Control of cell cycle length in amphibian eggs: evidence for a temporal relationship between the nucleus and egg cytoplasm

Development ◽  
1988 ◽  
Vol 104 (3) ◽  
pp. 415-422
Author(s):  
C. Aimar
Keyword(s):  
Cell Cycle ◽  
Embryonic Development ◽  
Early Phase ◽  
Nuclear Transfer ◽  
Cycle Length ◽  
Temporal Relationship ◽  
Activation Time ◽  
Pleurodeles Waltl ◽  
Cell Cycle Length

The role of the cytoplasm and nucleus in the control of the length of the division cycle was investigated in Pleurodeles waltl eggs. Injection of spermine into enucleated eggs showed that the ability to cleave was not restricted just to the period of normal cytokinesis (T=1.0) but was possible throughout most of the first egg cycle. The cytoplasmic components required for cytokinesis seem to increase progressively during the first division cycle. Nuclear transfer experiments indicated that the timing of cleavage was normal only when the nucleus and egg cytoplasm were reassociated between T=0.0 (activation time) and T=0.50. Delayed associations, after T=0.50, provoked an alteration in the chronology of first cleavage and led to abnormal embryonic development. In the absence of a nucleus, the egg cycle seemed to stop at T=0.50. These different observations suggest that the normal timing of cleavage not only depends on a ‘cytoplasmic clock’ but is also determined by an isochronous nucleocytoplasmic relationship during the early phase of egg development.

171. PARENTAL OBESITY RETARDS EARLY EMBRYONIC DEVELOPMENT AND ALTERS CARBOHYDRATE UTILISATION

2010 ◽  
Vol 22 (9) ◽  
pp. 89
Author(s):  
N. K. Binder ◽  
M. Mitchell ◽  
D. K. Gardner
Keyword(s):  
Cell Cycle ◽  
Embryonic Development ◽  
Cycle Length ◽  
Embryo Quality ◽  
Preimplantation Embryo ◽  
Glucose Consumption ◽  
The Impact ◽  
Paternal Obesity ◽  
Cell Cycle Length ◽  
Glycolytic Rate

Parental obesity impacts reproductive success and often results in gestational complications. In this study the effects of maternal and paternal obesity on preimplantation embryo quality were investigated through analysis of cell cycle length and carbohydrate utilisation. Zygotes derived from matings of lean or obese C57BL/6J mice were used to evaluate separately maternal and paternal obesity. Embryos were cultured individually, and development monitored with high temporal time-lapse microscopy (every 15 min). After 78 h of culture, glucose consumption and lactate production by expanded blastocysts was determined using ultramicrofluorimetry. Maternal obesity was associated with a significant delay (P < 0.01) in pre-compaction cell cycle length of approximately 1.5 h. Post-compaction there was a significant increase (P < 0.05) in glucose consumption by embryos from obese mothers compared to control embryos, while the glycolytic rate was unchanged. Paternal obesity was associated with a significant cell cycle delay (P < 0.05) of approximately 1h from the second cleavage stage onwards. Resultant blastocysts showed disproportionate changes in carbohydrate metabolism, with a significantly increased (P < 0.05) glycolytic rate compared to control embryos. Metabolic changes were still permissive to blastocyst formation, however cell numbers were significantly reduced (P < 0.001) with both maternal (lean: 54.2 ± 0.8 vs obese: 48.4 ± 1.0) and paternal (lean: 60.5 ± 0.09 vs obese: 50.9 ± 0.09) obesity. These data will help to determine the impact of parental obesity on preimplantation embryo physiology. Slow embryonic development and high glycolytic rate have been linked to reduced implantation rates and are general indicators of compromised embryo quality.

scholarly journals Inhibition of Aurora Kinase B activity disrupts development and differentiation of salivary glands

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Abeer K. Shaalan ◽  
Tathyane H. N. Teshima ◽  
Abigail S. Tucker ◽  
Gordon B. Proctor
Keyword(s):  
Cell Cycle ◽  
Embryonic Development ◽  
Salivary Glands ◽  
Aurora Kinase ◽  
Serine Threonine Kinase ◽  
Aurora Kinase B ◽  
Development And Differentiation ◽  
Differentiation Marker ◽  
Key Events

AbstractLittle is known about the key molecules that regulate cell division during organogenesis. Here we determine the role of the cell cycle promoter aurora kinase B (AURKB) during development, using embryonic salivary glands (E-SGs) as a model. AURKB is a serine/threonine kinase that regulates key events in mitosis, which makes it an attractive target for tailored anticancer therapy. Many reports have elaborated on the role of AURKB in neoplasia and cancer; however, no previous study has shown its role during organ development. Our previous experiments have highlighted the essential requirement for AURKB during adult exocrine regeneration. To investigate if AURKB is similarly required for progression during embryonic development, we pharmacologically inhibited AURKB in developing submandibular glands (SMGs) at embryonic day (E)13.5 and E16.5, using the highly potent and selective drug Barasertib. Inhibition of AURKB interfered with the expansion of the embryonic buds. Interestingly, this effect on SMG development was also seen when the mature explants (E16.5) were incubated for 24 h with another cell cycle inhibitor Aphidicolin. Barasertib prompted apoptosis, DNA damage and senescence, the markers of which (cleaved caspase 3, γH2AX, SA-βgal and p21, respectively), were predominantly seen in the developing buds. In addition to a reduction in cell cycling and proliferation of the epithelial cells in response to AURKB inhibition, Barasertib treatment led to an excessive generation of reactive oxygen species (ROS) that resulted in downregulation of the acinar differentiation marker Mist1. Importantly, inhibition of ROS was able to rescue this loss of identity, with Mist1 expression maintained despite loss of AURKB. Together, these data identify AURKB as a key molecule in supporting embryonic development and differentiation, while inhibiting senescence-inducing signals during organogenesis.

scholarly journals A Branching Process to Characterize the Dynamics of Stem Cell Differentiation

2015 ◽  
Author(s):  
david miguez
Keyword(s):  
Mathematical Model ◽  
Cell Cycle ◽  
Stem Cell ◽  
Cycle Length ◽  
Branching Process ◽  
Stem Cell Differentiation ◽  
Stem Cell Population ◽  
Mathematical Framework ◽  
Average Cell ◽  
Cell Cycle Length

The understanding of the regulatory processes that orchestrate stem cell maintenance is a cornerstone in developmental biology. Here, we present a mathematical model based on a branching process formalism that predicts average rates of proliferative and differentiative divisions in a given stem cell population. In the context of vertebrate spinal neurogenesis, the model predicts complex non-monotonic variations in the rates of pp, pd and dd modes of division as well as in cell cycle length, in agreement with experimental results. Moreover, the model shows that the differentiation probability follows a binomial distribution, allowing us to develop equations to predict the rates of each mode of division. A phenomenological simulation of the developing spinal cord informed with the average cell cycle length and division rates predicted by the mathematical model reproduces the correct dynamics of proliferation and differentiation in terms of average numbers of progenitors and differentiated cells. Overall, the present mathematical framework represents a powerful tool to unveil the changes in the rate and mode of division of a given stem cell pool by simply quantifying numbers of cells at different times.

scholarly journals Theoretical Basis for the Measurement of Small Differences in the Length of the Cell Cycle between Two Cell Populations

2009 ◽  
Vol 2 (1) ◽  
pp. 95-100
Author(s):  
Juan Sebastian Yakisich
Keyword(s):  
Experimental Data ◽  
Cell Cycle ◽  
Theoretical Basis ◽  
Cycle Length ◽  
Cell Populations ◽  
Experimental Variability ◽  
Cell Strains ◽  
Novel Strategy ◽  
Cell Cycle Length

The length of the cell cycle (TC) is a tight regulated process and is important for proper development and homeostasis. Although several methods are available for estimating the duration of the cell cycle, it is difficult to determinate small differences of TC between two different cell populations due to biological and/or experimental variability. A novel strategy based in co-cultivation of two cell strains followed by a series of dilution and propagation of the culture will allow the quantification of very small differences in the length of two cell populations at resolution levels not possible at present with current methods. This is achieved by a separation of the endpoint variable measured to compare between two cell populations. The theoretical basis of this approach is discussed in the context of published experimental data and simulation of idealized experiments using virtual strains of different cell cycle length.

scholarly journals Replication fork rate and origin activation during the S phase of Saccharomyces cerevisiae.

1980 ◽  
Vol 85 (1) ◽  
pp. 108-115 ◽  
Author(s):  
C J Rivin ◽  
W L Fangman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cycle Length ◽  
Replication Fork ◽  
Nitrogen Sources ◽  
S Phase ◽  
Phase Duration ◽  
Yeast Saccharomyces Cerevisiae ◽  
Origin Activation ◽  
Cell Cycle Length

When the growth rate of the yeast Saccharomyces cerevisiae is limited with various nitrogen sources, the duration of the S phase is proportional to cell cycle length over a fourfold range of growth rates (C.J. Rivin and W. L. Fangman, 1980, J. Cell Biol. 85:96-107). Molecular parameters of the S phases of these cells were examined by DNA fiber autoradiography. Changes in replication fork rate account completely for the changes in S-phase duration. No changes in origin-to-origin distances were detected. In addition, it was found that while most adjacent replication origins are activated within a few minutes of each other, new activations occur throughout the S phase.

435 REDUCTION OF CELL CYCLE LENGTH AND INCREASE IN S-PHASE BY GROWTH FACTORS IN PIG FETAL FIBROBLASTS

2010 ◽  
Vol 22 (1) ◽  
pp. 374
Author(s):  
S. Waghmare ◽  
B. Mir
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Growth Factors ◽  
Growth Factor ◽  
Cycle Length ◽  
S Phase ◽  
Proliferation Rate ◽  
Fetal Fibroblasts ◽  
Cell Cycle Length ◽  
Number Of Cells

Gene targeting in primary somatic cells is inefficient compared with embryonic stem cells. This is because of a slow rate of cell proliferation, fewer cells in S-phase at a given time point under normal culture conditions, and low rate of homologous recombination. Homologous recombination occurs mainly in late S-phase and increase in gene targeting efficiency has been reported in S-phase synchronized cells in bovine and rhesus macaque fetal fibroblasts. In this study we tested several growth factors: platelet-derived growth factor (PDGF), tumor necrosis factor a (TNFα), epidermal growth factor (EGF), fibroblast growth factor (FGF), transforming growth factor β1 (TGFβ1), insulin-like growth factor 1 (ILGF-1) and insulin-like growth factor II (ILGF-II) individually and in various combinations to see the effect on cell proliferation rate. Each experimental set consisted of 3 replicates. TGFβ1-, ILGF1-, ILGFII-, and FGF-treated cells grew very slowly compared with untreated cells. However, a combination of 3 growth factors: PDGF (15 ng mL-1), EGF (50 ng mL-1) and TNFa (100 pg mL-1), herein referred to as the cocktail, accelerated cell proliferation rate and reduced cell cycle length on average from 24.5 ± 0.2 to 20.4 ± 0.5 h with no significant change in number of cells in S-phase. Further, cells grown in the presence of the cocktail showed changes in morphology. The cells became spindle-shaped and occupied less surface area per cell compared with untreated cells. Importantly, cocktail-treated cells maintained a normal karyotype without any chromosomal abnormality. Thymidine has been used successfully to block various cell types in S-phase but it failed to synchronize these cells in S-phase in the concentration range of 2 to 10 mM for 24 to 48 h. However, serum starvation (0.2% fetal bovine serum) for 48 h blocked the cell proliferation rate effectively and synchronized cells in G0 phase (80-82% cells). After releasing from the block, cells were grown in the absence or presence of cocktail and cell cycle analysis was done at different time points by flow cytometry. Each time point was repeated 3 times. We observed the maximum number of cells in S-phase at 22 to 23 h (61.33% ± 7.77 in cocktail-treated cells v. 41.7% ± 3.28 in untreated cells). In summary, the cocktail-treated cells showed changes in cell morphology, higher proliferation rate, reduction in cell cycle length by 16.7%, and maximum percentage of cells in S-phase following serum starvation but maintained normal karyotypes. This high proliferation rate, reduction in cell cycle length, and maximum number of cells in S-phase should be very helpful in increasing the efficiency of gene-targeting in pig fetal fibroblasts.

scholarly journals MicroRNA 22 Regulates Cell Cycle Length in Cerebellar Granular Neuron Precursors

2013 ◽  
Vol 33 (14) ◽  
pp. 2706-2717 ◽  
Author(s):  
J. Berenguer ◽  
A. Herrera ◽  
L. Vuolo ◽  
B. Torroba ◽  
F. Llorens ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cycle Length ◽  
Cell Cycle Length
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