scholarly journals Centriole triplet microtubules are required for stable centriole formation and inheritance in human cells

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Jennifer T Wang ◽  
Dong Kong ◽  
Christian R Hoerner ◽  
Jadranka Loncarek ◽  
Tim Stearns
Keyword(s):  
Cell Cycle ◽  
De Novo ◽  
Family Members ◽  
Human Cells ◽  
Null Mutant ◽  
Futile Cycle ◽  
Unicellular Eukaryotes ◽  
Microtubule Formation ◽  
Paclitaxel Treatment

Centrioles are composed of long-lived microtubules arranged in nine triplets. However, the contribution of triplet microtubules to mammalian centriole formation and stability is unknown. Little is known of the mechanism of triplet microtubule formation, but experiments in unicellular eukaryotes indicate that delta-tubulin and epsilon-tubulin, two less-studied tubulin family members, are required. Here, we report that centrioles in delta-tubulin and epsilon-tubulin null mutant human cells lack triplet microtubules and fail to undergo centriole maturation. These aberrant centrioles are formed de novo each cell cycle, but are unstable and do not persist to the next cell cycle, leading to a futile cycle of centriole formation and disintegration. Disintegration can be suppressed by paclitaxel treatment. Delta-tubulin and epsilon-tubulin physically interact, indicating that these tubulins act together to maintain triplet microtubules and that these are necessary for inheritance of centrioles from one cell cycle to the next.

scholarly journals Centriole triplet microtubules are required for stable centriole formation and inheritance in human cells

2017 ◽  
Author(s):  
Jennifer T. Wang ◽  
Dong Kong ◽  
Christian R. Hoerner ◽  
Jadranka Loncarek ◽  
Tim Stearns
Keyword(s):  
Cell Cycle ◽  
De Novo ◽  
Human Cells ◽  
Futile Cycle ◽  
Unicellular Eukaryotes ◽  
Paclitaxel Treatment ◽  
Microtubule Structure ◽  
In Cells

SummaryCentrioles are composed of long-lived microtubules arranged in nine triplets. In unicellular eukaryotes, loss of the noncanonical tubulins, delta-tubulin and epsilon tubulin, result in loss of the triplet microtubule structure. However, the contribution of triplet microtubules to mammalian centriole formation and stability is unknown. Here, we report the first characterization of delta-tubulin and epsilon-tubulin null human cells. Centrioles in cells lacking either delta-tubulin or epsilon-tubulin lack triplet microtubules and fail to undergo centriole maturation. These aberrant centrioles are formed de novo each cell cycle, but are unstable and do not persist to the next cell cycle, leading to a futile cycle of centriole formation and disintegration. Disintegration can be suppressed by paclitaxel treatment. Delta-tubulin and epsilon-tubulin physically interact, indicating that these tubulins act together to maintain triplet microtubules and that these are necessary for inheritance of centrioles from one cell cycle to the next.

Mycotoxin Citrinin Induced Cell Cycle G2/M Arrest and Numerical Chromosomal Aberration Associated with Disruption of Microtubule Formation in Human Cells

2010 ◽  
Vol 119 (1) ◽  
pp. 84-92 ◽  
Author(s):  
Chia-Hao Chang ◽  
Feng-Yih Yu ◽  
Ting-Shun Wu ◽  
Li-Ting Wang ◽  
Biing-Hui Liu
Keyword(s):  
Cell Cycle ◽  
Chromosomal Aberration ◽  
Human Cells ◽  
Microtubule Formation

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.

Cytotoxic, genotoxic and cell-cycle disruptive effects of thio-dimethylarsinate in cultured human cells and the role of glutathione

2008 ◽  
Vol 228 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Takafumi Ochi ◽  
Kayoko Kita ◽  
Toshihide Suzuki ◽  
Alice Rumpler ◽  
Walter Goessler ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Human Cells ◽  
Cultured Human Cells

scholarly journals Target Gene Specificity of E2F and Pocket Protein Family Members in Living Cells

2000 ◽  
Vol 20 (16) ◽  
pp. 5797-5807 ◽  
Author(s):  
Julie Wells ◽  
Kathryn E. Boyd ◽  
Christopher J. Fry ◽  
Stephanie M. Bartley ◽  
Peggy J. Farnham
Keyword(s):  
Cell Cycle ◽  
Target Gene ◽  
Target Genes ◽  
Protein Complexes ◽  
Current Model ◽  
Family Members ◽  
Living Cells ◽  
Gene Promoters ◽  
Pocket Protein ◽  
Protein Dna Interactions

ABSTRACT E2F-mediated transcription is thought to involve binding of an E2F-pocket protein complex to promoters in the G0 phase of the cell cycle and release of the pocket protein in late G1, followed by release of E2F in S phase. We have tested this model by monitoring protein-DNA interactions in living cells using a formaldehyde cross-linking and immunoprecipitation assay. We find that E2F target genes are bound by distinct E2F-pocket protein complexes which change as cells progress through the cell cycle. We also find that certain E2F target gene promoters are bound by pocket proteins when such promoters are transcriptionally active. Our data indicate that the current model applies only to certain E2F target genes and suggest that Rb family members may regulate transcription in both G0 and S phases. Finally, we find that a given promoter can be bound by one of several different E2F-pocket protein complexes at a given time in the cell cycle, suggesting that cell cycle-regulated transcription is a stochastic, not a predetermined, process.

Replication and transcription sites are colocalized in human cells

1994 ◽  
Vol 107 (2) ◽  
pp. 425-434 ◽  
Author(s):  
A.B. Hassan ◽  
R.J. Errington ◽  
N.S. White ◽  
D.A. Jackson ◽  
P.R. Cook
Keyword(s):  
Cell Cycle ◽  
Confocal Microscopy ◽  
Dna Synthesis ◽  
Fluorescent Probes ◽  
Hela Cells ◽  
Nuclear Architecture ◽  
Human Cells ◽  
Dynamic Nature ◽  
Nucleotide Triphosphates ◽  
Transcription Sites

HeLa cells synchronized at different stages of the cell cycle were permeabilized and incubated with analogues of nucleotide triphosphates; then sites of incorporation were immunolabeled with the appropriate fluorescent probes. Confocal microscopy showed that sites of replication and transcription were not diffusely spread throughout nuclei, reflecting the distribution of euchromatin; rather, they were concentrated in ‘foci’ where many polymerases act together. Transcription foci aggregated as cells progressed towards the G1/S boundary; later they dispersed and became more diffuse. Replication was initiated only at transcription sites; later, when heterochromatin was replicated in enlarged foci, these remained sites of transcription. This illustrates the dynamic nature of nuclear architecture and suggests that transcription may be required for the initiation of DNA synthesis.

Abstract 396: Regulation of Cardiomyocyte Proliferation by the Hippo Pathway and Dystrophin Complex

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Yuka Morikawa ◽  
John Leach ◽  
Todd Heallen ◽  
Ge Tao ◽  
James F Martin
Keyword(s):  
Cell Cycle ◽  
Muscular Dystrophy ◽  
Dna Synthesis ◽  
De Novo ◽  
Hippo Pathway ◽  
Myocardial Damage ◽  
Heart Regeneration ◽  
Cardiomyocyte Proliferation ◽  
Heart Repair ◽  
The Hippo Pathway

Regeneration in mammalian hearts is limited due to the extremely low renewal rate of cardiomyocytes and their inability to reenter the cell cycle. In rodent hearts, endogenous regenerative capacity exists during development but is rapidly repressed after birth, at which time growth is by hypertrophy. During the developmental and neonatal periods, heart regeneration occurs through proliferation of pre-existing cardiomyocytes. Our approach of activating heart regeneration is to uncover the mechanisms responsible for repression of cardiomyocyte proliferation. The Hippo pathway controls heart size by repressing cardiomyocyte proliferation during development. By deleting Salv , a modulator of the Hippo pathway, we found that myocardial damage in postnatal and adult hearts was repaired both anatomically and functionally. This heart repair occurred primary through proliferation of preexisting cardiomyocytes. During repair, cardiomyocytes reenter the cell cycle; de novo DNA synthesis, karyokinesis, and cytokinesis all take place. The dystrophin glycoprotein complex (DGC) is essential for muscle maintenance by anchoring the cytoskeleton and extracellular matrix. Disruption of the DGC results in muscular dystrophies, including Duchenne muscular dystrophy, resulting in both skeletal and cardiac myopathies. Recently the DGC was shown to regulate cardiomyocyte proliferation and we found that the DGC and the Hippo pathway components directly interact. To address if the DGC and the Hippo pathway coordinately regulate cardiomyocyte proliferation, we conditionally deleted Salv in the mouse model of muscular dystrophy, the mdx line. We found that simultaneous disruption of both the DGC and Hippo pathway leads an increased de novo DNA synthesis and cytokinesis in cardiomyocytes after heart damage. Our findings provide new insights into the mechanisms leading to heart repair through proliferation of endogenous cardiomyocytes.

scholarly journals Avidin inhibits PHA-induced human peripheral blood mononuclear cell proliferation

2016 ◽  
Vol 25 (1) ◽  
pp. 19-24
Author(s):  
Cicia Firakania ◽  
Indra G. Mansur ◽  
Sri W.A. Jusman ◽  
Mohamad Sadikin
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Peripheral Blood Mononuclear Cell ◽  
Mononuclear Cell ◽  
Peripheral Blood ◽  
De Novo ◽  
Human Peripheral Blood ◽  
Interleukin 2 ◽  
Peripheral Blood Mononuclear ◽  
Cell Proliferation Inhibition

Background: Cell proliferation occurs not only in normal but also in cancer cells. Most of cell proliferation inhibition can be done by inhibiting the DNA synthesis, notably by intervening the formation of purine or pyrimidine. In purine de novo synthesis, it was assumed that biotin plays a role as a coenzyme in carboxylation reaction, one of the pivotal steps in the purine de novo pathways. The aim of this study was to see the avidin potency to bind biotin and inhibit mitosis.Methods: Peripheral blood mononuclear cell (PBMC) was cultured in RPMI-1640 medium and stimulated by phytohemagglutinin (PHA) in the presence or absence of interleukin-2 (IL-2), with or without avidin. The effect of avidin addition was observed at 24, 48, and 72 hours for cell proliferation, viability, and cell cycle. Statistical analysis was done by one-way ANOVA.Results: Avidin inhibited cell proliferation and viability in culture under stimulation by PHA with and without IL-2. Cell cycle analysis showed that avidin arrested the progression of PBMC after 72 hours of culture. Most cells were found in G0/G1 phase.Conclusion: Inhibition of biotin utilization by avidin binding can halt cell proliferation.

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