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.

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.

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.

scholarly journals STIMULATION BY INSULIN OF RNA SYNTHESIS IN CHICK FIBROBLASTS

1974 ◽  
Vol 60 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Joel B. Baseman ◽  
Domenic Paolini ◽  
Harold Amos
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Polymerase Activity ◽  
Serum Free Medium ◽  
5S Rna ◽  
Fresh Serum ◽  
Protein And Rna Synthesis ◽  
Rna Polymerase Activity ◽  
Kinetics Of ◽  
Stimulation Of

After the addition of insulin to monolayers of chick fibroblasts previously incubated in serum-free medium, the rates of protein and RNA synthesis increase continuously during the first 8–10 h. Little stimulation of DNA synthesis or mitosis results with the addition of insulin alone in contrast to the addition of fresh serum which stimulates both markedly. The stimulation in RNA synthesis does not result from expansion of the nucleotide pool but is correlated with increases in RNA polymerase activity. All major classes of RNA are stimulated; processing of preribosomal RNA to 28S and 18S and the association of this mature RNA with ribosomes appear to occur normally. The kinetics of stimulation of 5S RNA differ from those of the synthesis of 4S and of ribosomal RNA. Insulin and serum appear to affect the synthesis or stability of certain transcripts differentially.

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 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 Determinants of RNA metabolism in the Schizosaccharomyces pombe genome

2015 ◽  
Author(s):  
Philipp Eser ◽  
Leonhard Wachutka ◽  
Kerstin C Maier ◽  
Carina Demel ◽  
Mariana Boroni ◽  
...  
Keyword(s):  
Rna Synthesis ◽  
Model Organism ◽  
Rna Metabolism ◽  
Dna And Rna ◽  
Rna Labeling ◽  
Sequence Elements ◽  
Antisense Regulation ◽  
Kinetics Of ◽  
Synthesis And Degradation

To decrypt the regulatory code of the genome, sequence elements must be defined that determine the kinetics of RNA metabolism and thus gene expression. Here we attempt such decryption in an eukaryotic model organism, the fission yeast S. pombe. We first derive an improved genome annotation that redefines borders of 36% of expressed mRNAs and adds 487 non-coding RNAs (ncRNAs). We then combine RNA labeling in vivo with mathematical modeling to obtain rates of RNA synthesis and degradation for 5,484 expressed RNAs and splicing rates for 4,958 introns. We identify functional sequence elements in DNA and RNA that control RNA metabolic rates, and quantify the contributions of individual nucleotides to RNA synthesis, splicing, and degradation. Our approach reveals distinct kinetics of mRNA and ncRNA metabolism, separates antisense regulation by transcription interference from RNA interference, and provides a general tool for studying the regulatory code of genomes.

scholarly journals GENETIC MODULATION OF RNA METABOLISM IN DROSOPHILA. II. COORDINATE RATE CHANGE IN 4S, 5S, AND POLY-A ASSOCIATED RNA SYNTHESIS

Genetics ◽  
1977 ◽  
Vol 86 (4) ◽  
pp. 801-811
Author(s):  
Stephen H Clark ◽  
Barry I Kiefer
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Liquid Scintillation ◽  
Molecular Mechanisms ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Similar Rate ◽  
Wild Type ◽  
Initial Attempt ◽  
Polyadenylated Rna

ABSTRACT It has been demonstrated that a particular rDNA-deficient Y chromosome (YbbSuVar-5) increases the rate of ribosomal RNA synthesis in adult testes (Shermoen and Kiefer 1975) and in whole flies (Clark, Strausbaugh and Kiefer 1977). As an initial attempt to explore the molecular basis of this phenomenon, experiments were designed to determine if the rate increase was specific for rRNA as opposed to the other species of RNA. The genotypes used in these studies were car bb/Ybb-, car bb/YbbSuVar-5, and Sam+ iso. car bb/YbbSuVar-5 and car bb/Ybb- are deficient to the same extent in rDNA and Sam+ iso is a wild-type stock. Following isotope incorporation, total RNA was extracted by a phenol:chloroform method and separated by polyacrylamide gel electrophoresis. The various RNA species were quantified by UV absorption and their radioactivity determined by gel fractionation and liquid scintillation counting. The resulting data permitted the calculation of a specific activity (i.e., dpm/µg RNA) which was defined as synthetic rate. Polyadenylated RNA was isolated using a poly-U sepharose column and similar rate calculations were made. The data from these studies indicate that the rate of synthesis of all species of RNA examined (28S + 18S, 5S, 4S transfer RNA and polyadenylated RNA) is increased by the presence of the YbbSuVar-5 chromosome. Genetic and molecular mechanisms are discussed.

Hormonal Stimulation of Ribosomal RNA Synthesis in Achlya ambisexualis

1975 ◽  
Vol 53 (12) ◽  
pp. 1341-1345 ◽  
Author(s):  
Paul A. Horgen ◽  
Robin Smith ◽  
Julie C. Silver ◽  
Gary Craig
Keyword(s):  
Ribosomal Rna ◽  
18S Rrna ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Dry Weight ◽  
Sex Hormone ◽  
Hormonal Stimulation ◽  
Achlya Ambisexualis ◽  
Early Effects ◽  
Stimulation Of

The experiments reported show that one of the early effects of the steroid sex hormone antheridiol is on the synthesis of rRNA and ribosomes. This is demonstrated in hormone treated cultures of Achlya ambisexualis (strain E87) by an enhancement of the incorporation of [3H]uridine into 26S and 18S rRNA and by an increase in measurable amounts of ribosomes per milligram dry weight of mycelium. Furthermore, since the hormone does not significantly alter the pool size or the specific activity of uridine triphosphate, this effect appears to represent an increased rate of RNA synthesis.

The Morphology of the Rat Kidney Following Folic Acid Administration

1970 ◽  
Vol 28 ◽  
pp. 200-201
Author(s):  
Aline Byrnes ◽  
Elsa E. Ramos ◽  
Minoru Suzuki ◽  
E.D. Mayfield
Keyword(s):  
Folic Acid ◽  
De Novo ◽  
Specific Activity ◽  
Rat Kidney ◽  
Present Report ◽  
Intracellular Localization ◽  
Male Rats ◽  
Renal Hypertrophy ◽  
Electron Microscopic ◽  
Biochemical Alterations

Renal hypertrophy was induced in 100 g male rats by the injection of 250 mg folic acid (FA) dissolved in 0.3 M NaHCO3/kg body weight (i.v.). Preliminary studies of the biochemical alterations in ribonucleic acid (RNA) metabolism of the renal tissue have been reported recently (1). They are: RNA content and concentration, orotic acid-c14 incorporation into RNA and acid soluble nucleotide pool, intracellular localization of the newly synthesized RNA, and the specific activity of enzymes of the de novo pyrimidine biosynthesis pathway. The present report describes the light and electron microscopic observations in these animals. For light microscopy, kidney slices were fixed in formalin, embedded, sectioned, and stained with H & E and PAS.

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