p15PAF Is an Rb/E2F-Regulated S-Phase Protein Essential for DNA Synthesis and Cell Cycle Progression

ABSTRACT Novel techniques were used to determine when in the cell cycle of proliferating NIH 3T3 cells cellular Ras and cyclin D1 are required. For comparison, in quiescent cells, all four of the inhibitors of cell cycle progression tested (anti-Ras, anti-cyclin D1, serum removal, and cycloheximide) became ineffective at essentially the same point in G1 phase, approximately 4 h prior to the beginning of DNA synthesis. To extend these studies to cycling cells, a time-lapse approach was used to determine the approximate cell cycle position of individual cells in an asynchronous culture at the time of inhibitor treatment and then to determine the effects of the inhibitor upon recipient cells. With this approach, anti-Ras antibody efficiently inhibited entry into S phase only when introduced into cells prior to the preceding mitosis, several hours before the beginning of S phase. Anti-cyclin D1, on the other hand, was an efficient inhibitor when introduced up until just before the initiation of DNA synthesis. Cycloheximide treatment, like anti-cyclin D1 microinjection, was inhibitory throughout G1 phase (which lasts a total of 4 to 5 h in these cells). Finally, serum removal blocked entry into S phase only during the first hour following mitosis. Kinetic analysis and a novel dual-labeling technique were used to confirm the differences in cell cycle requirements for Ras, cyclin D1, and cycloheximide. These studies demonstrate a fundamental difference in mitogenic signal transduction between quiescent and cycling NIH 3T3 cells and reveal a sequence of signaling events required for cell cycle progression in proliferating NIH 3T3 cells.

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The jun and fos protein families are both required for cell cycle progression in fibroblasts.

Molecular and Cellular Biology ◽

10.1128/mcb.11.9.4466 ◽

1991 ◽

Vol 11 (9) ◽

pp. 4466-4472 ◽

Cited By ~ 260

Author(s):

K Kovary ◽

R Bravo

Keyword(s):

Cell Cycle ◽

Transcription Factors ◽

Dna Synthesis ◽

Cell Cycle Progression ◽

S Phase ◽

3T3 Cells ◽

Cycle Progression ◽

Serum Stimulation ◽

Fos Protein ◽

Stimulation Of

The expression of different members of the Jun and Fos families of transcription factors is rapidly induced following serum stimulation of quiescent fibroblasts. To determine whether these proteins are required for cell cycle progression, we microinjected affinity-purified antibodies directed against c-Fos, FosB, Fra-1, c-Jun, JunB, and JunD, and antibodies that recognize either the Fos or the Jun family of proteins, into Swiss 3T3 cells and determined their effects in cell cycle progression by monitoring DNA synthesis. We found that microinjection of anti-Fos and anti-Jun family antibodies efficiently blocked the entrance to the S phase of serum-stimulated or asynchronously growing cells. However, the antibodies against single members of the Fos family only partially inhibited DNA synthesis. In contrast, all three Jun antibodies prevented DNA synthesis more effectively than did any of the anti-Fos antibodies.

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Cell Cycle Dysregulation by Human Cytomegalovirus: Influence of the Cell Cycle Phase at the Time of Infection and Effects on Cyclin Transcription

Journal of Virology ◽

10.1128/jvi.72.5.3729-3741.1998 ◽

1998 ◽

Vol 72 (5) ◽

pp. 3729-3741 ◽

Cited By ~ 135

Author(s):

Bryan S. Salvant ◽

Elizabeth A. Fortunato ◽

Deborah H. Spector

Keyword(s):

Cell Cycle ◽

Dna Synthesis ◽

Cell Cycle Progression ◽

Hcmv Infection ◽

Cyclin A ◽

S Phase ◽

Cyclin B ◽

Cycle Progression ◽

Cycle Arrest ◽

Time Of Infection

ABSTRACT Human cytomegalovirus (HCMV) infection inhibits cell cycle progression and alters the expression of cyclins E, A, and B (F. M. Jault, J.-M. Jault, F. Ruchti, E. A. Fortunato, C. Clark, J. Corbeil, D. D. Richman, and D. H. Spector, J. Virol. 69:6697–6704, 1995). In this study, we examined cell cycle progression, cyclin gene expression, and early viral events when the infection was initiated at different points in the cell cycle (G0, G1, and S). In all cases, infection led to cell cycle arrest. Cells infected in G0 or G1phase also showed a complete or partial absence, respectively, of cellular DNA synthesis at a time when DNA synthesis occurred in the corresponding mock-infected cells. In contrast, when cells were infected near or during S phase, many cells were able to pass through S phase and undergo mitosis prior to cell cycle arrest. S-phase infection also produced a delay in the appearance of the viral cytopathic effect and in the synthesis of immediate-early and early proteins. Labeling of cells with bromodeoxyuridine immediately prior to HCMV infection in S phase revealed that viral protein expression occurred primarily in cells which were not engaged in DNA synthesis at the time of infection. The viral-mediated induction of cyclin E, maintenance of cyclin-B protein levels, and inhibitory effects on the accumulation of cyclin A were not significantly affected when infection occurred during different phases of the cell cycle (G0, G1, and S). However, there was a delay in the observed inhibition of cyclin A in cells infected during S phase. This finding was in accord with the pattern of cell cycle progression and delay in viral gene expression associated with S-phase infection. Analysis of the mRNA revealed that the effects of the virus on cyclin E and cyclin A, but not on cyclin B, were primarily at the transcriptional level.

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The jun and fos protein families are both required for cell cycle progression in fibroblasts

Molecular and Cellular Biology ◽

10.1128/mcb.11.9.4466-4472.1991 ◽

1991 ◽

Vol 11 (9) ◽

pp. 4466-4472

Author(s):

K Kovary ◽

R Bravo

Keyword(s):

Cell Cycle ◽

Transcription Factors ◽

Dna Synthesis ◽

Cell Cycle Progression ◽

S Phase ◽

3T3 Cells ◽

Cycle Progression ◽

Serum Stimulation ◽

Fos Protein ◽

Stimulation Of

The expression of different members of the Jun and Fos families of transcription factors is rapidly induced following serum stimulation of quiescent fibroblasts. To determine whether these proteins are required for cell cycle progression, we microinjected affinity-purified antibodies directed against c-Fos, FosB, Fra-1, c-Jun, JunB, and JunD, and antibodies that recognize either the Fos or the Jun family of proteins, into Swiss 3T3 cells and determined their effects in cell cycle progression by monitoring DNA synthesis. We found that microinjection of anti-Fos and anti-Jun family antibodies efficiently blocked the entrance to the S phase of serum-stimulated or asynchronously growing cells. However, the antibodies against single members of the Fos family only partially inhibited DNA synthesis. In contrast, all three Jun antibodies prevented DNA synthesis more effectively than did any of the anti-Fos antibodies.

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Role of androgen receptor in prostate cancer cell cycle progression from G1 into S phase and in the onset of DNA synthesis

European Urology Supplements ◽

10.1016/s1569-9056(03)90422-2 ◽

2003 ◽

Vol 2 (6) ◽

pp. 43

Author(s):

G Prem-Veer Reddy ◽

Eugenia Cifuentes ◽

Umai Bai ◽

Richard Croxen ◽

Mani Menon ◽

...

Keyword(s):

Prostate Cancer ◽

Cell Cycle ◽

Androgen Receptor ◽

Dna Synthesis ◽

Cancer Cell ◽

Cell Cycle Progression ◽

Prostate Cancer Cell ◽

S Phase ◽

Cycle Progression

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Inhibition of endothelial cell proliferation by platelet factor-4 involves a unique action on S phase progression.

The Journal of Cell Biology ◽

10.1083/jcb.127.4.1121 ◽

1994 ◽

Vol 127 (4) ◽

pp. 1121-1127 ◽

Cited By ~ 81

Author(s):

S K Gupta ◽

J P Singh

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Endothelial Cells ◽

Endothelial Cell ◽

Dna Synthesis ◽

Cell Cycle Progression ◽

S Phase ◽

Endothelial Cell Proliferation ◽

Platelet Factor ◽

Cycle Progression

Modulation of endothelial cell proliferation and cell cycle progression by the "chemokine" platelet factor-4 (PF-4) was investigated. PF-4 inhibited DNA synthesis, as well as proliferation of endothelial cells derived from large and small blood vessels. Inhibition by PF-4 was independent of the type and the concentration of stimuli used for the induction of endothelial cell proliferation. Inhibition of cell growth by PF-4 was reversible. The effects of PF-4 were antagonized by heparin. Cell cycle analysis using [3H]thymidine pulse labeling during traverse of synchronous cells from G0/G1 to S phase revealed that addition of PF-4 during G1 phase completely abolished the entry of cells into S phase. In addition, PF-4 also inhibited DNA synthesis in cells that were already in S phase. In exponentially growing cells, addition of PF-4 resulted in an accumulation of > 70% of the cells in early S phase, as determined by FACS (Becton-Dickinson Immunocytometry Systems, Mountain View, CA). In cells synchronized in S phase by hydroxyurea and then released, addition of PF-4 promptly blocked further progression of DNA synthesis. These results demonstrate that in G0/G1-arrested cells, PF-4 inhibited entry of endothelial cells into S phase. More strikingly, our studies have revealed a unique mode of endothelial cell growth inhibition whereby PF-4 effectively blocked cell cycle progression during S phase.

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The Meiosis-Specific Crs1 Cyclin Is Required for Efficient S-Phase Progression and Stable Nuclear Architecture

International Journal of Molecular Sciences ◽

10.3390/ijms22115483 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5483

Author(s):

Luisa F. Bustamante-Jaramillo ◽

Celia Ramos ◽

Cristina Martín-Castellanos

Keyword(s):

Cell Cycle ◽

Translational Control ◽

Cell Cycle Progression ◽

Nuclear Architecture ◽

Strand Break ◽

Spindle Pole ◽

S Phase ◽

Cycle Progression ◽

Single Wave ◽

Phase Progression

Cyclins and CDKs (Cyclin Dependent Kinases) are key players in the biology of eukaryotic cells, representing hubs for the orchestration of physiological conditions with cell cycle progression. Furthermore, as in the case of meiosis, cyclins and CDKs have acquired novel functions unrelated to this primal role in driving the division cycle. Meiosis is a specialized developmental program that ensures proper propagation of the genetic information to the next generation by the production of gametes with accurate chromosome content, and meiosis-specific cyclins are widespread in evolution. We have explored the diversification of CDK functions studying the meiosis-specific Crs1 cyclin in fission yeast. In addition to the reported role in DSB (Double Strand Break) formation, this cyclin is required for meiotic S-phase progression, a canonical role, and to maintain the architecture of the meiotic chromosomes. Crs1 localizes at the SPB (Spindle Pole Body) and is required to stabilize the cluster of telomeres at this location (bouquet configuration), as well as for normal SPB motion. In addition, Crs1 exhibits CDK(Cdc2)-dependent kinase activity in a biphasic manner during meiosis, in contrast to a single wave of protein expression, suggesting a post-translational control of its activity. Thus, Crs1 displays multiple functions, acting both in cell cycle progression and in several key meiosis-specific events.

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Spirulina Crude Protein Promotes the Migration and Proliferation in IEC-6 Cells by Activating EGFR/MAPK Signaling Pathway

Marine Drugs ◽

10.3390/md17040205 ◽

2019 ◽

Vol 17 (4) ◽

pp. 205

Author(s):

Su-Jin Jeong ◽

Jeong-Wook Choi ◽

Min-Kyeong Lee ◽

Youn-Hee Choi ◽

Taek-Jeong Nam

Keyword(s):

Cell Cycle ◽

Epithelial Cells ◽

Signaling Pathway ◽

Crude Protein ◽

Cell Cycle Progression ◽

Intestinal Epithelial Cells ◽

Mapk Signaling ◽

S Phase ◽

Intestinal Epithelial ◽

Cycle Progression

Spirulina is a type of filamentous blue-green microalgae known to be rich in nutrients and to have pharmacological effects, but the effect of spirulina on the small intestine epithelium is not well understood. Therefore, this study aims to investigate the proliferative effects of spirulina crude protein (SPCP) on a rat intestinal epithelial cells IEC-6 to elucidate the mechanisms underlying its effect. First, the results of wound-healing and cell viability assays demonstrated that SPCP promoted migration and proliferation in a dose-dependent manner. Subsequently, when the mechanisms of migration and proliferation promotion by SPCP were confirmed, we found that the epidermal growth factor receptor (EGFR) and mitogen-activated protein (MAPK) signaling pathways were activated by phosphorylation. Cell cycle progression from G0/G1 to S phase was also promoted by SPCP through upregulation of the expression levels of cyclins and cyclin-dependent kinases (Cdks), which regulate cell cycle progression to the S phase. Meanwhile, the expression of cyclin-dependent kinase inhibitors (CKIs), such as p21 and p27, decreased with SPCP. In conclusion, our results indicate that activation of EGFR and its downstream signaling pathway by SPCP treatment regulates cell cycle progression. Therefore, these results contribute to the research on the molecular mechanism for SPCP promoting the migration and proliferation of rat intestinal epithelial cells.

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Cubic Membranes Formation in Synchronized Human Hepatocellular Carcinoma Cells Reveals a Possible Role as a Structural Antioxidant Defense System in Cell Cycle Progression

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2020.617406 ◽

2020 ◽

Vol 8 ◽

Author(s):

Deqin Kong ◽

Rui Liu ◽

Jiangzheng Liu ◽

Qingbiao Zhou ◽

Jiaxin Zhang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Cell Cycle ◽

Cell Cycle Progression ◽

S Phase ◽

Carcinoma Cells ◽

Human Hepatocellular Carcinoma ◽

Cycle Progression ◽

Hepatocellular Carcinoma Cells ◽

G2 Phase ◽

Human Hepatocellular Carcinoma Cells

Cubic membranes (CMs) represent unique biological membrane structures with highly curved three-dimensional periodic minimal surfaces, which have been observed in a wide range of cell types and organelles under various stress conditions (e. g., starvation, virus-infection, and oxidation). However, there are few reports on the biological roles of CMs, especially their roles in cell cycle. Hence, we established a stable cell population of human hepatocellular carcinoma cells (HepG2) of 100% S phase by thymidine treatment, and determined certain parameters in G2 phase released from S phase. Then we found a close relationship between CMs formation and cell cycle, and an increase in reactive oxygen species (ROS) and mitochondrial function. After the synchronization of HepG2 cells were induced, CMs were observed through transmission electron microscope in G2 phase but not in G1, S and M phase. Moreover, the increased ATP production, mitochondrial and intracellular ROS levels were also present in G2 phase, which demonstrated a positive correlation with CMs formation by Pearson correlation analysis. This study suggests that CMs may act as an antioxidant structure in response to mitochondria-derived ROS during G2 phase and thus participate in cell cycle progression.

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