scholarly journals SYNTHESIS OF PLASMA MEMBRANE-ASSOCIATED AND SECRETORY IMMUNOGLOBULIN IN DIPLOID LYMPHOCYTES

1972 ◽  
Vol 135 (1) ◽  
pp. 136-149 ◽  
Author(s):  
Richard A. Lerner ◽  
Patricia J. McConahey ◽  
Inga Jansen ◽  
Frank J. Dixon
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Plasma Membrane ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
G1 Phase ◽  
Synchronized Cells ◽  
Disappearance Time ◽  
Protein And Rna Synthesis ◽  
Secretory Immunoglobulin

The half disappearance time for detectable plasma membrane-associated and cytoplasmic immunoglobulin after treatment of continuously growing diploid lymphocytes with inhibitors of protein and RNA synthesis was studied. Also, the amount of plasma membrane-associated and cytoplasmic immunoglobulin of synchronized cells in the G1 phase of the cell cycle has been studied. Plasma membrane-associated immunoglobulin has a half disappearance time of 45 min after inhibition of protein synthesis. By contrast, after treatment of cells with actinomycin D for 24 hr, plasma membrane-associated immunoglobulin remains relatively unchanged whereas cytoplasmic immunoglobulin decreased by almost 90%. In the G1 phase of the cell cycle, plasma membrane-associated immunoglobulin and cytoplasmic immunoglobulin were 70 and 10%, respectively, of that in logarithmically growing cells, and the half disappearance of M-Ig after treatment of cells with puromycin was again 45 min. In toto, these results suggest that perhaps secreted and plasma membrane-associated immunoglobulin may be separately controlled by the cells.

scholarly journals ON THE RECOVERY OF TRANSCRIPTION AFTER INHIBITION BY ACTINOMYCIN D

1972 ◽  
Vol 55 (2) ◽  
pp. 299-309 ◽  
Author(s):  
Stanley G. Sawicki ◽  
Gabriel C. Godman
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Cell Types ◽  
Vero Cells ◽  
Sufficient Condition ◽  
Long Period ◽  
Different Cell Types ◽  
Early Restoration

After pulse exposure to concentrations of actinomycin D (AMD) sufficient to abolish transcription, Vero cells recover RNA synthesis much more rapidly than most other cell types. This is only in part attributable to the remarkable capacity of Vero very promptly to excrete bound AMD, elimination of which, although necessary, is not a sufficient condition for resurgence of RNA synthesis. After elimination of higher concentrations of AMD from Vero, although over-all RNA synthesis resumes a normal rate within 24 hr, protein synthesis lags, and a long period of division-delay ensues. Division-delay lasting 2–3 days results from exposure of Vero to doses of AMD greater than those that suppress RNA synthesis by greater than 90% (e.g. 1 µg/ml for 2 hr) but not by lower doses, which permit almost immediate reentry into the cell cycle. In contrast, although L cells recover over-all RNA synthesis very slowly after pulse treatment with AMD, resumption of protein synthesis or cell division is not comparably delayed thereafter. These and other data suggest that the early restoration of RNA synthesis in Vero after relief of inhibition by AMD is qualitatively imperfect. The results reported herein are explainable by the hypothesis that the synthesis of those species of RNA which are involved, directly or indirectly, in reactivating the transcription of genes controlling progression in the cell cycle is relatively resistant to suppression by AMD. Decay of such RNA templates and their products, which differs in different cell types during inhibition by AMD, determines the duration of division-delay.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

Wachstumsparameter in normalen und durch Actinomycin verlängerten Zellzyklen von Tetrahymena / Growth Parameters in Normal and Actinomycin-induced prolonged Cell Cycles of Tetrahymena

1969 ◽  
Vol 24 (12) ◽  
pp. 1624-1629 ◽  
Author(s):  
Günter Cleffmann
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Dna Replication ◽  
Cell Growth ◽  
Rna Synthesis ◽  
Growth Parameters ◽  
Average Duration ◽  
Cell Cycles ◽  
Growing Cell

Actinomycin in low concentration (0,2 μg/ml — 0,5 μg/ml) prolongs the average duration of the cell cycle of Tetrahymena considerably, but does not inhibit cell division completely. Some parameters of the growing cell have been tested in cell cycles extended in this way and compared to those of normally growing cells. The RNA synthesis of treated cells is reduced to such an extent that the RNA content per cell decreases during the prolonged cell cycle. Nevertheless cell growth, protein synthesis and DNA replication proceed at almost the same rate as in untreated cells. These findings indicate that the presence of actinomycin does not interfere with RNA fractions necessary for growth but reduce the synthesis of RNA fractions which are essential for cell division. Therefore a longer period is needed for their accumulation.

Investigation of cell cycle arrest effects of actinomycin D at G1 phase using proteomic methods in B104-1-1 cells

2005 ◽  
Vol 37 (9) ◽  
pp. 1921-1929 ◽  
Author(s):  
Hyae-Kyeong Kim ◽  
Mi-Young Kong ◽  
Moon-Jin Jeong ◽  
Dong-Cho Han ◽  
Jung-Do Choi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Actinomycin D ◽  
G1 Phase ◽  
Cycle Arrest ◽  
Proteomic Methods

scholarly journals Specific mRNA destabilization in Dictyostelium discoideum requires RNA synthesis.

1987 ◽  
Vol 7 (12) ◽  
pp. 4585-4588 ◽  
Author(s):  
J F Amara ◽  
H F Lodish
Keyword(s):  
Protein Synthesis ◽  
Dictyostelium Discoideum ◽  
Rna Synthesis ◽  
Protein Synthesis Inhibitors ◽  
Protein And Rna Synthesis ◽  
The Common ◽  
Mrna Destabilization ◽  
Actin Protein ◽  
Specific Mrna

We tested the effects of inhibitors of protein and RNA synthesis on the disaggregation-mediated destabilization of prespore mRNAs in Dictyostelium discoideum. Incubating disaggregated cells with daunomycin to inhibit RNA synthesis prevented the loss of prespore mRNAs, whereas the inhibitor decreased or did not affect levels of the common mRNAs CZ22 and actin. Protein synthesis inhibitors varied in their effects. Cycloheximide, which inhibited protein synthesis almost completely, prevented the loss of the prespore mRNAs, but puromycin, which inhibited protein synthesis less well, did not. These results indicate that the process of specific mRNA destabilization requires the synthesis of RNA and possibly of protein.

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.

Biotin and glucose metabolism

1970 ◽  
Vol 48 (4) ◽  
pp. 493-500 ◽  
Author(s):  
K. Dakshinamurti ◽  
L. Tarrago-Litvak ◽  
Ho Chong Hong
Keyword(s):  
Protein Synthesis ◽  
Glucose Metabolism ◽  
Pyruvate Kinase ◽  
Rna Synthesis ◽  
De Novo ◽  
Diabetic Rat ◽  
Bifunctional Enzyme ◽  
Protein And Rna Synthesis ◽  
Rat Experiments ◽  
De Novo Protein Synthesis

Biotin enhances liver glucokinase in the diabetic rat. Experiments using inhibitors of protein and RNA synthesis suggest that this is mediated through de novo protein synthesis. Biotin treatment also increases the activities of other key glycolytic kinases, phosphofructokinase and pyruvate kinase, but has no effect on a bifunctional enzyme like phosphohexose isomerase.

STUDIES ON THE MECHANISM OF ACTION OF ANGIOTENSIN ON FLUID TRANSPORT BY THE MUCOSA OF RAT DISTAL COLON

1972 ◽  
Vol 54 (3) ◽  
pp. 483-492 ◽  
Author(s):  
N. T. DAVIES ◽  
K. A. MUNDAY ◽  
B. J. PARSONS
Keyword(s):  
Protein Synthesis ◽  
Cyclic Amp ◽  
Rna Synthesis ◽  
Fluid Transport ◽  
Actinomycin D ◽  
Distal Colon ◽  
Rat Colon ◽  
Colon Mucosa ◽  
Rat Distal Colon ◽  
Stimulation Of

SUMMARY A study was made of the effects of cyclic AMP, theophylline, cycloheximide, puromycin and actinomycin D on the stimulation by angiotensin of fluid transport by sacs of rat colon mucosa. Cyclic AMP and theophylline, added together or separately, had no effect on fluid transport by colon sacs, suggesting that the stimulation of fluid transport after the application of angiotensin is not mediated through cyclic AMP. Cycloheximide and puromycin (used at concentrations which block colon protein synthesis by 50–90%) had no effect on fluid transport by control colon sacs, but completely blocked the stimulatory response of the colon to angiotensin. In contrast, actinomycin D (at a concentration which significantly inhibits RNA synthesis) did not affect fluid transport in control or angiotensin-stimulated colon sacs. The results are discussed in relation to the possibility that protein synthesis, at the stage of translation, is involved in the action of angiotensin on fluid transport by the colon.

scholarly journals The mechanism of formation of inhibitor-induced ribosome helices in Entamoeba invadens.

1975 ◽  
Vol 65 (3) ◽  
pp. 529-539 ◽  
Author(s):  
T Kusamrarn ◽  
P Sobhon ◽  
G B Bailey
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Aggregate Formation ◽  
Mechanism Of Formation ◽  
Helix Formation ◽  
Aggregation Inhibition ◽  
Chromatoid Bodies ◽  
Entamoeba Invadens ◽  
Slow Growing

Helices andaggregates of helices (chromatoid bodies) composed of ribosomelike particles appear in cysts and slow-growing trophozoites of Entamoeba invadens. We found that similar helix aggregates were formed abundantly in actively growing E. invadens trophozoites treated with a variety of direct or indirect inhibitors of protein synthesis. The inhibitor-induced helices appeared cytochemically and ultrastructurally identical to those seen in cysts. Numerous single helices and small arrays occurred randomly distributed throughout the trophozoite cytoplasm within 15 min after treatment with NaF, which rapidly and completely stopped all nucleic acid and protein synthesis. Cycloheximide (CH), which inhibited protein synthesis as effectively a NaF, stimulated aggregate formation more slowly, and only after a delay of 30-60 min. CH temporarily blocked NaF-stimulated aggregated formation. Aggregation was slowest with actinomycin-D, which strongly inhibited RNA synthesis but depressed protein synthesis only slowly. These results suggested that release of ribosomes from mRNA was required for aggregation. Inhibition by CH was reversible, and aggregates disappeared from CH-treated amebas shortly after they were transferred to inhibitor-free frowth medium. There was no evidence that helices assembled about a structural organizer within the cell or that the process involved metabloc activity. It was concluded that the inhibitor-induced helices were composed of mature, normally functional ribosomes and that helix formation was a spontaneous and reversible consequence of the accumulation withing the cell of free monosomes (or subunits) which were prevented from binding to mRNA.

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