Search results for "Reduplication"
showing 10 items of 12 documents
“ArgumenteHin, ArgumenteHer.” Regularity and Idiomaticity in GermanN Hin,N Her
2017
This paper seeks to find the best linguistic analysis of the German semispecified, productive patternN hin, N her(for example,Krieg hin, Krieg her, es muss eine gute Show werden‘War or no war, it must be a good show’). The basic question is whether the properties ofN hin, N hercan be accounted for in a rule-based approach or whether they are to be regarded as idiosyncratic properties of this construction. One of the characteristic features ofN hin, N heris the identity of the nouns. This raises the question of whether or notN hin, N heris an instance of syntactic reduplication. It is shown that rule-based copying accounts fail when they are applied to the case ofN hin, N her. The paper argu…
Tumor cells can escape DNA-damaging cisplatin through DNA endoreduplication and reversible polyploidy
2008
Cancer chemotherapy can induce tumor regression followed, in many cases, by relapse in the long-term. Thus this study was performed to assess the determinants of such phenomenon using an in vivo cancer model and in vitro approaches. When animals bearing an established tumor are treated by cisplatin, the tumor initially undergoes a dramatic shrinkage and is characterized by giant tumor cells that do not proliferate but maintain DNA synthesis. After several weeks of latency, the tumor resumes its progression and consists of small proliferating cells. Similarly, when tumor cells are exposed in vitro to pharmacological concentrations of cisplatin, mitotic activity stops initially but cells main…
The high rate of endoreduplication in the repair deficient CHO mutant EM9 parallels a reduced level of methylated deoxycytidine in DNA
2008
It has been recently proposed that hypomethylation of DNA induced by 5-azacytidine (5-azaC) leads to reduced chromatid decatenation that ends up in endoreduplication, most likely due to a failure in topo II function [S. Mateos, I. Domínguez, N. Pastor, G. Cantero, F. Cortés, The DNA demethylating 5-azaC induces endoreduplication in cultured Chinese hamster cells, Mutat. Res. 578 (2005) 33-42]. The Chinese hamster mutant cell line EM9 has a high spontaneous frequency of endoreduplication as compared to its parental line AA8. In order to see if this is related to the degree of DNA methylation, we have investigated the basal levels of both endpoints in AA8 and EM9, as well as the effect of ext…
Cisplatin-induced endoreduplication in CHO cells: DNA damage and inhibition of topoisomerase II.
2006
It has been proposed that polyploid cells that arise during a variety of pathological conditions and as a result of exposure to genotoxicants, typically in the liver, become aneuploid through genetic instability. Aneuploidy contributes to, or even drives, tumour development. We have assessed the capacity of the drug cisplatin, one of the most commonly used compounds for the treatment of malignancies, to induce endoreduplication, a particular type of polyploidy, in cultured Chinese hamster AA8 cells. Taking into account that any interference with DNA topoisomerase II (topo II) function leads to endoreduplication, we have found that treatment of the cells with this platinum compound results i…
The DNA topoisomerase II catalytic inhibitor merbarone is genotoxic and induces endoreduplication
2012
Abstract In the last years a number of reports have shown that the so-called topoisomerase II (topo II) catalytic inhibitors are able to induce DNA and chromosome damage, an unexpected result taking into account that they do not stabilize topo II-DNA cleavable complexes, a feature of topo II poisons such as etoposide and amsacrine. Merbarone inhibits the catalytic activity of topo II by blocking DNA cleavage by the enzyme. While it was first reported that merbarone does not induce genotoxic effects in mammalian cells, this has been challenged by reports showing that the topo II inhibitor induces efficiently chromosome and DNA damage, and the question as to a possible behavior as a topo II p…
Spontaneous Endoreduplication, Tetraploidy and Chromosome Breakage in Lymphocyte Cultures from Healthy Subjects
1984
SUMMARY42,703 metaphases of peripheral lymphocytes from 20 healthy subjects (10 women and 10 men) were examined in order to establish the frequency of endoreduplicated cells and of tetraploid cells without diplochromosomes. Frequencies were found to be 0.016% and 0.112%, respectively. The two sexes did not differ as to the frequency of tetraploid cells, with and without diplochromosomes (about 0.13% in either sex). In a total of 2,135 well spread metaphases examined, 26 cells (i.e. 1.2%) with chromosomal breaks were found. Again, no significant differences between the two sexes were found as to such chromosome abnormalities.
Topoisomerase II inhibition and high yield of endoreduplication induced by the flavonoids luteolin and quercetin
2006
Luteolin and quercetin are widely distributed plant flavonoids that possess a variety of chemical and biological activities, including free-radical scavenging and antioxidant activity. Recently, both flavonoids have been reported to inhibit DNA topoisomerases I and II (topo I and topo II), a property that, together with their ability to induce DNA and chromosome damage, has made them candidate anticancer compounds. In the present study, we confirmed that both compounds are topo II inhibitors by conducting a comparative study of their effect on topo II activity from Chinese hamster ovary AA8 cells. Because interference with the function of topo II to resolve DNA entanglement at the end of re…
Sequence of lethal events in HeLa cells exposed to the G2 blocking cytolethal distending toxin
2000
The bacterial cytolethal distending toxin (CDT) was previously shown to block the cell cycle of several cell lines at stage G2 through inactivation of the cyclin-dependent kinase Cdkl and without induction of DNA strand breaks. In the present study, we have analyzed, using various methods of analytical cytometry, the progressive transformation and delayed lethal events in the tumor-derived HeLa cell line temporarily exposed to CDT. The cell proliferation arrest induced by CDT was irreversible but, starting about two days after exposure, the G2 block released partially, concomitantly with a decline in the level of Cdkl phosphorylation. This partial release resulted in endoreduplication, lead…
Dissecting the factors controlling seed development in the model legume Medicago truncatula
2012
Legumes are not only indispensible for sustainable agriculture but are also a rich source of protein in food and feed for humans and animals, respectively. However, major proteins stored in legume seeds are poor in sulfur-containing amino acids, and may be accompanied by anti-nutritional factors causing low protein digestibility problems. In this regard, Medicago truncatula serves as a model legume to study legume seed development especially the phase of seed storage protein accumulation. As developing legume seeds are complex structures, a thorough knowledge of the morphogenesis of the seed and the characterization of regulatory mechanisms underlying the embryo development and seed filling…
p27Kip1participates in the regulation of endoreplication in differentiating chick retinal ganglion cells
2015
Nuclear DNA duplication in the absence of cell division (i.e. endoreplication) leads to somatic polyploidy in eukaryotic cells. In contrast to some invertebrate neurons, whose nuclei may contain up to 200,000-fold the normal haploid DNA amount (C), polyploid neurons in higher vertebrates show only 4C DNA content. To explore the mechanism that prevents extra rounds of DNA synthesis in these latter cells we focused on the chick retina, where a population of tetraploid retinal ganglion cells (RGCs) has been described. We show that differentiating chick RGCs that express the neurotrophic receptors p75 and TrkB while lacking retinoblastoma protein, a feature of tetraploid RGCs, also express p27K…