Effects of biochemical inhibitors on positional signalling in the chick limb bud

Development ◽  
1981 ◽  
Vol 62 (1) ◽  
pp. 203-216
Author(s):  
Lawrence S. Honig ◽  
J. C. Smith ◽  
Amata Hornbruch ◽  
L. Wolpert
Keyword(s):  
Dna Synthesis ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Positional Information ◽  
Limb Bud ◽  
Limb Buds ◽  
Protein And Rna Synthesis ◽  
Zone Of Polarizing Activity ◽  
Rna And Dna Synthesis ◽  
Rna And Dna

In 3- to 4-day embryonic chick limb buds, a region at the posterior margin of the limb, the zone of polarizing activity, appears to be responsible for signalling positional information along the anteroposterior axis. Our experiments were designed to test which biosynthetic processes are required for polarizing activity. We have treated polarizing regions with biochemical inhibitors, and then assayed their abilities to induce limb reduplications when grafted into anterior sites on host limb buds, and also measured their capacities for protein, RNA, and DNA synthesis. DNA synthesis, and possibly oxidative phosphorylation, do not seem to be required for polarizing activity. But, glycolysis and protein and RNA synthesis are necessary, although not sufficient, for polarizing region activity. Activity seems particularly sensitive to inhibitors (actinomycin D and α-amanitin) of RNA synthesis.

scholarly journals Lomofungin as an inhibitor of nucleic acid synthesis in Saccharomyces cerevisiae

1974 ◽  
Vol 142 (3) ◽  
pp. 457-463 ◽  
Author(s):  
Michael Cannon ◽  
Antonio Jimenez
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Growth Conditions ◽  
Dna And Rna ◽  
Dna And Rna Synthesis ◽  
Inhibition Of Dna Synthesis ◽  
Rna And Dna Synthesis ◽  
Rna And Dna

1. The antibiotic lomofungin was found to be a potent inhibitor of both DNA and RNA synthesis in Saccharomyces cerevisiae. Under selected growth conditions inhibition of DNA synthesis by the drug preceded inhibition of RNA synthesis. 2. Although in general lomofungin inhibited synthesis of ribosomal RNA and polydisperse RNA more effectively than that of low-molecular-weight RNA, under certain conditions the drug inhibited almost completely synthesis of both 4S and 5S RNA. 3. Inhibition of both RNA and DNA synthesis may be explained if RNA synthesis is required for DNA synthesis in yeast. Alternatively, lomofungin, in addition to interacting with DNA-dependent RNA polymerase, might interfere with a component(s) of the DNA-synthetic apparatus. The drug may thus prove to be of considerable value in studies of DNA synthesis in eukaryotes.

scholarly journals RNA Synthesis in Cultures of Normal Human Peripheral Blood

Blood ◽  
1964 ◽  
Vol 24 (1) ◽  
pp. 69-75 ◽  
Author(s):  
LOIS B. EPSTEIN ◽  
FREDERICK STOHLMAN
Keyword(s):  
Dna Synthesis ◽  
Peripheral Blood ◽  
Rna Synthesis ◽  
Human Peripheral Blood ◽  
Mechanisms Of Action ◽  
Normal Human ◽  
Normal Human Peripheral Blood ◽  
Rna And Dna Synthesis ◽  
Rna And Dna

Abstract RNA and DNA synthesis were measured in cultures of normal human peripheral blood using tritiated cytidine and thymidine and autoradiographic technics. RNA synthesis preceded DNA synthesis by 24 hours. RNA synthesis occurred predominantly in the large and medium-sized "blast-like" cells, but did occur, to a lesser extent, in the small lymphocytes. RNA synthesis did not occur in the absence of phytohemagglutinin, nor did DNA synthesis. Mechanisms of action of phytohemagglutinin are discussed with particular reference to its possible antigenic nature.

EFFECT OF PROLACTIN ON NUCLEIC ACID METABOLISM DURING LACTOGENESIS IN THE RABBIT

1971 ◽  
Vol 51 (2) ◽  
pp. 265-270 ◽  
Author(s):  
A. A. SIMPSON ◽  
G. H. SCHMIDT
Keyword(s):  
Nucleic Acid ◽  
Dna Synthesis ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Acid Metabolism ◽  
Nucleic Acid Metabolism ◽  
Specific Effects ◽  
Intraductal Injection ◽  
Rna And Dna Synthesis ◽  
Rna And Dna

SUMMARY Lactogenesis was initiated by intraductal injection of prolactin into individual lobes of rabbit mammary glands previously developed by injections of oestrogen and progesterone. Nucleic acid metabolism was assessed at various times after prolactin treatment. A systemic pulse of [3H]thymidine or [3H]uridine was used to determine the specific effects of prolactin treatment on RNA and DNA synthesis and metabolism. Prolactin increased the rate of RNA synthesis. It is suggested that prolactin enhanced both the rate of RNA movement from the nucleus, and its rate of metabolism in the cytoplasm. The greatest increase in the rate of synthesis occurred in non-ribosomal RNA. Subsequent to its effect on RNA, prolactin enhanced DNA synthesis. Total RNA per cell increased as indicated by an increased RNA:DNA ratio. These changes are considered to be specifically due to the local action of prolactin.

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).

Interaction between the proximo-distal and antero-posterior co-ordinates of positional value during the specification of positional information in the early development of the chick limb-bud

Development ◽  
1974 ◽  
Vol 32 (1) ◽  
pp. 227-237
Author(s):  
Dennis Summerbell
Keyword(s):  
Early Development ◽  
Anterior Margin ◽  
Positional Information ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Anteroposterior Axis ◽  
Zone Of Polarizing Activity ◽  
Positional Value ◽  
Special Region

The experiments examine the extent of reduplication of skeletal parts across the anteroposterior axis, following the transplantation of a zone of polarizing activity (ZPA) to the anterior margin of the limb-bud at successively later stages. Previous studies have suggested that the function of the apical ectodermal ridge (AER) is to maintain cells in a special region at the distal tip (the progress zone) labile, with respect to their positional value along the proximo-distal axis. Similarly, the results of these experiments demonstrate that cells in the progress zone are able to change their antero-posterior positional value under the influence of the grafted ZPA, while cells at more proximal levels remain unaffected. In turn, the ZPA may effect the activity of the AER and hence the progress zone.

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