scholarly journals THE STRUCTURE AND FUNCTION OF CENTRIOLES AND THEIR SATELLITES IN THE JELLYFISH PHIALIDIUM GREGARIUM

1964 ◽  
Vol 21 (3) ◽  
pp. 465-479 ◽  
Author(s):  
Daniel Szollosi
Keyword(s):  
Cell Cycle ◽  
Structure And Function ◽  
Developmental Phase ◽  
Circular Region ◽  
Axial Filament ◽  
Thin Sections ◽  
Cell Life ◽  
Distal Centriole ◽  
And Function ◽  
Spindle Fibers

Testes of jellyfish Phialidium gregarium were fixed in 2 per cent OsO4 in Veronal-acetate buffer at pH 7.4. Thin sections showed that in young spermatids the spindle fibers of the last maturation division are attached to satellites of the filament-forming centriole. In more mature spermatids this attachment is not observed. During the developmental phase, nine satellites can be observed emanating from the interspaces between the nine tubular triplets of this centriole. A circular region on each of the enlarged distal ends of the satellites attaches them to the cell membrane. The satellites apparently provide a firm anchor for the axial filament. Each of the epithelial cells covering the testis produces a single long flagellum. On the filament-forming centriole often a satellite can be observed to which tubules are attached. These tubules are 180 A in diameter and probably represent remnants of spindle fibers. It is suggested that the distal centriole has the ability to form several satellites or appendages at appropriate times during the cell cycle. These satellites are distinct from the daughter centrioles in that they are supportive structures: in certain phases of cell life, spindle fibers may attach to them, while in other instances the distal centriole and the flagellum it is forming are anchored by them.

Review: The Dynamics of the Nuclear Lamins during the Cell Cycle— Relationship between Structure and Function

2000 ◽  
Vol 129 (2-3) ◽  
pp. 324-334 ◽  
Author(s):  
Robert D. Moir ◽  
Timothy P. Spann ◽  
Reynold I. Lopez-Soler ◽  
Miri Yoon ◽  
Anne E. Goldman ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Structure And Function ◽  
Nuclear Lamins ◽  
And Function

scholarly journals Drosophila dCBP Is Involved in Establishing the DNA Replication Checkpoint

2006 ◽  
Vol 27 (1) ◽  
pp. 135-146 ◽  
Author(s):  
Sarah Smolik ◽  
Kristen Jones
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Arrest ◽  
Chromatin Structure ◽  
Genetic Interaction ◽  
Structure And Function ◽  
Replication Checkpoint ◽  
Cycle Arrest ◽  
Dna Replication Checkpoint ◽  
And Function

ABSTRACT The CBP/p300 family of proteins comprises related acetyltransferases that coactivate signal-responsive transcription. Recent evidence suggests that p300/CBP may also interact directly with complexes that mediate different aspects of DNA metabolism such as replication and repair. In this report, we show that loss of dCBP in Drosophila cells and eye discs results in a defect in the cell cycle arrest induced by stalled DNA replication. We show that dCBP and the checkpoint kinase Mei-41 can be found together in a complex and, furthermore, that dCBP has a genetic interaction with mei-41 in the response to stalled DNA replication. These observations suggest a broader role for the p300/CBP acetyltransferases in the modulation of chromatin structure and function during DNA metabolic events as well as for transcription.

scholarly journals STUDIES ON NUCLEAR STRUCTURE AND FUNCTION IN TETRAHYMENA PYRIFORMIS

1969 ◽  
Vol 42 (3) ◽  
pp. 673-682 ◽  
Author(s):  
Martin A. Gorovsky ◽  
John Woodard
Keyword(s):  
Cell Cycle ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Tetrahymena Pyriformis ◽  
Small Population ◽  
Structure And Function ◽  
Camera Lucida ◽  
Frequency Distributions ◽  
And Function ◽  
Growth And Reproduction

Tetrahymena in the log phase of growth were pulse labeled with uridine-3H, fixed in acetic-alcohol, extracted with DNase, and embedded in Epon. 0.5-µ sections were cut, coated with Kodak NTB-2 emulsion, and developed after suitable exposures. Grains were counted above macronuclei, above 1000 micronuclei, and above 1000 micronucleus-sized "blanks" which were situated next to micronuclei in the visual field by means of a camera lucida. An analysis of grain counts showed that micronuclei were less than ½000 as active as macronuclei on the basis of grains per nucleus. Since micronuclei contained, on the average, about ½0 as much DNA as macronuclei, micronuclear DNA had less than 1% of the specific activity of macronuclear DNA in RNA synthesis. However, even this small amount of apparent incorporation was not significantly different from zero. Comparisons of the frequency distributions of labeled micronuclei with those of micronuclear "blanks" showed no evidence of a small population of labeled nuclei such as might be expected if micronuclei synthesized RNA for only a brief portion of the cell cycle. We conclude from these studies that there is no detectable RNA synthesis in Tetrahymena micronuclei during vegetative growth and reproduction.

scholarly journals Exploring the evolutionary history of centrosomes

2014 ◽  
Vol 369 (1650) ◽  
pp. 20130453 ◽  
Author(s):  
Juliette Azimzadeh
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Evolutionary History ◽  
Structural Diversity ◽  
Structure And Function ◽  
Different Types ◽  
History Of ◽  
Tight Association ◽  
And Function ◽  
Molecular Components

The centrosome is the main organizer of the microtubule cytoskeleton in animals, higher fungi and several other eukaryotic lineages. Centrosomes are usually located at the centre of cell in tight association with the nuclear envelope and duplicate at each cell cycle. Despite a great structural diversity between the different types of centrosomes, they are functionally equivalent and share at least some of their molecular components. In this paper, we explore the evolutionary origin of the different centrosomes, in an attempt to understand whether they are derived from an ancestral centrosome or evolved independently from the motile apparatus of distinct flagellated ancestors. We then discuss the evolution of centrosome structure and function within the animal lineage.

scholarly journals A Proximity Mapping Journey into the Biology of the Mammalian Centrosome/Cilium Complex

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1390 ◽  
Author(s):  
Melis Dilara Arslanhan ◽  
Dila Gulensoy ◽  
Elif Nur Firat-Karalar
Keyword(s):  
Cell Cycle ◽  
Neurodegenerative Diseases ◽  
Cell Polarity ◽  
Primary Cilium ◽  
Developmental Disorders ◽  
Structure And Function ◽  
Temporal Interaction ◽  
And Function ◽  
Structure And Functions

The mammalian centrosome/cilium complex is composed of the centrosome, the primary cilium and the centriolar satellites, which together regulate cell polarity, signaling, proliferation and motility in cells and thereby development and homeostasis in organisms. Accordingly, deregulation of its structure and functions is implicated in various human diseases including cancer, developmental disorders and neurodegenerative diseases. To better understand these disease connections, the molecular underpinnings of the assembly, maintenance and dynamic adaptations of the centrosome/cilium complex need to be uncovered with exquisite detail. Application of proximity-based labeling methods to the centrosome/cilium complex generated spatial and temporal interaction maps for its components and provided key insights into these questions. In this review, we first describe the structure and cell cycle-linked regulation of the centrosome/cilium complex. Next, we explain the inherent biochemical and temporal limitations in probing the structure and function of the centrosome/cilium complex and describe how proximity-based labeling approaches have addressed them. Finally, we explore current insights into the knowledge we gained from the proximity mapping studies as it pertains to centrosome and cilium biogenesis and systematic characterization of the centrosome, cilium and centriolar satellite interactomes.

scholarly journals Archaeal DNA Replication

2020 ◽  
Vol 74 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Mark D. Greci ◽  
Stephen D. Bell
Keyword(s):  
Cell Cycle ◽  
Information Processing ◽  
Dna Replication ◽  
Structure And Function ◽  
Dna Unwinding ◽  
Macromolecular Assemblies ◽  
Replicative Polymerases ◽  
Dna Replication Origins ◽  
And Function ◽  
Archaeal Dna Replication

It is now well recognized that the information processing machineries of archaea are far more closely related to those of eukaryotes than to those of their prokaryotic cousins, the bacteria. Extensive studies have been performed on the structure and function of the archaeal DNA replication origins, the proteins that define them, and the macromolecular assemblies that drive DNA unwinding and nascent strand synthesis. The results from various archaeal organisms across the archaeal domain of life show surprising levels of diversity at many levels—ranging from cell cycle organization to chromosome ploidy to replication mode and nature of the replicative polymerases. In the following, we describe recent advances in the field, highlighting conserved features and lineage-specific innovations.

scholarly journals Structure and function of ribosomes in cell cycle and embryonal differentiation

1980 ◽  
Vol 47 (3-4) ◽  
pp. 321-334 ◽  
Author(s):  
Harry Manelli ◽  
Umberto Ferrini
Keyword(s):  
Cell Cycle ◽  
Structure And Function ◽  
And Function

scholarly journals Inhibition of Uncoupling Protein 2 Enhances the Radiosensitivity of Cervical Cancer Cells by Promoting the Production of Reactive Oxygen Species

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Cui Hua Liu ◽  
Zhe Hao Huang ◽  
Xin Yu Dong ◽  
Xin Qiang Zhang ◽  
Yuan Hang Li ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Cycle ◽  
Cervical Cancer ◽  
Hela Cells ◽  
Uncoupling Protein ◽  
Structure And Function ◽  
Oxygen Species ◽  
Mitochondrial Structure ◽  
Cervical Cancer Cells ◽  
And Function

Objective. The mechanism of enhanced radiosensitivity induced by mitochondrial uncoupling protein UCP2 was investigated in HeLa cells to provide a theoretical basis as a novel target for cervical cancer treatment. Methods. HeLa cells were irradiated with 4 Gy X-radiation at 1.0 Gy/min. The expression of UCP2 mRNA and protein was assayed by real-time quantitative polymerase chain reaction and western blotting. UCP2 siRNA and negative control siRNA fragments were constructed and transfected into HeLa cells 24 h after irradiation. The effect of UCP2 silencing and irradiation on HeLa cells was determined by colony formation, CCK-8 cell viability, γH2AX immunofluorescence assay of DNA damage, Annexin V-FITC/PI apoptosis assay, and propidium iodide cell cycle assay. The effects on mitochondrial structure and function were investigated with fluorescent probes including dichlorodihydrofluorescein diacetate (DCFH-DA) assay of reactive oxygen species (ROS), rhodamine 123, and MitoTracker Green assay of mitochondrial structure and function. Results. Irradiation upregulated UCP2 expression, and UCP2 knockdown decreased the survival of irradiated HeLa cells. UCP2 silencing sensitized HeLa cells to irradiation-induced DNA damage and led to increased apoptosis, cell cycle arrest in G2/M, and increased mitochondrial ROS. Increased radiosensitivity was associated with an activation of P53, decreased Bcl-2, Bcl-xl, cyclin B, CDC2, Ku70, and Rad51 expression, and increased Apaf-1, cytochrome c, caspase-3, and caspase-9 expression. Conclusions. UCP2 inhibition augmented the radiosensitivity of cervical cancer cells, and it may be a potential target of radiotherapy of advanced cervical cancer.

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