The D-type alfalfa cyclin gene cycMs4 complements G1 cyclin-deficient yeast and is induced in the G1 phase of the cell cycle.

Exposure of yeast a cells to alpha-factor causes cells to arrest in the G1 phase of the cell cycle. The FAR1 gene is required for this cell-cycle arrest; its product is necessary for the inhibition of a G1 cyclin, CLN2. Earlier work demonstrated that alpha-factor caused an increase in the transcription of FAR1 severalfold over a measurable basal level. We now show that transcriptional induction of FAR1 from a heterologous promoter is not sufficient to inhibit CLN2 in the absence of alpha-factor. We also show that FAR1 is phosphorylated in response to alpha-factor and propose that this phosphorylation may be required for FAR1 activity.

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Connections between the Ras-cyclic AMP pathway and G1 cyclin expression in the budding yeast Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.13.10.6274-6282.1993 ◽

1993 ◽

Vol 13 (10) ◽

pp. 6274-6282

Author(s):

L Hubler ◽

J Bradshaw-Rouse ◽

W Heideman

Keyword(s):

Saccharomyces Cerevisiae ◽

Protein Synthesis ◽

Cyclic Amp ◽

G1 Phase ◽

Yeast Saccharomyces Cerevisiae ◽

Rapid Induction ◽

Camp Pathway ◽

G1 Cyclin ◽

Proliferative Growth ◽

Cyclin Gene

We have identified two processes in the G1 phase of the Saccharomyces cerevisiae cell cycle that are required before nutritionally arrested cells are able to return to proliferative growth. The first process requires protein synthesis and is associated with increased expression of the G1 cyclin gene CLN3. This process requires nutrients but is independent of Ras and cyclic AMP (cAMP). The second process requires cAMP. This second process is rapid, is independent of protein synthesis, and produces a rapid induction of START-specific transcripts, including CLN1 and CLN2. The ability of a nutritionally arrested cell to respond to cAMP is dependent on completion of the first process, and this is delayed in cells carrying a CLN3 deletion. Mating pheromone blocks the cAMP response but does not alter the process upstream of Ras-cAMP. These results suggest a model linking the Ras-cAMP pathway with regulation of G1 cyclin expression.

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A Drosophila G1-specific cyclin E homolog exhibits different modes of expression during embryogenesis

Development ◽

10.1242/dev.119.3.673 ◽

1993 ◽

Vol 119 (3) ◽

pp. 673-690 ◽

Cited By ~ 23

Author(s):

H.E. Richardson ◽

L.V. O'Keefe ◽

S.I. Reed ◽

R. Saint

Keyword(s):

Phase Transition ◽

Cell Cycle ◽

Nervous System ◽

Peripheral Nervous System ◽

Cyclin E ◽

S Phase ◽

G1 Phase ◽

Cycle Phase ◽

E Gene ◽

G1 Cyclin

We have isolated a Drosophila homolog of the human G1-specific cyclin E gene. Cyclin E proteins thus constitute an evolutionarily conserved subfamily of metazoan cyclins. The Drosophila cyclin E gene, DmcycE, encodes two proteins with a common C-terminal region and unique N-terminal regions. Unlike other Drosophila cyclins, DmcycE exhibits a dynamic pattern of expression during development. DmcycE is supplied maternally, but at the completion of the cleavage divisions and prior to mitosis 14, the maternal transcripts are rapidly degraded in all cells except the pole (germ) cells. Two modes of DmcycE expression are observed in the subsequent divisions. During cycles 14, 15 and 16 in non-neural cells, DmcycE mRNA levels show no cell-cycle-associated variation. DmcycE expression in these cells is therefore independent of the cell cycle phase. In contrast, expression in proliferating embryonic peripheral nervous system cells occurs during interphase as a brief pulse that initiates before and overlaps with S phase, demonstrating the presence of a G1 phase in these embryonic neural cell cycles. DmcycE appears not to be expressed in cells that undergo endoreplication cycles during polytenization. The structural homology to human cyclin E, the ability of DmcycE to rescue a G1 cyclin-deficient yeast strain, the presence of multiple PEST sequences characteristic of G1-specific cyclins and expression during G1 phase in proliferating peripheral nervous system cells all argue that Drosophila cyclin E is a G1 cyclin. Constitutive DmcycE expression in embryonic cycles lacking a G1 phase, in contrast to expression during the G1-S phase transition in cycles exhibiting a G1 phase, implicates DmcycE expression in the regulation of the G1 to S phase transition during Drosophila embryogenesis.

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Connections between the Ras-cyclic AMP pathway and G1 cyclin expression in the budding yeast Saccharomyces cerevisiae.

Molecular and Cellular Biology ◽

10.1128/mcb.13.10.6274 ◽

1993 ◽

Vol 13 (10) ◽

pp. 6274-6282 ◽

Cited By ~ 34

Author(s):

L Hubler ◽

J Bradshaw-Rouse ◽

W Heideman

Keyword(s):

Saccharomyces Cerevisiae ◽

Protein Synthesis ◽

Cyclic Amp ◽

G1 Phase ◽

Yeast Saccharomyces Cerevisiae ◽

Rapid Induction ◽

Camp Pathway ◽

G1 Cyclin ◽

Proliferative Growth ◽

Cyclin Gene

We have identified two processes in the G1 phase of the Saccharomyces cerevisiae cell cycle that are required before nutritionally arrested cells are able to return to proliferative growth. The first process requires protein synthesis and is associated with increased expression of the G1 cyclin gene CLN3. This process requires nutrients but is independent of Ras and cyclic AMP (cAMP). The second process requires cAMP. This second process is rapid, is independent of protein synthesis, and produces a rapid induction of START-specific transcripts, including CLN1 and CLN2. The ability of a nutritionally arrested cell to respond to cAMP is dependent on completion of the first process, and this is delayed in cells carrying a CLN3 deletion. Mating pheromone blocks the cAMP response but does not alter the process upstream of Ras-cAMP. These results suggest a model linking the Ras-cAMP pathway with regulation of G1 cyclin expression.

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Faculty Opinions recommendation of Coordination of mitochondrial bioenergetics with G1 phase cell cycle progression.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1116434.572453 ◽

2008 ◽

Author(s):

Robert Abraham

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Phase Cell ◽

G1 Phase ◽

Mitochondrial Bioenergetics ◽

Cycle Progression

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The pro-apoptosis effects of Echinacea purpurea and Cannabis sativa extracts in human lung cancer cells through caspase-dependent pathway

BMC Complementary Medicine and Therapies ◽

10.1186/s12906-021-03204-6 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Fatemeh Hosami ◽

Azadeh Manayi ◽

Vahid Salimi ◽

Farshad Khodakhah ◽

Mitra Nourbakhsh ◽

...

Keyword(s):

Lung Cancer ◽

Cell Cycle ◽

Caspase 3 ◽

Cannabis Sativa ◽

A549 Cells ◽

Echinacea Purpurea ◽

G1 Phase ◽

Cell Cycle Distribution ◽

Cb2 Receptor ◽

Anti Cancer

Abstract Background Considering the advantages of using medicinal herbs as supplementary treatments to sensitize conventional anti-cancer drugs, studying functional mechanisms and regulatory effects of Echinacea purpurea (as a non-cannabinoid plant) and Cannabis sativa (as a cannabinoid plant) are timely and required. The potential effects of such herbs on lung cancer cell growth, apoptosis, cell cycle distribution, cellular reactive oxygen species (ROS) level, caspase activity and their cannabinomimetic properties on the CB2 receptor are addressed in the current study. Methods The cytotoxic effect of both herb extracts on the growth of lung cancer cells (A549) was assessed using the MTT assay. The annexin-V-FITC staining and propidium iodide (PI) staining methods were applied for the detection of apoptosis and cell cycle distribution using flow cytometry. The cellular level of ROS was measured using 7′-dichlorofluorescin diacetate (DCFH-DA) as a fluorescent probe in flow cytometry. The caspase 3 activity was assessed using a colorimetric assay Kit. Results Echinacea purpurea (EP) root extract induced a considerable decrease in A549 viable cells, showing a time and dose-dependent response. The cell toxicity of EP was accompanied by induction of early apoptosis and cell accumulation at the sub G1 phase of the cell cycle. The elevation of cellular ROS level and caspase 3 activity indicate ROS-induced caspase-dependent apoptosis following the treatment of A549 cells by EP extract. The observed effects of EP extract on A549 growth and death were abrogated following blockage of CB2 using AM630, a specific antagonist of the CB2 receptor. Increasing concentrations of Cannabis sativa (CS) induced A549 cell death in a time-dependent manner, followed by induction of early apoptosis, cell cycle arrest at sub G1 phase, elevation of ROS level, and activation of caspase 3. The CB2 blockage caused attenuation of CS effects on A549 cell death which revealed consistency with the effects of EP extract on A549 cells. Conclusions The pro-apoptotic effects of EP and CS extracts on A549 cells and their possible regulatory role of CB2 activity might be attributed to metabolites of both herbs. These effects deserve receiving more attention as alternative anti-cancer agents. Graphical abstract

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Yeast dom34 Mutants Are Defective in Multiple Developmental Pathways and Exhibit Decreased Levels of Polyribosomes

Genetics ◽

10.1093/genetics/149.1.45 ◽

1998 ◽

Vol 149 (1) ◽

pp. 45-56

Author(s):

Luther Davis ◽

JoAnne Engebrecht

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Heterologous Expression ◽

Protein Translation ◽

Developmental Pathways ◽

G1 Phase ◽

Growth Defect ◽

Wild Type ◽

Drosophila Homolog ◽

Mutant Cells

Abstract The DOM34 gene of Saccharomyces cerevisiae is similar togenes found in diverse eukaryotes and archaebacteria. Analysis of dom34 strains shows that progression through the G1 phase of the cell cycle is delayed, mutant cells enter meiosis aberrantly, and their ability to form pseudohyphae is significantly diminished. RPS30A, which encodes ribosomal protein S30, was identified in a screen for high-copy suppressors of the dom34Δ growth defect. dom34Δ mutants display an altered polyribosome profile that is rescued by expression of RPS30A. Taken together, these data indicate that Dom34p functions in protein translation to promote G1 progression and differentiation. A Drosophila homolog of Dom34p, pelota, is required for the proper coordination of meiosis and spermatogenesis. Heterologous expression of pelota in dom34Δ mutants restores wild-type growth and differentiation, suggesting conservation of function between the eukaryotic members of the gene family.

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Cannabidiol Induces Cell Cycle Arrest and Cell Apoptosis in Human Gastric Cancer SGC-7901 Cells

Biomolecules ◽

10.3390/biom9080302 ◽

2019 ◽

Vol 9 (8) ◽

pp. 302 ◽

Cited By ~ 10

Author(s):

Xin Zhang ◽

Yao Qin ◽

Zhaohai Pan ◽

Minjing Li ◽

Xiaona Liu ◽

...

Keyword(s):

Gastric Cancer ◽

Cell Cycle ◽

Protein Expression ◽

Cell Cycle Arrest ◽

Phase Cell ◽

G1 Phase ◽

Therapeutic Effects ◽

Human Gastric Cancer ◽

Expression Levels ◽

Cycle Arrest

The main chemical component of cannabis, cannabidiol (CBD), has been shown to have antitumor properties. The present study examined the in vitro effects of CBD on human gastric cancer SGC-7901 cells. We found that CBD significantly inhibited the proliferation and colony formation of SGC-7901 cells. Further investigation showed that CBD significantly upregulated ataxia telangiectasia-mutated gene (ATM) and p53 protein expression and downregulated p21 protein expression in SGC-7901 cells, which subsequently inhibited the levels of CDK2 and cyclin E, thereby resulting in cell cycle arrest at the G0–G1 phase. In addition, CBD significantly increased Bax expression levels, decreased Bcl-2 expression levels and mitochondrial membrane potential, and then upregulated the levels of cleaved caspase-3 and cleaved caspase-9, thereby inducing apoptosis in SGC-7901 cells. Finally, we found that intracellular reactive oxygen species (ROS) increased after CBD treatment. These results indicated that CBD could induce G0–G1 phase cell cycle arrest and apoptosis by increasing ROS production, leading to the inhibition of SGC-7901 cell proliferation, thereby suggesting that CBD may have therapeutic effects on gastric cancer.

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The Small Subunit Processome Is Required for Cell Cycle Progression at G1

Molecular Biology of the Cell ◽

10.1091/mbc.e04-06-0515 ◽

2004 ◽

Vol 15 (11) ◽

pp. 5038-5046 ◽

Cited By ~ 44

Author(s):

Kara A. Bernstein ◽

Susan J. Baserga

Keyword(s):

Cell Cycle ◽

Ribosome Biogenesis ◽

Cell Cycle Progression ◽

Small Subunit ◽

Cellular Growth ◽

Yeast Cells ◽

G1 Phase ◽

Relay Cell ◽

Ssu Processome ◽

Nucleolar Rna

Without ribosome biogenesis, translation of mRNA into protein ceases and cellular growth stops. We asked whether ribosome biogenesis is cell cycle regulated in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, and we determined that it is not regulated in the same manner as in metazoan cells. We therefore turned our attention to cellular sensors that relay cell size information via ribosome biogenesis. Our results indicate that the small subunit (SSU) processome, a complex consisting of 40 proteins and the U3 small nucleolar RNA necessary for ribosome biogenesis, is not mitotically regulated. Furthermore, Nan1/Utp17, an SSU processome protein, does not provide a link between ribosome biogenesis and cell growth. However, when individual SSU processome proteins are depleted, cells arrest in the G1 phase of the cell cycle. This arrest was further supported by the lack of staining for proteins expressed in post-G1. Similarly, synchronized cells depleted of SSU processome proteins did not enter G2. This suggests that when ribosomes are no longer made, the cells stall in the G1. Therefore, yeast cells must grow to a critical size, which is dependent upon having a sufficient number of ribosomes during the G1 phase of the cell cycle, before cell division can occur.

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