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 GENETIC MODULATION OF RNA METABOLISM IN DROSOPHILA. IV. MEASUREMENT OF RATES OF RNA SYNTHESIS BY DENSITY LABELING

Genetics ◽  
1979 ◽  
Vol 93 (3) ◽  
pp. 655-661
Author(s):  
Linda D Strausbaugh ◽  
Stephen H Clark ◽  
Robert M Grainger
Keyword(s):  
Rna Synthesis ◽  
Genetic Regulation ◽  
Rna Metabolism ◽  
Rrna Synthesis ◽  
Adult Males ◽  
Wild Type ◽  
Genetic Modulation ◽  
Wild Type Phenotype ◽  
Regulation Of Synthesis ◽  
Pool Sizes

ABSTRACT Accumulation of RNA was measured in adult males of two genotypes: car bb/Ybb- and car bb/YbbSuvar-5. The two genotypes have similar amounts of rDNA, which is reduced in comparison to wild type (CLARK, STRAUSBAUGH and KIErm 1977). Although genotypically bobbed, car bb/YbbSuVar-5 flies have a wild-type phenotype; car bb/Ybb- flies are both phenotypically and genotypically bobbed (CLARK, STRAUSBAUGH and KIEFER 1977). The wild-type phenotype observed in the car bb/YbbsuVar-5 flies is thought to be the result of an increased rate of rRNA synthesis due ot the presence of the YbbSuVar-5 chromosome (SHERMOEN and KIFFER 1975; CLARK, STRAUSBAUGH and KIEFER 1977; CLARK and KIEFER 1977). To further define this phenomenon, the absolute accumulation of RNA was measured in the two genotypes, using density labeling methods. The accumulation of RNA is 1.4 to 1.8 times higher in car bb/YbbSuVar-5 flies than in car bb/Ybb- flies, demonstrating that there is genetic regulation of synthesis in this genotype. The use of density-labeled nucleosides has clearly shown that there is no difference in precusor pool sizes or use between the two genotypes studied.

scholarly journals REGULATION OF RIBOSOMAL RNA AND 5s RNA SYNTHESIS IN DROSOPHILA MELANOGASTER: I. BOBBED MUTANTS

Genetics ◽  
1972 ◽  
Vol 72 (2) ◽  
pp. 267-276
Author(s):  
Roberto Weinmann
Keyword(s):  
Drosophila Melanogaster ◽  
Developmental Delay ◽  
Ribosomal Rna ◽  
Gel Electrophoresis ◽  
Rna Synthesis ◽  
Rrna Synthesis ◽  
Wild Type ◽  
5S Rna ◽  
Wild Type Level

ABSTRACT Analysis of the rates and amounts of rRNA and 5s RNA synthesized in Drosophila melanogaster bobbed mutants was done by using acrylamide-gel electrophoresis. The results show that the amounts of rRNA synthesized are constant, although the rates of rRNA synthesis in bb's are reduced to 30% of the wild-type level. The rates of synthesis of 5s RNA were constant. The rate of synthesis of the two kinds of molecules that enter in equimolar amounts into the mature ribosome is non-coordinated.—The rates of rRNA synthesis were shown to be proportional to the length of the scutellar bristles, supporting the notion that in trichogen cells there is no developmental delay, but the size of the bristle depends directly on the rate of rRNA synthesis.

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.

scholarly journals DIFFERENTIATION OF DROSOPHILA CELLS LACKING RIBOSOMAL DNA, IN VITRO

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 429-434
Author(s):  
J James Donady ◽  
R L Seecof ◽  
M A Fox
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribosomal Dna ◽  
Rna Synthesis ◽  
Wild Type ◽  
Drosophila Cells

ABSTRACT Drosophila melanogaster embryos that lacked ribosomal DNA were obtained from appropriate crosses. Cells were taken from such embryos before overt differentiation took place and were cultured in vitro. These cells differentiated into neurons and myocytes with the same success as did wild-type controls. Therefore, ribosomal RNA synthesis is not necessary for the differentiation of neurons and myocytes in vitro.

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.

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.

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