scholarly journals Microsecond Time-Scale Discrimination Among Polycytidylic Acid, Polyadenylic Acid, and Polyuridylic Acid as Homopolymers or as Segments Within Single RNA Molecules

1999 ◽  
Vol 77 (6) ◽  
pp. 3227-3233 ◽  
Author(s):  
Mark Akeson ◽  
Daniel Branton ◽  
John J. Kasianowicz ◽  
Eric Brandin ◽  
David W. Deamer
Keyword(s):  
Time Scale ◽  
Rna Molecules ◽  
Polycytidylic Acid ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid

Ultraviolet circular dichroism studies on synthetic polynucleotides

1969 ◽  
Vol 47 (6) ◽  
pp. 637-642 ◽  
Author(s):  
Fred H. Wolfe ◽  
Kimio Oikawa ◽  
Cyril M. Kay
Keyword(s):  
Circular Dichroism ◽  
Wavelength Region ◽  
Ph Values ◽  
Polycytidylic Acid ◽  
Naturally Occurring ◽  
Polyinosinic Acid ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid ◽  
Extreme Sensitivity ◽  
Circular Dichroïsm

The ultraviolet circular dichroism spectra of polyadenylic acid, polyguanylic acid, polycytidylic acid, polyinosinic acid, and polyuridylic acid have been examined at neutral and acidic pH values, and at moderate and low ionic strengths, over the wavelength range 300–185 mμ. Increased resolution of spectra below 225 mμ has revealed heretofore unexamined ellipticity bands in the low wavelength region, which are sensitive to conformational alterations for those polynucleotides which exhibit both single and multistranded secondary structures. It is concluded that these ellipticity bands, in view of their extreme sensitivity to conformation, will be of significance in increasing the usefulness of the homopolynucleotides as model compounds in conformational studies of naturally occurring RNAs.

Zum Wirkungsmechanismus von 1-Nitroso-3-nitro-1-methyl-guanidin bei der Mutationsauslösung

1967 ◽  
Vol 22 (5) ◽  
pp. 512-517 ◽  
Author(s):  
P. Chandra ◽  
A. Wacker ◽  
R. Süssmuth ◽  
F. Lingens
Keyword(s):  
Methyl Group ◽  
Polycytidylic Acid ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid ◽  
Acceptor Activity ◽  
Maximum Inhibition

The effect of NNMG on the template activities of different polynucleotides (polyuridylic acid, polycytidylic acid, polyadenylic acid and copolymer of adenylic and guanylic acid 5,5:1) and t-RNS was studied. The maximum inhibition of the messenger activity was found for poly-C, followed by poly-Α and poly-U. The acceptor activity of t-RNA was found to be inhibited by NNMG: maximum for proline, followed by serine, leucine, phenylalanine and lysine. The mechanism of these inhibitions was studied using NNMG radioactively labelled on the methyl group. Different amounts of radioactivity were found in the various polynucleotides and t-RNS.

scholarly journals The interaction of aflatoxin B1 with polynucleotides and its effect on ribonucleic acid polymerase

1969 ◽  
Vol 114 (4) ◽  
pp. 679-687 ◽  
Author(s):  
A. M. Q. King ◽  
B. H. Nicholson
Keyword(s):  
Ionic Strength ◽  
Aflatoxin B1 ◽  
Polycytidylic Acid ◽  
Spectral Shifts ◽  
Bivalent Cations ◽  
Polyinosinic Acid ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid ◽  
Calf Thymus

1. The interaction of aflatoxin B1 with different polynucleotides was studied spectrophotometrically. Equations were derived that enable the degree of binding to be determined without first determining the extinction coefficient of the bound form. 2. The interaction with calf thymus DNA obeys first-order relationships with an association constant of 0·40mm−1, but there is some evidence for a secondary binding process from results obtained at 390nm. 3. The spectral shifts decreased in the order polyadenylic acid+polyuridylic acid>DNA>polyadenylic acid>polyadenylic acid+polyinosinic acid. Polycytidylic acid, polyuridylic acid, polyinosinic acid (both single- and triple-stranded), AMP, CMP, GMP and UMP did not interact with aflatoxin. It was concluded that there is a requirement for the amino group of adenine (or possibly guanine) for binding of aflatoxin to polynucleotides to occur. 4. Binding is reversed by increasing ionic strength, and by Mn2+ and Mg2+ in the concentration range studied (0–5mm). The effect of the Mn2+ or Mg2+ was far greater than would be expected on the basis of their ionic strength. With both the bivalent cations and sodium chloride the reversal is greatest with double-stranded polynucleotides. 5. Inhibition in vitro of the DNA-dependent RNA polymerase of Escherichia coli by aflatoxin B1 was detected only in the absence of Mg2+ and at concentrations of Mn2+ below the optimum for RNA synthesis in vitro. 6. The degree of inhibition (maximally 30%) was dependent on the concentration of Mn2+ and decreased during incubation.

scholarly journals A ribonuclease from human skeletal muscle

1970 ◽  
Vol 118 (1) ◽  
pp. 9-13 ◽  
Author(s):  
D. F. Goldspink ◽  
R. J. Pennington
Keyword(s):  
Gel Filtration ◽  
Maximal Activity ◽  
Exchange Chromatography ◽  
Heat Stable ◽  
Polycytidylic Acid ◽  
Bivalent Cations ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid ◽  
Ammonium Sulphate Fractionation ◽  
Cyclic Phosphates

1. A ribonuclease has been prepared from human muscle by ammonium sulphate fractionation, heat treatment and ion-exchange chromatography. 2. The enzyme degrades polycytidylic acid and polyuridylic acid to the nucleoside 3′-phosphates, with nucleoside 2′:3′-cyclic phosphates as intermediates. Polyadenylic acid and polyguanylic acid are not attacked. 3. The enzyme has maximal activity at pH8.5. The molecular weight (by gel filtration) is between 11000 and 12000. It is relatively heat-stable. It exhibits optimum activity in a medium of high ionic strength, and is inhibited by several bivalent cations, particularly Zn2+.

scholarly journals The histochemical demonstration of hydrolase activities with films of homopolyribonucleotides.

1975 ◽  
Vol 23 (1) ◽  
pp. 51-58 ◽  
Author(s):  
R Daoust
Keyword(s):  
Ribonucleic Acid ◽  
Histochemical Demonstration ◽  
Tissue Sections ◽  
Polycytidylic Acid ◽  
Polyadenylic Acid ◽  
Polyuridylic Acid

Films of polycytidylic acid, polyuridylic acid and polyguanylic acid were exposed to tissue sections and the results were compared with those obtained in previous studies on polyadenylic acid and ribonucleic acid. Important variations were observed in the distribution of the hydrolases acting on the different polyribonucleotides, suggesting that a variety of nucleases with marked proclivity for particular nucleotide residues can be demonstrated by the use of films of homopolymers.

scholarly journals Polyribonucleotide synthesis by subfractions of microsomes from rat liver

1968 ◽  
Vol 109 (2) ◽  
pp. 229-238 ◽  
Author(s):  
N. M. Wilkie ◽  
R. M. S. Smellie
Keyword(s):  
Acetic Acid ◽  
Rat Liver ◽  
Transfer Rna ◽  
Light Fraction ◽  
Free Ribosome ◽  
Polyadenylic Acid ◽  
Insoluble Material ◽  
Polyuridylic Acid ◽  
Microsome Fraction

1. The microsome fraction of rat liver has been fractionated and the ability of the fractions to incorporate ribonucleotides into polyribonucleotides has been studied. Activity was found in the rough-surfaced vesicle (light) fraction and in the free-ribosome fraction and this latter activity has been examined. 2. The free-ribosome fraction contains ribosome monomers, dimers and trimers together with some higher oligomers and ferritin. In addition to catalysing the incorporation of ribonucleotides into acid-insoluble material it contains diesterase activity. It catalyses the incorporation of UMP from UTP, but not UDP, AMP from ATP and CMP from CTP into polyribonucleotide material, and for UTP the product appears to be a homopolymer not more than eight units long attached to the ends of primer polyribonucleotide strands. 3. The activity could not be removed from the free-ribosome fraction by washing or by isolation in the presence of ethylenediaminetetra-acetic acid. 4. Partially hydrolysed polyuridylic acid but not polyadenylic acid could serve as a primer for the incorporation of UMP, but some activity was always associated with an endogenous primer. 5. Analysis of RNA extracted from the free-ribosome fraction after incubation with [3H]UTP showed the presence of 28s, 18s, 5s and transfer RNA types, but no radioactivity was associated with any of these RNA fractions.

Further Evidence That the Majority of Primary Nuclear RNA Transcripts in Mammalian Cells Do Not Contribute to mRNA

1982 ◽  
Vol 2 (6) ◽  
pp. 701-707
Author(s):  
M. Salditt-Georgieff ◽  
J. E. Darnell
Keyword(s):  
Mammalian Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cdna Clones ◽  
Ovary Cells ◽  
Rna Molecules ◽  
Rna Transcripts ◽  
Polyadenylic Acid ◽  
Nuclear Molecules ◽  
Nuclear Rna

Nuclear RNA from Chinese hamster ovary cells was effectively separated into polyadenylic acid [poly(A)]-containing [poly (A) + ] and non-poly(A)-containing [poly(A) − ] fractions so that ∼90% of the poly(A) was present in the (A) + fraction. Only 25% of the 5′-terminal caps of the large nuclear molecules were present in the (A) + class, but about 70% of the specific mRNA sequences (assayed with cDNA clones) were in the (A) + class. It appears that many long capped heterogeneous nuclear RNA molecules are of a different sequence category from those molecules that are successfully processed into mRNA.

scholarly journals Large heterogeneous nuclear ribonucleic acid has three times as many 5' caps as polyadenylic acid segments, and most caps do not enter polyribosomes.

1981 ◽  
Vol 1 (2) ◽  
pp. 179-187 ◽  
Author(s):  
M Salditt-Georgieff ◽  
M M Harpold ◽  
M C Wilson ◽  
J E Darnell
Keyword(s):  
Ribonucleic Acid ◽  
Messenger Rna ◽  
Turnover Rate ◽  
Chinese Hamster ◽  
Chinese Hamster Cells ◽  
Rna Molecules ◽  
Rapid Turnover ◽  
Polyadenylic Acid ◽  
Nuclear Rna ◽  
Unstable Molecules

The rate of synthesis in Chinese hamster cells of 5' cap structures, m7 GpppNmp, in large (greater than 700 bases) heterogeneous nuclear ribonucleic acid (RNA) molecules is two to three times faster than the synthesis of 3'-terminal polyadenylic acid segments. As judged by presence of caps, newly synthesized polysomal messenger RNA, exclusive of messenger RNA the size of histone messenger RNA, is more than 90% in the polyadenylated category. It appears, therefore, that between half and two-thirds of the long capped heterogeneous nuclear RNA molecules do not contribute a capped polysomal derivative to the cytoplasm. There are capped, nonpolysomal, non-polyadenylated molecules with a rapid turnover rate that fractionate with the cytoplasm. These metabolically unstable molecules either could represent leakage into the cytoplasm during fractionation or could truly spend a brief time in the cytoplasm before decay.

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