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    Wyświetlanie 1-12 z 12
    Tytuł:
    DNA double-strand break rejoining in radioadapted human lymphocytes: evaluation by neutral comet assay and pulse-field gel electrophoresis
    Autorzy:
    Wojewódzka, M.
    Buraczewska, I.
    Szumiel, I.
    Grądzka, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/146153.pdf
    Data publikacji:
    2006
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    human lymphocytes
    radioadaptation
    DNA double-strand break rejoining
    neutral comet assay
    pulsefield gel electrophoresis
    Opis:
    Adaptive response (AR), an enhanced resistance to a high dose of ionising radiation acquired after pretreatment with a very low dose, was estimated in normal human lymphocytes. The question posed was whether the extent of radioadaptation, assessed by micronucleus test, would be related to the rate of DNA double-strand break (DSB) rejoining. Phytohemagglutinin-stimulated G1-lymphocytes from 5 healthy male volunteers were pre-treated (or not) with an adaptive (5 cGy) dose of X-rays, followed by a higher (5 or 10 Gy) challenge dose after 20-22 h. DSB rejoining after the challenge dose was monitored with the use of two methods: neutral comet assay, modified to reduce the contribution of single-strand breaks (SSBs) and thermolabile sites, and pulse-field gel electrophoresis (PFGE), specific for DSBs. At the level of micronuclei, an AR was observed in lymphocytes of 3 of 5 donors. Up to 60 min, comet assay showed no statistically significant differences in DNA break rejoining between adapted and non-adapted lymphocytes, independently of AR appearance. PFGE gave similar results, although in three donors it revealed secondary increases in DSBs levels at 30 min and/or 60 min post-irradiation in the adapted vs. the non-adapted samples. Failure to demonstrate changes in DSBs rejoining rate in the adapted lymphocytes could be due to diversity of AR intensity/timing at the level of DNA repair in not fully homogenous cell populations. Also, “rare” DNA cuts characteristic of early apoptosis/necrosis could overlap the process of DNA break rejoining.
    Źródło:
    Nukleonika; 2006, 51, 4; 185-191
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modified neutral comet assay for human lymphocytes
    Autorzy:
    Wojewódzka, M.
    Grądzka, I.
    Buraczewska, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/147130.pdf
    Data publikacji:
    2002
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    DNA double strand breaks
    human lymphocyte
    neutral comet assay
    Opis:
    Comet assay under neutral conditions allows the detection of DNA double-strand breaks, considered to be the biologically relevant radiation-induced lesion. In this report we describe modifications of the neutral comet method, which simplify and facilitate its use for estimation of DNA double strand breaks in human lymphocytes irradiated with doses of 60Co gamma-rays (from 10 to 100 Gy). The analysis carried out according to this protocol takes less time than those published so far. Also, the use of lysis at 50°C is avoided; this is important in view of the presence of heat-labile sites in the DNA of irradiated cells, recently reported by Rydberg [12]. The comets have well defined, sharp limits, are suitable for computer image analysis and chromatin of the control cells remains condensed.
    Źródło:
    Nukleonika; 2002, 47, 1; 1-5
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Metoda znajdowania komórek i zliczania ognisk występowania histonu γ-H2AX w obrazach na potrzeby detekcji dwuniciowych pęknięć DNA
    Method for cell finding and histone γ-H2AX foci counting in images for detecting DNA double-strand breaks
    Autorzy:
    Wojciechowski, P.
    Bal, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/154831.pdf
    Data publikacji:
    2012
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    γ-H2AX
    dwuniciowe pęknięcia DNA
    przetwarzanie obrazów
    obrazy biomedyczne
    segmentacja wododziałowa
    double-strand breaks (DSB)
    image processing
    biomedical images
    watershed segmentation
    Opis:
    Niniejsza praca opisuje algorytm automatyzujący proces zliczania ognisk histonu γ-H2AX w obrazach mikroskopowych. Ogniska te są miejscami, w których doszło do fosforylacji białka histonu H2AX w pozycji seryny 139 wskutek dwuniciowych pęknięć DNA. Propono-wana metoda działa dwuetapowo. Najpierw w obrazie mikroskopowym selekcjonowane są obiekty uznawane za komórki, a następnie na obszarze tych obiektów poszukiwane są miejsca wyznakowane barwnikiem fluorescencyjnym związanym z przeciwciałem anty-γ-H2AX - miejsca te wskazują na lokalizację ognisk γ-H2AX.
    This paper describes an algorithm for automating the process of counting foci of histone γ-H2AX in microscope images. Foci are the places where there occurred H2AX protein phosphorylation on Ser139 site in response to DNA double-strand breaks (DSBs). In a γ-H2AX genotoxic test the number of foci per a single cell is counted. The proposed method works in two stages. The first stage is segmentation of a microscopic image (Fig. 1a) for selecting cell regions. For this purpose fusion of binarization methods is used - for the each pixel the result is obtained by comparison of the results from the Otsu method, the triangle method and the method in which the threshold is equal to the image average brightness. The pixel is classified as an object's pixel when at least two methods give such results. For improving segmentation results a morphological filter is used. The results (Fig. 1b) usually comprise regions representing single cells (Fig. 1c) and a set of agglomerated cells (Fig. 1d). A modified watershed segmentation and region classify method is used for separation of agglomerated cells into regions representing only one cell. The final result (Fig.1e) contains only regions representing single cells. In the second stage for each single cell region the foci (which are marked with a fluorescent indicator joined with anti- γ-H2AX antibody) are found (Fig. 3) with use of watershed segmentation on the pseudogradient image (which is obtained by aggregation of the results of cell image binarization with different thresholds; Fig. 2). The final results in form of foci number as a function of time after irradiation (Fig. 4) are similar to the test results of non-lethal DNA damages founded in the literature (e.g. [5]) - this allows stating that the presented method gives good results.
    Źródło:
    Pomiary Automatyka Kontrola; 2012, R. 58, nr 4, 4; 387-390
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chromatin acetylation, β-amyloid precursor protein and its binding partner FE65 in DNA double strand break repair
    Autorzy:
    Szumiel, Irena
    Foray, Nicolas
    Powiązania:
    https://bibliotekanauki.pl/articles/1039940.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    chromatin acetylation
    FE65
    MOF acetyltransferase
    DNA double strand break repair
    β-amyloid precursor protein
    Tip60 histone acetyltransferase
    heterochromatin protein 1
    Opis:
    Among post-translational modifications of chromatin proteins taking place in DNA double strand break (DSB) repair, acetylation plays a prominent role. This review lists several facts and hypotheses concerning this process. Lack of acetyltransferase TIP60 (HIV-Tat interacting protein of 60 kDa) activity results in cells with defective DSB repair. The enzyme is present in the nucleus in a multimeric protein complex. TIP60 dependent activation of ATM (ataxia telangiectasia mutated kinase) is an early event in the response to DNA breakage. Other important acetylations are those of histones H4 and γH2AX. Correct reconstruction of the damaged site is critical for survival and prevention of genetic and epigenetic changes in the cell that may affect the function of its daughter cells. Recently, two proteins with previously unsuspected functions in DSB repair have been identified as active in this process: Alzheimer β-amyloid precursor protein (APP) and its binding partner FE65, β-amyloid precursor binding protein. Their participation in DSB repair in both neuronal and non-neuronal cells is related to acetylation carried out by the acetyltransferase complex. The same function is ascribed to heterochromatin protein 1 (HP1). So far, the relations (if any) between TIP60 activation by HP1 and by the FE65 complex remain unidentified.
    Źródło:
    Acta Biochimica Polonica; 2011, 58, 1; 11-18
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The expression of UVR3 and two putative photolyases, PHR2 and At4g25290, is regulated by light
    Autorzy:
    Sztatelman, O.
    Labuz, J.
    Banas, A.K.
    Powiązania:
    https://bibliotekanauki.pl/articles/80793.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    conference
    DNA strand
    RNA polymerase
    DNA polymerase
    replication
    transcription
    light regulation
    putative photolyase
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 3
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Concerted control of DNA double strand break repair and cell cycle progression in X-irradiated mammalian cells
    Autorzy:
    Sochanowicz, B.
    Szumiel, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/148697.pdf
    Data publikacji:
    2005
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    ATM kinase
    DNA double strand break repair
    RAD50
    cell cycle arrest
    repair foci
    BRCT domain
    Opis:
    Upon examination of cell cycle regulation in a damaged cell, relations were discovered of the cell cycle control mechanisms with a complicated web of signalling pathways, eventually called the genome surveillance system. After infliction of DNA double strand breaks (DSB), the signalling is initiated by sensor proteins and transducer protein kinase ATM. This kinase phosphorylates downstream effector proteins, such as checkpoint kinases CHK1 and CHK2, which initiate the pathways leading to cell cycle arrest. In contrast with the older model of linear transmission of signals in a certain sequence, it is now accepted that the damage signalling system is branched and contains feedback loops. DSB's presence is signalled by sensor proteins (MRE11-RAD50-nibrin complex, MRN) to ATM and the signal is amplified through adaptor proteins, MDC1/NFBD1 or 53BP1 (Tp53 binding protein). MRN contains a forkheadassociated (FHA) domain and BRCA1 carboxyl-terminal (BRCT) domain. The combination of the FHA/BRCT domains has a crucial role for the binding of nibrin to the H2AX histone, assembling the components of repair foci. These domains also are important for interaction of other proteins localised in the foci. For example, MDC1/NFBD1 contains a FHA domain and two BRCT domains which are involved in protein interactions. The signal generated at DSBs is amplified and transduced to recruit components of DNA repair systems. In a concerted way with the sequential recruitment of components of repair foci, activation of transcription of genes takes place, that is necessary for blocking progression through the cell cycle, for DNA repair or apoptosis.
    Źródło:
    Nukleonika; 2005, 50, 4; 129-138
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Inhibition of poly(ADP-ribose) polymerase activity affects its subcellular localization and DNA strand break rejoining
    Autorzy:
    Ryabokon, Nadezhda
    Cieślar-Pobuda, Artur
    Rzeszowska-Wolny, Joanna
    Powiązania:
    https://bibliotekanauki.pl/articles/1040571.pdf
    Data publikacji:
    2009
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    DNA strand break rejoining
    efficiency of PARP inhibition
    PARP foci
    poly(ADP-ribose) polymerase (PARP)
    PARP inhibitors
    Opis:
    Poly(ADP-ribose) polymerase (PARP) plays a crucial role in DNA repair. Modulation of its activity by stimulation or inhibition is considered as a potentially important strategy in clinical practice, especially to sensitize tumor cells to chemo- and radiotherapy through inhibition of DNA repair. Here we studied the effect of the three PARP inhibitors, 5-iodo-6-amino-benzopyrone (INH2BP), 1,5-isoquinolinediol (1,5-dihydroxyisoquinolinediol (1,5-IQD) and 8-hydroxy-2-methylquinazolin-4-[3H]one (NU1025), and for two of them the efficiency in slowing the rejoining of DNA strand breaks induced by H2O2 was compared. Inhibition of PARP changed its intranuclear localization markedly; cells exposed to the inhibitor NU1025 showed a significant tendency to accumulate PARP in large foci, whereas in untreated cells its distribution was more uniform. The speed and efficiency of rejoining of H2O2-induced DNA strand breaks were lower in cells incubated with a PARP inhibitor, and the kinetics of rejoining were modulated in a different manner by each inhibitor. At a concentration of 100 µM the efficiency of the inhibitors could be ranked in the order NU1025 > IQD > INH2BP. The two first compounds were able to decrease the overall PARP activity below the level detected in control cells, while INH2BP showed up to 40% PARP activity after exposure to H2O2.
    Źródło:
    Acta Biochimica Polonica; 2009, 56, 2; 243-248
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Non-homologous DNA end joining.
    Autorzy:
    Pastwa, Elżbieta
    Błasiak, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/1043360.pdf
    Data publikacji:
    2003
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    Ku proteins
    DNA-PK
    homologous recombination
    non-homologous end joining
    DSB; DNA repair
    DNA ligase IV
    DNA double-strand breaks
    NHEJ
    Opis:
    DNA double-strand breaks (DSBs) are a serious threat for the cell and when not repaired or misrepaired can result in mutations or chromosome rearrangements and eventually in cell death. Therefore, cells have evolved a number of pathways to deal with DSB including homologous recombination (HR), single-strand annealing (SSA) and non-homologous end joining (NHEJ). In mammals DSBs are primarily repaired by NHEJ and HR, while HR repair dominates in yeast, but this depends also on the phase of the cell cycle. NHEJ functions in all kinds of cells, from bacteria to man, and depends on the structure of DSB termini. In this process two DNA ends are joined directly, usually with no sequence homology, although in the case of same polarity of the single stranded overhangs in DSBs, regions of microhomology are utilized. The usage of microhomology is common in DNA end-joining of physiological DSBs, such as at the coding ends in V(D)J (variable(diversity) joining) recombination. The main components of the NHEJ system in eukaryotes are the catalytic subunit of DNA protein kinase (DNA-PKcs), which is recruited by DNA Ku protein, a heterodimer of Ku70 and Ku80, as well as XRCC4 protein and DNA ligase IV. A complex of Rad50/Mre11/Xrs2, a family of Sir proteins and probably other yet unidentified proteins can be also involved in this process. NHEJ and HR may play overlapping roles in the repair of DSBs produced in the S phase of the cell cycle or at replication forks. Aside from DNA repair, NHEJ may play a role in many different processes, including the maintenance of telomeres and integration of HIV-1 genome into a host genome, as well as the insertion of pseudogenes and repetitive sequences into the genome of mammalian cells. Inhibition of NHEJ can be exploited in cancer therapy in radio-sensitizing cancer cells. Identification of all key players and fundamental mechanisms underlying NHEJ still requires further research.
    Źródło:
    Acta Biochimica Polonica; 2003, 50, 4; 891-908
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Intranuclear trafficking of plasmid DNA is mediated by nuclear polymeric proteins lamins and actin
    Autorzy:
    Ondřej, Vladan
    Lukášová, Emilie
    Krejčí, Jana
    Kozubek, Stanislav
    Powiązania:
    https://bibliotekanauki.pl/articles/1040744.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    plasmid DNA
    DNA double-strand breaks
    nuclear actin
    lamin A/C
    Opis:
    Functions of nuclear polymeric proteins such as lamin A/C and actin in transport of plasmid DNA were studied. The results show that the lamina plays an important role in plasmid DNA's entry into the cell nucleus from the cytoplasm. Selective disruption of lamin A/C led to a halt in plasmid DNA transport through the nuclear envelope. Inside the nucleus, plasmid DNA was frequently localized at sites with impaired genome integrity, such as DNA double-strand breaks (DSBs), occurring spontaneously or induced by ionizing radiation. Polymeric actin obviously participates in nuclear transport of plasmid DNA, since inhibition of actin polymerization by latrunculin B disturbed plasmid transport inside the cell nucleus. In addition, precluding of actin polymerization inhibited plasmid co-localization with newly induced DSBs. These findings indicate the crucial role of polymeric actin in intranuclear plasmid transport.
    Źródło:
    Acta Biochimica Polonica; 2008, 55, 2; 307-315
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Histone H2AX in DNA repair
    Autorzy:
    Lewandowska, H.
    Szumiel, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/147030.pdf
    Data publikacji:
    2002
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    DNA double strand breaks
    DNA repair
    histone gamma-H2AX
    ionising radiation
    Opis:
    The paper reviews the recent reports on the role of the phosphorylated histone H2AX (gamma-H2AX). The modification of this histone is an important part of the cellular response to the induction of DNA double strand breaks (DSB) by ionising radiation and other DSB-generating factors. In irradiated cell the modification is carried out mainly by ATM (ataxia- -telangiectasia mutated) kinase, the enzyme that starts the alarm signalling upon induction of DSB. gamma-H2AX molecules are formed within 1 3 min after irradiation and form foci at the sites of DSB. This seems to be necessary for the recruitment of repair factors that are later present in foci of damaged nuclei. Modification of a constant percentage of H2AX molecules per DSB takes place, corresponding to chromatin domains of megabase pairs of DNA.
    Źródło:
    Nukleonika; 2002, 47, 4; 127-131
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Relationships between EGFR-initiated signalling, DNA double-strand break rejoining and survival in X-irradiated human glioma M059 cells
    Autorzy:
    Grądzka, I.
    Buraczewska, I.
    Szumiel, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/146764.pdf
    Data publikacji:
    2008
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    human glioma M059 K and J cells
    DNA-dependent protein kinase (DNA-PK)
    radiosensitivity
    DNA double-strand break (DSB) rejoining
    epidermal-growth-factor-receptor (EGFR)
    signalling inhibitors: tyrphostin
    Opis:
    The aim of this study was to investigate the effect of signalling inhibition on survival and double-strand break (DSB) rejoining in cells differing in sensitivity to inhibitors, X-rays and bleomycin. Human glioma M059 cells, K (relatively radioresistant) and J (radiosensitive, defective in DSB rejoining for lack of DNA-dependent protein kinase catalytic subunit, DNA-PKcs) were pretreated with signalling inhibitors: tyrphostin AG 1478, specific for epidermalgrowth- factor-receptor (EGFR) kinase or PD 98059, specific for kinase MEK 1/2 (mitogen-activated, extracellular signal-activated kinases 1 and 2). Subsequently, the cells were X-irradiated or treated with bleomycin. Cell survival was determined by clonogenicity test. DSB rejoining was monitored with the use of pulsed-field gel electrophoresis (PFGE). We found that in X-irradiated M059 K cells EGFR kinase activity was necessary for efficient DSB rejoining and the kinase inhibitor, tyrphostin AG 1478, acted as radiosensitizer in the dose range that reduced cell survival to 0.7-0.8. Inhibition of EGFR kinase, however, did not decrease survival or affect DSB rejoining in DNA-PKcs-deficient M059 J cells. These results indicated that the decrease in cell survival was due to a disturbed DSB rejoining by the DNA-PK dependent system. In contrast, inhibition of MEK 1/2 kinase on EGFR downstream signalling pathway by PD 98059 did not affect DSB rejoining in either cell line and exerted a radioprotective effect.
    Źródło:
    Nukleonika; 2008, 53, 2; 37-44
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonhomologous end-joining deficiency of L5178Y-S cells is not associated with mutation in the ABCDE autophosphorylation cluster
    Autorzy:
    Brzóska, Kamil
    Kruszewski, Marcin
    Szumiel, Irena
    Powiązania:
    https://bibliotekanauki.pl/articles/1041297.pdf
    Data publikacji:
    2006
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    mouse lymphoma L5178Y
    nonhomologous end-joining
    autophosphorylation
    DNA-dependent protein kinase
    double strand break repair
    Opis:
    Cells with mutated autophosphorylation sites in the ABCDE cluster of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are defective in the repair of ionising radiation-induced DSB, but show in an in vitro test the same DNA-PK activity as the cells possessing wild type enzyme. Nevertheless, the mutated DNA-PK is able to undergo ATP-dependent autophosphorylation and inactivation. This characteristics correspond well with the phenotypic features of the L5178Y-S (LY-S) cell line that is defective in DSB repair, shows a pronounced G1 phase radiosensitivity, but in which the level of DNA-PK activity present in total cell extracts is similar to that of its radioresistant counterpart L5178Y-R (LY-R) cell line. The purpose of this work was to examine the possible alterations in the sequence encoding the cluster of autophosphorylation sites in the DNA-dependent protein kinase in LY-S cells. Despite the presence of phenotypic features indicating the possibility of such alterations, no differences were found between the sequences coding for the autophosphorylation sites in L5178Y-R and L5178Y-S cells. In conclusion, the repair defect in LY-S cells is not related to the structure of the DNA-PK autophosphorylation sites (ABCDE casette).
    Źródło:
    Acta Biochimica Polonica; 2006, 53, 1; 233-236
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-12 z 12

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