scholarly journals Changes in the distribution of a major fibroblast protein, fibronectin, during mitosis and interphase

1977 ◽  
Vol 74 (2) ◽  
pp. 453-467 ◽  
Author(s):  
S Stenman ◽  
J Wartiovaara ◽  
A Vaheri
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Growth Control ◽  
Structural Role ◽  
Fibrillar Material ◽  
Interphase Cells ◽  
Dividing Cells ◽  
Mitotic Cells ◽  
In Cells

The distribution of a major fibroblast protein, fibronectin, was studied by immunofluorescence and immunoscanning electron microscopy in cultures of human and chicken fibroblasts during different phases of the cell cycle. The main findings were: (a) In interphase cells, the intensity of surface-associated fibronectin fluorescence correlated with that of intracellular fibronectin fluorescence. (b) The intensity of the fluorescence of both surface-associated and intracellular fibronectins was not changed in cells that were synthesizing DNA. (c) Mitotic cells had reduced amounts of surface-associated but not of intracellular fibronectin. The surface fibronectin that remained on meta-, ana-, or telophase cells had a distinct punctate distribution and was also localized to strands attaching the cells to the substratum. Fibronectin strands first reappeared on the surface of flattening cytoplasmic parts of telophase cells. (d) Fibronectin was also detected in extracellular fibrillar material on the growth substratum, particularly around dividing cells. Thus, surface-associated fibrillar fibronectin was present during G(1), S, and G(2) but in cells undergoing mitosis the distribution was altered and the amount appeared to be reduced. The observations on the distribution of surface-associated fibronectin suggest that rather than being involved in growth control this fibronectin plays a structural role in interactions of cells with the environment.

scholarly journals Accumulation of adrenocorticotropin secretory granules in the midbody of telophase AtT20 cells: evidence that secretory granules move anterogradely along microtubules

1987 ◽  
Vol 104 (4) ◽  
pp. 1047-1057 ◽  
Author(s):  
J Tooze ◽  
B Burke
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Mitotic Spindle ◽  
Secretory Granules ◽  
Thin Sections ◽  
Large Numbers ◽  
Golgi Region ◽  
Interphase Cells ◽  
Immunofluorescence Labeling ◽  
Mitotic Cells

During the cell cycle the distribution of the ACTH-containing secretory granules in AtT20 cells, as revealed by immunofluorescence labeling and electron microscopy of thin sections, undergoes a cycle of changes. In interphase cells the granules are concentrated in the Golgi region, where they form, and also at the tips of projections from the cells, where they accumulate. These projections contain many microtubules extending to their tips. During metaphase and anaphase the granules are randomly distributed in the cytoplasm of the rounded-up mitotic cells. On entry into telophase there is a rapid and striking redistribution of the granules, which accumulate in large numbers in the midbody as it develops during cytokinesis. This accumulation of secretory granules in the midbody is dependent upon the presence of microtubules. The changing pattern of distribution of the secretory granules during the cell cycle fulfills the predictions of a model envisaging first that secretory granules associate with and move along interphase microtubules in a net anterograde direction away from the centrioles, and secondly that they do not associate with microtubules of the mitotic spindle during metaphase and anaphase.

scholarly journals REPOPULATION OF POSTMITOTIC NUCLEOLI BY PREFORMED RNA

1973 ◽  
Vol 58 (1) ◽  
pp. 54-63 ◽  
Author(s):  
David M. Phillips ◽  
Stephanie Gordon Phillips
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Normal Morphology ◽  
L929 Cells ◽  
Full Cell ◽  
Nucleolar Rna ◽  
Mitotic Cells

The reconstruction of the nucleolus after mitosis was analyzed by electron microscopy in cultured mammalian (L929) cells in which nucleolar RNA synthesis was inhibited for a 3 h period either after or before mitosis. When synchronized mitotic cells were plated into a concentration of actinomycin D sufficient to block nucleolar RNA synthesis preferentially, nucleoli were formed at telophase as usual. 3 h after mitosis, these nucleoli had fibrillar and particulate components and possessed the segregated appearance characteristic of nucleoli of actinomycin D-treated cells. Cells in which actinomycin D was present for the last 3 h preceding mitosis did not form nucleoli by 3 h after mitosis though small fibrillar prenucleolar bodies were detectable at this time. These bodies subsequently grew in size and eventually acquired a particulate component. It took about a full cell cycle before nucleoli of these cells were completely normal in appearance. Thus, nucleolar RNA synthesis after mitosis is not necessary for organization of nucleoli after mitosis. However, inhibition of nucleolar RNA synthesis before mitosis renders the cell incapable of forming nucleoli immediately after mitosis. If cells are permitted to resume RNA synthesis after mitosis, they eventually regain nucleoli of normal morphology.

scholarly journals CENP-C is required for maintaining proper kinetochore size and for a timely transition to anaphase.

1994 ◽  
Vol 125 (3) ◽  
pp. 531-545 ◽  
Author(s):  
J Tomkiel ◽  
C A Cooke ◽  
H Saitoh ◽  
R L Bernat ◽  
W C Earnshaw
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Immunoelectron Microscopy ◽  
Indirect Immunofluorescence ◽  
Critical Role ◽  
Cell Cycle Checkpoint ◽  
Metaphase Arrest ◽  
Kinetochore Assembly ◽  
Cycle Checkpoint ◽  
In Cells

The human autoantigen CENP-C has been demonstrated by immunoelectron microscopy to be a component of the inner kinetochore plate. Here we have used antibodies raised against various portions of CENP-C to probe its function in mitosis. We show that nuclear microinjection of anti-CENP-C antibodies during interphase causes a transient arrest at the following metaphase. Injection of the same antibodies after the initiation of prophase, however, does not disrupt mitosis. Correspondingly, indirect immunofluorescence using affinity-purified human anti-CENP-C antibodies reveals that levels of CENP-C staining are reduced at centromeres in cells that were injected during interphase, but appear unaffected in cells which were injected during mitosis. Thus, we suggest that the injected antibodies cause metaphase arrest by reducing the amount of CENP-C at centromeres. Examination of kinetochores in metaphase-arrested cells by electron microscopy reveals that the number of trilaminar structures is reduced. More surprisingly, the few remaining kinetochores in these cells retain a normal trilaminar morphology but are significantly reduced in diameter. In cells arrested for extended periods, these small kinetochores become disrupted and apparently no longer bind microtubules. These observations are consistent with an involvement of CENP-C in kinetochore assembly, and suggest that CENP-C plays a critical role in both establishing and/or maintaining proper kinetochore size and stabilizing microtubule attachments. These findings also support the idea that proper assembly of kinetochores may be monitored by the cell cycle checkpoint preceding the transition to anaphase.

Cellular compartmentalization of protein kinase activity during the cell cycle

1987 ◽  
Vol 65 (12) ◽  
pp. 1070-1079
Author(s):  
Anna A. Fabisz-Kijowska ◽  
Katherine Lumley-Sapanski ◽  
Margaret S. Halleck ◽  
Robert A. Schlegel
Keyword(s):  
Cell Cycle ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein Kinase Activity ◽  
Culture Cells ◽  
Nuclear Extracts ◽  
Interphase Cells ◽  
Cellular Compartmentalization ◽  
Mitotic Cells

The quantities and types of protein kinases found in the cytoplasmic and nuclear or chromosomal compartments of interphase and mitotic human culture cells were compared. Using histone as substrate, the total quantity of kinases recovered from cytoplasmic and chromosomal fractions of mitotic cells was several times greater than from cytoplasmic and nuclear fractions of interphase cells. In both mitotic and interphase cells, more activity was recovered from cytoplasmic fractions than from chromosomal or nuclear fractions, respectively. When activity against various substrates was examined, mitotic chromosomal extracts were found to display the greatest preference for the H1 fraction of histones. Neither cytoplasmic nor chromosomal fractions from mitotic cells exhibited enhanced activity in the presence of cAMP, whereas the activity of both cytoplasmic and nuclear fractions of interphase cells was enhanced. Protein kinases, previously identified by nondenaturing polyacrylamide gel electrophoresis as present in the cytoplasmic fraction of mitotic but not interphase cells, were also present in chromosomal fractions of mitotic cells; only one of these kinases may be present in nuclear extracts of interphase cells. In addition, the profiles of nuclear extracts of interphase cells differ from their cytoplasmic fractions. These results indicate that there are protein kinases which are restricted to the mitotic phase of the cell cycle and that they apparently partition between the cytoplasmic and chromosomal compartments of cells in mitosis.

scholarly journals Tubulin dynamics in cultured mammalian cells.

1984 ◽  
Vol 99 (6) ◽  
pp. 2175-2186 ◽  
Author(s):  
W M Saxton ◽  
D L Stemple ◽  
R J Leslie ◽  
E D Salmon ◽  
M Zavortink ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Indirect Immunofluorescence ◽  
Mammalian Cells ◽  
Temporal Patterns ◽  
Apparent Difference ◽  
Rapid Phase ◽  
Cell Cycle Stage ◽  
Interphase Cells ◽  
Mitotic Cells

Bovine neurotubulin has been labeled with dichlorotriazinyl-aminofluorescein (DTAF-tubulin) and microinjected into cultured mammalian cells strains PTK1 and BSC. The fibrous, fluorescence patterns that developed in the microinjected cells were almost indistinguishable from the pattern of microtubules seen in the same cells by indirect immunofluorescence. DTAF-tubulin participated in the formation of all visible, microtubule-related structures at all cell cycle stages for at least 48 h after injection. Treatments of injected cells with Nocodazole or Taxol showed that DTAF-tubulin closely mimicked the behavior of endogenous tubulin. The rate at which microtubules incorporated DTAF-tubulin depended on the cell-cycle stage of the injected cell. Mitotic microtubules became fluorescent within seconds while interphase microtubules required minutes. Studies using fluorescence redistribution after photobleaching confirmed this apparent difference in tubulin dynamics between mitotic and interphase cells. The temporal patterns of redistribution included a rapid phase (approximately 3 s) that we attribute to diffusion of free DTAF-tubulin and a second, slower phase that seems to represent the exchange of bleached DTAF-tubulin in microtubules with free, unbleached DTAF-tubulin. Mean half times of redistribution were 18-fold shorter in mitotic cells than they were in interphase cells.

scholarly journals A Preliminary Study on the Relationship between Micronucleus Formation and Cell Cycle

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Ku Weihao
Keyword(s):  
Cell Cycle ◽  
Micronucleus Formation ◽  
Abnormal Structure ◽  
Interphase Cells ◽  
Dividing Cells ◽  
Chemical Factors ◽  
Preliminary Study ◽  
Physical And Chemical ◽  
The Relationship

Micronucleus is an abnormal structure in eukaryotic cells. It is the result of various physical and chemical factors,such as radiation and chemical drugs acting on dividing cells. It is generally believed that micronuclei are originatedin backward chromosomes and fragments that have lost centromere and are formed at the end of mitosis. However,other experiments suggest that interphase cells can also form micronuclei. In this study, human peripheral bloodlymphocytes were cultured in vitro and cyclophosphamide 20 ug/ml was injected at specifi c times of the cell cycle toobserve the relationship between micronuclei formation and cell cycle. The experimental results confi rmed that thecell cycle micronucleus formation.

Domain-specific changes of ciliary striated rootlets during the cell cycle in the hypotrich ciliate Paraurostyla weissei

1990 ◽  
Vol 96 (4) ◽  
pp. 617-630
Author(s):  
MARIA JERKA-DZIADOSZ
Keyword(s):  
Cell Cycle ◽  
Basal Body ◽  
Polyclonal Antibody ◽  
Paramecium Tetraurelia ◽  
Site Specific ◽  
Domain Specific ◽  
Interphase Cells ◽  
Cr System ◽  
The Right ◽  
In Cells

The dynamics of striated ciliary rootlets (cr) during development of ciliary structures in cells of the hypotrich ciliate Paraurostyla weissei was studied by immunostaining with polyclonal antibody raised against isolated cr of Paramecium tetraurelia. Wildtype cells and two mutants: mlm/pl showing multiple left marginal cirri and mlm/pl showing in addition a certain degree of pattern lability were used to study the boundaries of particular cortex domains. In interphase cells, cr are attached to all left marginal and caudal cirri and to only the posterior third of the right marginal cirri, cr appear in all nonoral primordia during the first wave of basal body proliferation. After nucleation and early elongation of cr, some cr undergo site-specific regression or stabilization. The spatial deployment of these different modes of development corresponds to specific cortical domains. In mlm/pl mutants, where specific cortical domains are broadened, changes in the cr system are characteristic for a given domain, regardless of its broadening, but boundaries between adjacent domains are weakened.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

Revisiting staining of biological samples for electron microscopy: perspectives for recent research

2021 ◽  
Author(s):  
Maren T. Kuchenbrod ◽  
Ulrich S. Schubert ◽  
Rainer Heintzmann ◽  
Stephanie Hoeppener
Keyword(s):  
Electron Microscopy ◽  
Biological Samples ◽  
Active Sites ◽  
In Cells

This review revisits staining protocols for electron microscopy focussing on the visualization of active sites, i.e. enzymes, metabolites or proteins, in cells and tissues, which were never established as standard protocols in electron microscopy.

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