Dolichol delays G1-arrest for one cell cycle in human fibroblasts subjected to depletion of serum or mevalonate

1992 ◽  
Vol 103 (4) ◽  
pp. 1065-1072 ◽  
Author(s):  
O. Larsson ◽  
J. Wejde
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Human Fibroblasts ◽  
Video Recording ◽  
Time Lapse ◽  
G1 Arrest ◽  
Proliferating Cells ◽  
Serum Factors

It is well-established that some product(s) or metabolite(s) of mevalonate is (are) critical for growth of mammalian cells. In the search for this (these) compound(s) it seems meaningful to distinguish between compounds needed for cell cycle progression in proliferating cells and compounds needed for growth activation of arrested cells. By using time-lapse video recording we have studied the possible regulatory role of cholesterol, dolichol and mevalonate in the cell cycle of human diploid fibroblasts (HDF). HDF, which are serum-dependent, were rapidly growth-arrested in the first part of G1 upon removal of serum factors. They also responded to mevinolin (an HMG CoA reductase inhibitor) by a similar G1-block, indicating that a mevalonate-derived product is involved in the G1-located cell cycle control of HDF. Interestingly, dolichol counteracted the G1-block caused by both types of treatment. Hence, the early G1-cells could traverse the remainder of the cell cycle and divide despite depletion of serum or mevalonate. We also demonstrated that addition of dolichol resulted in a significant decrease in the rate of protein degradation. This protein stabilizing effect may constitute the mechanism by which dolichol delays the G1-arrest of HDF.

scholarly journals Primase p49 mRNA expression is serum stimulated but does not vary with the cell cycle.

1989 ◽  
Vol 9 (5) ◽  
pp. 1940-1945 ◽  
Author(s):  
B Y Tseng ◽  
C E Prussak ◽  
M T Almazan
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Small Subunit ◽  
Mrna Levels ◽  
Proliferating Cells ◽  
Restriction Point ◽  
Serum Stimulation ◽  
G1 Cells

Expression of the small-subunit p49 mRNA of primase, the enzyme that synthesizes oligoribonucleotides for initiation of DNA replication, was examined in mouse cells stimulated to proliferate by serum and in growing cells. The level of p49 mRNA increased approximately 10-fold after serum stimulation and preceded synthesis of DNA and histone H3 mRNA by several hours. Expression of p49 mRNA was not sensitive to inhibition by low concentrations of cycloheximide, which suggested that the increase in mRNA occurred before the restriction point control for cell cycle progression described for mammalian cells and was not under its control. p49 mRNA levels were not coupled to DNA synthesis, as observed for the replication-dependent histone genes, since hydroxyurea or aphidicolin had no effect on p49 mRNA levels when added before or during S phase. These inhibitors did have an effect, however, on the stability of p49 mRNA and increased the half-life from 3.5 h to about 20 h, which suggested an interdependence of p49 mRNA degradation and DNA synthesis. When growing cells were examined after separation by centrifugal elutriation, little difference was detected for p49 mRNA levels in different phases of the cell cycle. This was also observed when elutriated G1 cells were allowed to continue growth and then were blocked in M phase with colcemid. Only a small decrease in p49 mRNA occurred, whereas H3 mRNA rapidly decreased, when cells entered G2/M. These results indicate that the level of primase p49 mRNA is not cell cycle regulated but is present constitutively in proliferating cells.

scholarly journals Cell cycle progression after cleavage failure

2004 ◽  
Vol 165 (5) ◽  
pp. 609-615 ◽  
Author(s):  
Yumi Uetake ◽  
Greenfield Sluder
Keyword(s):  
Cell Cycle ◽  
Cell Line ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Human Fibroblasts ◽  
Human Cell Line ◽  
Cycle Progression ◽  
Binucleate Cells ◽  
Normal Human ◽  
Cleavage Failure

Failure of cells to cleave at the end of mitosis is dangerous to the organism because it immediately produces tetraploidy and centrosome amplification, which is thought to produce genetic imbalances. Using normal human and rat cells, we reexamined the basis for the attractive and increasingly accepted proposal that normal mammalian cells have a “tetraploidy checkpoint” that arrests binucleate cells in G1, thereby preventing their propagation. Using 10 μM cytochalasin to block cleavage, we confirm that most binucleate cells arrest in G1. However, when we use lower concentrations of cytochalasin, we find that binucleate cells undergo DNA synthesis and later proceed through mitosis in >80% of the cases for the hTERT-RPE1 human cell line, primary human fibroblasts, and the REF52 cell line. These observations provide a functional demonstration that the tetraploidy checkpoint does not exist in normal mammalian somatic cells.

scholarly journals CDKs family -a glimpse into the past and present: from cell cycle control to current biological functions

2020 ◽  
Vol 5 (1) ◽  
pp. 1-9
Author(s):  
Muzna Shah ◽  
Muhammad Fazal Hussain Qureshi ◽  
Danish Mohammad ◽  
Mahira Lakhani ◽  
Tabinda Urooj ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Cell Renewal ◽  
Catalytic Subunits ◽  
Cyclin Dependent Kinases ◽  
Stem Cell Renewal ◽  
Cyclin Protein ◽  
Cycle Regulation

Cyclin-dependent kinases (CDKs) are the catalytic subunits or protein kinases characterized by separate subunit “cyclin” that are essential for their enzymatic activity. CDKs play important roles in the control of cell cycle progression, cell division, neuronal function, epigenetic regulation, metabolism, stem cell renewal and transcription. However, they can accomplish some of these tasks independently, without binding with cyclin protein or kinase activity. Thus, so far, twenty different CDKs and cyclins have been reported in mammalian cells. The evolutionary expansion of the CDK family in mammals led to the division of CDKs into three cell-cycle-related subfamilies (Cdk1, Cdk4 and Cdk5) and five transcriptional subfamilies (Cdk7, Cdk8, Cdk9, Cdk11 and Cdk20). In this review, we summarizes that how CDKs are traditionally involve their latest revelations, their functional diversity beyond cell cycle regulation and their impact on development of disease in mammals.  

scholarly journals Cell cycle control by Xenopus p28Kix1, a developmentally regulated inhibitor of cyclin-dependent kinases.

1996 ◽  
Vol 7 (3) ◽  
pp. 457-469 ◽  
Author(s):  
W Shou ◽  
W G Dunphy
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cyclin E ◽  
Cell Cycle Control ◽  
Cyclin A ◽  
Cyclin B ◽  
Nuclear Antigen ◽  
Cdk Inhibitors ◽  
Egg Extracts

We have isolated Xenopus p28Kix1, a member of the p21CIP1/p27KIP1/p57KIP2 family of cyclin-dependent kinase (Cdk) inhibitors. Members of this family negatively regulate cell cycle progression in mammalian cells by inhibiting the activities of Cdks. p28 shows significant sequence homology with p21, p27, and p57 in its N-terminal region, where the Cdk inhibition domain is known to reside. In contrast, the C-terminal domain of p28 is distinct from that of p21, p27, and p57. In co-immunoprecipitation experiments, p28 was found to be associated with Cdk2, cyclin E, and cyclin A, but not the Cdc2/cyclin B complex in Xenopus egg extracts. Xenopus p28 associates with the proliferating cell nuclear antigen, but with a substantially lower affinity than human p21. In kinase assays with recombinant Cdks, p28 inhibits pre-activated Cdk2/cyclin E and Cdk2/cyclin A, but not Cdc2/cyclin B. However, at high concentrations, p28 does prevent the activation of Cdc2/cyclin B by the Cdk-activating kinase. Consistent with the role of p28 as a Cdk inhibitor, recombinant p28 elicits an inhibition of both DNA replication and mitosis upon addition to egg extracts, indicating that it can regulate multiple cell cycle transitions. The level of p28 protein shows a dramatic developmental profile: it is low in Xenopus oocytes, eggs, and embryos up to stage 11, but increases approximately 100-fold between stages 12 and 13, and remains high thereafter. The induction of p28 expression temporally coincides with late gastrulation. Thus, although p28 may play only a limited role during the early embryonic cleavages, it may function later in development to establish a somatic type of cell cycle. Taken together, our results indicate that Xenopus p28 is a new member of the p21/p27/p57 class of Cdk inhibitors, and that it may play a role in developmental processes.

scholarly journals Raf-induced proliferation or cell cycle arrest is determined by the level of Raf activity with arrest mediated by p21Cip1.

1997 ◽  
Vol 17 (9) ◽  
pp. 5598-5611 ◽  
Author(s):  
D Woods ◽  
D Parry ◽  
H Cherwinski ◽  
E Bosch ◽  
E Lees ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cyclin E ◽  
G1 Arrest ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Primary Mouse

The Raf family of protein kinases display differences in their abilities to promote the entry of quiescent NIH 3T3 cells into the S phase of the cell cycle. Although conditional activation of deltaA-Raf:ER promoted cell cycle progression, activation of deltaRaf-1:ER and deltaB-Raf:ER elicited a G1 arrest that was not overcome by exogenously added growth factors. Activation of all three deltaRaf:ER kinases led to elevated expression of cyclin D1 and cyclin E and reduced expression of p27Kip1. However, activation of deltaB-Raf:ER and deltaRaf-1:ER induced the expression of p21Cip1, whereas activation of deltaA-Raf:ER did not. A catalytically potentiated form of deltaA-Raf:ER, generated by point mutation, strongly induced p21Cip1 expression and elicited cell cycle arrest similarly to deltaB-Raf:ER and deltaRaf-1:ER. These data suggested that the strength and duration of signaling by Raf kinases might influence the biological outcome of activation of this pathway. By titration of deltaB-Raf:ER activity we demonstrated that low levels of Raf activity led to activation of cyclin D1-cdk4 and cyclin E-cdk2 complexes and to cell cycle progression whereas higher Raf activity elicited cell cycle arrest correlating with p21Cip1 induction and inhibition of cyclin-cdk activity. Using green fluorescent protein-tagged forms of deltaRaf-1:ER in primary mouse embryo fibroblasts (MEFs) we demonstrated that p21Cip1 was induced by Raf in a p53-independent manner, leading to cell cycle arrest. By contrast, activation of Raf in p21Cip1(-/-) MEFs led to a robust mitogenic response that was similar to that observed in response to platelet-derived growth factor. These data indicate that, depending on the level of kinase activity, Raf can elicit either cell cycle progression or cell cycle arrest in mouse fibroblasts. The ability of Raf to elicit cell cycle arrest is strongly associated with its ability to induce the expression of the cyclin-dependent kinase inhibitor p21Cip1 in a manner that bears analogy to alpha-factor arrest in Saccharomyces cerevisiae. These data are consistent with a role for Raf kinases in both proliferation and differentiation of mammalian cells.

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.

Functional conservation of the cell cycle-regulating transcription factor DRTF1/E2F and its pathway of control in Drosophila melanogaster

1995 ◽  
Vol 108 (9) ◽  
pp. 2945-2954 ◽  
Author(s):  
X.F. Hao ◽  
L. Alphey ◽  
L.R. Bandara ◽  
E.W. Lam ◽  
D. Glover ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Dna Binding ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cellular Proliferation ◽  
Expression Patterns ◽  
Proliferating Cells ◽  
Cycle Progression ◽  
Pocket Proteins

The cellular transcription factor DRTF1/E2F is implicated in the control of early cell cycle progression due to its interaction with important regulators of cellular proliferation, such as pocket proteins (for example, the retinoblastoma tumour suppressor gene product), cyclins and cyclin-dependent kinase subunits. In mammalian cells DRTF1/E2F is a heterodimeric DNA binding activity which arises when a DP protein interacts with an E2F protein. Here, we report an analysis of DRTF1/E2F in Drosophila cells, and show that many features of the pathway which regulate its transcriptional activity are conserved in mammalian cells, such as the interaction with pocket proteins, binding to cyclin A and cdk2, and its modulation by viral oncoproteins. We show that a Drosophila DP protein which can interact co-operatively with E2F proteins is a physiological DNA binding component of Drosophila DRTF1/E2F. An analysis of the expression patterns of a Drosophila DP and E2F protein indicated that DmDP is developmentally regulated and in later embryonic stages preferentially expressed in proliferating cells. In contrast, the expression of DmE2F-1 in late stage embryos occurs in a restricted group of neural cells, whereas in early embryos it is widely expressed, but in a segmentally restricted fashion. Some aspects of the mechanisms which integrate early cell cycle progression with the transcription apparatus are thus conserved between Drosophila and mammalian cells. The distinct expression patterns of DmDP and DmE2F-1 suggest that the formation of DP/E2F heterodimers, and hence DRTF1/E2F, is subject to complex regulatory cues.

Primase p49 mRNA expression is serum stimulated but does not vary with the cell cycle

1989 ◽  
Vol 9 (5) ◽  
pp. 1940-1945
Author(s):  
B Y Tseng ◽  
C E Prussak ◽  
M T Almazan
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Small Subunit ◽  
Mrna Levels ◽  
Proliferating Cells ◽  
Restriction Point ◽  
Serum Stimulation ◽  
G1 Cells

Expression of the small-subunit p49 mRNA of primase, the enzyme that synthesizes oligoribonucleotides for initiation of DNA replication, was examined in mouse cells stimulated to proliferate by serum and in growing cells. The level of p49 mRNA increased approximately 10-fold after serum stimulation and preceded synthesis of DNA and histone H3 mRNA by several hours. Expression of p49 mRNA was not sensitive to inhibition by low concentrations of cycloheximide, which suggested that the increase in mRNA occurred before the restriction point control for cell cycle progression described for mammalian cells and was not under its control. p49 mRNA levels were not coupled to DNA synthesis, as observed for the replication-dependent histone genes, since hydroxyurea or aphidicolin had no effect on p49 mRNA levels when added before or during S phase. These inhibitors did have an effect, however, on the stability of p49 mRNA and increased the half-life from 3.5 h to about 20 h, which suggested an interdependence of p49 mRNA degradation and DNA synthesis. When growing cells were examined after separation by centrifugal elutriation, little difference was detected for p49 mRNA levels in different phases of the cell cycle. This was also observed when elutriated G1 cells were allowed to continue growth and then were blocked in M phase with colcemid. Only a small decrease in p49 mRNA occurred, whereas H3 mRNA rapidly decreased, when cells entered G2/M. These results indicate that the level of primase p49 mRNA is not cell cycle regulated but is present constitutively in proliferating cells.

scholarly journals Absence of SKP2 expression attenuates BCR-ABL–induced myeloproliferative disease

Blood ◽  
2008 ◽  
Vol 112 (5) ◽  
pp. 1960-1970 ◽  
Author(s):  
Anupriya Agarwal ◽  
Thomas G. P. Bumm ◽  
Amie S. Corbin ◽  
Thomas O'Hare ◽  
Marc Loriaux ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Tyrosine Kinases ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Ectopic Expression ◽  
Leukemic Cells ◽  
G1 Arrest ◽  
Myeloproliferative Disease

Abstract BCR-ABL is proposed to impair cell-cycle control by disabling p27, a tumor suppressor that inhibits cyclin-dependent kinases. We show that in cell lines p27 expression is inversely correlated with expression of SKP2, the F-box protein of SCFSKP2 (SKP1/Cul1/F-box), the E3 ubiquitin ligase that promotes proteasomal degradation of p27. Inhibition of BCR-ABL kinase causes G1 arrest, down-regulation of SKP2, and accumulation of p27. Ectopic expression of wild-type SKP2, but not a mutant unable to recognize p27, partially rescues cell-cycle progression. A similar regulation pattern is seen in cell lines transformed by FLT3-ITD, JAK2V617F, and TEL-PDGFRβ, suggesting that the SKP2/p27 conduit may be a universal target for leukemogenic tyrosine kinases. Mice that received transplants of BCR-ABL–infected SKP2−/− marrow developed a myeloproliferative syndrome but survival was significantly prolonged compared with recipients of BCR-ABL-expressing SKP2+/+ marrow. SKP2−/− leukemic cells demonstrated higher levels of nuclear p27 than SKP2+/+ counterparts, suggesting that the attenuation of leukemogenesis depends on increased p27 expression. Our data identify SKP2 as a crucial mediator of BCR-ABL–induced leukemogenesis and provide the first in vivo evidence that SKP2 promotes oncogenesis. Hence, stabilization of p27 by inhibiting its recognition by SCFSKP2 may be therapeutically useful.

scholarly journals Alu RNA Modulates the Expression of Cell Cycle Genes in Human Fibroblasts

2019 ◽  
Vol 20 (13) ◽  
pp. 3315 ◽  
Author(s):  
Simona Cantarella ◽  
Davide Carnevali ◽  
Marco Morselli ◽  
Anastasia Conti ◽  
Matteo Pellegrini ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Human Fibroblasts ◽  
Rna Polymerase Iii ◽  
Protein Coding ◽  
Non Coding Rna ◽  
Genome Wide ◽  
Hela Cell Lines ◽  
Significant Enrichment ◽  
Alu Rna

Alu retroelements, whose retrotransposition requires prior transcription by RNA polymerase III to generate Alu RNAs, represent the most numerous non-coding RNA (ncRNA) gene family in the human genome. Alu transcription is generally kept to extremely low levels by tight epigenetic silencing, but it has been reported to increase under different types of cell perturbation, such as viral infection and cancer. Alu RNAs, being able to act as gene expression modulators, may be directly involved in the mechanisms determining cellular behavior in such perturbed states. To directly address the regulatory potential of Alu RNAs, we generated IMR90 fibroblasts and HeLa cell lines stably overexpressing two slightly different Alu RNAs, and analyzed genome-wide the expression changes of protein-coding genes through RNA-sequencing. Among the genes that were upregulated or downregulated in response to Alu overexpression in IMR90, but not in HeLa cells, we found a highly significant enrichment of pathways involved in cell cycle progression and mitotic entry. Accordingly, Alu overexpression was found to promote transition from G1 to S phase, as revealed by flow cytometry. Therefore, increased Alu RNA may contribute to sustained cell proliferation, which is an important factor of cancer development and progression.

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