The appearance and quantitation of cytoplasmic ribonucleic acid in the early chick embryo

Development ◽  
1972 ◽  
Vol 28 (2) ◽  
pp. 367-384
Author(s):  
C. C. Wylie
Keyword(s):  
Chick Embryo ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Cell Number ◽  
Present Knowledge ◽  
Precursor Pool ◽  
Cytoplasmic Rna ◽  
Labelling Experiment ◽  
Neurula Stage

This paper seeks to extend our knowledge about RNA synthesis in early embryogenesis to the domestic fowl, Gallus domesticus. Using this species for research, apart from increasing our knowledge of higher vertebrate embryology, has certain advantages such as rapid uptake of isotopic precursors and ease of microdissection in culture. The following results are presented: (1) The cell number in the whole chick embryos is shown to be increasing logarithmically between the time of laying and the early neurula stage; with a doubling time of 7·4 h. (2) The onset of ribosomal RNA synthesis has been shown to be during mid-cleavage of the chick embryo, while development is taking place in the oviduct and uterus of the mother. (3) In a cumulative labelling experiment, embryos were labelled at the unincubated-egg stage, allowed to develop to various morphological stages up to neurulation, and their cytoplasmic RNA prepared and analysed by gel electrophoresis. (4) The specific activity of the precursor pool for RNA synthesis was measured at several stages, using the same labelling conditions, and the results were used to quantitate the RNA synthesis from the incorporated radioactivity. (5) Using these techniques, it was found that newly synthesized cytoplasmic RNA accumulates steadily in the whole chick embryo, reaching a level of 104 μg by the early neurula stage. On a per cell basis, however, the amount of newly synthesized cytoplasmic RNA seems to decrease slightly. These findings are discussed in the light of present knowledge about embryos of other vertebrates and certain invertebrates.

NUCLEIC ACID SYNTHESIS AND TRANSFER IN NORMAL, SECOND GENERATION CHICK EMBRYO FIBROBLASTS

1961 ◽  
Vol 39 (10) ◽  
pp. 1625-1633 ◽  
Author(s):  
R. Bather ◽  
Elizabeth Purdie-Pepper
Keyword(s):  
Chick Embryo ◽  
Rna Synthesis ◽  
Second Generation ◽  
Acid Synthesis ◽  
Quantitative Estimates ◽  
Cytoplasmic Rna ◽  
Embryo Fibroblasts ◽  
Slight Rise ◽  
Zero Time ◽  
Rna And Dna

The stripping film technique of autoradiography has been used to study some aspects of RNA and DNA metabolism in chick embryo fibroblasts in second generation tissue culture.Approximately one third of the cells incorporated thymidine-H3into DNA in a 20-minute uptake period. The duration of DNA synthesis, the generation time (time elapsing between two successive cell divisions), and the duration of mitosis have been calculated and are very similar to the values obtained for pure strains of hamster cells maintained in culture for several months by another author.RNA synthesis, as measured by uridine-H3incorporation, occurred only in the nucleus and nucleolus. Both sites synthesized RNA simultaneously beginning at zero time. The ratio of the number of grains over the nucleolus to that over the whole nucleus remained constant throughout the uptake of uridine-H3and its transfer to the cytoplasm.A small amount of labelled soluble RNA precursors remain in the nucleus after removal of uridine-H3from the medium. This results in a slight rise in radioactivity of the nucleus after uridine-H3removal. RNA then leaves the nucleus rapidly and appears in the cytoplasm. The half life of RNA in the nucleus is about 4 hours. Some turnover of cytoplasmic RNA seems to occur after 8 hours but quantitative estimates of its rate cannot be made due to changing geometry of the cells as the RNA migrates from the nuclear to the peripheral parts of the cell.Finally, little or no RNA synthesis occurs for a period of about 30 minutes during contraction of the chromosomes in mitosis.

scholarly journals Synthesis and turnover of mitochondrial ribonucleic acid in HeLa cells: the mature ribosomal and messenger ribonucleic acid species are metabolically unstable.

1981 ◽  
Vol 1 (6) ◽  
pp. 497-511 ◽  
Author(s):  
R Gelfand ◽  
G Attardi
Keyword(s):  
Ribosomal Rna ◽  
Hela Cells ◽  
Ribonucleic Acid ◽  
Half Life ◽  
Messenger Rna ◽  
Specific Activity ◽  
Mitochondrial Rna ◽  
Messenger Rnas ◽  
Precursor Pool ◽  
Messenger Ribonucleic Acid

The synthesis rates and half-lives of the individual mitochondrial ribosomal ribonucleic acid (RNA) and polyadenylic acid-containing RNA species in HeLa cells have been determined by analyzing their kinetics of labeling with [5-3H]-uridine and the changes in specific activity of the mitochondrial nucleotide precursor pools. In one experiment, a novel method for determining the nucleotide precursor pool specific activities, using nascent RNA chains, has been utilized. All mitochondrial RNA species analyzed were found to be metabolically unstable, with half-lives of 2.5 to 3.5 h for the two ribosomal RNA components and between 25 and 90 min for the various putative messenger RNAs. A cordycepin "chase" experiment yielded half-life values for the messenger RNA species which were, in general, larger by a factor of 1.5 to 2.5 than those estimated in the labeling kinetics experiments. On the basis of previous observations, a model is proposed whereby the rate of mitochondrial RNA decay is under feedback control by some mechanism linked to RNA synthesis or processing. A short half-life was determined for five large polyadenylated RNAs, which are probably precursors of mature species. A rate of synthesis of one to two molecules per minute per cell was estimated for the various H-strand-coded messenger RNA species, and a rate of synthesis 50 to 100 times higher was estimated for the ribosomal RNA species. These data indicate that the major portion of the H-strand in each mitochondrial deoxyribonucleic acid molecule is transcribed very infrequently, possibly as rarely as once or twice per cell generation. Furthermore, these results are consistent with a previously proposed model of H-strand transcription in the form of a single polycistronic molecule.

Control of RNA Synthesis by Amino Acids in Landschutz Ascites Tumor Cells

1974 ◽  
Vol 52 (10) ◽  
pp. 867-876 ◽  
Author(s):  
Paul Jolicoeur ◽  
Fernand Labrie
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Inhibitory Effect ◽  
Amino Acid Starvation ◽  
Cytoplasmic Rna ◽  
Polysomal Mrna ◽  
Deficient Medium ◽  
Synthesis And Processing

Landschutz cells incubated in amino acid-deficient medium for 2.5 h show a markedly reduced incorporation of [3H]uridine into 18 S and 28 S cytoplasmic ribosomal RNA (rRNA) and into 28 S, 32 S, and 36 S nuclear RNA measured during the last 90 min of incubation, whereas the radioactivity associated with 45 S pre-rRNA is not affected. Ten-minute pulse-labeling and 15-min pulse-chase experiments show that amino acid starvation inhibits both the synthesis and processing of 45 S pre-rRNA. Amino acid starvation has no significant effect on the labeling of the nucleotide pools. This effect of amino acids was specific for rRNA since the synthesis of 4 S and 5 S cytoplasmic RNA separated on polyacrylamide gels and of polysomal mRNA analyzed on sucrose gradients was not significantly affected during amino acid starvation. These data also indicate that RNA synthesis is non-coordinated in Landschutz cells. Among the 13 amino acids essential for growth of these cells, arginine and glutamine appear to be mainly responsible for the inhibition of synthesis of 18 S and 28 S rRNA measured during incubation in complete amino acid-deficient medium. The removal of any one of the other amino acids has a small inhibitory effect on the incorporation of [3H]uridine into rRNA and their effect on the synthesis of 18 S rRNA is more pronounced than on that of 28 S rRNA. Such effect results in an unbalanced production of these two ribosomal RNA species.

scholarly journals RNA SYNTHESIS IN CHINESE HAMSTER CELLS

1968 ◽  
Vol 36 (3) ◽  
pp. 583-593 ◽  
Author(s):  
M. D. Enger ◽  
R. A. Tobey ◽  
A. G. Saponara
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Sedimentation Analysis ◽  
Ovary Cells ◽  
Chinese Hamster Cells ◽  
Mechanical Selection ◽  
Selection Of

The incorporation of methionine-methyl-14C into 18S ribosomal RNA of cultured Chinese hamster ovary cells in early and late interphase has been determined by zone-sedimentation analysis of phenol-extracted RNA preparations. Synchronized cell cultures were prepared for these studies by thymidine treatment and by mechanical selection of mitotic cells. The specific activity of 18S RNA labeled in late interphase was found to be 1.1–1.2 times that of 18S RNA labeled in early interphase. Upon correction for increase in RNA mass, the rate of methylation of 18S RNA in late interphase is about 1.9 times that in early interphase.

Synthese von Ribonucleinsäuren in Ganzkeimen und im isolierten Ektoderm von Triturus alpestris

1965 ◽  
Vol 20 (10) ◽  
pp. 997-1004 ◽  
Author(s):  
H. Tiedemann ◽  
J. Born ◽  
U. Kocher-Becker
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Transfer Rna ◽  
Sedimentation Pattern ◽  
Triturus Alpestris ◽  
Different Ages

The correlation between the synthesis of different RNA-fractions and embryonic differentiation was compared by studying the RNA-synthesis in whole Triturus embryos of different ages and isolated ectoderm not induced to develop into special tissues.In the isolated ectoderm, having the same age as neurulae, transfer-RNA as well as ribosomal-RNA is synthesized. The transfer-RNA has about the same specific activity and the ribosomal-RNA a somewhat lower specific activity compared to neurulae. Pulse-labelled RNA with a heterogeneous sedimentation pattern is likewise synthesized in whole embryos and in isolated ectoderm. — The results are in accord with the hypothesis that embryonic differentiation is directed by informational-RNA, which is only a very small part of the whole RNA.

RNA SYNTHESIS IN THE RAT ANTERIOR HYPOTHALAMUS AND PITUITARY: RELATION TO NEONATAL ANDROGEN AND THE OESTROUS CYCLE

1970 ◽  
Vol 48 (1) ◽  
pp. 125-137 ◽  
Author(s):  
D. F. SALAMAN
Keyword(s):  
Ribosomal Rna ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Gradient Centrifugation ◽  
Anterior Hypothalamus ◽  
Oestrous Cycle ◽  
Uridine Incorporation ◽  
Cyclic Changes

SUMMARY RNA from the anterior hypothalamus and anterior pituitary of rats has been labelled by incubation in vitro with [3H]uridine and characterized by density gradient centrifugation. A study of normal females during the oestrous cycle showed cyclic changes in [3H]uridine incorporation into rapidly labelled RNA (rl-RNA) both in the anterior pituitary and hypothalamus. In both tissues the specific activity of RNA was low at dioestrus and high at oestrus and metoestrus. In androgenized females, incorporation into hypothalamic rl-RNA was less than the oestrus—metoestrus level and similar to that at dioestrus, while incorporation into anterior pituitary rl-RNA was similar to the oestrus—metoestrus level and greater than at dioestrus. [3H]Uridine incorporation into ribosomal RNA (r-RNA) of anterior hypothalamus and pituitary was also demonstrated by incubation for 4 h. Under these conditions there was no effect of androgenization on hypothalamic r-RNA, but the specific activity of pituitary r-RNA was greater than normal.

scholarly journals Ribosomal RNA metabolism during renal hypertrophy. Evidence of decreased degradation of newly synthesized ribosomal RNA.

1975 ◽  
Vol 64 (1) ◽  
pp. 260-265 ◽  
Author(s):  
J M Hill
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Rna Metabolism ◽  
Renal Hypertrophy ◽  
Degradation Rates ◽  
Kinetics Of

The degradation rates of kidney rRNA labeled before UNI or sham are unchanged 5 days after the operations (t one-and-a half, 88 h). Therefore, there is no contribution from pre-existing rRNA to the increased amount of rRNA in the stimulated kidney. After labeling with L-(methyl-3H)methionine, the kinetics of incorporation into rRNA precursors, 10-60 min and at the postoperative times of 4, 16, 36, and 96 h. The specific activity of cytoplasmic rRNA after 1-h labeling with L-(methyl-3H)methionine increased occured at 4 or 96 h. Since (a) the rate of degradation of rRNA, (b) the kinetics of incorporation and processing of rRNA precursors, and (c) the rate of RNA synthesis appear unchanged after UNI, the accretion of rRNA must involve decreased degradation of newly synthesized rRNA.

scholarly journals GENETIC MODULATION OF RNA METABOLISM IN DROSOPHILA. I. INCREASED RATE OF RIBOSOMAL RNA SYNTHESIS

Genetics ◽  
1977 ◽  
Vol 86 (4) ◽  
pp. 789-800
Author(s):  
Stephen H Clark ◽  
Linda D Strausbaugh ◽  
Barry I Kiefer
Keyword(s):  
Y Chromosome ◽  
Ribosomal Rna ◽  
Development Time ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Rrna Synthesis ◽  
Adult Males ◽  
Wild Type ◽  
Wild Type Phenotype ◽  
Activity Measurements

ABSTRACT It has been suggested that a particular Y chromosome which is rDNA-deficient (YbbSuVar-5) may be associated with an increased utilization of rDNA template in adult testes (Shermoen and Kiefer 1975). To extend the observations on this chromosome, experiments were designed to determine if the chromosome has an effect on rRNA synthesis in bobbed adults and on classic bobbed phenotypes (shortened and thinner scutellar bristles and delayed development). Specific activity measurements were made on rRNA extracted from adult males of the genotypes car bb/Ybb- and car bb/YbbSuVar-5, which are rDNA-deficient to the same extent, and from Samarkand+ isogenic (Sam+ iso), which is a wild-type stock. The resulting data demonstrated that the presence of the YbbSuVar-5 chromosome increases the rate of ribosomal RNA synthesis in adult flies. In addition, it was found that the presence of this particular Y chromosome restores wild-type bristle phenotype and development time. Appropriate genetic crosses indicate that the observed effects (increased rRNA synthesis, restoration of wild-type phenotype) are a function of this particular Y chromosome, and are not due to autosomal factors. The results of these experiments suggest that the rate of rRNA accumulation is under genetic control.

scholarly journals Synthesis and turnover of mitochondrial ribonucleic acid in HeLa cells: the mature ribosomal and messenger ribonucleic acid species are metabolically unstable

1981 ◽  
Vol 1 (6) ◽  
pp. 497-511
Author(s):  
R Gelfand ◽  
G Attardi
Keyword(s):  
Ribosomal Rna ◽  
Hela Cells ◽  
Ribonucleic Acid ◽  
Half Life ◽  
Messenger Rna ◽  
Specific Activity ◽  
Mitochondrial Rna ◽  
Messenger Rnas ◽  
Precursor Pool ◽  
Messenger Ribonucleic Acid

The synthesis rates and half-lives of the individual mitochondrial ribosomal ribonucleic acid (RNA) and polyadenylic acid-containing RNA species in HeLa cells have been determined by analyzing their kinetics of labeling with [5-3H]-uridine and the changes in specific activity of the mitochondrial nucleotide precursor pools. In one experiment, a novel method for determining the nucleotide precursor pool specific activities, using nascent RNA chains, has been utilized. All mitochondrial RNA species analyzed were found to be metabolically unstable, with half-lives of 2.5 to 3.5 h for the two ribosomal RNA components and between 25 and 90 min for the various putative messenger RNAs. A cordycepin "chase" experiment yielded half-life values for the messenger RNA species which were, in general, larger by a factor of 1.5 to 2.5 than those estimated in the labeling kinetics experiments. On the basis of previous observations, a model is proposed whereby the rate of mitochondrial RNA decay is under feedback control by some mechanism linked to RNA synthesis or processing. A short half-life was determined for five large polyadenylated RNAs, which are probably precursors of mature species. A rate of synthesis of one to two molecules per minute per cell was estimated for the various H-strand-coded messenger RNA species, and a rate of synthesis 50 to 100 times higher was estimated for the ribosomal RNA species. These data indicate that the major portion of the H-strand in each mitochondrial deoxyribonucleic acid molecule is transcribed very infrequently, possibly as rarely as once or twice per cell generation. Furthermore, these results are consistent with a previously proposed model of H-strand transcription in the form of a single polycistronic molecule.

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