Methylation of histones H4 at lysine 20 position (H4K20me), which is functional in DNA repair, represents a binding site for the 53BP1 protein. Here, we show a radiation-induced increase in the level of H4K20me3 while the levels of H4K20me1 and H4K20me2 remained intact. H4K20me3 was significantly pronounced at DNA lesions in only the G1 phase of the cycle, while this histone mark was reduced in very late S and G2 phases when PCNA was recruited to locally micro-irradiated chromatin. H4K20me3 was diminished in locally irradiated Suv39h1/h2 double knockout (dn) fibroblasts, and the same phenomenon was observed for H3K9me3 and its binding partner, the HP1β protein. Immunoprecipitation showed the existence of an interaction between H3K9me3-53BP1 and H4K20me3-53BP1; however, HP1β did not interact with 53BP1. Together, H3K9me3 and H4K20me3 represent epigenetic markers that are important for the function of the 53BP1 protein in non-homologous end joining (NHEJ) repair. The very late S phase represents the cell cycle breakpoint when a DDR function of the H4K20me3-53BP1 complex is abrogated due to recruitment of the PCNA protein and other DNA repair factors of homologous recombination to DNA lesions.

• Klíčová slova
• DNA damage, H3K9me3, H4K20me1/me2/me3, Suv39h1/h2, epigenetics,
• MeSH
• 53BP1 genetika   metabolismus   MeSH
• buněčné jádro genetika   metabolismus   účinky záření   MeSH
• buněčné linie MeSH
• buněčný cyklus MeSH
• chromozomální proteiny, nehistonové metabolismus   MeSH
• epigeneze genetická * účinky záření   MeSH
• histony metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• lidé MeSH
• metylace DNA * účinky záření   MeSH
• metylace MeSH
• myši MeSH
• oprava DNA spojením konců * MeSH
• poškození DNA * MeSH
• proliferační antigen buněčného jádra metabolismus   MeSH
• restrukturace chromatinu MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 53BP1 MeSH
• CBX1 protein, human MeSH Prohlížeč
• Cbx1 protein, mouse MeSH Prohlížeč
• chromozomální proteiny, nehistonové MeSH
• histony MeSH
• homolog proteinu s chromoboxem 5 MeSH
• PCNA protein, human MeSH Prohlížeč
• proliferační antigen buněčného jádra MeSH
• TP53BP1 protein, human MeSH Prohlížeč
• Trp53bp1 protein, mouse MeSH Prohlížeč

Two chromosomal structures, known as monocentric and holocentric chromosomes, have evolved in eukaryotes. Acentric fragments of monocentric chromosomes are unequally distributed to daughter cells and/or lost, while holocentric fragments are inherited normally. In monocentric species, unequal distribution should generate chimeras of cells with different nuclear DNA content. We investigated whether such differences in monocentric species are detectable by flow cytometry (FCM) as (i) a decreased nuclear DNA content and (ii) an increased coefficient of variance (CV) of the G1 peak after gamma radiation-induced fragmentation. We compared 13 monocentric and 9 holocentric plant species. Unexpectedly, monocentrics and holocentrics did not differ with respect to parameters (i) and (ii) in their response to gamma irradiation. However, we found that the proportion of G2 nuclei was highly elevated in monocentrics after irradiation, while holocentrics were negligibly affected. Therefore, we hypothesize that DNA-damaging agents induce cell cycle arrest leading to endopolyploidy only in monocentric and not (or to much lesser extent) in holocentric plants. While current microscope-dependent methods for holocentrism detection are unreliable for small and numerous chromosomes, which are common in holocentrics, FCM can use somatic nuclei. Thus, FCM may be a rapid and reliable method of high-throughput screening for holocentric candidates across plant phylogeny.

• MeSH
• buněčné jádro genetika   účinky záření   ultrastruktura   MeSH
• chromozomy rostlin účinky záření   ultrastruktura   MeSH
• fylogeneze MeSH
• mikroskopie MeSH
• průtoková cytometrie MeSH
• rostliny genetika   účinky záření   ultrastruktura   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

By means of fluorescence microscopy the intracellular distribution of fluorescent drugs with different hydrophobicity (quinizarin, emodin and hypericin) was studied. Selective photoactivation of these drugs in precisely defined position (nuclear envelope) allowed moderately hydrophobic emodin enter the nucleus. Highly hydrophobic hypericin was predominantly kept in the membranes with no fluorescence observed in the nucleus. The redistribution of quinizarin, emodin and hypericin between lipids, proteins and DNA was studied in solutions and cells. Based on these results was proposed theoretical model of hydrophobic drugs' nuclear internalization after photo-activation. Molecular docking models showed that hypericin has the strongest affinity to P-glycoprotein involved in the cell detoxification. Presence of 10 μM quinizarin, emodin or hypericin increased P-glycoprotein function in U87 MG cells. Moreover, emodin pretreatment allowed quinizarin nuclear internalization without photo-activation, which was not the case for hypericin. The synergy of such pretreatment and photo-activation should lessen the drug doses with simultaneous increase of drug efficacy triggering cell apoptosis/necrosis.

• Klíčová slova
• Antraquinones, Glioma cells, Hypericin, P-glycoprotein, Selective photo-activation,
• MeSH
• anthraceny MeSH
• anthrachinony chemie   farmakologie   účinky záření   MeSH
• buněčné jádro metabolismus   účinky záření   MeSH
• DNA chemie   MeSH
• emodin chemie   farmakologie   účinky záření   MeSH
• gliom metabolismus   MeSH
• hydrofobní a hydrofilní interakce MeSH
• LDL-cholesterol chemie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• P-glykoprotein metabolismus   MeSH
• perylen analogy a deriváty   chemie   farmakologie   účinky záření   MeSH
• sérový albumin chemie   MeSH
• simulace molekulového dockingu MeSH
• světlo MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,4-dihydroxyanthraquinone MeSH Prohlížeč
• anthraceny MeSH
• anthrachinony MeSH
• DNA MeSH
• emodin MeSH
• hypericin MeSH Prohlížeč
• LDL-cholesterol MeSH
• P-glykoprotein MeSH
• perylen MeSH
• sérový albumin MeSH

Recent groundbreaking developments in Omics and bioinformatics have generated new hope for overcoming the complexity and variability of (radio)biological systems while simultaneously shedding more light on fundamental radiobiological questions that have remained unanswered for decades. In the era of Omics, our knowledge of how genes and dozens of proteins interact in the frame of complex signaling and repair pathways (or, rather, networks) to preserve the integrity of the genome has been rapidly expanding. Nevertheless, these functional networks must be observed with strong correspondence to the cell nucleus, which is the main target of ionizing radiation. Information regarding these intricate processes cannot be achieved using high-throughput Omics approaches alone; it requires sophisticated structural probing and imaging. In the first part of this review, the article "Giving Omics Spatiotemporal Dimensions Using Exciting New Nanoscopy Techniques to Assess Complex Cell Responses to DNA Damage: Part A--Radiomics," we showed the development of different Omics solutions and how they are contributing to a better understanding of cellular radiation response. In this Part B we show how high-resolution confocal microscopy as well as novel approaches of molecular localization nanoscopy fill the gaps to successfully place Omics data in the context of space and time. The dynamics of double-strand breaks during repair processes and chromosomal rearrangements at the microscale correlated to aberration induction are explained. For the first time we visualize pan-nuclear nucleosomal rearrangements and clustering at the nanoscale during repair processes. Finally, we introduce a novel method of specific chromatin nanotargeting based on a computer database search of uniquely binding oligonucleotide combinations (COMBO-FISH). With these challenging techniques on hand, we speculate future perspectives that may combine specific COMBO-FISH nanoprobing and structural nanoscopy to observe structure-function correlations in living cells in real-time. Thus, the Omics networks obtained from function analyses may be enriched by real-time visualization of Structuromics.

• MeSH
• buněčné jádro účinky záření   MeSH
• chromatin genetika   účinky záření   MeSH
• DNA účinky záření   MeSH
• dvouřetězcové zlomy DNA účinky záření   MeSH
• genom genetika   MeSH
• ionizující záření MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• nestabilita genomu MeSH
• oprava DNA genetika   MeSH
• translokace genetická genetika   účinky záření   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• chromatin MeSH
• DNA MeSH

Cajal bodies are important nuclear structures containing proteins that preferentially regulate RNA-related metabolism. We investigated the cell-type specific nuclear distribution of Cajal bodies and the level of coilin, a protein of Cajal bodies, in non-irradiated and irradiated human tumor cell lines and embryonic stem (ES) cells. Cajal bodies were localized in different nuclear compartments, including DAPI-poor regions, in the proximity of chromocenters, and adjacent to nucleoli. The number of Cajal bodies per nucleus was cell cycle-dependent, with higher numbers occurring during G2 phase. Human ES cells contained a high coilin level in the nucleoplasm, but coilin-positive Cajal bodies were also identified in nuclei of mouse and human ES cells. Coilin, but not SMN, recognized UVA-induced DNA lesions, which was cell cycle-independent. Treatment with γ-radiation reduced the localized movement of Cajal bodies in many cell types and GFP-coilin fluorescence recovery after photobleaching was very fast in nucleoplasm in comparison with GFP-coilin recovery in DNA lesions. By contrast, nucleolus-localized coilin displayed very slow fluorescence recovery after photobleaching, which indicates very slow rates of protein diffusion, especially in nucleoli of mouse ES cells.

• Klíčová slova
• Cajal bodies, DNA repair, chromatin, coilin, nucleolus, nucleus,
• MeSH
• buněčné jádro genetika   metabolismus   účinky záření   MeSH
• buněčné linie MeSH
• buňky K562 MeSH
• Cajalova tělíska genetika   metabolismus   účinky záření   MeSH
• DNA genetika   účinky záření   MeSH
• G2 fáze genetika   MeSH
• HeLa buňky MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• rekombinantní fúzní proteiny genetika   metabolismus   MeSH
• ultrafialové záření škodlivé účinky   MeSH
• záření gama škodlivé účinky   MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• jaderné proteiny MeSH
• p80-coilin MeSH Prohlížeč
• rekombinantní fúzní proteiny MeSH
• zelené fluorescenční proteiny MeSH

According to their physical characteristics, protons and ion beams promise a revolution in cancer radiotherapy. Curing protocols however reflect rather the empirical knowledge than experimental data on DNA repair. This especially holds for the spatio-temporal organization of repair processes in the context of higher-order chromatin structure-the problematics addressed in this work. The consequences for the mechanism of chromosomal translocations are compared for gamma rays and proton beams.

• Klíčová slova
• DNA double-strand breaks (DSBs), Formation of chromosomal translocations, Gamma rays and proton beams, Higher-order chromatin structure and DSB repair, γH2AX foci,
• MeSH
• buněčné jádro účinky záření   MeSH
• chromatin chemie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• mikroskopie MeSH
• oprava DNA * MeSH
• poškození DNA * MeSH
• protony * MeSH
• translokace genetická MeSH
• záření gama * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chromatin MeSH
• protony * MeSH

The BRCA1 gene codes for a protein involved in the DNA double strand break (DDSB) repair. Alongside the dominant full-length splicing form of BRCA1, numerous endogenously expressed alternative splicing variants of unknown significance have been described in various tissues. Some of them retain the original BRCA1 reading frame but lack several critical BRCA1 structural domains, suggesting an altered function of the resulting protein in the BRCA1-regulated processes. To characterize the effect of the BRCA1Δ14-15 splicing variant (with an in-frame deletion affecting the regulatory serine-containing domain) on the DDSB repair, we constructed the MCF-7 clones stably expressing the analyzed variant with/without a shRNA-mediated downregulation of the endogenous full-length wild-type BRCA1 expression. Our results show that the expression of the BRCA1Δ14-15 variant delays the γ-radiation-induced DDSB repair, alters the kinetics of irradiation-induced foci formation/decomposition and reduces the non-homologous end-joining capacity in MCF-7 cells. Therefore, the BRCA1Δ14-15 is not able to functionally replace the full-length wt BRCA1 in the DDSB repair. Our findings indicate that the endogenously expressed BRCA1 alternative splicing variants may negatively influence genome stability and support the growing evidence of the pathological potential of the sequence variants generated by an altered or misregulated alternative splicing in the process of mammary malignant transformation.

• MeSH
• buněčné jádro metabolismus   účinky záření   MeSH
• čtecí rámce MeSH
• dvouřetězcové zlomy DNA MeSH
• exprese genu MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• nádorové buněčné linie MeSH
• nádory prsu MeSH
• oprava DNA spojením konců * MeSH
• protein - isoformy genetika   metabolismus   MeSH
• protein BRCA1 genetika   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční delece * MeSH
• terciární struktura proteinů MeSH
• záření gama MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BRCA1 protein, human MeSH Prohlížeč
• protein - isoformy MeSH
• protein BRCA1 MeSH

The transformed C6 glial cells in cultures were treated with sodium mercaptoborate (Na(2)B(12)H(11)SH, BSH), a carrier of atomic targets ((10)B) of thermal neutrons for the neutron capture therapy of brain tumors. As shown by light microscopy, the therapeutic dose of BSH (100 microg/ml) did not alter the gross morphology and growth of the population of cells within a 72 h treatment interval. Electron microscopic analysis of these cells revealed activation of nucleoli and, occasionally, enlarged and bifurcated mitochondria. After 200 microg BSH/ml and 72 h treatment, growth of the cell population was inhibited and ultrastructural changes became more profound. They included condensation of chromatin and its allocation to the nuclear envelope which formed deeper invaginations. Mitochondria further increased in size and were characterized by slim or angular cristae. Moreover, in circumscribed segments of some of the slightly swollen mitochondria their cristae disappeared or were reduced to fine pouch-like structures localized near the continuous outer membrane, suggestive for a non-destructive restructuring of the inner mitochondrial membrane. The smooth pinocytotic vesicles near the plasma membrane, lysosomes and heterogeneous dense bodies were more frequent. The revealed subcellular targets of BSH may initiate the development of pharmacological protocols aimed to further improve the tolerance to BSH by the healthy tissues of patients undergoing BNCT of brain tumors, e.g. by intervention into the oxidative stress triggered likely by the altered mitochondria.

• MeSH
• bor MeSH
• borohydridy farmakologie   MeSH
• buněčné jádro účinky léků   účinky záření   ultrastruktura   MeSH
• elektronová mikroskopie MeSH
• izotopy MeSH
• krysa rodu Rattus MeSH
• mikroskopie fázově kontrastní MeSH
• mitochondrie účinky léků   účinky záření   ultrastruktura   MeSH
• nádorové buněčné linie MeSH
• nádory mozku patologie   radioterapie   MeSH
• počet buněk MeSH
• sulfhydrylové sloučeniny farmakologie   MeSH
• terapie metodou neutronového záchytu (bor-10) MeSH
• viabilita buněk účinky léků   účinky záření   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bor MeSH
• borohydridy MeSH
• izotopy MeSH
• mercaptoundecahydrododecaborate MeSH Prohlížeč
• sulfhydrylové sloučeniny MeSH

The aim of this study was to investigate early histological and stereological changes in enterocytes, lymphocytes, mast cells, serotonin- and somatostatin-secreting cells in colon mucosa the first day after the end of combined radiotherapy and chemotherapy. For experimental model 20 Beagle dogs were used. Ten dogs were given platinol every 5 days over 20 days and they were irradiated 20 days with 32 Gy (every second day with a fractional dose of 3.2 Gy) onto the whole pelvis and tail. Another 10 dogs represented a control group. For detection of apoptosis the TUNEL technique was used, whereas immunohistochemical methods were performed for detection of somatostatin- and serotonin-secreting cells, and for proliferating cell nuclear antigen in epithelial cells. The volume density of enterocytes in apoptosis was increased, and Vv of paracrine cells (mast cells, somatostatin and serotonin positive cells) was significantly increased in the treated group compared to the control group. In the treated group a significantly lower Vv of lymphocytes and PCNA-positive enterocytes was shown compared to the control group. The results of our experiments showed that combined radiotherapy and chemotherapy caused loss of enterocytes and lymphocytes early after the therapy. It was associated with an increased volume density of paracrine cells. These morphological changes in the colon mucosa might be the earliest changes leading to disruption of the mucosal barrier, malabsoption syndrome, stenosis, inflammation and other complications resulting from the radiotherapy and chemotherapy.

• MeSH
• apoptóza účinky léků   účinky záření   MeSH
• buněčné jádro účinky léků   účinky záření   MeSH
• cisplatina farmakologie   MeSH
• enterocyty cytologie   účinky léků   patologie   účinky záření   MeSH
• imunohistochemie MeSH
• kolon cytologie   účinky léků   patologie   účinky záření   MeSH
• kombinovaná terapie MeSH
• koncové značení zlomů DNA in situ MeSH
• proliferační antigen buněčného jádra analýza   MeSH
• psi MeSH
• serotonin analýza   MeSH
• somatostatin analýza   MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cisplatina MeSH
• proliferační antigen buněčného jádra MeSH
• serotonin MeSH
• somatostatin MeSH

A new formula linking the shape of survival curve to the inactivation probabilities after different numbers of cell hits has been derived. It has been used in analyzing recent experimental data obtained with monolayer cells irradiated at definite values of LET (in different parts of Bragg peaks). The new approach allows not only deriving the values of inactivation probabilities at given LET values; unexpected consequences seem to follow especially for inactivation characteristics of carbon ions in different parts of the Bragg peak, too.

• MeSH
• biologické modely * MeSH
• buněčné jádro účinky záření   MeSH
• buňky účinky záření   MeSH
• ionty * MeSH
• kůže cytologie   účinky záření   MeSH
• lidé MeSH
• lineární přenos energie * MeSH
• myši MeSH
• protony MeSH
• uhlík * MeSH
• viabilita buněk účinky záření   MeSH
• vztah dávky záření a odpovědi MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• ionty * MeSH
• protony MeSH
• uhlík * MeSH