scholarly journals The de novo centriole assembly pathway in HeLa cells

2005 ◽  
Vol 168 (5) ◽  
pp. 713-722 ◽  
Author(s):  
Sabrina La Terra ◽  
Christopher N. English ◽  
Polla Hergert ◽  
Bruce F. McEwen ◽  
Greenfield Sluder ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
De Novo ◽  
Variable Number ◽  
S Phase ◽  
Cycle Progression ◽  
Assembly Pathway ◽  
Centriole Assembly

It has been reported that nontransformed mammalian cells become arrested during G1 in the absence of centrioles (Hinchcliffe, E., F. Miller, M. Cham, A. Khodjakov, and G. Sluder. 2001. Science. 291:1547–1550). Here, we show that removal of resident centrioles (by laser ablation or needle microsurgery) does not impede cell cycle progression in HeLa cells. HeLa cells born without centrosomes, later, assemble a variable number of centrioles de novo. Centriole assembly begins with the formation of small centrin aggregates that appear during the S phase. These, initially amorphous “precentrioles” become morphologically recognizable centrioles before mitosis. De novo–assembled centrioles mature (i.e., gain abilities to organize microtubules and replicate) in the next cell cycle. This maturation is not simply a time-dependent phenomenon, because de novo–formed centrioles do not mature if they are assembled in S phase–arrested cells. By selectively ablating only one centriole at a time, we find that the presence of a single centriole inhibits the assembly of additional centrioles, indicating that centrioles have an activity that suppresses the de novo pathway.

scholarly journals Cell cycle progression and de novo centriole assembly after centrosomal removal in untransformed human cells

2007 ◽  
Vol 176 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Yumi Uetake ◽  
Jadranka Lončarek ◽  
Joshua J. Nordberg ◽  
Christopher N. English ◽  
Sabrina La Terra ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
De Novo ◽  
S Phase ◽  
Human Cells ◽  
G1 Arrest ◽  
Cycle Progression ◽  
Normal Human ◽  
Centrosomal Proteins

How centrosome removal or perturbations of centrosomal proteins leads to G1 arrest in untransformed mammalian cells has been a mystery. We use microsurgery and laser ablation to remove the centrosome from two types of normal human cells. First, we find that the cells assemble centrioles de novo after centrosome removal; thus, this phenomenon is not restricted to transformed cells. Second, normal cells can progress through G1 in its entirety without centrioles. Therefore, the centrosome is not a necessary, integral part of the mechanisms that drive the cell cycle through G1 into S phase. Third, we provide evidence that centrosome loss is, functionally, a stress that can act additively with other stresses to arrest cells in G1 in a p38-dependent fashion.

scholarly journals Plk4 triggers autonomous de novo centriole biogenesis and maturation

2021 ◽  
Vol 220 (5) ◽  
Author(s):  
Catarina Nabais ◽  
Delphine Pessoa ◽  
Jorge de-Carvalho ◽  
Thomas van Zanten ◽  
Paulo Duarte ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
De Novo ◽  
Cell Types ◽  
Proliferating Cells ◽  
Cycle Progression ◽  
Controlled System ◽  
Pericentriolar Material ◽  
Centriole Assembly ◽  
Critical Components

Centrioles form centrosomes and cilia. In most proliferating cells, centrioles assemble through canonical duplication, which is spatially, temporally, and numerically regulated by the cell cycle and the presence of mature centrioles. However, in certain cell types, centrioles assemble de novo, yet by poorly understood mechanisms. Herein, we established a controlled system to investigate de novo centriole biogenesis, using Drosophila melanogaster egg explants overexpressing Polo-like kinase 4 (Plk4), a trigger for centriole biogenesis. We show that at a high Plk4 concentration, centrioles form de novo, mature, and duplicate, independently of cell cycle progression and of the presence of other centrioles. Plk4 concentration determines the temporal onset of centriole assembly. Moreover, our results suggest that distinct biochemical kinetics regulate de novo and canonical biogenesis. Finally, we investigated which other factors modulate de novo centriole assembly and found that proteins of the pericentriolar material (PCM), and in particular γ-tubulin, promote biogenesis, likely by locally concentrating critical components.

scholarly journals Histone supply regulates S phase timing and cell cycle progression

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Ufuk Günesdogan ◽  
Herbert Jäckle ◽  
Alf Herzig
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
De Novo ◽  
S Phase ◽  
Histone Genes ◽  
Nucleosome Assembly ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
A Cell ◽  
Surveillance Mechanism

Eukaryotes package DNA into nucleosomes that contain a core of histone proteins. During DNA replication, nucleosomes are disrupted and re-assembled with newly synthesized histones and DNA. Despite much progress, it is still unclear why higher eukaryotes contain multiple core histone genes, how chromatin assembly is controlled, and how these processes are coordinated with cell cycle progression. We used a histone null mutation of Drosophila melanogaster to show that histone supply levels, provided by a defined number of transgenic histone genes, regulate the length of S phase during the cell cycle. Lack of de novo histone supply not only extends S phase, but also causes a cell cycle arrest during G2 phase, and thus prevents cells from entering mitosis. Our results suggest a novel cell cycle surveillance mechanism that monitors nucleosome assembly without involving the DNA repair pathways and exerts its effect via suppression of CDC25 phosphatase String expression.

scholarly journals Plk4 triggers autonomous de novo centriole biogenesis and maturation

2020 ◽  
Author(s):  
Catarina Nabais ◽  
Delphine Pessoa ◽  
Jorge de-Carvalho ◽  
Thomas van Zanten ◽  
Paulo Duarte ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
De Novo ◽  
Cell Types ◽  
Proliferating Cells ◽  
Cycle Progression ◽  
Controlled System ◽  
Centriole Assembly ◽  
Critical Components ◽  
Kinetics Of

AbstractCentrioles form centrosomes and cilia. In most proliferating cells, centrioles assemble through canonical duplication, which is spatially, temporally and numerically regulated by the cell cycle and the presence of mature centrioles. However, in certain cell-types, centrioles assemble de novo, yet by poorly understood mechanisms. Here, we established a controlled system to investigate de novo centriole biogenesis, using Drosophila melanogaster egg explants overexpressing Polo-like kinase 4 (Plk4), a trigger for centriole biogenesis. We show that at high Plk4 concentration, centrioles form de novo, mature and duplicate, independently of cell cycle progression and of the presence of other centrioles. Plk4 concentration determines the kinetics of centriole assembly. Moreover, our results suggest Plk4 operates in a switch-like manner to control the onset of de novo centriole formation, and that distinct biochemical kinetics regulate de novo and canonical biogenesis. Finally, we investigated which other factors modulate de novo centriole assembly and reveal that proteins of the pericentriolar matrix (PCM) promote biogenesis, likely by locally concentrating critical components.

scholarly journals NPAT Expression Is Regulated by E2F and Is Essential for Cell Cycle Progression

2003 ◽  
Vol 23 (8) ◽  
pp. 2821-2833 ◽  
Author(s):  
Guang Gao ◽  
Adrian P. Bracken ◽  
Karina Burkard ◽  
Diego Pasini ◽  
Marie Classon ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Histone Gene ◽  
Cycle Progression ◽  
Histone Gene Transcription ◽  
E2f Proteins ◽  
Phase Entry

ABSTRACT NPAT is an in vivo substrate of cyclin E-Cdk2 kinase and is thought to play a critical role in coordinated transcriptional activation of histone genes during the G1/S-phase transition and in S-phase entry in mammalian cells. Here we show that NPAT transcription is up-regulated at the G1/S-phase boundary in growth-stimulated cells and that the NPAT promoter responds to activation by E2F proteins. We demonstrate that endogenous E2F proteins interact with the promoter of the NPAT gene in vivo and that induced expression of E2F1 stimulates NPAT mRNA expression, supporting the idea that the expression of NPAT is regulated by E2F. Consistently, we find that the E2F sites in the NPAT promoter are required for its activation during the G1/S-phase transition. Moreover, we show that the expression of NPAT accelerates S-phase entry in cells released from quiescence. The inhibition of NPAT expression by small interfering RNA duplexes impedes cell cycle progression and histone gene expression in tissue culture cells. Thus, NPAT is an important E2F target that is required for cell cycle progression in mammalian cells. As NPAT is involved in the regulation of S-phase-specific histone gene transcription, our findings indicate that NPAT links E2F to the activation of S-phase-specific histone gene transcription.

scholarly journals Centrobin

2005 ◽  
Vol 171 (3) ◽  
pp. 437-445 ◽  
Author(s):  
Chaozhong Zou ◽  
Jun Li ◽  
Yujie Bai ◽  
William T. Gunning ◽  
David E. Wazer ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Cycle Progression ◽  
Centriole Duplication ◽  
Pericentriolar Material ◽  
Core Components ◽  
Interfering Rna ◽  
Daughter Centriole

In mammalian cells, the centrosome consists of a pair of centrioles and amorphous pericentriolar material. The pair of centrioles, which are the core components of the centrosome, duplicate once per cell cycle. Centrosomes play a pivotal role in orchestrating the formation of the bipolar spindle during mitosis. Recent studies have linked centrosomal activity on centrioles or centriole-associated structures to cytokinesis and cell cycle progression through G1 into the S phase. In this study, we have identified centrobin as a centriole-associated protein that asymmetrically localizes to the daughter centriole. The silencing of centrobin expression by small interfering RNA inhibited centriole duplication and resulted in centrosomes with one or no centriole, demonstrating that centrobin is required for centriole duplication. Furthermore, inhibition of centriole duplication by centrobin depletion led to impaired cytokinesis.

scholarly journals A UV-responsive G2 checkpoint in rodent cells.

1995 ◽  
Vol 15 (7) ◽  
pp. 3722-3730 ◽  
Author(s):  
D K Orren ◽  
L N Petersen ◽  
V A Bohr
Keyword(s):  
Cell Cycle ◽  
Uv Irradiation ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Chinese Hamster Ovary Cells ◽  
S Phase ◽  
Serum Starvation ◽  
Cycle Progression ◽  
Synchronized Cells ◽  
G2 Phase

We have studied the effect of UV irradiation on the cell cycle progression of synchronized Chinese hamster ovary cells. Synchronization of cells in S or G2 phase was accomplished by the development of a novel protocol using mimosine, which blocks cell cycle progression at the G1/S boundary. After removal of mimosine, cells proceed synchronously through the S and G2 phases, allowing manipulation of cells at specific points in either phase. Synchronization of cells in G1 was achieved by release of cells after a period of serum starvation. Cells synchronized by these methods were UV irradiated at defined points in G1, S, and G2, and their subsequent progression through the cell cycle was monitored. UV irradiation of G1-synchronized cells caused a dose-dependent delay in entry into S phase. Irradiation of S-phase-synchronized cells inhibited progression through S phase and then resulted in accumulation of cells for a prolonged interval in G2. Apoptosis of a subpopulation of cells during this extended period was noted. UV irradiation of G2-synchronized cells caused a shorter G2 arrest. The arrest itself and its duration were dependent upon the timing (within G2 phase) of the irradiation and the UV dose, respectively. We have thus defined a previously undescribed (in mammalian cells) UV-responsive checkpoint in G2 phase. The implications of these findings with respect to DNA metabolism are discussed.

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

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.

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

Marine Drugs ◽  
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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