Comparative Analysis of the Kinetics of DNA Synthesis after Exposure during Different Phases of the Cell Cycle S Period

2013 ◽  
Vol 156 (2) ◽  
pp. 260-265 ◽  
Author(s):  
I. P. Shabalkin ◽  
E. Yu. Grigor’eva ◽  
P. I. Shabalkin ◽  
M. V. Gudkova ◽  
A. S. Yagubov
Keyword(s):  
Cell Cycle ◽  
Comparative Analysis ◽  
Dna Synthesis ◽  
S Period ◽  
Kinetics Of

scholarly journals CHANGES IN THE DNA SYNTHESIS PATTERN OF PARAMECIUM WITH INCREASED CLONAL AGE AND INTERFISSION TIME

1974 ◽  
Vol 61 (3) ◽  
pp. 591-598 ◽  
Author(s):  
Joan Smith-Sonneborn ◽  
Michael Klass
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Unicellular Organism ◽  
Time Intervals ◽  
Synchronized Cells ◽  
Different Ages ◽  
Self Fertilization ◽  
Autoradiographic Analysis ◽  
S Period ◽  
First Time

The clonal age in paramecia refers to the total number of vegetative divisions a clone has undergone since its origin at autogamy (self-fertilization). As clonal age increases, the interfission time usually increases. The DNA synthesis pattern of cells of different ages was compared by autoradiographic analysis of the DNA synthesis of synchronized cells at various time intervals during the cell cycle (from one division to the next). The study showed that the G1 period (the lag in DNA synthesis post division) was constant, irrespective of interfission time or clonal age; but the duration of the DNA synthesis period increased with increased interfission time or clonal age. Therefore, we have shown for the first time that the G1 period is fixed, and the S period is increased in a eukaryotic unicellular organism as a function of interfission time and clonal age.

scholarly journals Cell cycle-dependent expression of thymidylate synthase in Saccharomyces cerevisiae.

1984 ◽  
Vol 4 (12) ◽  
pp. 2858-2864 ◽  
Author(s):  
R K Storms ◽  
R W Ord ◽  
M T Greenwood ◽  
B Mirdamadi ◽  
F K Chu ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Synthesis ◽  
Thymidylate Synthase ◽  
S Phase ◽  
Mrna Levels ◽  
Activity Profile ◽  
S Period ◽  
Cycle Dependent ◽  
Specific Mrna

Synchronous populations of Saccharomyces cerevisiae cells, generated by two independent methods, have been used to show that thymidylate synthase, in contrast to the vast majority of cellular proteins thus far examined, fluctuates periodically during the S. cerevisiae cell cycle. The enzyme, as assayed by two different methods, accumulated during S period and peaked in mid to late S phase, and then its level dropped. These observations suggest that both periodic synthesis and the instability of the enzyme contribute to the activity profile seen during the cell cycle. Accumulation of thymidylate synthase is determined at the level of its transcript, with synthase-specific mRNA levels increasing at least 10-fold to peak near the beginning of S period and then falling dramatically to basal levels after the onset of DNA synthesis. This mRNA peak coincided with the time during the cell cycle when thymidylate synthase levels were increasing maximally and immediately preceded the peak of DNA synthesis, for which the enzyme provides precursor dTMP.

scholarly journals Regulation of human histone gene expression: kinetics of accumulation and changes in the rate of synthesis and in the half-lives of individual histone mRNAs during the HeLa cell cycle.

1983 ◽  
Vol 3 (4) ◽  
pp. 539-550 ◽  
Author(s):  
N Heintz ◽  
H L Sive ◽  
R G Roeder
Keyword(s):  
Cell Cycle ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Fold Increase ◽  
S Phase ◽  
Histone Mrna ◽  
Mrna Accumulation ◽  
Histone Mrnas ◽  
The Individual ◽  
Kinetics Of

We have analyzed the kinetics of accumulation of each of the individual core histone mRNAs throughout the HeLa cell cycle in cells synchronized by sequential thymidine and aphidicolin treatments. These analyses showed that during the S phase there was a 15-fold increase in the levels of histone mRNAs and that this resulted from both an increased rate of synthesis and a lengthening of the half-life of histone mRNAs. A comparison of the kinetics of accumulation of histone mRNA in the total cellular and nuclear RNA populations suggested an increased transcription rate through the S phase. Within 30 min after the inhibition of DNA synthesis in mid-S phase, the steady-state concentration and the rate of synthesis of histone mRNA each declined to their non-S-phase levels. Reactivation of histone mRNA accumulation could occur even after an extended mid-S-phase block in DNA synthesis. These results suggest that the mechanisms responsible for histone mRNA synthesis are not restricted to the G1/S boundary of the HeLa cell cycle, but can operate whenever DNA synthesis is occurring.

scholarly journals Differential response of cycling and noncycling cells to inducers of DNA synthesis and mitosis

1981 ◽  
Vol 88 (3) ◽  
pp. 649-653 ◽  
Author(s):  
PN Rao ◽  
ML Smith
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Uv Irradiation ◽  
Hela Cells ◽  
Cell Cycle Progression ◽  
Sendai Virus ◽  
Nonhistone Proteins ◽  
Interesting Observation ◽  
Human Diploid Fibroblasts ◽  
Kinetics Of

The objective of this study was to determine whether cells in G(0) phase are functionally distinct from those in G(1) with regard to their ability to respond to the inducers of DNA synthesis and to retard the cell cycle traverse of the G(2) component after fusion. Synchronized populations of HeLa cells in G(1) and human diploid fibroblasts in G(1) and G(0) phases were separately fused using UV-inactivated Sendai virus with HeLa cells prelabeled with [(3)H]ThdR and synchronized in S or G(2) phases. The kinetics of initiation of DNA synthesis in the nuclei of G(0) and G(1) cells residing in G(0)/S and G(1)/S dikaryons, respectively, were studied as a function of time after fusion. In the G(0)/G(2) and G(1)/G(2) fusions, the rate of entry into mitosis of the heterophasic binucleate cells was monitored in the presence of Colcemid. The effects of protein synthesis inhibition in the G(1) cells, and the UV irradiation of G(0) cells before fusion, on the rate of entry of the G(2) component into mitosis were also studied. The results of this study indicate that DNA synthesis can be induced in G(0)nuclei after fusion between G(0)- and S-phase cells, but G(0) nuclei are much slower than G(1) nuclei in responding to the inducers of DNA synthesis because the chromatin of G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells differ from G(1) cells with regard to their effects on the cell cycle progression of the G(2) nucleus into mitosis. This difference between G(0) and G(1) cells appears to depend on certain factors, probably nonhistone proteins, present in G(1) cells but absent in G(0) cells. These factors can be induced in G(0) cells by UV irradiation and inhibited in G(1) cells by cycloheximide treatment.

scholarly journals ANALYSIS OF THE SCHEDULE OF DNA REPLICATION IN HEAT-SYNCHRONIZED TETRAHYMENA

1973 ◽  
Vol 59 (1) ◽  
pp. 1-11 ◽  
Author(s):  
William R. Jeffery ◽  
Joseph Frankel ◽  
Lawrence E. de Bault ◽  
Leslie M. Jenkins
Keyword(s):  
Cell Cycle ◽  
High Temperature ◽  
Dna Replication ◽  
Heat Shock ◽  
Dna Synthesis ◽  
Shock Treatment ◽  
Heat Shock Treatment ◽  
Dividing Cells ◽  
S Period ◽  
Selection Of

The temporal schedule of DNA replication in heat-synchronized Tetrahymena was studied by autoradiographic and cytofluorometric methods. It was shown that some cells, which were synchronized by selection of individual dividing cells or by temporary thymidine starvation, incorporated [3H]thymidine into macronuclei in a periodic fashion during the heat-shock treatment. It was concluded that supernumerary S periods occurred while cell division was blocked by high temperature. The proportion of cells which initiated supernumerary S periods was found to be dependent on the duration of the heat-shock treatment and on the cell cycle stage when the first heat shock was applied. Cytofluorometric measurements of Feulgen-stained macronuclei during the heat-shock treatment indicated that the DNA complement of these cells was substantially increased and probably duplicated during the course of each S period. Estimates of DNA content also suggested that the rate of DNA synthesis progressively declined during long heat-shock treatments. These results indicate that the mechanism which brings about heat-induced division synchrony is not an interruption of the process of DNA replication. Further experiments were concerned with the regulation of DNA synthesis during the first synchronized division cycle. It was shown that participation in DNA synthesis at this time increased as more cells were able to conclude the terminal S period during the preceding heat-shock treatment. It is suggested that a discrete period of time is necessary after the completion of DNA synthesis before another round of DNA synthesis can be initiated.

Cell cycle-dependent expression of thymidylate synthase in Saccharomyces cerevisiae

1984 ◽  
Vol 4 (12) ◽  
pp. 2858-2864
Author(s):  
R K Storms ◽  
R W Ord ◽  
M T Greenwood ◽  
B Mirdamadi ◽  
F K Chu ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Synthesis ◽  
Thymidylate Synthase ◽  
S Phase ◽  
Mrna Levels ◽  
Activity Profile ◽  
S Period ◽  
Cycle Dependent ◽  
Specific Mrna

Synchronous populations of Saccharomyces cerevisiae cells, generated by two independent methods, have been used to show that thymidylate synthase, in contrast to the vast majority of cellular proteins thus far examined, fluctuates periodically during the S. cerevisiae cell cycle. The enzyme, as assayed by two different methods, accumulated during S period and peaked in mid to late S phase, and then its level dropped. These observations suggest that both periodic synthesis and the instability of the enzyme contribute to the activity profile seen during the cell cycle. Accumulation of thymidylate synthase is determined at the level of its transcript, with synthase-specific mRNA levels increasing at least 10-fold to peak near the beginning of S period and then falling dramatically to basal levels after the onset of DNA synthesis. This mRNA peak coincided with the time during the cell cycle when thymidylate synthase levels were increasing maximally and immediately preceded the peak of DNA synthesis, for which the enzyme provides precursor dTMP.

STUDIES OF THE HERBICIDE PARAQUAT: I. Effects on the cell cycle and DNA synthesis in Vicia faba

1976 ◽  
Vol 18 (1) ◽  
pp. 93-99 ◽  
Author(s):  
Sandra L. Bell ◽  
O. J. Schwarz ◽  
Karen W. Hughes
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Vicia Faba ◽  
Chromosome Aberrations ◽  
Thymidine Incorporation ◽  
Significant Inhibition ◽  
Root Tips ◽  
Total Inhibition ◽  
S Period ◽  
Number Of Cells

Vicia faba root tips were exposed to concentrations of paraquat ranging from 10−3M to 10−6M. There was a statistically significant inhibition in 3H-thymidine incorporation, and, therefore, presumably of DNA synthesis by all concentrations of paraquat studied. All concentrations of paraquat also had a statistically significant effect on the percentage of cells in division at various hours following paraquat treatment. At 10−3M and 10−4M paraquat there was an almost total inhibition in the number of cells moving from the S period and through the G2 period and into division. Cells treated with 10−6M paraquat, however, did move through the G2 period and into division. A concentration of 10−4M paraquat did not result in an increase in chromosome aberrations.

scholarly journals EVIDENCE FOR A TEMPORAL INCOMPATIBILITY BETWEEN DNA REPLICATION AND DIVISION DURING THE CELL CYCLE OF TETRAHYMENA

1972 ◽  
Vol 53 (3) ◽  
pp. 624-634 ◽  
Author(s):  
William R. Jeffery
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Replication ◽  
Heat Shock ◽  
Dna Synthesis ◽  
Shock Treatment ◽  
Coupling Mechanism ◽  
Complete Suppression ◽  
Heat Shock Treatment ◽  
S Period

The mechanism of coordination between DNA replication and cell division was studied in Tetrahymena pyriformis GL-C by manipulation of the timing of these events with heat shocks and inhibition of DNA synthesis. Preliminary experiments showed that the inhibitor combination methotrexate and uridine (M + U) was an effective inhibitor of DNA synthesis. Inhibition of the progression of DNA synthesis with M + U in exponentially growing cells, in which one S period usually occurs between two successive divisions, or in heat-shocked cells, when successive S periods are known to occur between divisions, resulted in the complete suppression of the following division. In further experiments in which the division activities were reassociated with the DNA synthetic cycle by premature termination of the heat-shock treatment, it was shown that (a) the completion of one S period during the treatment was sufficient for cell division, (b) the beginning of division events suppressed the initiation of further S periods, and (c) if further S periods were initiated while the heat-shock treatment was continued, division preparations could not begin until the necessary portion of the S period was completed, even though DNA had previously been duplicated. It was concluded that a temporal incompatibility exists between DNA synthesis and division which may reflect a coupling mechanism which insures their coordination during the normal cell cycle.

scholarly journals MICRONUCLEAR RNA SYNTHESIS IN PARAMECIUM CAUDATUM

1967 ◽  
Vol 33 (2) ◽  
pp. 281-285 ◽  
Author(s):  
M. V. Narasimha Rao ◽  
David M. Prescott
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Generation Time ◽  
Rna Synthesis ◽  
Paramecium Caudatum ◽  
S Period

In a generation time of 8 hr in Paramecium caudatum, the bulk of DNA synthesis detected by thymidine-3H incorporation takes place in the latter part of the cell cycle. The micronuclear cycle includes a G1 of 3 hr followed by an S period of 3–3½ hr. G2 and division occupies the remaining period of the cycle. Macronuclear RNA synthesis detected by 5'-uridine-3H incorporation is continuous throughout the cell cycle. Micronuclear RNA synthesis is restricted to the S period. Ribonuclease removes 80–90% of the incorporated label. Pulse-chase experiments showed that part of the RNA is conserved and released to the cytoplasm during the succeeding G1 period.

Differential Induction of Apoptosis in Human Leukemia Cells (ML-1, ML-2, CTV-1 and KASUMI-1) Exposed to the Proteasome Inhibitor Bortezomib and the Effect of Transforming Growth Factor-beta Signaling Pathway.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4359-4359 ◽  
Author(s):  
Ota Fuchs ◽  
Dana Provaznikova ◽  
Gabriela Peslova ◽  
Marcela Kocova ◽  
Iuri Marinov ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Proteasome Inhibitors ◽  
Leukemia Cells ◽  
Human Leukemia ◽  
Growth Factor Beta ◽  
Kinetics Of ◽  
Tgf Β1

Abstract Bortezomib (N-pyrazinecarbonyl-L-phenylalanine-L-leucine boronic acid; VELCADE, formely known as PS-341 or MLN-341; Millenium Pharmaceuticals, Inc., Cambridge, MA) is a potent and specific proteasome inhibitor. It is the first member of proteasome inhibitors which obtained approval as chemotherapeutic agent for the treatment of relapsed or refractory multiple myeloma. First clinical experience of bortezomib in patiens with follicular lymphoma and mantle cell non-Hodgkin lymphoma suggest that bortezomib is well tolerated and has significant single-agent activity. Several phase I trials on the use of bortezomib as a novel treatment strategy in leukemia have been started. We studied the effect of of bortezomib and of transforming growth factor-beta (TGF-β) on induction of cell cycle arrest and apoptosis in human leukemia cells (ML-1, ML-2, CTV-1 and KASUMI-1) established from the peripheral blood of patients with acute myeloid leukemia (AML). [6-3H] thymidine incorporation was used as a measure of DNA synthesis to estimate cell proliferation. Apoptosis was detected by flow cytometry using annexin V-FITC/propidium iodide assay and results were confirmed by cell cycle analysis. The profiles of cellular DNA contents indicated the distribution of the cells in different phases of the cell cycle and any possible DNA loss due to DNA fragmentation during apoptosis. The cells with a DNA content less than that of G1 cells were considered as apoptotic cells. Statistical significance of the experimental results was analyzed by Student’s paired t-test. Leukemia cells were preincubated for 24–96 h without addition (control) or with bortezomib (4 nM or 10 nM) or with TGF-β1 (5 ng/ml or 10 ng/ml). TGF-β1 inhibited DNA synthesis only in KASUMI-1 cells but not in other leukemia cells used. Bortezomib (10 nM) was potent inhibitor of DNA synthesis in all four types of leukemia cells and induced apoptosis in KASUMI-1, ML-2 and CTV-1 cells but not in ML-1 cells [Figure 1]. Kinetics of apoptosis was different in individual cell lines. The peak of apoptosis was reached in 24 h in ML-2 cells, however in KASUMI-1 and CTV-1 cells in 48h. KASUMI-1 cells were most sensitive to bortezomib. In addition KASUMI-1 and ML-2 cells were also sensitive to induction of apoptosis by TGF-β1 but in lesser extent than by bortezomib [Figure 1]. Kinetics of apoptosis induction by TGF-β1 was slower than with bortezomib and lasted 48–96 h. Different sensitivity of human leukemic cell lines to bortezomib likely mimics behaviour of primary leukemic cells of patients and thus limits the use of proteasome inhibitors in therapy. Figure 1 Figure 1.

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