scholarly journals Evidence for Two Metabolically Distinct Types of Ribonucleic Acid in Chromatin and Nucleoli

1958 ◽  
Vol 4 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Rachel McMaster-Kaye ◽  
J. Herbert Taylor
Keyword(s):  
Maximum Activity ◽  
The Other ◽  
Precise Localization ◽  
Isolated Nuclei ◽  
Metabolic Characteristics ◽  
Nucleolar Activity ◽  
Cytoplasmic Rna ◽  
Nuclear Rna ◽  
Time Courses ◽  
Nucleolar Rna

Patterns of radioisotope incorporation are useful characteristics in describing cellular RNA fractions, and have indicated a distinctive "nuclear" RNA. In order to characterize the RNA fractions of the two nuclear components, nucleoli and chromatin, and to determine thereby the precise localization of the RNA typical of isolated nuclei, time-courses of P32 incorporation into nucleolar, chromosomal, and cytoplasmic RNA of Drosophila salivary glands have been determined from autoradiograms. Two experiments are reported which cover 12 and 18 hour periods, including an initial 2 hour feeding on P32. Concentrations of RNA-P32 (identified by ribonuclease digestion) were determined by grain counts. After 1 hour only the nucleolar RNA is labelled. Activity is detectible in chromosomal and cytoplasmic RNA after the 2nd hour. The nucleolar fraction reaches its maximum activity shortly after transfer of the larvae to non-radioactive food, the other fractions several hours later. Maximum activities persist in the chromosomal and cytoplasmic fractions; nucleolar activity decreases after the 9th hour. The observed differences in times at which incorporation begins and maximum activities are reached, and in maintenance of maximum activities indicate that chromosomal and nucleolar RNA are distinct fractions. The metabolic characteristics which have been ascribed to "nuclear" RNA apply only to the nucleolar fraction.

scholarly journals THE METABOLIC CHARACTERISTICS OF NUCLEOLAR, CHROMOSOMAL, AND CYTOPLASMIC RIBONUCLEIC ACID OF DROSOPHILA SALIVARY GLANDS

1960 ◽  
Vol 8 (2) ◽  
pp. 365-378 ◽  
Author(s):  
Rachel McMaster-Kaye
Keyword(s):  
Salivary Glands ◽  
Ribonucleic Acid ◽  
Turnover Rate ◽  
Specific Activity ◽  
Rna Turnover ◽  
Metabolic Characteristics ◽  
Cytoplasmic Rna ◽  
Lower Maximum ◽  
Rna Accumulation ◽  
Nucleolar Rna

Incorporation and retention of adenine-8-C14 and of P32O4 by nucleolar, chromosomal, and cytoplasmic RNA have been studied. Radioisotope concentrations were determined from autoradiographs, by grain counting, and RNA concentrations by microphotometry after basic staining. The relation between rates of RNA accumulation and rates of adenine incorporation was used to determine if synthesis was used to replace RNA which was lost from a fraction, and to obtain estimates of turnover rate. Nucleolar incorporation patterns indicate its incorporation is independent of growth, and there is complete turnover of the fraction in an hour or less. Nucleolar turnover is attributed to degradation of RNA within the nucleolus rather than to movement of intact molecules from the nucleolus. Chromosomal RNA reaches a much lower maximum specific activity than nucleolar, and a slightly higher maximum than cytoplasmic RNA. It showed faster incorporation than cytoplasmic RNA while accumulating RNA at the same rate as the cytoplasm, suggesting chromosomal RNA turnover. No evidence of cytoplasmic RNA turnover was found: rate of incorporation and rate of growth were correlated, and retention studies detected no decrease in amount of RNA-C14, RNA-P32, or RNA. Different ultimate precursors are indicated for nucleolar and non-nucleolar RNA by the observation that the nucleolar precursor is labeled before the precursor of non-nucleolar RNA.

scholarly journals Some Chemical Properties of Isolated Pea Nucleoli

1959 ◽  
Vol 6 (1) ◽  
pp. 57-60 ◽  
Author(s):  
Herbert Stern ◽  
F. B. Johnston ◽  
G. Setterfield
Keyword(s):  
Light Microscope ◽  
Chemical Properties ◽  
Nucleolar Protein ◽  
The Other ◽  
Cytoplasmic Protein ◽  
High Concentration ◽  
Isolated Nuclei ◽  
Protein Sulfhydryl ◽  
Protein Sulfhydryl Groups ◽  
Nucleolar Rna

Isolated nuclei and nucleoli of ungerminated pea embryos have been analyzed chemically for their content of DNA, RNA, zinc, iron, phosphorus, and protein sulfhydryl groups. The values obtained cannot be considered to represent the whole of the living nucleolar body as an undetermined amount of material is extracted from nucleoli in the course of their isolation. Only negligible amounts of DNA have been found in the isolated nucleoli; most of the DNA released on disruption of nuclei appears in a fraction showing very few structures under the light microscope. RNA is more concentrated in the nucleolus than in the nucleus or cytoplasm, but since nucleolar protein is 6 per cent of nuclear and less than 1 per cent of cytoplasmic protein, the total amount of nucleolar RNA is comparatively small. None of the other components listed occurs in high concentration in either nucleus or nucleolus.

scholarly journals An assessment of some methodological criticisms of studies of RNA efflux from isolated nuclei

1983 ◽  
Vol 214 (3) ◽  
pp. 915-921 ◽  
Author(s):  
P S Agutter
Keyword(s):  
Proteinase Inhibitors ◽  
Serine Proteinase ◽  
General Mechanism ◽  
Nuclear Surface ◽  
Efflux Rate ◽  
Isolated Nuclei ◽  
Cytoplasmic Rna ◽  
Nuclear Rna

RNA efflux from isolated nuclei can be studied either as a means of elucidating the general mechanism of nucleo-cytoplasmic RNA transport, or as part of an investigation of the processing and utilization of particular gene transcripts. The present paper describes an assessment of three methodological criticisms of RNA-efflux measurements that are made for the former reason: for such measurements, it is sufficient to show that the post-incubation supernatant RNA is similar overall to homologous cytoplasmic mRNA, rather than to nuclear RNA, that is nevertheless of intranuclear origin, and that alterations to the medium during experiments do not markedly perturb this general nuclear restriction. The results seem to justify the following conclusions. (1) Although degradation of the nuclear RNA occurs during incubation in vitro, this process does not account for the appearance of RNA in the postnuclear supernatant. The degradation can be largely prevented by the addition of serine-proteinase inhibitors without altering the RNA efflux rate. (2) Some adsorption of labelled cytoplasmic RNA to the nuclear surface occurs during both isolation and incubation of the nuclei, and some desorption occurs during incubation. However, these effects introduce errors of less than 10% into the measurements of efflux rates. (3) Exogenous acidic polymers, including polyribonucleotides, disrupt nuclei and increase the apparent RNA efflux rate by causing leakage of nuclear contents. However, this effect can largely be overcome by including the nuclear stabilizers spermidine, Ca2+ and Mn2+ in the medium. In terms of this assessment, it appears that RNA efflux from isolated nuclei in media containing nuclear stabilizers serves as a reasonable model for transport in vivo.

scholarly journals THE INTRACELLULAR DISTRIBUTION AND HETEROGENEITY OF RIBONUCLEIC ACID IN STARFISH OOCYTES

1961 ◽  
Vol 11 (3) ◽  
pp. 549-557 ◽  
Author(s):  
Jan-Erik Edström ◽  
Wolfgang Grampp ◽  
Norberto Schor
Keyword(s):  
Ribosomal Rna ◽  
Messenger Rna ◽  
The Other ◽  
Asterias Rubens ◽  
Cell Component ◽  
Cytoplasmic Rna ◽  
Stable Part ◽  
Unstable Part ◽  
Nucleolar Rna ◽  
Purine Pyrimidine

A study has been made of the content and composition of RNA in cytoplasm, nucleoplasm, and nucleoli from growing oocytes of the starfish Asterias rubens. The determinations were carried out, using ultramicrochemical methods, on units isolated by microdissection from fixed sections. Macrochemical and interferometric control experiments show that RNA can be quantitatively evaluated in this way. The results show that the growing oocyte represents a system in which the relations between the quantities of nucleolar, nucleoplasmic, and cytoplasmic RNA undergo great changes. These changes are continuous for nucleolar and cytoplasmic RNA so that their amounts may be predicted from the size of the cell. Nucleoplasmic RNA, on the other hand, shows great variations among different cells, independent of cell size. Purine-pyrimidine analyses show that each cell component contains an RNA which differs significantly from that of the other two. Cytoplasmic and nucleolar RNA are closely related, the only difference being a slightly higher guanine/uracil quotient for the nucleolar RNA. They are both of the usual tissue RNA type, i.e., they show a preponderance of guanine and cytosine over adenine and uracil. Nucleoplasmic RNA deviates grossly from the RNA of the other two components. Here the concentrations of adenine and uracil are higher than those of guanine and cytosine, respectively. This RNA consequently shows some resemblance to the general type of animal DNA although the purine/pyrimidine ratio is far from unity. Our data favor a nucleolar origin for the stable part of the ribosomal RNA and a nucleoplasmic one for the unstable part (the messenger RNA).

Über die Beziehungen der RNS- und Proteinsynthese zum Zellkern in Siebzellen von Vicia faba

1964 ◽  
Vol 19 (11) ◽  
pp. 1066-1071 ◽  
Author(s):  
Stefanie Neumann ◽  
Reinhold Wollgiehn
Keyword(s):  
Vicia Faba ◽  
Rna Synthesis ◽  
The Other ◽  
Other Hand ◽  
Cytoplasmic Rna ◽  
Nuclear Rna ◽  
Sieve Tubes

Autoradiographic investigations on the dependency of the RNA and protein syntheses on the nucleus have been carried out in sieve tubes of Vicia faba.In young nucleated sieve tubes 3H-uridine is incorporated primarily into the nuclear RNA and later into the cytoplasmic RNA. In sieve tubes with degenerated nuclei no incorporation of uridine in RNA takes place. On the other hand, 3H-phenylalanine is incorporated also into the proteins of old sieve tubes without RNA synthesis.

scholarly journals COMPOSITION OF RIBONUCLEIC ACID FROM VARIOUS PARTS OF SPIDER OOCYTES

1960 ◽  
Vol 8 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Jan-Erik Edström
Keyword(s):  
Ribonucleic Acid ◽  
The Other ◽  
Total Rna ◽  
Other Hand ◽  
Cytoplasmic Rna ◽  
The Difference ◽  
Nucleolar Rna ◽  
Purine Pyrimidine ◽  
Different Parts

Microphoretic purine-pyrimidine analyses of the ribonucleic acid (RNA) in nucleoli, nucleoplasm, cytoplasm, and yolk nuclei of spider oocytes have been carried out. The material necessary for the analyses was isolated by micromanipulation. Determinations of the amounts of RNA in the different parts of the cell were also performed. No differences between the composition of RNA in the nucleolus and the cytoplasm could be disclosed. Nucleoplasmic RNA was, on the other hand, distinctly different from that in the nucleolus and in the cytoplasm. The difference lies in the content of adenine, which is highest in nucleoplasmic RNA. The few analyses carried out on yolk nuclei showed their RNA to be variable in composition with a tendency to high purine values. The cytoplasm contains about 99 per cent of the total RNA in these cells, the nucleoplasm about 1 per cent, and the nucleolus not more than 0.3 per cent, although the highest concentrations are found in these latter structures. When considered in the light of other recent findings the results are compatible with the view that nucleolar RNA is the precursor of cytoplasmic RNA.

Effect of growth hormone and hydrocortisone on the synthesis of rapidly labeled, high molecular weight, nuclear RNA in rat liver

1969 ◽  
Vol 47 (2) ◽  
pp. 226-229 ◽  
Author(s):  
Maurice Brossard ◽  
Louis Nicole
Keyword(s):  
Molecular Weight ◽  
Growth Hormone ◽  
High Molecular Weight ◽  
Rat Liver ◽  
Orotic Acid ◽  
The Other ◽  
Other Hand ◽  
Nuclear Rna ◽  
Nucleolar Rna

The effects of growth hormone and hydrocortisone on the synthesis of rat liver RNA have been studied. Administration of growth hormone stimulated the incorporation of 14C-orotic acid into 45 S preribosomal nucleolar RNA, and had no effect on the 6–50 S polydisperse nuclear RNA of extra-nucleolar origin. On the other hand, hydrocortisone stimulated the synthesis of all types of nuclear RNA, but mainly that of the 18 S class of 6–50 S polydisperse nuclear RNA.

scholarly journals INHIBITING EFFECT OF THE NEW CYTOTOXIC ANTIBIOTIC DAUNOMYCIN ON NUCLEIC ACIDS AND MITOTIC ACTIVITY OF HELA CELLS

1965 ◽  
Vol 27 (3) ◽  
pp. 545-550 ◽  
Author(s):  
A. Di Marco ◽  
R. Silvestrini ◽  
S. Di Marco ◽  
T. Dasdia
Keyword(s):  
Mitotic Activity ◽  
Rna Synthesis ◽  
Thymidine Incorporation ◽  
Acid Synthesis ◽  
Acetyl Derivative ◽  
Total Inhibition ◽  
Nuclear Rna ◽  
Nucleolar Rna ◽  
Higher Doses

The effect has been studied of Actinomycin D, Daunomycin (Da.), and Da. N acetyl derivative on mitotic activity and on the nucleic acid synthesis of in vitro HeLa cell cultures. The experiments were carried out by means of the radioautographic technique using stripping films. The relative uptake of thymidine-H3 and uridine-H3 was determined by means of the reduced silver grain count present in the nuclei of controls and treated cells. The mitotic activity and thymidine incorporation were noticeably reduced by Daunomycin and Actinomycin, whereas both processes appeared less affected by Da. N acetyl derivative. As regards nuclear RNA synthesis, all three antibiotics at low doses chiefly inhibit nucleolar RNA synthesis. On the other hand, whilst Actinomycin at higher doses causes an almost total inhibition of the synthesis of the whole nuclear RNA, in Daunomycin- and Da. N acetyl derivative-treated cells extranucleolar RNA synthesis is less susceptible to inhibition.

STUDIES ON THE BIOSYNTHESIS OF NUCLEOTIDES IN EHRLICH ASCITES CARCINOMA CELLS IN VITRO

1965 ◽  
Vol 43 (2) ◽  
pp. 209-224 ◽  
Author(s):  
B. I. Uppin ◽  
P. G. Scholefield
Keyword(s):  
Exchange Reaction ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
The Other ◽  
Metabolic Inhibitors ◽  
Ehrlich Ascites ◽  
Oxidative Pathway ◽  
Time Courses ◽  
Oxidation Of Glucose

Studies have been made of the effects of metabolic inhibitors on the oxidation and incorporation of radioactivity into nucleotides of glucose labelled in the 1, 2, and 6 positions. The results indicate that in Ehrlich ascites carcinoma cells the predominant oxidative pathway is the hexosemonophosphate shunt. Investigation of the time courses of oxidation of the labelled glucose molecules confirms this conclusion. The pattern of incorporation of radioactivity initially suggests that nucleotide ribose is not formed via this pathway. However, it is shown that the coupling of an active transketolase system with the other enzymes of the hexosemonophosphate shunt provides a sufficient explanation of all the experimental observations. The conclusion is reached that pentose is formed by oxidation of glucose through the shunt but that the labelling pattern is largely established as the result of the exchange reaction catalyzed by transketolase.

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