scholarly journals A cell cycle-associated change in Ca2+ releasing activity leads to the generation of Ca2+ transients in mouse embryos during the first mitotic division.

1996 ◽  
Vol 132 (5) ◽  
pp. 915-923 ◽  
Author(s):  
T Kono ◽  
K T Jones ◽  
A Bos-Mikich ◽  
D G Whittingham ◽  
J Carroll
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Fluorescent Dyes ◽  
Mitotic Division ◽  
Mouse Embryos ◽  
Dependent Manner ◽  
Nuclear Envelope Breakdown ◽  
A Cell ◽  
Dose Dependent ◽  
Parthenogenetic Embryos

We have used Ca2+-sensitive fluorescent dyes to monitor intracellular Ca2+ during mitosis in one-cell mouse embryos. We find that fertilized embryos generate Ca2+ transients at nuclear envelope breakdown (NEBD) and during mitosis. In addition, fertilized embryos arrested in metaphase using colcemid continue to generate Ca2+ transients. In contrast, parthenogenetic embryos produced by a 2-h exposure to strontium containing medium do not generate detectable Ca2+ transients at NEBD or in mitosis. However, when parthenogenetic embryos are cultured continuously in strontium containing medium Ca2+ transients are detected in mitosis but not in interphase. This suggests that mitotic Ca2+ transients are detected in the presence of an appropriate stimulus such as fertilization or strontium. The Ca2+ transient detected in fertilized embryos is not necessary for inducing NEBD since parthenogenetic embryos undergo nuclear envelope breakdown (NEBD). Also the first sign that NEBD is imminent occurs several minutes before the Ca2+ transient. The Ca2+ transient at NEBD appears to be associated with the nucleus since nuclear transfer experiments show that the presence of a karyoplast from a fertilized embryo is essential. Finally, we show that the intracellular Ca2+ chelator Bapta inhibits NEBD in fertilized and parthenogenetic embryos in a dose-dependent manner. These studies show that during mitosis there is an endogenous increase in Ca2+ releasing activity that leads to the generation of Ca2+ transients specifically during mitosis. The ability of Ca2+ buffers to inhibit NEBD regardless of the presence of global Ca2+ transients suggests that the underlying cell cycle-associated Ca2+ releasing activity may take the form of localized Ca2+ transients.

Repetitive sperm-induced Ca2+ transients in mouse oocytes are cell cycle dependent

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3259-3266 ◽  
Author(s):  
K.T. Jones ◽  
J. Carroll ◽  
J.A. Merriman ◽  
D.G. Whittingham ◽  
T. Kono
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Dependent Manner ◽  
Nuclear Envelope Breakdown ◽  
Mouse Oocytes ◽  
A Cell ◽  
Mature Mouse ◽  
Cycle Dependent ◽  
Stage 1

Mature mouse oocytes are arrested at metaphase of the second meiotic division. Completion of meiosis and a block to polyspermy is caused by a series of repetitive Ca2+ transients triggered by the sperm at fertilization. These Ca2+ transients have been widely reported to last for a number of hours but when, or why, they cease is not known. Here we show that Ca2+ transients cease during entry into interphase, at the time when pronuclei are forming. In fertilized oocytes arrested at metaphase using colcemid, Ca2+ transients continued for as long as measurements were made, up to 18 hours after fertilization. Therefore sperm is able to induce Ca2+ transients during metaphase but not during interphase. In addition metaphase II oocytes, but not pronuclear stage 1-cell embryos showed highly repetitive Ca2+ oscillations in response to microinjection of inositol trisphosphate. This was explored further by treating in vitro maturing oocytes at metaphase I for 4–5 hours with cycloheximide, which induced nuclear progression to interphase (nucleus formation) and subsequent re-entry to metaphase (nuclear envelope breakdown). Fertilization of cycloheximide-treated oocytes revealed that continuous Ca2+ oscillations in response to sperm were observed after nuclear envelope breakdown but not during interphase. However interphase oocytes were able to generate Ca2+ transients in response to thimerosal. This data suggests that the ability of the sperm to trigger repetitive Ca2+ transients in oocytes is modulated in a cell cycle-dependent manner.

scholarly journals Cell Cycle-Dependent Dynamics of the Golgi-Centrosome Association in Motile Cells

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1069 ◽  
Author(s):  
Keyada Frye ◽  
Fioranna Renda ◽  
Maria Fomicheva ◽  
Xiaodong Zhu ◽  
Lisa Gong ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Golgi Complex ◽  
Cell Polarization ◽  
Dependent Manner ◽  
Nuclear Envelope Breakdown ◽  
Motile Cells ◽  
A Cell ◽  
Cycle Dependent ◽  
Prevailing View

Here, we characterize spatial distribution of the Golgi complex in human cells. In contrast to the prevailing view that the Golgi compactly surrounds the centrosome throughout interphase, we observe characteristic differences in the morphology of Golgi ribbons and their association with the centrosome during various periods of the cell cycle. The compact Golgi complex is typical in G1; during S-phase, Golgi ribbons lose their association with the centrosome and extend along the nuclear envelope to largely encircle the nucleus in G2. Interestingly, pre-mitotic separation of duplicated centrosomes always occurs after dissociation from the Golgi. Shortly before the nuclear envelope breakdown, scattered Golgi ribbons reassociate with the separated centrosomes restoring two compact Golgi complexes. Transitions between the compact and distributed Golgi morphologies are microtubule-dependent. However, they occur even in the absence of centrosomes, which implies that Golgi reorganization is not driven by the centrosomal microtubule asters. Cells with different Golgi morphology exhibit distinct differences in the directional persistence and velocity of migration. These data suggest that changes in the radial distribution of the Golgi around the nucleus define the extent of cell polarization and regulate cell motility in a cell cycle-dependent manner.

Two proteins that cycle asynchronously between centrosomes and nuclear structures: Drosophila CP60 and CP190

1997 ◽  
Vol 110 (14) ◽  
pp. 1573-1583 ◽  
Author(s):  
K. Oegema ◽  
W.F. Marshall ◽  
J.W. Sedat ◽  
B.M. Alberts
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Wide Field ◽  
Dependent Manner ◽  
Independent Manner ◽  
Nuclear Envelope Breakdown ◽  
Nuclear Structures ◽  
Dynamic Structures ◽  
Cycle Dependent

Both the nucleus and the centrosome are complex, dynamic structures whose architectures undergo cell cycle-specific rearrangements. CP190 and CP60 are two Drosophila proteins of unknown function that shuttle between centrosomes and nuclei in a cell cycle-dependent manner. These two proteins are associated in vitro, and localize to centrosomes in a microtubule independent manner. We injected fluorescently labeled, bacterially expressed CP190 and CP60 into living Drosophila embryos and followed their behavior during the rapid syncytial blastoderm divisions (nuclear cycles 10–13). Using quantitative 3-D wide-field fluorescence microscopy, we show that CP190 and CP60 cycle between nuclei and centrosomes asynchronously with the accumulation of CP190 leading that of CP60 both at centrosomes and in nuclei. During interphase, CP190 is found in nuclei. Immediately following nuclear envelope breakdown, CP190 localizes to centrosomes where it remains until telophase, thereafter accumulating in reforming nuclei. Unlike CP190, CP60 accumulates at centrosomes primarily during anaphase, where it remains into early interphase. During nuclear cycles 10 and 11, CP60 accumulates in nuclei simultaneous with nuclear envelope breakdown, suggesting that CP60 binds to an unknown nuclear structure that persists into mitosis. During nuclear cycles 12 and 13, CP60 accumulates gradually in nuclei during interphase, reaching peak levels just before nuclear envelope breakdown. Once in the nucleus, both CP190 and CP60 appear to form fibrous intranuclear networks that remain coherent even after nuclear envelope breakdown. The CP190 and CP60 networks do not co-localize extensively with each other or with DNA. This work provides direct evidence, in living cells, of a coherent protein network that may represent a nuclear skeleton.

scholarly journals Cell Cycle-dependent Regulation of Structure of Endoplasmic Reticulum and Inositol 1,4,5-Trisphosphate-induced Ca2+ Release in Mouse Oocytes and Embryos

2003 ◽  
Vol 14 (1) ◽  
pp. 288-301 ◽  
Author(s):  
Greg FitzHarris ◽  
Petros Marangos ◽  
John Carroll
Keyword(s):  
Cell Cycle ◽  
Endoplasmic Reticulum ◽  
Mitotic Spindle ◽  
Mitotic Division ◽  
Cyclin B ◽  
Dependent Manner ◽  
Inositol 1,4,5 Trisphosphate ◽  
A Cell ◽  
Cycle Dependent ◽  
Mouse Eggs

The organization of endoplasmic reticulum (ER) was examined in mouse eggs undergoing fertilization and in embryos during the first cell cycle. The ER in meiosis II (MII)-arrested mouse eggs is characterized by accumulations (clusters) that are restricted to the cortex of the vegetal hemisphere of the egg. Monitoring ER structure with DiI18 after egg activation has demonstrated that ER clusters disappear at the completion of meiosis II. The ER clusters can be maintained by inhibiting the decrease in cdk1-cyclin B activity by using the proteasome inhibitor MG132, or by microinjecting excess cyclin B. A role for cdk1-cyclin B in ER organization is further suggested by the finding that the cdk inhibitor roscovitine causes the loss of ER clusters in MII eggs. Cortical clusters are specific to meiosis as they do not return in the first mitotic division; rather, the ER aggregates around the mitotic spindle. Inositol 1,4,5-trisphosphate-induced Ca2+ release is also regulated in a cell cycle-dependent manner where it is increased in MII and in the first mitosis. The cell cycle dependent effects on ER structure and inositol 1,4,5-trisphosphate-induced Ca2+ release have implications for understanding meiotic and mitotic control of ER structure and inheritance, and of the mechanisms regulating mitotic Ca2+signaling.

scholarly journals Changes in the nuclear distribution of DNA polymerase alpha and PCNA/cyclin during the progress of the cell cycle, in a cell-free extract of Xenopus eggs

1989 ◽  
Vol 93 (4) ◽  
pp. 605-613
Author(s):  
C. Hutchison ◽  
I. Kill
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Dna Polymerase ◽  
Cell Free Extract ◽  
Dna Polymerase Alpha ◽  
Nuclear Envelope Breakdown ◽  
Nuclear Distribution ◽  
A Cell ◽  
Mitotic Figures

The nuclear distribution of DNA polymerase alpha and PCNA/cyclin in embryonic nuclei has been investigated, in a cell-free extract of Xenopus eggs that recapitulates a basic cell-cycle in vitro, by indirect immunofluorescence microscopy. Both antigens co-distribute with the chromatin in S-phase nuclei; however, as DNA replication is completed and nuclei progress into a G2 state anti-PCNA fluorescence disappears and anti-DNA polymerase alpha fluorescence becomes resolved into bright spots. These spots are initially associated with the chromatin strands and can be seen to share both anti-PCNA and anti-DNA polymerase alpha fluorescence, but as anti-PCNA fluorescence fades the spots become dissociated from the chromatin and are redistributed throughout the nucleus until they are dispersed during nuclear envelope breakdown. The loss of anti-PCNA fluorescence and displacement of anti-DNA polymerase alpha fluorescence from the chromatin can be prevented by inhibiting DNA synthesis with aphidicolin. Under these conditions both antigens remain associated with the chromatin even after nuclear envelope breakdown and lamin dispersal. The association of these antigens with mitotic figures appears to be functional, as both biotin-11-dUTP and [32P]dCTP can be incorporated efficiently into DNA during the mitotic period.

Synthesis and Biological Evaluation of Novel Heterocyclic Imines Linked Coumarin- Thiazole Hybrids as Anticancer Agents

2019 ◽  
Vol 19 (4) ◽  
pp. 557-566 ◽  
Author(s):  
Nerella S. Goud ◽  
Mahammad S. Ghouse ◽  
Jatoth Vishnu ◽  
Jakkula Pranay ◽  
Ravi Alvala ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Membrane Potential ◽  
Fluorescence Spectroscopy ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Annexin V ◽  
Biological Evaluation ◽  
Dependent Manner ◽  
Dapi Staining ◽  
Dose Dependent

Background: Human Galectin-1, a protein of lectin family showing affinity towards β-galactosides has emerged as a critical regulator of tumor progression and metastasis, by modulating diverse biological events including homotypic cell aggregation, migration, apoptosis, angiogenesis and immune escape. Therefore, galectin-1 inhibitors might represent novel therapeutic agents for cancer. Methods: A new series of heterocyclic imines linked coumarin-thiazole hybrids (6a-6r) was synthesized and evaluated for its cytotoxic potential against a panel of six human cancer cell lines namely, lung (A549), prostate (DU-145), breast (MCF-7 & MDA-MB-231), colon (HCT-15 & HT-29) using MTT assay. Characteristic apoptotic assays like DAPI staining, cell cycle, annexin V and Mitochondrial membrane potential studies were performed for the most active compound. Furthermore, Gal-1 inhibition was confirmed by ELISA and fluorescence spectroscopy. Results: Among all, compound 6g 3-(2-(2-(pyridin-2-ylmethylene) hydrazineyl) thiazol-4-yl)-2H-chromen-2- one exhibited promising growth inhibition against HCT-15 colorectal cancer cells with an IC50 value of 1.28 ± 0.14 µM. The characteristic apoptotic morphological features like chromatin condensation, membrane blebbing and apoptotic body formation were clearly observed with compound 6g on HCT-15 cells using DAPI staining studies. Further, annexin V-FITC/PI assay confirmed effective early apoptosis induction by treatment with compound 6g. Loss of mitochondrial membrane potential and enhanced ROS generation were confirmed with JC-1 and DCFDA staining method, respectively by treatment with compound 6g, suggesting a possible mechanism for inducing apoptosis. Moreover, flow cytometric analysis revealed that compound 6g blocked G0/G1 phase of the cell cycle in a dose-dependent manner. Compound 6g effectively reduced the levels of Gal-1 protein in a dose-dependent manner. The binding constant (Ka) of 6g with Gal-1 was calculated from the intercept value which was observed as 1.9 x 107 M-1 by Fluorescence spectroscopy. Molecular docking studies showed strong interactions of compound 6g with Gal-1 protein. Conclusion: Our studies demonstrate the anticancer potential and Gal-1 inhibition of heterocyclic imines linked coumarin-thiazole hybrids.

scholarly journals Mutational analyses of fs(1)Ya, an essential, developmentally regulated, nuclear envelope protein in Drosophila.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1473-1481 ◽  
Author(s):  
J Liu ◽  
K Song ◽  
M F Wolfner
Keyword(s):  
Cell Cycle ◽  
Embryonic Development ◽  
Nuclear Envelope ◽  
Envelope Protein ◽  
Chromatin Condensation ◽  
Cell Cycle Control ◽  
Nuclear Lamina ◽  
Mitotic Division ◽  
Developmentally Regulated ◽  
Egg Maturation

Abstract The fs(1)Ya protein (YA) is an essential, maternally encoded, nuclear lamina protein that is under both developmental and cell cycle control. A strong Ya mutation results in early arrest of embryos. To define the function of YA in the nuclear envelope during early embryonic development, we characterized the phenotypes of four Ya mutants alleles and determined their molecular lesions. Ya mutant embryos arrest with abnormal nuclear envelopes prior to the first mitotic division; a proportion of embryos from two leaky Ya mutants proceed beyond this but arrest after several abnormal divisions. Ya unfertilized eggs contain nuclei of different sizes and condensation states, apparently due to abnormal fusion of the meiotic products immediately after meiosis. Lamin is localized at the periphery of the uncondensed nuclei in these eggs. These results suggest that YA function is required during and after egg maturation to facilitate proper chromatin condensation, rather than to allow a lamin-containing nuclear envelope to form. Two leaky Ya alleles that partially complement have lesions at opposite ends of the YA protein, suggesting that the N- and C-termini are important for YA function and that YA might interact with itself either directly or indirectly.

scholarly journals The Olive Leaves Extract Has Anti-Tumor Effects against Neuroblastoma through Inhibition of Cell Proliferation and Induction of Apoptosis

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2178
Author(s):  
Fabio Morandi ◽  
Veronica Bensa ◽  
Enzo Calarco ◽  
Fabio Pastorino ◽  
Patrizia Perri ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Viability ◽  
Cell Cycle Progression ◽  
Treatment Strategies ◽  
Annexin V ◽  
Dependent Manner ◽  
Induction Of Apoptosis ◽  
Dose Dependent

Neuroblastoma (NB) is the most common extra-cranial solid tumor of pediatric age. The prognosis for high-risk NB patients remains poor, and new treatment strategies are desirable. The olive leaf extract (OLE) is constituted by phenolic compounds, whose health beneficial effects were reported. Here, the anti-tumor effects of OLE were investigated in vitro on a panel of NB cell lines in terms of (i) reduction of cell viability; (ii) inhibition of cell proliferation through cell cycle arrest; (iii) induction of apoptosis; and (iv) inhibition of cell migration. Furthermore, cytotoxicity experiments, by combining OLE with the chemotherapeutic topotecan, were also performed. OLE reduced the cell viability of NB cells in a time- and dose-dependent manner in 2D and 3D models. NB cells exposed to OLE underwent inhibition of cell proliferation, which was characterized by an arrest of the cell cycle progression in G0/G1 phase and by the accumulation of cells in the sub-G0 phase, which is peculiar of apoptotic death. This was confirmed by a dose-dependent increase of Annexin V+ cells (peculiar of apoptosis) and upregulation of caspases 3 and 7 protein levels. Moreover, OLE inhibited the migration of NB cells. Finally, the anti-tumor efficacy of the chemotherapeutic topotecan, in terms of cell viability reduction, was greatly enhanced by its combination with OLE. In conclusion, OLE has anti-tumor activity against NB by inhibiting cell proliferation and migration and by inducing apoptosis.

scholarly journals Truncated APC regulates the transcriptional activity of β-catenin in a cell cycle dependent manner

2006 ◽  
Vol 16 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Jean Schneikert ◽  
Annette Grohmann ◽  
Jürgen Behrens
Keyword(s):  
Cell Cycle ◽  
Transcriptional Activity ◽  
Dependent Manner ◽  
A Cell ◽  
Cycle Dependent

scholarly journals Baicalein Inhibits the Proliferation of Cervical Cancer Cells Through the GSK3β-Dependent Pathway

2018 ◽  
Vol 26 (4) ◽  
pp. 645-653 ◽  
Author(s):  
Xiaoling Wu ◽  
Zhiqin Yang ◽  
Huimin Dang ◽  
Huixia Peng ◽  
Zhijun Dai
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Cyclin D1 ◽  
Cancer Cells ◽  
Hela Cells ◽  
Glycogen Synthase ◽  
Dependent Manner ◽  
Cervical Cancer Cells ◽  
Dose Dependent ◽  
Dependent Pathway

Baicalein, a flavonoid derived from the root of Scutellaria baicalensis, has been reported to possess multiple pharmacological activities, such as anticancer and anti-inflammatory properties. This study investigated the effect of baicalein in cervical cancer cells. Cell growth curve and MTT assay were performed and revealed that baicalein inhibited the proliferation of SiHa and HeLa cells in a dose-dependent manner. We further found that baicalein arrested the cell cycle of SiHa and HeLa cells at the G0/G1 phase by suppressing the expression of cyclin D1 through the downregulation of phosphorylated protein kinase B (p-AKT) and phosphorylated glycogen synthase kinase 3β (p-GSK3β) according to FACS assays and Western blotting. Moreover, when CHIR-99021, a GSK3β inhibitor, was added to baicalein-treated SiHa cells, the expression of cyclin D1 was recovered, and cell proliferation was promoted. In conclusion, these data indicated that baicalein suspended the cell cycle at the G0/G1 phase via the downregulation of cyclin D1 through the AKT‐GSK3β signaling pathway and further inhibited the proliferation of SiHa and HeLa cervical cancer cells.

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