DNA replication stress induces deregulation of the cell cycle events in root meristems of Allium cepa

Żabka, Aneta; Polit, Justyna Teresa; Maszewski, Janusz

doi:10.1093/aob/mcs215

Cited by 19 publications

(42 citation statements)

References 44 publications

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“…Selected dark-grown seedlings with primary roots reaching 1.5 ± 0.2 cm were cultivated at 20°C in Petri dishes (Ø 6 cm) filled with 10 mL of either distilled water (control samples) or 0.75 mM HU solution (for 24, 48 and 72 h, without renewal of the medium, as described by _ Zabka et al (2012). During incubations, roots were permanently aerated by gentle rotation of Petri dishes (20 r.p.m.…”

Section: Plant Materialsmentioning

confidence: 99%

“…All images micrographs were recorded at exactly the same time of integration using a DS-Fi1 CCD camera (Nikon). Quantitative analyses and nuclear DNA fluorescence measurements were made after converting color images into greyscale and expressed in arbitrary units as mean pixel value (pv) spanning the range from 0 (dark) to 255 (white) according to described methods ( _ Zabka et al 2010( _ Zabka et al , 2012. Confocal observations were made with Leica SP8 (Germany) using laser lines 405 nm (DAPI) and 553 nm (Alexa Fluor Ò 555).…”

Section: Microscopic Measurements Observations and Analysesmentioning

confidence: 99%

“…Both abnormal types of M-phase cells have been considered as the final outcome of three successive phases including: (1) an inhibitory stage directly caused by the impaired DNA synthesis, (2) an adaptation to the DNA replication stress, and (3) a recovery stage, during which some cells restore their lost functions despite the continued presence of the drug ( _ Zabka et al 2012). Consequently, the early observed effects of HU consist in a decreased frequency of mitotic divisions, which is succeeded by a period of constant cell enlargement.…”

mentioning

confidence: 99%

“…This in turn is followed by a renewed rise in mitotic activity, resulting in a high degree of diversity among root meristem cells, with the dominant population of S/G2 phase cells and a minor fraction of M-phase cells with both normal and abnormal morphology of their chromosomes. The appearance of aberrant mitotic structures has been interpreted as a consequence of adaptation processes which abrogate the DNA stress response pathway and allow cell cycle progression regardless of the incomplete DNA replication ( _ Zabka et al 2012( _ Zabka et al , 2013.…”

mentioning

confidence: 99%

“…Continuous treatment of primary roots with low doses of HU results in c-phosphorylation of H2AX histones (Rybaczek and Maszewski 2007; _ Zabka et al 2012), which is regarded as one of the earliest events critical for recognition and repair of DNA damage in eukaryotes (Paull et al 2000;Stiff et al 2004). The key role in these processes is played by three sensor kinases related to phosphoinositide 3-kinase (PI3K): ataxia-telangiectasia mutated (ATM), ATM-Rad3-related (ATR), and DNA-dependent protein kinase (DNA-PK), which is essential for the repair of DNA double-strand breaks (Bensimon et al 2011;Liu et al 2012).…”

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confidence: 99%

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Localization sites of nuclear envelope SUN2-like proteins in root meristem cells of Allium cepa under hydroxyurea-induced DNA replication stress

et al. 2015

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Regardless of the DNA replication stress induced by low concentration of hydroxyurea (HU), root apical meristem cells of Allium cepa keep growing, and some of them override the DNA damage checkpoint mechanisms initiating either premature or an abnormal mitotic chromosome condensation. Prolonged incubation of onion seedlings with HU results in an increased level of immunodetectable proteins sharing epitopes with SUN2, one of the highly conserved elements linking nuclear envelope (NE) to the cytoand nucleoskeletal structures. In addition to NE, phragmoplast and cell plate, our observations extend an array of subcellular compartments at which SUN2-like proteins (SUN2-LPs) are localized. These include cortical preprophase band of microtubules, centromeric regions of ana-and telophase chromosomes, and nuclear bodies (SUN2-NBs) polarly localized in interphase nuclei according to Rabl's configuration. SUN2-NBs (distinct from fibrillarin-rich Cajal bodies) colocalize with late-replicating areas of heterochromatin and are thought to represent clustered centromeres. Three-dimensional spatial analysis of SUN2-NBs suggests their connections with NE. An enhanced expression and additional localization sites of SUN2-LPs may be correlated with a considerable reprogramming of cellular functions triggered in response to prolonged HU treatment.

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Section: Plant Materialsmentioning

confidence: 99%

Section: Microscopic Measurements Observations and Analysesmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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Localization sites of nuclear envelope SUN2-like proteins in root meristem cells of Allium cepa under hydroxyurea-induced DNA replication stress

et al. 2015

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DNA topoisomerase II‐dependent control of the cell cycle progression in root meristems of Allium cepa

Żabka¹,

Polit²,

Bernasińska³

et al. 2013

Cell Biology International

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The catalytic ability of DNA topoisomerases (Topo) to generate short-term DNA breaks allow these enzymes to play crucial functions in managing DNA topology during S-phase replication, transcription, and chromatin-remodelling processes required to achieve commitment for the onset and transition through mitosis. Our experiments on root meristem cells of onion (Allium cepa) were designed to gain insight into the contribution of Topo II to plant-specific progression throughout interphase and mitosis. Irrespective of the position of the cell in interphase, the immunofluorescence of Topo II revealed similar nuclear labelling pattern with well defined signals dispersed in the nucleoplasm and the cortical zone of the nucleolus. Only weak labelling was detected in metaphase and anaphase chromosomes. Experiments with two potent anti-Topo II agents, doxorubicin (DOX, an anthracycline) and a bisdioxopiperazine derivative, ICRF-193, suggest that the inhibition-mediated increase in Topo II immunofluorescence may represent a compensatory mechanism, by which an up-regulated expression of the enzyme tends to counteract the drug-induced loss of indispensable catalytic and relaxation functions. γ-H2AX immunolabelling seems to indicate that both DOX- and ICRF-193-induced alterations in cell cycle progression reflect primarily the activity of the G2/M DNA damage checkpoint. Our findings provide evidence for the plant-specific cell cycle control mechanism induced by Topo II inhibitors under DNA stress conditions.

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Ultrastructural changes associated with the induction of premature chromosome condensation in Vicia faba root meristem cells

Rybaczek

2014

Plant Cell Rep

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Key messagePCC induction is regulated by several signaling pathways, and all observed effects associated with PCC induction are strongly dependent on the mechanism of action of each PCC inducer used.AbstractElectron microscopic observations of cells with symptoms of premature chromosome condensation (PCC) showed that the interphase chromatin and mitotic chromosomes differed with respect to a chemical compound inducing PCC. Induction of this process under the influence of hydroxyurea and caffeine as well as hydroxyurea and sodium metavanadate led to a slight decrease in interphase chromatin condensation and the formation of chromosomes with a considerably loosened structure in comparison with the control. Incubation in the mixture of hydroxyurea and 2-aminopurine brought about clear chromatin dispersion in interphase and very strong mitotic chromosome condensation. Electron microscopic examinations also revealed the characteristic features of the structural organization of cytoplasm of Vicia faba root meristems, which seemed to be dependent on the type of the PCC inducer used. The presence of the following was observed: (i) large plastids filled with starch grains (caffeine), (ii) mitochondria and plastids of electron dense matrix with dilated invaginations of their internal membranes (2-aminopurine), and (iii) large mitochondria of electron clear matrix and plastids containing protein crystals in their interior (sodium metavanadate). Moreover, since caffeine causes either the most effective loosening of chromatin fibrils (within the prematurely condensed chromosomes) or induction of starch formation (in the plastids surrounding the nuclei), this may be a proof that demonstrates the existence of a link between physical accessibility to chromatin and the effectiveness of cellular signaling (e.g., phosphothreonine-connected).

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DNA replication stress induces deregulation of the cell cycle events in root meristems of Allium cepa

Cited by 19 publications

References 44 publications

Localization sites of nuclear envelope SUN2-like proteins in root meristem cells of Allium cepa under hydroxyurea-induced DNA replication stress

Localization sites of nuclear envelope SUN2-like proteins in root meristem cells of Allium cepa under hydroxyurea-induced DNA replication stress

DNA topoisomerase II‐dependent control of the cell cycle progression in root meristems of Allium cepa

Ultrastructural changes associated with the induction of premature chromosome condensation in Vicia faba root meristem cells

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