Nucleolar RNA synthetic activity in chinese hamster cellsin vitro and the effects of actinomycin D and nogalamycin

1967 ◽  
Vol 69 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Frances E. Arrighi
Keyword(s):  
Actinomycin D ◽  
Chinese Hamster ◽  
Synthetic Activity ◽  
Nucleolar Rna

scholarly journals REPOPULATION OF THE POSTMITOTIC NUCLEOLUS BY PREFORMED RNA

1972 ◽  
Vol 53 (3) ◽  
pp. 611-623 ◽  
Author(s):  
Stephanie Gordon Phillips
Keyword(s):  
Actinomycin D ◽  
Chinese Hamster ◽  
Mitotic Cell ◽  
Fast Green ◽  
Azure B ◽  
Mouse Cells ◽  
Nucleolar Rna ◽  
L929 Mouse ◽  
Nucleolar Components ◽  
Mitotic Cells

This study is concerned with the fate of the nucleolar contents, particularly nucleolar RNA, during mitosis Mitotic cells harvested from monolayer cultures of Chinese hamster embryonal cells, KB6 (human) cells, or L929 (mouse) cells were allowed to proceed into interphase in the presence or absence (control) of 0.04–0 08 µg/ml of actinomycin D, a concentration which preferentially inhibits nucleolar (ribosomal) RNA synthesis 3 hr after mitosis, control cells had large, irregularly shaped nucleoli which stained intensely for RNA with azure B and for protein with fast green. In cells which had returned to interphase in the presence of actinomycin D, nucleoli were segregated into two components easily resolvable in the light microscope, and one of these components stained intensely for RNA with azure B. Both nucleolar components stained for protein with fast green In parallel experiments, cultures were incubated with 0.04–0 08 µg/ml actinomycin D for 3 hr before harvesting of mitotic cells, then mitotic cells were washed and allowed to return to interphase in the absence of actinomycin D. 3 hr after mitosis, nuclei of such cells were devoid of large RNA-containing structures, though small, refractile nucleolus-like bodies were observed by phase-contrast microscopy or in material stained for total protein. These experiments indicate that nucleolar RNA made several hours before mitosis persists in the mitotic cell and repopulates nucleoli when they reform after mitosis

Correlation between resistance to actinomycin D, karyology, agglutination by concanavalin A and tumorigenicity in Chinese hamster hybrid cells

1975 ◽  
Vol 18 (1) ◽  
pp. 67-77
Author(s):  
I. Imbert ◽  
Y. Barra ◽  
M. Berebbi
Keyword(s):  
Statistical Analysis ◽  
Concanavalin A ◽  
Actinomycin D ◽  
Marker Chromosome ◽  
Chinese Hamster ◽  
Inverse Correlation ◽  
Sensitive Strain ◽  
Hybrid Cells ◽  
Hybrid Line

Subclones isolated from a Chinese hamster hybrid line, derived from fusion of an actinomycin D-resistant and an actinomycin D-sensitive strain, were studied with respect to their resistance to actinomycin D, karyology, transplantability and agglutination by concanavalin A. Statistical analysis of the results allowed the establishment of a classification of the strains based on increasing resistance to actinomycin D. There appeared to be an inverse correlation between actinomycin D-resistance and tumorigenicity and a positive correlation between this resistance and the presence of a marker chromosome.

Intranuclear Accumulation of Rna Resembling the Smaller Ribosomal Rna Component

1970 ◽  
Vol 6 (1) ◽  
pp. 53-72
Author(s):  
M. E. BRAMWELL
Keyword(s):  
Ribosomal Rna ◽  
Base Composition ◽  
Actinomycin D ◽  
Total Radioactivity ◽  
16S Ribosomal Rna ◽  
Low Concentrations ◽  
Rapid Accumulation ◽  
Nuclear Rna ◽  
Step Down ◽  
Nucleolar Rna

A study was made of the nuclear RNA in HeLa cells with particular reference to the rapidly labelled fractions. It was found that if cells were incubated at a high density, that is, under ‘step-down’ conditions, there was a rapid accumulation of RNA in the nucleus. The fraction of the nuclear RNA which includes rapidly labelled RNA and which binds tightly to columns of methylated albumin on kieselguhr increased in amount and reached levels which permitted enough of the material to be isolated for direct measurement of its base composition. This was found to be very similar to that of 16s ribosomal RNA. When cells growing logarithmically were treated with low concentrations of actinomycin D and then incubated in the presence of [3H]uridine it was found that an RNA fraction which bound tightly to methylated albumin on kieselguhr again accumulated in the nucleus. This fraction resembled that which accumulated under ‘step-down’ conditions. It contained over 85% of the total radioactivity in the nuclear RNA and again had a base composition very similar to 16s ribosomal RNA. Since nucleolar RNA synthesis was inhibited by the concentrations of actinomycin D used, it appeared that an RNA closely resembling 16s ribosomal RNA was synthesized outside the nucleolus. Sedimentation patterns on sucrose density gradients and thermal denaturation profiles lent support to the view that the RNA which binds tightly to columns of methylated albumin on kieselguhr probably represents ‘nascent’ 16s ribosomal RNA.

scholarly journals Effects of Actinomycin D on Spermatogenesis in the Chinese Hamster

1973 ◽  
Vol 8 (3) ◽  
pp. 335-349 ◽  
Author(s):  
Wayne J. Barcellona ◽  
B. R. Brinkley
Keyword(s):  
Actinomycin D ◽  
Chinese Hamster

Mutational Extinction Induced by Sequential X Irradiation and Actinomycin D Treatments in Chinese Hamster Ovary Cells

1986 ◽  
Vol 107 (2) ◽  
pp. 216
Author(s):  
N. Tokita ◽  
M. A. MacInnes ◽  
M. E. Wilder ◽  
D. J. Chen ◽  
S. G. Carpenter ◽  
...  
Keyword(s):  
Chinese Hamster Ovary ◽  
Actinomycin D ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
X Irradiation

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.

In vitro synthesis of β-galactosidase by membrane fractions of Escherichia coli

1970 ◽  
Vol 48 (8) ◽  
pp. 893-907 ◽  
Author(s):  
W. Chefurka ◽  
A. Yapo ◽  
B. Nisman
Keyword(s):  
Escherichia Coli ◽  
Actinomycin D ◽  
Heavy Fraction ◽  
Synthetic Activity ◽  
In Vitro Synthesis ◽  
Absolute Requirement ◽  
Discontinuous Sucrose Gradient ◽  
Reconstituted System ◽  
High Concentrations

The induction of β-galactosidase by a membranous fraction P1, prepared by digitonin lysis of spheroplasts of Escherichia coli, was studied in vitro. Electron micrographs of P1 show it to be a heterogeneous mixture of smooth vesicles, rough vesicles, rough vesicles attached to DNA, and ribosomes attached to DNA. P1 was subfractionated by differential centrifugation into an active heavy fraction, P4, and a relatively inactive light fraction, Pm. The P4 fraction consisted mainly of rough vesicles while the Pm fraction consisted mainly of smooth vesicles, but also of some rough vesicles. These vesicles of the Pm fraction were further separated by discontinuous sucrose gradient centrifugation.The induction of β-galactosidase by P1, P4, and Pm fractions was not related to mild contamination by unbroken viable spheroplasts. It was only partially sensitive to DNase and RNase. High concentrations of actinomycin D were required for complete inhibition of activity. This suggests that the transcription and translation components were shielded by the membranes. The synthetic activity of Pm was enhanced by fortification with DNA and/or S30. Only lac-containing DNA was active. The induction of β-galactosidase by this reconstituted system showed an absolute requirement for Pm membranes and for the inducer but only a partial requirement for nucleoside triphosphates. It was completely inhibited by puromycin and chloramphenicol.

Induction of the bystander effect in Chinese hamster V79 cells by actinomycin D

2011 ◽  
Vol 202 (3) ◽  
pp. 178-185 ◽  
Author(s):  
Cuihong Jin ◽  
Shengwen Wu ◽  
Xiaobo Lu ◽  
Qiufang Liu ◽  
Ming Qi ◽  
...  
Keyword(s):  
Actinomycin D ◽  
Bystander Effect ◽  
Chinese Hamster ◽  
V79 Cells ◽  
Chinese Hamster V79 Cells

scholarly journals LIGHT AND ELECTRON MICROSCOPIC RADIOAUTOGRAPHY OF HEPATIC CELL NUCLEOLI IN MICE TREATED WITH ACTINOMYCIN D

1967 ◽  
Vol 33 (3) ◽  
pp. 489-496 ◽  
Author(s):  
J. C. H. de Man ◽  
N. J. A. Noorduyn
Keyword(s):  
Orotic Acid ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Electron Microscopic ◽  
Granular Component ◽  
Hepatic Cells ◽  
Progressive Loss ◽  
Nucleolar Rna ◽  
Silver Grains ◽  
Electron Microscopic Radioautography

Nucleolar partition induced by actinomycin D was used to demonstrate some aspects of nucleolar RNA synthesis and release in mouse hepatic cells, with light and electron microscopic radioautography. The effect of the drug on RNA synthesis and nucleolar morphology was studied when actinomycin D treatment preceded labeling with tritiated orotic acid. Nucleolar partition, consisting of a segegration into granular and fibrillar parts was visible if a dosage of 25 µg of actinomycin D was used, but nucleolar RNA was still synthesized. After a dosage of 400 µg of actinomycin D, nucleolar RNA synthesis was completely stopped If labeling with tritiated orotic acid preceded treatment with 400 µg of actinomycin D, labeled nucleolar RNA was present 15 min after actinomycin D treatment while high resolution radioautography showed an association of silver grains with the granular component. At 30 min after actinomicyn D treatment all labeling was lost. Since labeling was associated with the granular component the progressive loss of label as a result of actinomycin D treatment indicated a release of nucleolar granules. The correlation between this release and the loss of 28S RNA from actinomycin D treated nucleoli as described in the literature is discussed.

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