain knowledge of the extent of genetic diversity in this region, we investigated Y-chromosomal diversity in five population samples repr...

Social chromosome variants differentially affect queen determination and the survival of workers in the fire ant Solenopsis invicta.

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Buechel, Séverine D; Wurm, Yanick; Keller, Laurent

2014-10-01

Intraspecific variation in social organization is common, yet the underlying causes are rarely known. An exception is the fire ant Solenopsis invicta in which the existence of two distinct forms of social colony organization is under the control of the two variants of a pair of social chromosomes, SB and Sb. Colonies containing exclusively SB/SB workers accept only one single queen and she must be SB/SB. By contrast, when colonies contain more than 10% of SB/Sb workers, they accept several queens but only SB/Sb queens. The variants of the social chromosome are associated with several additional important phenotypic differences, including the size, fecundity and dispersal strategies of queens, aggressiveness of workers, and sperm count in males. However, little is known about whether social chromosome variants affect fitness in other life stages. Here, we perform experiments to determine whether differential selection occurs during development and in adult workers. We find evidence that the Sb variant of the social chromosome increases the likelihood of female brood to develop into queens and that adult SB/Sb workers, the workers that cull SB/SB queens, are overrepresented in comparison to SB/SB workers. This demonstrates that supergenes such as the social chromosome can have complex effects on phenotypes at various stages of development. © 2014 John Wiley & Sons Ltd.

Highly significant linkage to chromosome 3q13.31 for rhinitis and related allergic diseases

DEFF Research Database (Denmark)

Andersen, Charlotte Brasch; Haagerup, Annette; Børglum, Anders D.

2006-01-01

or all are still inconclusive. Following genome-wide scans on multiple phenotypes, we previously suggested that chromosome 3q13.12-q21.2 harbours an allergy locus. OBJECTIVE: To identify candidate loci in the Danish population, two additional independent sets of sib-pair families were fine-scale mapped......BACKGROUND: Allergic diseases such as asthma and rhinitis have closely related phenotypes and often occur with atopy. They show strong familial and intra-individual clustering, suggesting overlapping disease aetiology. Various loci and candidate genes have been suggested to underlie allergy. Many...... in candidate regions showing maximum likelihood scores (MLS) > or =1.5 in the genome-wide scans. RESULTS: Twenty eight microsatellite markers in a denser map on chromosome 3q were analysed in 236 allergy sib-pair families including 125 sib pairs with rhinitis. We report significant evidence for linkage...

ATM promotes the obligate XY crossover and both crossover control and chromosome axis integrity on autosomes.

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Marco Barchi

2008-05-01

Full Text Available During meiosis in most sexually reproducing organisms, recombination forms crossovers between homologous maternal and paternal chromosomes and thereby promotes proper chromosome segregation at the first meiotic division. The number and distribution of crossovers are tightly controlled, but the factors that contribute to this control are poorly understood in most organisms, including mammals. Here we provide evidence that the ATM kinase or protein is essential for proper crossover formation in mouse spermatocytes. ATM deficiency causes multiple phenotypes in humans and mice, including gonadal atrophy. Mouse Atm-/- spermatocytes undergo apoptosis at mid-prophase of meiosis I, but Atm(-/- meiotic phenotypes are partially rescued by Spo11 heterozygosity, such that ATM-deficient spermatocytes progress to meiotic metaphase I. Strikingly, Spo11+/-Atm-/- spermatocytes are defective in forming the obligate crossover on the sex chromosomes, even though the XY pair is usually incorporated in a sex body and is transcriptionally inactivated as in normal spermatocytes. The XY crossover defect correlates with the appearance of lagging chromosomes at metaphase I, which may trigger the extensive metaphase apoptosis that is observed in these cells. In addition, control of the number and distribution of crossovers on autosomes appears to be defective in the absence of ATM because there is an increase in the total number of MLH1 foci, which mark the sites of eventual crossover formation, and because interference between MLH1 foci is perturbed. The axes of autosomes exhibit structural defects that correlate with the positions of ongoing recombination. Together, these findings indicate that ATM plays a role in both crossover control and chromosome axis integrity and further suggests that ATM is important for coordinating these features of meiotic chromosome dynamics.

Chromosome

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... St Louis, MO: Elsevier; 2017:chap 69. Taber's Medical Dictionary Online. Chromosome. www.tabers.com/tabersonline/view/Tabers-Dictionary/753321/all/chromosome?q=Chromosome&ti=0 . Accessed June 11, 2017.

Recombinant 4 syndrome due to an unbalanced pericentric inversion of chromosome 4.

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Battaglia, A; Brothman, A R; Carey, J C

2002-09-15

An informative patient with a MCA/MR syndrome consisting of developmental delay, prenatal onset growth delay, microcephaly, distinctive face, iris coloboma, and a congenital heart defect was found, on chromosome analysis, to have the following complement: 46,XY,rec(4) dup(4p) inv(4)(p14q35.1) mat. He has a partial 4p trisomy/distal 4q deletion due to an unbalanced pericentric inversion inherited from his mother. Dup (4p) trisomy was originally described by Wilson et al. [1970: Am J Hum Genet 22:679-690] in a similar case with the same chromosome 4 inversion. To date, at least 85 cases of dup (4p) syndrome have been published, mostly due to unbalanced translocations. Recent articles suggest that the phenotype is hard to recognize clinically due to the lack of specificity of findings. In contrast, 4p trisomy due to an unbalanced pericentric inversion of chromosome 4(p14q35), i.e., the recombinant 4 syndrome observed in our patient, appears to be a discrete entity with relatively consistent features. In total there are four other kindreds described in the literature with this inversion, and the phenotype seems recognizable. Thus, we suggest that recombinant 4 syndrome is a discrete entity among 4p trisomy patients. Copyright 2002 Wiley-Liss, Inc.

Characterization of apparently balanced chromosomal rearrangements from the developmental genome anatomy project.

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Higgins, Anne W; Alkuraya, Fowzan S; Bosco, Amy F; Brown, Kerry K; Bruns, Gail A P; Donovan, Diana J; Eisenman, Robert; Fan, Yanli; Farra, Chantal G; Ferguson, Heather L; Gusella, James F; Harris, David J; Herrick, Steven R; Kelly, Chantal; Kim, Hyung-Goo; Kishikawa, Shotaro; Korf, Bruce R; Kulkarni, Shashikant; Lally, Eric; Leach, Natalia T; Lemyre, Emma; Lewis, Janine; Ligon, Azra H; Lu, Weining; Maas, Richard L; MacDonald, Marcy E; Moore, Steven D P; Peters, Roxanna E; Quade, Bradley J; Quintero-Rivera, Fabiola; Saadi, Irfan; Shen, Yiping; Shendure, Jay; Williamson, Robin E; Morton, Cynthia C

2008-03-01

Apparently balanced chromosomal rearrangements in individuals with major congenital anomalies represent natural experiments of gene disruption and dysregulation. These individuals can be studied to identify novel genes critical in human development and to annotate further the function of known genes. Identification and characterization of these genes is the goal of the Developmental Genome Anatomy Project (DGAP). DGAP is a multidisciplinary effort that leverages the recent advances resulting from the Human Genome Project to increase our understanding of birth defects and the process of human development. Clinically significant phenotypes of individuals enrolled in DGAP are varied and, in most cases, involve multiple organ systems. Study of these individuals' chromosomal rearrangements has resulted in the mapping of 77 breakpoints from 40 chromosomal rearrangements by FISH with BACs and fosmids, array CGH, Southern-blot hybridization, MLPA, RT-PCR, and suppression PCR. Eighteen chromosomal breakpoints have been cloned and sequenced. Unsuspected genomic imbalances and cryptic rearrangements were detected, but less frequently than has been reported previously. Chromosomal rearrangements, both balanced and unbalanced, in individuals with multiple congenital anomalies continue to be a valuable resource for gene discovery and annotation.

Localization of the panhypopituitary dwarf mutation (df) on mouse chromosome 11 in an intersubspecific backcross.

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Buckwalter, M S; Katz, R W; Camper, S A

1991-07-01

Ames dwarf (df) is an autosomal recessive mutation characterized by severe dwarfism and infertility. This mutation provides a mouse model for panhypopituitarism. The dwarf phenotype results from failure in the differentiation of the cells which produce growth hormone, prolactin, and thyroid stimulating hormone. Using the backcross (DF/B-df/df X CASA/Rk) X DF/B-df/df, we confirmed the assignment of df to mouse chromosome 11 and demonstrated recombination between df and the growth hormone gene. This backcross is an invaluable resource for screening candidate genes for the df mutation. The df locus maps to less than 1 cM distal to Pad-1 (0.85 +/- 0.85 cM). Two new genes localized on mouse chromosome 11, Rpo2-1, and Edp-1, map to a region of conserved synteny with human chromosome 17. The localization of the alpha 1 adrenergic receptor, Adra-1, extends a known region of synteny conservation between mouse chromosome 11 and human chromosome 5, and suggests that a human counterpart to df would map to human chromosome 5.

Klinefelter syndrome comorbidities linked to increased X chromosome gene dosage and altered protein interactome activity

DEFF Research Database (Denmark)

Belling, Kirstine González-Izarzugaza; Russo, Francesco; Jensen, Anders Boeck

2017-01-01

Klinefelter syndrome (KS) (47,XXY) is the most common male sex chromosome aneuploidy. Diagnosis and clinical supervision remain a challenge due to varying phenotypic presentation and insufficient characterization of the syndrome. Here we combine health data-driven epidemiology and molecular level...

Hominoid chromosomal rearrangements on 17q map to complex regions of segmental duplication.

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Cardone, Maria Francesca; Jiang, Zhaoshi; D'Addabbo, Pietro; Archidiacono, Nicoletta; Rocchi, Mariano; Eichler, Evan E; Ventura, Mario

2008-01-01

Chromosomal rearrangements, such as translocations and inversions, are recurrent phenomena during evolution, and both of them are involved in reproductive isolation and speciation. To better understand the molecular basis of chromosome rearrangements and their part in karyotype evolution, we have investigated the history of human chromosome 17 by comparative fluorescence in situ hybridization (FISH) and sequence analysis. Human bacterial artificial chromosome/p1 artificial chromosome probes spanning the length of chromosome 17 were used in FISH experiments on great apes, Old World monkeys and New World monkeys to study the evolutionary history of this chromosome. We observed that the macaque marker order represents the ancestral organization. Human, chimpanzee and gorilla homologous chromosomes differ by a paracentric inversion that occurred specifically in the Homo sapiens/Pan troglodytes/Gorilla gorilla ancestor. Detailed analyses of the paracentric inversion revealed that the breakpoints mapped to two regions syntenic to human 17q12/21 and 17q23, both rich in segmental duplications. Sequence analyses of the human and macaque organization suggest that the duplication events occurred in the catarrhine ancestor with the duplication blocks continuing to duplicate or undergo gene conversion during evolution of the hominoid lineage. We propose that the presence of these duplicons has mediated the inversion in the H. sapiens/P. troglodytes/G. gorilla ancestor. Recently, the same duplication blocks have been shown to be polymorphic in the human population and to be involved in triggering microdeletion and duplication in human. These results further support a model where genomic architecture has a direct role in both rearrangement involved in karyotype evolution and genomic instability in human.

Molecular cytogenetic analysis and clinical manifestations of a case with de novo mosaic ring chromosome 7

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Fang Jye-Siung

2011-02-01

Full Text Available Abstract Aim Clinical and molecular cytogenetic investigations of a newborn girl exhibiting facial dysmorphism with developmental delay. Methods Phenotypic evaluation was first applied to examine the proband's developmental status. Computed tomography and colour transcranial Doppler were used then to investigate her brain structure and function. Subsequently, chromosomal abnormalities were examined by karyotyping and fluorescent in situ hybridization was performed to investigate size of fragments lost at the two distal ends of the ring chromosome 7. In addition, multicolour banding was applied to rule out structural rearrangement occurs in between the ring chromosome 7. Results The proband was born with mosaic supernumerary ring chromosome 7, without a normal karyotype detected in the peripheral blood lymphocytes. The distal arm of chromosome 7p (at least 255 kb from the telomere was part of an extra ring chromosome 7. In addition, the distal arm of 7q, at least 8 kb from the telomere, was missing. There was no other chromosomal rearrangement detected by multicolour banding. Interpretation This is the 19th reported case of complete ring chromosome 7 mosaicism and the first survived case with mosaic supernumerary ring 7 without a normal karyotype detected in the peripheral lymphocytes.

Prognostic value of X-chromosome inactivation in symptomatic female carriers of dystrophinopathy

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Juan-Mateu Jonàs

2012-10-01

Full Text Available Abstract Background Between 8% and 22% of female carriers of DMD mutations exhibit clinical symptoms of variable severity. Development of symptoms in DMD mutation carriers without chromosomal rearrangements has been attributed to skewed X-chromosome inactivation (XCI favouring predominant expression of the DMD mutant allele. However the prognostic use of XCI analysis is controversial. We aimed to evaluate the correlation between X-chromosome inactivation and development of clinical symptoms in a series of symptomatic female carriers of dystrophinopathy. Methods We reviewed the clinical, pathological and genetic features of twenty-four symptomatic carriers covering a wide spectrum of clinical phenotypes. DMD gene analysis was performed using MLPA and whole gene sequencing in blood DNA and muscle cDNA. Blood and muscle DNA was used for X-chromosome inactivation (XCI analysis thought the AR methylation assay in symptomatic carriers and their female relatives, asymptomatic carriers as well as non-carrier females. Results Symptomatic carriers exhibited 49.2% more skewed XCI profiles than asymptomatic carriers. The extent of XCI skewing in blood tended to increase in line with the severity of muscle symptoms. Skewed XCI patterns were found in at least one first-degree female relative in 78.6% of symptomatic carrier families. No mutations altering XCI in the XIST gene promoter were found. Conclusions Skewed XCI is in many cases familial inherited. The extent of XCI skewing is related to phenotype severity. However, the assessment of XCI by means of the AR methylation assay has a poor prognostic value, probably because the methylation status of the AR gene in muscle may not reflect in all cases the methylation status of the DMD gene.

Recombination between Homeologous Chromosomes in Lager Yeasts leads to Loss of Function of the Hybrid GPH1 Gene.

OpenAIRE

BOND, URSULA

2009-01-01

PUBLISHED Yeasts used in the production of lagers contain complex allopolyploid genomes, resulting from the fusion of two different yeast species closely related to Saccharomyces cerevisiae and Saccharomyces bayanus. Recombination between the homoeologous chromosomes has generated a number of hybrid chromosomes. These recombination events provide potential for adaptive evolution through the loss or gain of gene function. We have examined the genotypic and phenotypic effects of one of the c...

Genome-Wide Gene Expression Disturbance by Single A1/C1 Chromosome Substitution in Brassica rapa Restituted From Natural B. napus

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Bin Zhu

2018-03-01

Full Text Available Alien chromosome substitution (CS lines are treated as vital germplasms for breeding and genetic mapping. Previously, a whole set of nine Brassica rapa-oleracea monosonic alien addition lines (MAALs, C1-C9 was established in the background of natural B. napus genotype “Oro,” after the restituted B. rapa (RBR for Oro was realized. Herein, a monosomic substitution line with one alien C1 chromosome (Cs1 in the RBR complement was selected in the progenies of MAAL C1 and RBR, by the PCR amplification of specific gene markers and fluorescence in situ hybridization. Cs1 exhibited the whole plant morphology similar to RBR except for the defective stamens without fertile pollen grains, but it produced some seeds and progeny plants carrying the C1 chromosome at high rate besides those without the alien chromosome after pollinated by RBR. The viability of the substitution and its progeny for the RBR diploid further elucidated the functional compensation between the chromosome pairs with high homoeology. To reveal the impact of such aneuploidy on genome-wide gene expression, the transcriptomes of MAAL C1, Cs1 and euploid RBR were analyzed. Compared to RBR, Cs1 had sharply reduced gene expression level across chromosome A1, demonstrating the loss of one copy of A1 chromosome. Both additional chromosome C1 in MAAL and substitutional chromosome C1 in Cs1 caused not only cis-effect but also prevalent trans-effect differentially expressed genes. A dominant gene dosage effects prevailed among low expressed genes across chromosome A1 in Cs1, and moreover, dosage effects for some genes potentially contributed to the phenotype deviations. Our results provided novel insights into the transcriptomic perturbation and gene dosage effects on phenotype in CS related to one naturally evolved allopolyploid.

Genome-wide association study of multiple congenital heart disease phenotypes identifies a susceptibility locus for atrial septal defect at chromosome 4p16

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Cordell, Heather J.; Bentham, Jamie; Topf, Ana; Zelenika, Diana; Heath, Simon; Mamasoula, Chrysovalanto; Cosgrove, Catherine; Blue, Gillian; Granados-Riveron, Javier; Setchfield, Kerry; Thornborough, Chris; Breckpot, Jeroen; Soemedi, Rachel; Martin, Ruairidh; Rahman, Thahira J.; Hall, Darroch; van Engelen, Klaartje; Moorman, Antoon F.M.; Zwinderman, Aelko H; Barnett, Phil; Koopmann, Tamara T.; Adriaens, Michiel E.; Varro, Andras; George, Alfred L.; dos Remedios, Christobal; Bishopric, Nanette H.; Bezzina, Connie R.; O’Sullivan, John; Gewillig, Marc; Bu’Lock, Frances A.; Winlaw, David; Bhattacharya, Shoumo; Devriendt, Koen; Brook, J. David; Mulder, Barbara J.M.; Mital, Seema; Postma, Alex V.; Lathrop, G. Mark; Farrall, Martin; Goodship, Judith A.; Keavney, Bernard D.

2013-01-01

We carried out a genome-wide association study (GWAS) of congenital heart disease (CHD). Our discovery cohort comprised 1,995 CHD cases and 5,159 controls, and included patients from each of the three major clinical CHD categories (septal, obstructive and cyanotic defects). When all CHD phenotypes were considered together, no regions achieved genome-wide significant association. However, a region on chromosome 4p16, adjacent to the MSX1 and STX18 genes, was associated (P=9.5×10−7) with the risk of ostium secundum atrial septal defect (ASD) in the discovery cohort (N=340 cases), and this was replicated in a further 417 ASD cases and 2520 controls (replication P=5.0×10−5; OR in replication cohort 1.40 [95% CI 1.19-1.65]; combined P=2.6×10−10). Genotype accounted for ~9% of the population attributable risk of ASD. PMID:23708191

Recurrent duplications of 17q12 associated with variable phenotypes

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Mitchell, Elyse; Douglas, Andrew; Kjaegaard, Susanne

2015-01-01

The ability to identify the clinical nature of the recurrent duplication of chromosome 17q12 has been limited by its rarity and the diverse range of phenotypes associated with this genomic change. In order to further define the clinical features of affected patients, detailed clinical information......, potentially contributory copy number changes in a subset of patients, including one patient each with 16p11.2 deletion and 15q13.3 deletion. Our data further define and expand the clinical spectrum associated with duplications of 17q12 and provide support for the role of genomic modifiers contributing...... to phenotypic variability....

Construction of a DNA library representing 15q11-13 by subtraction of two flow sorted marker chromosome-specific libraries

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Blennow, E.; Werelius, B.; Nordenskjoeld, M. [Karolinska Hospital, Stockholm (Sweden)] [and others

1994-09-01

Constitutional extra {open_quotes}marker chromosomes{close_quotes} are found in {approx}0.5/1000 of newborns. Of these, 50% are inverted duplications of the pericentromeric region of chromosome 15, including two variants; (1) inv dup(15)(pter{yields}q11:q11{yields}pter) and (2) inv dup(15) (pter{yields}q12-13::q12-13{yields}pter). Variant (1) is found in phenotypically normal individuals, whereas variant (2) will produce a typical clinical picture including mental retardation, autism, hyperactivity and discrete dysmorphic features. Fluorescence in situ hybridization (FISH) using single copy probes from the Prader-Willi region confirms these observations as well as chromosome painting using a flow-sorted marker chromosome-specific library from a variant (1) marker, hybridized to the chromosomes of a patient with a variant (2) marker chromosome. Followingly, a flow-sorted biotinylated variant (1) library was subtracted from a non-labeled variant (2) library using magnetic beads and subsequent amplification by degenerate oligonucleotide-primed PCR (DOP-PCR). The successful result was demonstrated by using the amplified material for chromosome painting on chromosome slides from variant (1) and variant (2) patients. We have constructed a library from 15q11-13. This region contains genes producing a specific abnormal phenotype when found in a tri- or tetrasomic state. The region also contains the genes responsible for the Prader-Willi and Angelman syndromes when the paternal/maternal copy is missing, respectively. It is therefore a region where parental imprinting plays an important role. The isolated library may be used to isolate single copy clones which will allow further investigations of this region.

Breeding of fungal resistant varieties derived from Grüner Veltliner by chromosomal selection

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Regner Ferdinand

2016-01-01

Full Text Available Traditional cultivar Grüner Veltliner is the most appreciated vine in Austrian viticulture. Due to organic growing the demand for mildew resistance within the same wine profile has increased. Cross breeding can provide such new genotypes which combine traits from different sources by parenthood. Linkage of traits with chromosomes or markers allows to predict some aspects of the phenotype. Equipped with chromosomal assisted selection the development of new varieties could be much easier and faster. On the base of two segregating populations derived from crosses of Grüner Veltliner with Malverina and Seyval blanc we could define correlation of chromosomes with some traits. Mainly ampelographic descriptors and resistance against mildew could be aligned. As a quality parameter of the wine Rotundone analyses were performed and could be attributed to chromosome 5 and 9. Selection supported by the composition of the parental chromosomes enables breeding with some arguments of design. The limits for free choice were the availability of sufficient different genotypes with a broad spectrum of chromosomal combinations. Recently released descendent cultivar Donauveltliner was selected due to the high rate of Traminer alleles.

Genomic instability and radiation risk in molecular pathways to colon cancer.

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Jan Christian Kaiser

Full Text Available Colon cancer is caused by multiple genomic alterations which lead to genomic instability (GI. GI appears in molecular pathways of microsatellite instability (MSI and chromosomal instability (CIN with clinically observed case shares of about 15-20% and 80-85%. Radiation enhances the colon cancer risk by inducing GI, but little is known about different outcomes for MSI and CIN. Computer-based modelling can facilitate the understanding of the phenomena named above. Comprehensive biological models, which combine the two main molecular pathways to colon cancer, are fitted to incidence data of Japanese a-bomb survivors. The preferred model is selected according to statistical criteria and biological plausibility. Imprints of cell-based processes in the succession from adenoma to carcinoma are identified by the model from age dependences and secular trends of the incidence data. Model parameters show remarkable compliance with mutation rates and growth rates for adenoma, which has been reported over the last fifteen years. Model results suggest that CIN begins during fission of intestinal crypts. Chromosomal aberrations are generated at a markedly elevated rate which favors the accelerated growth of premalignant adenoma. Possibly driven by a trend of Westernization in the Japanese diet, incidence rates for the CIN pathway increased notably in subsequent birth cohorts, whereas rates pertaining to MSI remained constant. An imbalance between number of CIN and MSI cases began to emerge in the 1980s, whereas in previous decades the number of cases was almost equal. The CIN pathway exhibits a strong radio-sensitivity, probably more intensive in men. Among young birth cohorts of both sexes the excess absolute radiation risk related to CIN is larger by an order of magnitude compared to the MSI-related risk. Observance of pathway-specific risks improves the determination of the probability of causation for radiation-induced colon cancer in individual patients

Ring chromosome 4 and Wolf-Hirschhorn syndrome (WHS) in a child with multiple anomalies.

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Balci, Sevim; Engiz, Ozlem; Aktaş, Dilek; Vargel, Ibrahim; Beksaç, M S; Mrasek, Kristin; Vermeesch, Joris; Liehr, Thomas

2006-03-15

We report on a 16-month-old male patient with ring chromosome 4 and deletion of Wolf-Hirschhorn syndrome (WHS) region with multiple congenital anomalies including unilateral cleft lip and palate, iris coloboma, microcephaly, midgut malrotation, hypospadias, and double urethral orifices. Peripheral chromosome analysis of the patient showed 46,XY,r(4)(p16.3q35) de novo. Multicolor fluorescence in situ hybridization (FISH) study was also performed and according to multicolor banding (MCB) a r(4)(::p16.3 --> q34.3 approximately 35.1::) was found in all metaphases. Subtelomeric 4p region, subtelomeric 4q region, as well as, Wolf-Hirschhorn critical region were deleted in ring chromosome 4. Genomic microarray analysis was also performed to delineate the size of deletion. Cranial magnetic resonance imaging (MRI) showed hypoplastic corpus callosum, delayed myelinization, and frontal and occipital lobe atrophies. Both maternal and paternal chromosomal analyses were normal. We compare the phenotypic appearance of our patient with the previously reported 16 cases of ring chromosome 4 in the medical literature. 2006 Wiley-Liss, Inc.

Genetic linkage of mild pseudoachondroplasia (PSACH) to markers in the pericentromeric region of chromosome 19

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Briggs, M.D.; Rasmussen, M.; Garber, P.; Rimoin, D.L.; Cohn, D.H. (Steven Spielberg Pediatric Research Center, Los Angeles, CA (United States)); Weber, J.L. (Marshfield Medical Research Foundation, WI (United States)); Yuen, J.; Reinker, K. (Univ. of Hawaii, Honolulu, HI (United States))

1993-12-01

Pseudoachondroplasia (PSACH) is a dominantly inherited form of short-limb dwarfism characterized by dysplastic changes in the spine, epiphyses, and metaphyses and early onset osteoarthropathy. Chondrocytes from affected individuals accumulate an unusual appearing material in the rough endoplasmic reticulum, which has led to the hypothesis that a structural abnormality in a cartilage-specific protein produces the phenotype. The authors recently identified a large family with a mild form of pseudoachondroplasia. By genetic linkage to a dinucleotide repeat polymorphic marker (D19S199), they have localized the disease gene to chromosome 19 (maximum lod score of 7.09 at a recombination fraction of 0.03). Analysis of additional markers and recombinations between the linked markers and the phenotype suggests that the disease gene resides within a 6.3-cM interval in the immediate pericentromeric region of the chromosome. 39 refs., 2 figs., 1 tab.

Unexpected structural complexity of supernumerary marker chromosomes characterized by microarray comparative genomic hybridization

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Hing Anne V

2008-04-01

Full Text Available Abstract Background Supernumerary marker chromosomes (SMCs are structurally abnormal extra chromosomes that cannot be unambiguously identified by conventional banding techniques. In the past, SMCs have been characterized using a variety of different molecular cytogenetic techniques. Although these techniques can sometimes identify the chromosome of origin of SMCs, they are cumbersome to perform and are not available in many clinical cytogenetic laboratories. Furthermore, they cannot precisely determine the region or breakpoints of the chromosome(s involved. In this study, we describe four patients who possess one or more SMCs (a total of eight SMCs in all four patients that were characterized by microarray comparative genomic hybridization (array CGH. Results In at least one SMC from all four patients, array CGH uncovered unexpected complexity, in the form of complex rearrangements, that could have gone undetected using other molecular cytogenetic techniques. Although array CGH accurately defined the chromosome content of all but two minute SMCs, fluorescence in situ hybridization was necessary to determine the structure of the markers. Conclusion The increasing use of array CGH in clinical cytogenetic laboratories will provide an efficient method for more comprehensive characterization of SMCs. Improved SMC characterization, facilitated by array CGH, will allow for more accurate SMC/phenotype correlation.

Defects in the Fanconi Anemia Pathway and Chromatid Cohesion in Head and Neck Cancer.

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Stoepker, Chantal; Ameziane, Najim; van der Lelij, Petra; Kooi, Irsan E; Oostra, Anneke B; Rooimans, Martin A; van Mil, Saskia E; Brink, Arjen; Dietrich, Ralf; Balk, Jesper A; Ylstra, Bauke; Joenje, Hans; Feller, Stephan M; Brakenhoff, Ruud H

2015-09-01

Failure to repair DNA damage or defective sister chromatid cohesion, a process essential for correct chromosome segregation, can be causative of chromosomal instability (CIN), which is a hallmark of many types of cancers. We investigated how frequent this occurs in head and neck squamous cell carcinoma (HNSCC) and whether specific mechanisms or genes could be linked to these phenotypes. The genomic instability syndrome Fanconi anemia is caused by mutations in any of at least 16 genes regulating DNA interstrand crosslink (ICL) repair. Since patients with Fanconi anemia have a high risk to develop HNSCC, we investigated whether and to which extent Fanconi anemia pathway inactivation underlies CIN in HNSCC of non-Fanconi anemia individuals. We observed ICL-induced chromosomal breakage in 9 of 17 (53%) HNSCC cell lines derived from patients without Fanconi anemia. In addition, defective sister chromatid cohesion was observed in five HNSCC cell lines. Inactivation of FANCM was responsible for chromosomal breakage in one cell line, whereas in two other cell lines, somatic mutations in PDS5A or STAG2 resulted in inadequate sister chromatid cohesion. In addition, FANCF methylation was found in one cell line by screening an additional panel of 39 HNSCC cell lines. Our data demonstrate that CIN in terms of ICL-induced chromosomal breakage and defective chromatid cohesion is frequently observed in HNSCC. Inactivation of known Fanconi anemia and chromatid cohesion genes does explain CIN in the minority of cases. These findings point to phenotypes that may be highly relevant in treatment response of HNSCC. ©2015 American Association for Cancer Research.

Partial isodisomy for maternal chromosome 7 and short stature in an individual with a mutation at the COL1A2 locus

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Spotila, L.D.; Sereda, L.; Prockop, D.J. (Jefferson Medical College, Philadelphia, PA (United States))

1992-12-01

Uniparental disomy for chromosome 7 has been described previously in two individuals with cystic fibrosis. Here, the authors describe a third case that was discovered because the proband was homozygous for a mutation in the COL1A2 gene for type I procollagen, although his mother was heterozygous and his father did not have the mutation. Phenotypically, the proband was similar to the two previously reported cases with uniparental disomy for chromosome 7, in that he was short in stature and growth retarded. Paternity was assessed with five polymorphic markers. Chromosome 7 inheritance in the proband was analyzed using 12 polymorphic markers distributed along the entire chromosome. Similar analysis of the proband's two brothers established the phase of the alleles at the various loci, assuming minimal recombination. The proband inherited only maternal alleles at five loci and was homozygous at all loci examined, except one. He was heterozygous for an RFLP at the IGBP-1 locus at 7p13-p12. The results suggest that the isodisomy was not complete because of a recombination event involving the proximal short arms of two maternal chromosomes. In addition, the phenotype of proportional dwarfism in the proband suggests imprinting of one or more growth-related genes on chromosome 7. 42 refs., 5 figs., 3 tabs.

Gastric cancers of Western European and African patients show different patterns of genomic instability

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Mulder Chris JJ

2011-01-01

Full Text Available Abstract Background Infection with H. pylori is important in the etiology of gastric cancer. Gastric cancer is infrequent in Africa, despite high frequencies of H. pylori infection, referred to as the African enigma. Variation in environmental and host factors influencing gastric cancer risk between different populations have been reported but little is known about the biological differences between gastric cancers from different geographic locations. We aim to study genomic instability patterns of gastric cancers obtained from patients from United Kingdom (UK and South Africa (SA, in an attempt to support the African enigma hypothesis at the biological level. Methods DNA was isolated from 67 gastric adenocarcinomas, 33 UK patients, 9 Caucasian SA patients and 25 native SA patients. Microsatellite instability and chromosomal instability were analyzed by PCR and microarray comparative genomic hybridization, respectively. Data was analyzed by supervised univariate and multivariate analyses as well as unsupervised hierarchical cluster analysis. Results Tumors from Caucasian and native SA patients showed significantly more microsatellite instable tumors (p Conclusions Gastric cancers from SA and UK patients show differences in genetic instability patterns, indicating possible different biological mechanisms in patients from different geographical origin. This is of future clinical relevance for stratification of gastric cancer therapy.

Bystander-mediated genomic instability after high LET radiation in murine primary haemopoietic stem cells

International Nuclear Information System (INIS)

Bowler, Deborah A.; Moore, Stephen R.; Macdonald, Denise A.; Smyth, Sharon H.; Clapham, Peter; Kadhim, Munira A.

2006-01-01

Communication between irradiated and unirradiated (bystander) cells can result in responses in unirradiated cells that are similar to responses in their irradiated counterparts. The purpose of the current experiment was to test the hypothesis that bystander responses will be similarly induced in primary murine stem cells under different cell culture conditions. The experimental systems used here, co-culture and media transfer, are similar in that they both restrict communication between irradiated and bystander cells to media borne factors, but are distinct in that with the media transfer technique, cells can only communicate after irradiation, and with co-culture, cells can communication before, during and after irradiation. In this set of parallel experiments, cell type, biological endpoint, and radiation quality and dose, were kept constant. In both experimental systems, clonogenic survival was significantly decreased in all groups, whether irradiated or bystander, suggesting a substantial contribution of bystander effects (BE) to cell killing. Genomic instability (GI) was induced under all radiation and bystander conditions in both experiments, including a situation where unirradiated cells were incubated with media that had been conditioned for 24 h with irradiated cells. The appearance of delayed aberrations (genomic instability) 10-13 population doublings after irradiation was similar to the level of initial chromosomal damage, suggesting that the bystander factor is able to induce chromosomal alterations soon after irradiation. Whether these early alterations are related to those observed at later timepoints remains unknown. These results suggest that genomic instability may be significantly induced in a bystander cell population whether or not cells communicate during irradiation

Radiation-induced genomic instability and bystander effects: related inflammatory-type responses to radiation-induced stress and injury? A review.

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Lorimore, S A; Wright, E G

2003-01-01

To review studies of radiation responses in the haemopoietic system in the context of radiation-induced genomic instability, bystander effects and inflammatory-type processes. There is considerable evidence that cells that themselves are not exposed to ionizing radiation but are the progeny of cells irradiated many cell divisions previously may express a high frequency of gene mutations, chromosomal aberrations and cell death. These effects are collectively known as radiation-induced genomic instability. A second untargeted effect results in non-irradiated cells exhibiting responses typically associated with direct radiation exposure but occurs as a consequence of contact with irradiated cells or by receiving soluble signals from irradiated cells. These effects are collectively known as radiation-induced bystander effects. Reported effects include increases or decreases in damage-inducible and stress-related proteins; increases or decreases in reactive oxygen species, cell death or cell proliferation, and induction of mutations and chromosome aberrations. This array of responses is reminiscent of effects mediated by cytokines and other similar regulatory factors that may involve, but do not necessarily require, gap junction-mediated transfer, have multiple inducers and a variety of context-dependent consequences in different cell systems. That chromosomal instability in haemopoietic cells can be induced by an indirect bystander-type mechanism both in vitro and in vivo provides a potential link between these two untargeted effects and there are radiation responses in vivo consistent with the microenvironment contributing secondary cell damage as a consequence of an inflammatory-type response to radiation-induced injury. Intercellular signalling, production of cytokines and free radicals are features of inflammatory responses that have the potential for both bystander-mediated and persisting damage as well as for conferring a predisposition to malignancy. The

Nuclear organization in human sperm: preliminary evidence for altered sex chromosome centromere position in infertile males.

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Finch, K A; Fonseka, K G L; Abogrein, A; Ioannou, D; Handyside, A H; Thornhill, A R; Hickson, N; Griffin, D K

2008-06-01

Many genetic defects with a chromosomal basis affect male reproduction via a range of different mechanisms. Chromosome position is a well-known marker of nuclear organization, and alterations in standard patterns can lead to disease phenotypes such as cancer, laminopathies and epilepsy. It has been demonstrated that normal mammalian sperm adopt a pattern with the centromeres aligning towards the nuclear centre. The purpose of this study was to test the hypothesis that altered chromosome position in the sperm head is associated with male infertility. The average nuclear positions of fluorescence in-situ hybridization signals for three centromeric probes (for chromosomes X, Y and 18) were compared in normoozoospermic men and in men with compromised semen parameters. In controls, the centromeres of chromosomes X, Y and 18 all occupied a central nuclear location. In infertile men the sex chromosomes appeared more likely to be distributed in a pattern not distinguishable from a random model. Our findings cast doubt on the reliability of centromeric probes for aneuploidy screening. The analysis of chromosome position in sperm heads should be further investigated for the screening of infertile men.

Mice with a targeted disruption of the Fanconi anemia homolog Fanca.

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Cheng, N C; van de Vrugt, H J; van der Valk, M A; Oostra, A B; Krimpenfort, P; de Vries, Y; Joenje, H; Berns, A; Arwert, F

2000-07-22

Fanconi anemia (FA) is a hereditary chromosomal instability syndrome with cancer predisposition. Bone marrow failure resulting in pancytopenia is the main cause of death of FA patients. Diagnosis of FA is based on their cellular hypersensitivity to DNA crosslinking agents and chromosome breakages. Somatic complementation experiments suggest the involvement of at least eight genes in FA. The gene for complementation group A (FANCA) is defective in the majority of FA patients. We show here that mice deficient of FANCA: are viable and have no detectable developmental abnormalities. The hematological parameters showed a slightly decreased platelet count and a slightly increased erythrocyte mean cell volume in mice at young age, but this did not progress to anemia. Consistent with the clinical phenotype of FA patients, both male and female mice showed hypogonadism and impaired fertility. Furthermore, embryonic fibroblasts of the knock-out mice exhibited spontaneous chromosomal instability and were hyper-responsive to the clastogenic effect of the crosslinker mitomycin C.

A deficiency in chromatin repair, genetic instability, and predisposition to cancer

International Nuclear Information System (INIS)

Sanford, K.K.; Parshad, R.; Gantt, R.R.; Tarone, R.E.

1989-01-01

This review traces steps leading to malignant neoplastic transformation of rodent and human cells in culture and in vivo. Emphasis is placed on an abnormal response characterized by persistent chromatid damage following irradiation of cells in culture with X-rays or fluorescent light during G2 phase of the cell cycle. Evidence is presented that deficient or unbalanced DNA repair during G2 accounts for the abnormal response. This G2 repair deficiency can be inherited or acquired by normal tissue cells during the process of or following attainment of infinite lifespan. It appears as an early, possibly initiating step in neoplastic transformation. It characterizes all human tumor cells examined irrespective of histopathology or tissue of origin. It has a genetic basis. In an animal model, the BALB/c mouse, this phenotype is associated with genes on chromosomes 1 and 4. It characterizes skin fibroblasts and blood lymphocytes from individuals with genetic or familial conditions predisposing to cancer and can be used to identify clinically normal family members carrying a gene(s) for any one of the three cancer-prone genetic disorders studied to date. Furthermore, it can provide the basis of a test for carriers of genes predisposing to a high risk of cancer. We conclude that the G2 repair deficiency, whether inherited or acquired, is a prerequisite for cancer development and that it accounts for the genetic instability of the cancer cell. 167 refs

Dissociable effects of Sry and sex chromosome complement on activity, feeding and anxiety-related behaviours in mice.

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Kopsida, Eleni; Lynn, Phoebe M; Humby, Trevor; Wilkinson, Lawrence S; Davies, William

2013-01-01

Whilst gonadal hormones can substantially influence sexual differentiation of the brain, recent findings have suggested that sex-linked genes may also directly influence neurodevelopment. Here we used the well-established murine 'four core genotype' (FCG) model on a gonadally-intact, outbred genetic background to characterise the contribution of Sry-dependent effects (i.e. those arising from the expression of the Y-linked Sry gene in the brain, or from hormonal sequelae of gonadal Sry expression) and direct effects of sex-linked genes other than Sry ('sex chromosome complement' effects) to sexually dimorphic mouse behavioural phenotypes. Over a 24 hour period, XX and XY gonadally female mice (lacking Sry) exhibited greater horizontal locomotor activity and reduced food consumption per unit bodyweight than XX and XY gonadally male mice (possessing Sry); in two behavioural tests (the elevated plus and zero mazes) XX and XY gonadally female mice showed evidence for increased anxiety-related behaviours relative to XX and XY gonadally male mice. Exploratory correlational analyses indicated that these Sry-dependent effects could not be simply explained by brain expression of the gene, nor by circulating testosterone levels. We also noted a sex chromosome complement effect on food (but not water) consumption whereby XY mice consumed more over a 24hr period than XX mice, and a sex chromosome complement effect in a third test of anxiety-related behaviour, the light-dark box. The present data suggest that: i) the male-specific factor Sry may influence activity and feeding behaviours in mice, and ii) dissociable feeding and anxiety-related murine phenotypes may be differentially modulated by Sry and by other sex-linked genes. Our results may have relevance for understanding the molecular underpinnings of sexually dimorphic behavioural phenotypes in healthy men and women, and in individuals with abnormal sex chromosome constitutions.

Dissociable effects of Sry and sex chromosome complement on activity, feeding and anxiety-related behaviours in mice.

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Eleni Kopsida

Full Text Available Whilst gonadal hormones can substantially influence sexual differentiation of the brain, recent findings have suggested that sex-linked genes may also directly influence neurodevelopment. Here we used the well-established murine 'four core genotype' (FCG model on a gonadally-intact, outbred genetic background to characterise the contribution of Sry-dependent effects (i.e. those arising from the expression of the Y-linked Sry gene in the brain, or from hormonal sequelae of gonadal Sry expression and direct effects of sex-linked genes other than Sry ('sex chromosome complement' effects to sexually dimorphic mouse behavioural phenotypes. Over a 24 hour period, XX and XY gonadally female mice (lacking Sry exhibited greater horizontal locomotor activity and reduced food consumption per unit bodyweight than XX and XY gonadally male mice (possessing Sry; in two behavioural tests (the elevated plus and zero mazes XX and XY gonadally female mice showed evidence for increased anxiety-related behaviours relative to XX and XY gonadally male mice. Exploratory correlational analyses indicated that these Sry-dependent effects could not be simply explained by brain expression of the gene, nor by circulating testosterone levels. We also noted a sex chromosome complement effect on food (but not water consumption whereby XY mice consumed more over a 24hr period than XX mice, and a sex chromosome complement effect in a third test of anxiety-related behaviour, the light-dark box. The present data suggest that: i the male-specific factor Sry may influence activity and feeding behaviours in mice, and ii dissociable feeding and anxiety-related murine phenotypes may be differentially modulated by Sry and by other sex-linked genes. Our results may have relevance for understanding the molecular underpinnings of sexually dimorphic behavioural phenotypes in healthy men and women, and in individuals with abnormal sex chromosome constitutions.

Exclusion of candidate genes for coat colour phenotypes of the American mink (Neovison vison)

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Anistoroaei, Razvan Marian; Markakis, M. N.; Vissenberg, K.

2012-01-01

In a previous project, we screened the American mink Bacterial Artificial Chromosome library, CHORI-231, for genes potentially involved in various coat colour phenotypes in the American mink. Subsequently, we 454 sequenced the inserts containing these genes and developed microsatellite markers...... for each of these genes. Here, we describe a lack of association between three different ‘roan-type' phenotypes represented by Cross, Stardust and Cinnamon in American mink and six different genes that we considered to be potentially linked to these phenotypes. Thus, c-KIT (HUGO-approved symbol KIT), ATOH...

Identification of a novel asthma susceptibility gene on chromosome 1qter and its functional evaluation

DEFF Research Database (Denmark)

White, Julia H; Chiano, Mathias; Wigglesworth, Mark

2008-01-01

Asthma is a multifactorial disease, in which the intricate interplay between genetic and environmental factors underlies the overall phenotype of the disease. Using a genome-wide scan for linkage in a population comprising of Danish families, we identified a novel linked locus on chromosome 1qter...

Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids. II. Results obtained after induction of breaks in chromosome 1 by X-irradiation.

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Burgerhout, W G; Smit, S L; Jongsma, A P

1977-01-01

The position of genes coding for PGD, PPH1, UGPP, GuK1, PGM1, Pep-C, and FH on human chromosome 1 was investigated by analysis of karyotype and enzyme phenotypes in man-Chinese hamster somatic cell hybrids carrying aberrations involving chromosome 1. Suitable hybrid cell lines were obtained by X-irradiation of hybrid cells carrying an intact chromosome 1 and by fusion of human cells from a clonal population carrying a translocation involving chromosome 1 with Chinese hamster cells. The latter human cell population had been isolated following X-irradiation of primary Lesch-Nyhan fibroblasts. In addition, products of de novo chromosome breakage in the investigated hybrid lines were utilized. By integrating the results of these analyses with earlier findings in our laboratory, the following positions of genes are deduced: PGD and PPH1 in 1p36 leads to 1p34; PGM1 in 1p32; UGPP in 1q21 leads to 1q23; GuK1 in 1q31 leads to 1q42; Pep-C in 1q42; and FH in 1qter leads to 1q42.

Homozygous PMS2 deletion causes a severe colorectal cancer and multiple adenoma phenotype without extraintestinal cancer.

Science.gov (United States)

Will, Olivia; Carvajal-Carmona, Luis G; Gorman, Patricia; Howarth, Kimberley M; Jones, Angela M; Polanco-Echeverry, Guadalupe M; Chinaleong, Jo-Anne; Günther, Thomas; Silver, Andrew; Clark, Susan K; Tomlinson, Ian

2007-02-01

We report a patient of Indian descent with parental consanguinity, who developed 10 carcinomas and 35 adenomatous polyps at age 23 and duodenal adenocarcinoma at age 25. He also had dysmorphic features, mental retardation, and café-au-lait spots but no brain tumor. We aimed to establish his molecular diagnosis. Germ-line screening for APC and MYH/MUTYH mutations was normal as was immunohistochemistry for MLH1 and MSH2 proteins. Investigation by array-comparative genomic hybridization revealed deletion of a small region on chromosome 7. Using polymerase chain reaction, this region was refined to a 400-kilobase deletion, which included exons 9-15 of the PMS2 gene, and all coding regions of oncomodulin, TRIAD3, and FSCN1. The deletion was confirmed as homozygous, and both parents were carriers. Immunohistochemistry showed absent PMS2 expression in all tumors and normal tissue. Most tumors showed microsatellite instability, more marked at dinucleotide than mononucleotide repeats. The tumors harbored no somatic mutations in APC, BRAF, AXIN2, or beta-catenin, but KRAS2 and TGFBR2 mutations were found. Our patient represents a novel phenotype for homozygous PMS2 mutation and perhaps the most severe colorectal cancer phenotype-in terms of numbers of malignancies at an early age-described to date. PMS2 mutations-and perhaps other homozygous mismatch repair mutations-should be considered in any patient presenting with multiple gastrointestinal tumors, since our patient could not be distinguished clinically from cases with attenuated familial adenomatous polyposis or MUTYH-associated polyposis.

The down syndrome behavioral phenotype: implications for practice and research in occupational therapy.

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Daunhauer, Lisa A; Fidler, Deborah J

2011-01-01

ABSTRACT Down syndrome (DS) is the most common chromosomal cause of intellectual disability. The genetic causes of DS are associated with characteristic outcomes, such as relative strengths in visual-spatial skills and relative challenges in motor planning. This profile of outcomes, called the DS behavioral phenotype, may be a critical tool for intervention planning and research in this population. In this article, aspects of the DS behavioral phenotype potentially relevant to occupational therapy practice are reviewed. Implications and challenges for etiology-informed research and practice are discussed.

How accurate is the phenotype? – An analysis of developmental noise in a cotton aphid clone

Directory of Open Access Journals (Sweden)

Babbitt Gregory A

2008-02-01

Full Text Available Abstract Background The accuracy by which phenotype can be reproduced by genotype potentially is important in determining the stability, environmental sensitivity, and evolvability of morphology and other phenotypic traits. Because two sides of an individual represent independent development of the phenotype under identical genetic and environmental conditions, average body asymmetry (or "fluctuating asymmetry" can estimate the developmental instability of the population. The component of developmental instability not explained by intrapopulational differences in gene or environment (or their interaction can be further defined as internal developmental noise. Surprisingly, developmental noise remains largely unexplored despite its potential influence on our interpretations of developmental stability, canalization, and evolvability. Proponents of fluctuating asymmetry as a bioindicator of environmental or genetic stress, often make the assumption that developmental noise is minimal and, therefore, that phenotype can respond sensitively to the environment. However, biologists still have not measured whether developmental noise actually comprises a significant fraction of the overall environmental response of fluctuating asymmetry observed within a population. Results In a morphometric study designed to partition developmental noise from fluctuating asymmetry in the wing morphology of a monoclonal culture of cotton aphid, Aphis gossipyii, it was discovered that fluctuating asymmetry in the aphid wing was nearly four times higher than in other insect species. Also, developmental noise comprised a surprisingly large fraction (≈ 50% of the overall response of fluctuating asymmetry to a controlled graded temperature environment. Fluctuating asymmetry also correlated negatively with temperature, indicating that environmentally-stimulated changes in developmental instability are mediated mostly by changes in the development time of individuals

Heterogeneity of mammary lesions represent molecular differences

International Nuclear Information System (INIS)

Namba, Ruria; Gregg, Jeffrey P; Maglione, Jeannie E; Davis, Ryan R; Baron, Colin A; Liu, Stephenie; Carmack, Condie E; Young, Lawrence JT; Borowsky, Alexander D; Cardiff, Robert D

2006-01-01

Human breast cancer is a heterogeneous disease, histopathologically, molecularly and phenotypically. The molecular basis of this heterogeneity is not well understood. We have used a mouse model of DCIS that consists of unique lines of mammary intraepithelial neoplasia (MIN) outgrowths, the premalignant lesion in the mouse that progress to invasive carcinoma, to understand the molecular changes that are characteristic to certain phenotypes. Each MIN-O line has distinguishable morphologies, metastatic potentials and estrogen dependencies. We utilized oligonucleotide expression arrays and high resolution array comparative genomic hybridization (aCGH) to investigate whole genome expression patterns and whole genome aberrations in both the MIN-O and tumor from four different MIN-O lines that each have different phenotypes. From the whole genome analysis at 35 kb resolution, we found that chromosome 1, 2, 10, and 11 were frequently associated with whole chromosome gains in the MIN-Os. In particular, two MIN-O lines had the majority of the chromosome gains. Although we did not find any whole chromosome loss, we identified 3 recurring chromosome losses (2F1-2, 3E4, 17E2) and two chromosome copy number gains on chromosome 11. These interstitial deletions and duplications were verified with a custom made array designed to interrogate the specific regions at approximately 550 bp resolution. We demonstrated that expression and genomic changes are present in the early premalignant lesions and that these molecular profiles can be correlated to phenotype (metastasis and estrogen responsiveness). We also identified expression changes associated with genomic instability. Progression to invasive carcinoma was associated with few additional changes in gene expression and genomic organization. Therefore, in the MIN-O mice, early premalignant lesions have the major molecular and genetic changes required and these changes have important phenotypic significance. In contrast, the changes

Sex Chromosome Evolution, Heterochiasmy, and Physiological QTL in the Salmonid Brook Charr Salvelinus fontinalis

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Ben J.G. Sutherland

2017-08-01

Full Text Available Whole-genome duplication (WGD can have large impacts on genome evolution, and much remains unknown about these impacts. This includes the mechanisms of coping with a duplicated sex determination system and whether this has an impact on increasing the diversity of sex determination mechanisms. Other impacts include sexual conflict, where alleles having different optimums in each sex can result in sequestration of genes into nonrecombining sex chromosomes. Sex chromosome development itself may involve sex-specific recombination rate (i.e., heterochiasmy, which is also poorly understood. The family Salmonidae is a model system for these phenomena, having undergone autotetraploidization and subsequent rediploidization in most of the genome at the base of the lineage. The salmonid master sex determining gene is known, and many species have nonhomologous sex chromosomes, putatively due to transposition of this gene. In this study, we identify the sex chromosome of Brook Charr Salvelinus fontinalis and compare sex chromosome identities across the lineage (eight species and four genera. Although nonhomology is frequent, homologous sex chromosomes and other consistencies are present in distantly related species, indicating probable convergence on specific sex and neo-sex chromosomes. We also characterize strong heterochiasmy with 2.7-fold more crossovers in maternal than paternal haplotypes with paternal crossovers biased to chromosome ends. When considering only rediploidized chromosomes, the overall heterochiasmy trend remains, although with only 1.9-fold more recombination in the female than the male. Y chromosome crossovers are restricted to a single end of the chromosome, and this chromosome contains a large interspecific inversion, although its status between males and females remains unknown. Finally, we identify quantitative trait loci (QTL for 21 unique growth, reproductive, and stress-related phenotypes to improve knowledge of the genetic

Single-Cell Based Quantitative Assay of Chromosome Transmission Fidelity.

Science.gov (United States)

Zhu, Jin; Heinecke, Dominic; Mulla, Wahid A; Bradford, William D; Rubinstein, Boris; Box, Andrew; Haug, Jeffrey S; Li, Rong

2015-03-30

Errors in mitosis are a primary cause of chromosome instability (CIN), generating aneuploid progeny cells. Whereas a variety of factors can influence CIN, under most conditions mitotic errors are rare events that have been difficult to measure accurately. Here we report a green fluorescent protein-based quantitative chromosome transmission fidelity (qCTF) assay in budding yeast that allows sensitive and quantitative detection of CIN and can be easily adapted to high-throughput analysis. Using the qCTF assay, we performed genome-wide quantitative profiling of genes that affect CIN in a dosage-dependent manner and identified genes that elevate CIN when either increased (icCIN) or decreased in copy number (dcCIN). Unexpectedly, qCTF screening also revealed genes whose change in copy number quantitatively suppress CIN, suggesting that the basal error rate of the wild-type genome is not minimized, but rather, may have evolved toward an optimal level that balances both stability and low-level karyotype variation for evolutionary adaptation. Copyright © 2015 Zhu et al.

Effect of Rad 51 overexpression on chromosomal stability and radiation sensitivity in tumour cells

International Nuclear Information System (INIS)

Jend, C.; Stuerzbecher, H.W.; Dikomey, E.; Borgmann, K.

2004-01-01

The present study was dedicated to examining the effects of Rad51 overexpression on genomic instability, expressed in terms of chromosomal aberrations in G1 and G2 phases following X-ray irradiation. For this purpose an osteosarcoma cell line (Ui-OS) which shows inducing Rad51 overexpression (UiRad5-2) after stable transfection was compared with an isogenetic line (UiLacZ) which overexpresses beta-galactosidase instead of Rad51 [de

Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

Science.gov (United States)

Su, W-Y; Cong, W-W; Shu, Y-J; Wang, D; Xu, G-H; Guo, C-H

2013-07-08

The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

Fetal chromosome analysis: screening for chromosome disease?

DEFF Research Database (Denmark)

Philip, J; Tabor, Ann; Bang, J

1983-01-01

The aim of the study was to investigate the rationale of the current indications for fetal chromosome analysis. 5372 women had 5423 amniocentesis performed, this group constituting a consecutive sample at the chromosome laboratory, Rigshospitalet, Copenhagen from March 1973 to September 1980 (Group...... A + B). Pregnant women 35 years of age, women who previously had a chromosomally abnormal child, families with translocation carriers or other heritable chromosomal disease, families where the father was 50 years or more and women in families with a history of Down's syndrome (group A), were compared...... to women having amniocentesis, although considered not to have any increased risk of fetal chromosome abnormality (1390 pregnancies, group B). They were also compared with 750 consecutive pregnancies in women 25-34 years of age, in whom all heritable diseases were excluded (group C). The risk of unbalanced...

Phenotypic manifestations of copy number variation in chromosome 16p13.11

NARCIS (Netherlands)

Nagamani, Sandesh C. Sreenath; Erez, Ayelet; Bader, Patricia; Lalani, Seema R.; Scott, Daryl A.; Scaglia, Fernando; Plon, Sharon E.; Tsai, Chun-Hui; Reimschisel, Tyler; Roeder, Elizabeth; Malphrus, Amy D.; Eng, Patricia A.; Hixson, Patricia M.; Kang, Sung-Hae L.; Stankiewicz, Pawel; Patel, Ankita; Cheung, Sau Wai

The widespread clinical utilization of array comparative genome hybridization, has led to the unraveling of many new copy number variations (CNVs). Although some of these CNVs are clearly pathogenic, the phenotypic consequences of others, such as those in 16p13.11 remain unclear. Whereas deletions

Effects of aneuploidy on genome structure, expression, and interphase organization in Arabidopsis thaliana.

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Bruno Huettel

2008-10-01

Full Text Available Aneuploidy refers to losses and/or gains of individual chromosomes from the normal chromosome set. The resulting gene dosage imbalance has a noticeable affect on the phenotype, as illustrated by aneuploid syndromes, including Down syndrome in humans, and by human solid tumor cells, which are highly aneuploid. Although the phenotypic manifestations of aneuploidy are usually apparent, information about the underlying alterations in structure, expression, and interphase organization of unbalanced chromosome sets is still sparse. Plants generally tolerate aneuploidy better than animals, and, through colchicine treatment and breeding strategies, it is possible to obtain inbred sibling plants with different numbers of chromosomes. This possibility, combined with the genetic and genomics tools available for Arabidopsis thaliana, provides a powerful means to assess systematically the molecular and cytological consequences of aberrant numbers of specific chromosomes. Here, we report on the generation of Arabidopsis plants in which chromosome 5 is present in triplicate. We compare the global transcript profiles of normal diploids and chromosome 5 trisomics, and assess genome integrity using array comparative genome hybridization. We use live cell imaging to determine the interphase 3D arrangement of transgene-encoded fluorescent tags on chromosome 5 in trisomic and triploid plants. The results indicate that trisomy 5 disrupts gene expression throughout the genome and supports the production and/or retention of truncated copies of chromosome 5. Although trisomy 5 does not grossly distort the interphase arrangement of fluorescent-tagged sites on chromosome 5, it may somewhat enhance associations between transgene alleles. Our analysis reveals the complex genomic changes that can occur in aneuploids and underscores the importance of using multiple experimental approaches to investigate how chromosome numerical changes condition abnormal phenotypes and

Double-strand break repair-adox: Restoration of suppressed double-strand break repair during mitosis induces genomic instability.

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Terasawa, Masahiro; Shinohara, Akira; Shinohara, Miki

2014-12-01

Double-strand breaks (DSBs) are one of the severest types of DNA damage. Unrepaired DSBs easily induce cell death and chromosome aberrations. To maintain genomic stability, cells have checkpoint and DSB repair systems to respond to DNA damage throughout most of the cell cycle. The failure of this process often results in apoptosis or genomic instability, such as aneuploidy, deletion, or translocation. Therefore, DSB repair is essential for maintenance of genomic stability. During mitosis, however, cells seem to suppress the DNA damage response and proceed to the next G1 phase, even if there are unrepaired DSBs. The biological significance of this suppression is not known. In this review, we summarize recent studies of mitotic DSB repair and discuss the mechanisms of suppression of DSB repair during mitosis. DSB repair, which maintains genomic integrity in other phases of the cell cycle, is rather toxic to cells during mitosis, often resulting in chromosome missegregation and aberration. Cells have multiple safeguards to prevent genomic instability during mitosis: inhibition of 53BP1 or BRCA1 localization to DSB sites, which is important to promote non-homologous end joining or homologous recombination, respectively, and also modulation of the non-homologous end joining core complex to inhibit DSB repair. We discuss how DSBs during mitosis are toxic and the multiple safeguard systems that suppress genomic instability. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Resonant Drag Instabilities in protoplanetary disks: the streaming instability and new, faster-growing instabilities

Science.gov (United States)

Squire, Jonathan; Hopkins, Philip F.

2018-04-01

We identify and study a number of new, rapidly growing instabilities of dust grains in protoplanetary disks, which may be important for planetesimal formation. The study is based on the recognition that dust-gas mixtures are generically unstable to a Resonant Drag Instability (RDI), whenever the gas, absent dust, supports undamped linear modes. We show that the "streaming instability" is an RDI associated with epicyclic oscillations; this provides simple interpretations for its mechanisms and accurate analytic expressions for its growth rates and fastest-growing wavelengths. We extend this analysis to more general dust streaming motions and other waves, including buoyancy and magnetohydrodynamic oscillations, finding various new instabilities. Most importantly, we identify the disk "settling instability," which occurs as dust settles vertically into the midplane of a rotating disk. For small grains, this instability grows many orders of magnitude faster than the standard streaming instability, with a growth rate that is independent of grain size. Growth timescales for realistic dust-to-gas ratios are comparable to the disk orbital period, and the characteristic wavelengths are more than an order of magnitude larger than the streaming instability (allowing the instability to concentrate larger masses). This suggests that in the process of settling, dust will band into rings then filaments or clumps, potentially seeding dust traps, high-metallicity regions that in turn seed the streaming instability, or even overdensities that coagulate or directly collapse to planetesimals.

Unsuitability of lymphoblastoid cell lines as surrogate of cryopreserved isolated lymphocytes for the analysis of DNA double-strand break repair activity

Energy Technology Data Exchange (ETDEWEB)

Zijno, Andrea [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Porcedda, Paola [Department of Clinical and Biological Sciences, University of Turin (Italy); Saini, Francesca [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Allione, Alessandra [Institute for Scientific Interchange (ISI) Foundation, Villa Gualino, Turin (Italy); Garofalo, Bruno; Marcon, Francesca [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Guarrera, Simonetta [Institute for Scientific Interchange (ISI) Foundation, Villa Gualino, Turin (Italy); Turinetto, Valentina; Minieri, Valentina [Department of Clinical and Biological Sciences, University of Turin (Italy); Funaro, Ada [Department of Genetics, Biology and Biochemistry, University of Turin (Italy); Crebelli, Riccardo [Department of Environment and Primary Prevention, Istituto Superiore di Sanita, Rome (Italy); Giachino, Claudia [Department of Clinical and Biological Sciences, University of Turin (Italy); Matullo, Giuseppe, E-mail: giuseppe.matullo@unito.it [Institute for Scientific Interchange (ISI) Foundation, Villa Gualino, Turin (Italy); Department of Genetics, Biology and Biochemistry, University of Turin (Italy)

2010-02-03

As first task of a comprehensive investigation on DNA repair genotype-phenotype correlations, the suitability of Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs) as surrogate of cryopreserved peripheral blood mononuclear cells (PBMCs) in DNA repair phenotypic assays was evaluated. To this aim the amount of DNA damage induced by {gamma}-rays and DNA repair capacity were evaluated in unstimulated (G{sub 0}) and mitogen-simulated (G{sub 2}) PBMC from 20 healthy subjects and in EBV-transformed LCL obtained from the same individuals. Phosphorylation of histone H2AX, micronuclei and chromosomal aberrations were the end-points investigated. The results obtained show higher basal frequencies of binucleated cells bearing micronuclei and nucleoplasmic bridge (NPB) in LCL with respect to PBMC, suggesting that EBV transformation may be associated with chromosomal instability. After irradiation, higher levels of micronuclei were induced in G{sub 0}-treated PBMC compared to cycling LCL; conversely, NPB were more frequent in LCL than in PBMC. Moreover, higher levels of chromosomal aberrations were observed in G{sub 2}-treated PBMC compared to LCL. Concerning {gamma}-H2AX measurements, phosphorylation levels 1 h after treatment and dephosphorylation kinetics were basically similar in LCL and in PBMC. However, while Spearman's test showed a strong correlation between the results obtained in replicated experiments with PBMC, high inter-experimental variability and poor reproducibility was observed in the experiments performed with LCL, possibly due to the intrinsic instability of LCL. In summary, both the analysis of {gamma}-H2AX and the evaluation of chromosome damage highlighted a larger inter-experimental variability in the results obtained with LCL compared to PBMC. Noteworthy, the two set of results proved to lack any significant correlation at the individual level. These results indicate that LCL may be unsuitable for investigating genotype-phenotype

The effects of severe mixed environmental pollution on human chromosomes.

Science.gov (United States)

Katsantoni, A; Nakou, S; Antoniadou-Koumatou, I; Côté, G B

1986-01-01

Cytogenetic studies were conducted on healthy young mothers, shortly after child birth, in two residential areas each with an approximate population of 20,000, situated about 25 km from Athens, Greece. One of the areas, Elefsis, is subject to severe mixed industrial pollution, and the other, Koropi, is relatively free of pollution. Chromosomal aberrations were investigated in 16 women from each area in 72 hour lymphocyte cultures treated with gentian violet to enhance any chromosomal instability induced by the pollution. The women were of a comparable socioeconomic level, aged between 20 and 31 years, and with no history of factors associated with mutagenesis. Venous blood samples were taken from the two groups and processed concurrently. The slides were coded and examined independently by two observers, who were unaware of the source of the samples. A total of 100 cells was examined on each sample. The two observers obtained highly comparable results. Women from Elefsis had an average of 0.42 anomalies per cell and those from Koropi had 0.39. The absence of a statistically significant difference between the two groups clearly shows that the severe mixed environmental pollution of Elefsis has no significant visible effect on human chromosomes in most residents. However, two Elefsis women had abnormal results and could be at risk. Their presence is not sufficient to raise significantly their group's average, but the induction by pollution of an increased rate of chromosomal anomalies in only a few people at risk could account for the known association between urban residence and cancer mortality. PMID:3783622

Chromosomal contacts connect loci associated with autism, BMI and head circumference phenotypes

DEFF Research Database (Denmark)

Loviglio, M N; Leleu, M; Männik, K

2017-01-01

Copy number variants (CNVs) are major contributors to genomic imbalance disorders. Phenotyping of 137 unrelated deletion and reciprocal duplication carriers of the distal 16p11.2 220 kb BP2-BP3 interval showed that these rearrangements are associated with autism spectrum disorders and mirror phen...

Heregulin ameliorates the dystrophic phenotype in mdx mice

DEFF Research Database (Denmark)

Krag, Thomas O B; Bogdanovich, Sasha; Jensen, Claus J

2004-01-01

Duchenne's muscular dystrophy (DMD) is a fatal neuromuscular disease caused by absence of dystrophin. Utrophin is a chromosome 6-encoded dystrophin-related protein (DRP), sharing functional motifs with dystrophin. Utrophin's ability to compensate for dystrophin during development and when....... Therefore, this pathway offers a potential mechanism to modulate utrophin expression in muscle. We tested the ability of heregulin to improve the dystrophic phenotype in the mdx mouse model of DMD. Intraperitoneal injections of a small peptide encoding the epidermal growth factor-like region of heregulin...... ectodomain for 3 months in vivo resulted in up-regulation of utrophin, a marked improvement in the mechanical properties of muscle as evidenced by resistance to eccentric contraction mediated damage, and a reduction of muscle pathology. The amelioration of dystrophic phenotype by heregulin-mediated utrophin...

Mapping Breakpoints of Complex Chromosome Rearrangements Involving a Partial Trisomy 15q23.1-q26.2 Revealed by Next Generation Sequencing and Conventional Techniques.

Directory of Open Access Journals (Sweden)

Qiong Pan

Full Text Available Complex chromosome rearrangements (CCRs, which are rather rare in the whole population, may be associated with aberrant phenotypes. Next-generation sequencing (NGS and conventional techniques, could be used to reveal specific CCRs for better genetic counseling. We report the CCRs of a girl and her mother, which were identified using a combination of NGS and conventional techniques including G-banding, fluorescence in situ hybridization (FISH and PCR. The girl demonstrated CCRs involving chromosomes 3 and 8, while the CCRs of her mother involved chromosomes 3, 5, 8, 11 and 15. HumanCytoSNP-12 Chip analysis identified a 35.4 Mb duplication on chromosome 15q21.3-q26.2 in the proband and a 1.6 Mb microdeletion at chromosome 15q21.3 in her mother. The proband inherited the rearranged chromosomes 3 and 8 from her mother, and the duplicated region on chromosome 15 of the proband was inherited from the mother. Approximately one hundred genes were identified in the 15q21.3-q26.2 duplicated region of the proband. In particular, TPM1, SMAD6, SMAD3, and HCN4 may be associated with her heart defects, and HEXA, KIF7, and IDH2 are responsible for her developmental and mental retardation. In addition, we suggest that a microdeletion on the 15q21.3 region of the mother, which involved TCF2, TCF12, ADMA10 and AQP9, might be associated with mental retardation. We delineate the precise structures of the derivative chromosomes, chromosome duplication origin and possible molecular mechanisms for aberrant phenotypes by combining NGS data with conventional techniques.

HUWE1 mutation explains phenotypic severity in a case of familial idiopathic intellectual disability

OpenAIRE

Isrie, M.; Kalscheuer, V.; Holvoet, M.; Fieremans, N.; Van Esch, H.; Devriendt, K.

2013-01-01

The advent of next-generation sequencing has proven to be a key force in the identification of new genes associated with intellectual disability. In this study, high-throughput sequencing of the coding regions of the X-chromosome led to the identification of a missense variant in the HUWE1 gene. The same variant has been reported before by Froyen et al. (2008). We compare the phenotypes and demonstrate that, in the present family, the HUWE1 mutation segregates with the more severe ID phenotyp...

Periventricular heterotopia and white matter abnormalities in a girl with mosaic ring chromosome 6.