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DNA damage chromosome translocation

Anat Zimmer, Shlomit Amar-Farkash, Tamar Danon, Uri Alon
BACKGROUND: Drugs often kill some cancer cells while others survive. This stochastic outcome is seen even in clonal cells grown under the same conditions. Understanding the molecular reasons for this stochastic outcome is a current challenge, which requires studying the proteome at the single cell level over time. In a previous study we used dynamic proteomics to study the response of cancer cells to a DNA damaging drug, camptothecin. Several proteins showed bimodal dynamics: they rose in some cells and decreased in others, in a way that correlated with eventual cell fate: death or survival...
March 7, 2017: BMC Systems Biology
Julie Korda Holsclaw, Jeff Sekelsky
DNA double-strand breaks (DSBs) pose a serious threat to genomic integrity. If unrepaired, they can lead to chromosome fragmentation and cell death. If repaired incorrectly, they can cause mutations and chromosome rearrangements. DSBs are repaired using end-joining or homology-directed repair strategies, with the predominant form of homology-directed repair being synthesis-dependent strand annealing (SDSA). SDSA is the first defense against genomic rearrangements and information loss during DSB repair, making it a vital component of cell health and an attractive target for chemotherapeutic development...
March 3, 2017: Genetics
Megan R Fisher, Adrian Rivera-Reyes, Noah B Bloch, David G Schatz, Craig H Bassing
Mammalian cells have evolved a common DNA damage response (DDR) that sustains cellular function, maintains genomic integrity, and suppresses malignant transformation. In pre-B cells, DNA double-strand breaks (DSBs) induced at Igκ loci by the Rag1/Rag2 (RAG) endonuclease engage this DDR to modulate transcription of genes that regulate lymphocyte-specific processes. We previously reported that RAG DSBs induced at one Igκ allele signal through the ataxia telangiectasia mutated (ATM) kinase to feedback-inhibit RAG expression and RAG cleavage of the other Igκ allele...
April 1, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
Maryam Mahmoodi, Tu Nguyen-Dumont, Fleur Hammet, Bernard J Pope, Daniel J Park, Melissa C Southey, John M Darlow, Fiona Bruinsma, Ingrid Winship
An apparently balanced t(2;3)(q37.3;q13.2) translocation that appears to segregate with renal cell carcinoma (RCC) has indicated potential areas to search for the elusive genetic basis of clear cell RCC. We applied Hi-Plex targeted sequencing to analyse germline DNA from 479 individuals affected with clear cell RCC for this breakpoint translocation and genetic variants in neighbouring genes on chromosome 2, ACKR3 and COPS8. While only synonymous variants were found in COPS8, one of the missense variants in ACKR3:c...
January 6, 2017: Familial Cancer
Qiao Wang, Kyong-Rim Kieffer-Kwon, Thiago Y Oliveira, Christian T Mayer, Kaihui Yao, Joy Pai, Zhen Cao, Marei Dose, Rafael Casellas, Mila Jankovic, Michel C Nussenzweig, Davide F Robbiani
Activation-induced cytidine deaminase (AID) converts cytosine into uracil to initiate somatic hypermutation (SHM) and class switch recombination (CSR) of antibody genes. In addition, this enzyme produces DNA lesions at off-target sites that lead to mutations and chromosome translocations. However, AID is mostly cytoplasmic, and how and exactly when it accesses nuclear DNA remains enigmatic. Here, we show that AID is transiently in spatial contact with genomic DNA from the time the nuclear membrane breaks down in prometaphase until early G1, when it is actively exported into the cytoplasm...
January 2017: Journal of Experimental Medicine
Estela T Méndez-Olvera, Jaime A Bustos-Martínez, Yolanda López-Vidal, Antonio Verdugo-Rodríguez, Daniel Martínez-Gómez
BACKGROUND: Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. OBJECTIVES: The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus...
October 2016: Jundishapur Journal of Microbiology
Evelyne Sage, Naoya Shikazono
Clustered DNA lesions, also called Multiply Damaged Sites, is the hallmark of ionizing radiation. It is defined as the combination of two or more lesions, comprising strand breaks, oxidatively generated base damage, abasic sites within one or two DNA helix turns, created by the passage of a single radiation track. DSB clustered lesions associate DSB and several base damage and abasic sites in close vicinity, and are assimilated to complex DSB. Non-DSB clustered lesions comprise single strand break, base damage and abasic sites...
December 8, 2016: Free Radical Biology & Medicine
Maki Fukami, Hitohito Shima, Erina Suzuki, Tsutomu Ogata, Keiko Matsubara, Tsutomu Kamimaki
Although complex chromosomal rearrangements were thought to reflect the accumulation of DNA damage over time, recent studies have shown that such rearrangements frequently arise from "all-at-once" catastrophic cellular events. These events, designated chromothripsis, chromoanasynthesis, and chromoanagenesis, were first documented in the cancer genome and subsequently observed in the germline. These events likely result from micronucleus-mediated chromosomal shattering and subsequent random reassembly of DNA fragments, although several other mechanisms have also been proposed...
November 26, 2016: Clinical Genetics
Patrick H Maxwell
BACKGROUND: Accumulation of DNA damage, mutations, and chromosomal abnormalities is associated with aging in many organisms. How directly various forms of genomic instability contribute to lifespan in different aging contexts is still under active investigation. Testing whether treatments that alter lifespan change mutation rates early during lifespan could provide support for genomic instability being at least partly responsible for changes in the rates of aging. RESULTS: Rates of mutations, direct repeat recombination, or retrotransposition were measured in young cell populations from two strain backgrounds of Saccharomyces cerevisiae exposed to several growth conditions that shortened or extended yeast chronological lifespan...
October 21, 2016: BMC Genetics
Kit I Tong, Kazushige Ota, Akiyoshi Komuro, Takeshi Ueda, Akihiko Ito, C Anne Koch, Hitoshi Okada
Therapy-related cancers are potentially fatal late life complications for patients who received radio- or chemotherapy. So far, the mouse model showing reduction or delay of these diseases has not been described. We found that the disruption of Aplf in mice moderately attenuated DNA damage repair and, unexpectedly, impeded myeloid neoplasms after exposure to ionizing radiation (IR). Irradiated mutant mice showed higher rates of p53-dependent cell death, fewer chromosomal translocations, and a delay in malignancy-induced mortality...
October 6, 2016: Cell Death & Disease
Takahiro Kishikawa, Motoyuki Otsuka, Takeshi Yoshikawa, Motoko Ohno, Hideaki Ijichi, Kazuhiko Koike
Highly repetitive tandem arrays at the centromeric and pericentromeric regions in chromosomes, previously considered silent, are actively transcribed, particularly in cancer. This aberrant expression occurs even in K-ras-mutated pancreatic intraepithelial neoplasia (PanIN) tissues, which are precancerous lesions. To examine the biological roles of the satellite RNAs in carcinogenesis, we construct mouse PanIN-derived cells expressing major satellite (MajSAT) RNA and show increased malignant properties. We find an increase in frequency of chromosomal instability and point mutations in both genomic and mitochondrial DNA...
2016: Nature Communications
Katarina Ochodnicka-Mackovicova, Mahnoush Bahjat, Chiel Maas, Amélie van der Veen, Timon A Bloedjes, Alexander M de Bruin, Harmen van Andel, Carol E Schrader, Rudi W Hendriks, Els Verhoeyen, Richard J Bende, Carel J M van Noesel, Jeroen E J Guikema
The recombination activating gene (RAG) 1 and RAG2 protein complex introduces DNA breaks at Tcr and Ig gene segments that are required for V(D)J recombination in developing lymphocytes. Proper regulation of RAG1/2 expression safeguards the ordered assembly of Ag receptors and the development of lymphocytes, while minimizing the risk for collateral damage. The ataxia telangiectasia mutated (ATM) kinase is involved in the repair of RAG1/2-mediated DNA breaks and prevents their propagation. The simultaneous occurrence of RAG1/2-dependent and -independent DNA breaks in developing lymphocytes exposed to genotoxic stress increases the risk for aberrant recombinations...
October 1, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Ewa Wiland, Monika Fraczek, Marta Olszewska, Maciej Kurpisz
Several studies have shown that the 'poor' sperm DNA quality appears to be an important factor affecting male reproductive ability. In the case of sperm cells from males with the correct somatic karyotype but with deficient spermatogenesis, resulting in a high degree of sperm DNA fragmentation, we observed changes in the preferential topology of the chromosome 7, 9, 15, 18, X and Y centromeres. The changes occurred in radial localization and may have been directly linked to the sperm chromatin damage. This conclusion is mainly based on a comparison of FISH signals that were observed simultaneously in the TUNEL-positive and TUNEL-negative sperm cells...
2016: Scientific Reports
Brian McStay
Nucleoli form around tandem arrays of a ribosomal gene repeat, termed nucleolar organizer regions (NORs). During metaphase, active NORs adopt a characteristic undercondensed morphology. Recent evidence indicates that the HMG-box-containing DNA-binding protein UBF (upstream binding factor) is directly responsible for this morphology and provides a mitotic bookmark to ensure rapid nucleolar formation beginning in telophase in human cells. This is likely to be a widely employed strategy, as UBF is present throughout metazoans...
July 15, 2016: Genes & Development
Lili Wang, Li He, Guoqiang Bao, Xin He, Saijun Fan, Haichao Wang
OBJECTIVE: A nucleosomal protein, HMGB1, can be secreted by activated immune cells or passively released by dying cells, thereby amplifying rigorous inflammatory responses. In this study we aimed to test the possibility that ionizing radiation similarly induces cytoplasmic HMGB1 translocation and extracellular release. METHOD: Human skin fibroblast (GM0639) and bronchial epithelial (16HBE) cells and animals (rats) were exposed to X-ray radiation, and HMGB1 translocation and release were assessed by immunocytochemistry and immunoassay, respectively...
March 2016: Guo Ji Fang She Yi Xue He Yi Xue za Zhi, International Journal of Radiation Medicine and Nuclear Medicine
Agnes Schipler, Veronika Mladenova, Aashish Soni, Vladimir Nikolov, Janapriya Saha, Emil Mladenov, George Iliakis
Chromosome translocations are hallmark of cancer and of radiation-induced cell killing, reflecting joining of incongruent DNA-ends that alter the genome. Translocation-formation requires DNA end-joining mechanisms and incompletely characterized, permissive chromatin conditions. We show that chromatin destabilization by clusters of DNA double-strand-breaks (DSBs) generated by the I-SceI meganuclease at multiple, appropriately engineered genomic sites, compromises c-NHEJ and markedly increases cell killing and translocation-formation compared to single-DSBs...
September 19, 2016: Nucleic Acids Research
Judith W J Bergs, Arlene L Oei, Rosemarie Ten Cate, Hans M Rodermond, Lukas J Stalpers, Gerrit W Barendsen, Nicolaas A P Franken
Hyperthermia can transiently degrade BRCA2 and thereby inhibit the homologous recombination pathway. Induced DNA-double strand breaks (DSB) then have to be repaired via the error prone non-homologous end-joining pathway. In the present study, to investigate the role of hyperthermia in genotoxicity and radiosensitization, the induction of chromosomal aberrations was examined by premature chromosome condensation and fluorescence in situ hybridisation (PCC-FISH), and cell survival was determined by clonogenic assay shortly (0-1 h) and 24 h following exposure to hyperthermia in combination with ionizing radiation...
July 2016: International Journal of Molecular Medicine
Gordon K Livingston, Igor K Khvostunov, Eric Gregoire, Joan-Francesc Barquinero, Lin Shi, Satoshi Tashiro
The purpose of this study was to compare cytogenetic data in a patient before and after treatment with radioiodine to evaluate the assays in the context of biological dosimetry. We studied a 34-year-old male patient who underwent a total thyroidectomy followed by ablation therapy with (131)I (19.28 GBq) for a papillary thyroid carcinoma. The patient provided blood samples before treatment and then serial samples at monthly intervals during the first year period and quarterly intervals for 5 years and finally 20 years after treatment...
May 2016: Radiation and Environmental Biophysics
Maki Morishita, Tomoki Muramatsu, Yumiko Suto, Momoki Hirai, Teruaki Konishi, Shin Hayashi, Daichi Shigemizu, Tatsuhiko Tsunoda, Keiji Moriyama, Johji Inazawa
Chromothripsis is the massive but highly localized chromosomal rearrangement in response to a one-step catastrophic event, rather than an accumulation of a series of subsequent and random alterations. Chromothripsis occurs commonly in various human cancers and is thought to be associated with increased malignancy and carcinogenesis. However, the causes and consequences of chromothripsis remain unclear. Therefore, to identify the mechanism underlying the generation of chromothripsis, we investigated whether chromothripsis could be artificially induced by ionizing radiation...
March 1, 2016: Oncotarget
Jing Wang, Chenhui Ding, Yongming Zhang, Zhimin Zeng, Xuerong Hou, Baomin Lu, Yanwen Xu, Canquan Zhou
OBJECTIVE: To provide preimplantation genetic diagnosis(PGD) for two couples carrying thalassemia mutations and chromosomal abnormalities. METHODS: Couple 1 were both carriers of β 41/42 thalassemia mutations, while the husband has carried a reciprocal translocation with a karyotype of 46,XY,inv(9)(p11;q13),t(11;22)(q25;q13). Couple 2 were both carriers of α (-SEA) thalassemia mutation. Their chromosome karyotypes were both normal, but had two spontaneous abortions...
February 2016: Zhonghua Yi Xue Yi Chuan Xue za Zhi, Zhonghua Yixue Yichuanxue Zazhi, Chinese Journal of Medical Genetics
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