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.

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.

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 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 Deoxyribonucleic acid–ribonucleic acid hybridization. Annealing and quantitative recovery of intact ribosomal ribonucleic acid molecules from hybrids

1969 ◽  
Vol 115 (2) ◽  
pp. 287-294 ◽  
Author(s):  
Michael Fry ◽  
Michael Artman
Keyword(s):  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
Messenger Rna ◽  
Deoxyribonucleic Acid ◽  
Cellulose Nitrate ◽  
Absolute Size ◽  
Rna Molecules ◽  
Membrane Filters ◽  
Ribosomal Ribonucleic Acid

A simple and efficient method for hybridization and subsequent recovery of non-fragmented ribosomal RNA from the hybrid is described. The procedure involves annealing of immobilized denatured DNA bound on cellulose nitrate membrane filters to complementary RNA in 50% (v/v) formamide–0·33m-potassium chloride–10mm-tris–hydrochloric acid buffer, pH7·4, at 33° for 3hr. Under these conditions no detectable changes in the sedimentation coefficients of the input RNA were detected. The RNA can subsequently be recovered quantitatively from the hybrid in intact form by incubating the filters in formamide or in 85% (v/v) dimethyl sulphoxide. The applicability of the method for the evaluation of the absolute size of ribosomal RNA cistrons in Escherichia coli DNA and for the determination of the size of messenger RNA molecules is discussed.

II. Distribution of DNA base sequences - Introductory remarks: DNA and genes

1978 ◽  
Vol 283 (997) ◽  
pp. 305-307
Keyword(s):  
Genetic Code ◽  
Messenger Rna ◽  
Transfer Rnas ◽  
Rna Molecules ◽  
Dna Base ◽  
Base Sequences ◽  
Nuclear Rna

After the genetic code was discovered in the early 1960s, it was generally accepted that nearly all DNA in higher organisms was used to specify messenger RNA molecules at some time during their development. A small fraction could be set aside for the ribosomal and transfer RNAs and there was a problem about the rapidly turning over nuclear RNA which did not appear in the cytoplasm as message. By and large we considered that most DNA was potentially coding and the lone voices who talked of other kinds of DNA on the basis of somewhat flimsy evidence were largely ignored.

scholarly journals Molecular Aspects of Interferon Induction by Viruses

1970 ◽  
Vol 56 (1) ◽  
pp. 13-24 ◽  
Author(s):  
D. C. Burke
Keyword(s):  
Ribonucleic Acid ◽  
Messenger Rna ◽  
Viral Rna ◽  
Stable Configuration ◽  
Unknown Mechanism ◽  
Double Stranded Rna ◽  
Rna Molecules ◽  
Interferon Induction ◽  
Molecular Aspects

Virus-induced interferon formation depends on the presence within the cell of a viral ribonucleic acid. This RNA may either be double stranded or, in certain cases, single stranded. The double-stranded RNA can be derived from a virus, such as reovirus, which contains this type of RNA, or it may be synthesized within the cell using viral single-stranded RNA as a template. Single-stranded RNA must possess a stable configuration in solution to be active, and certain viral RNA molecules appear to be active for this reason. The presence of this RNA triggers a derepression event, which is probably nuclear, by an unknown mechanism, and this is followed by the production of an interferon messenger RNA and its translation. Little is known of the derepression event or the events that follow it.

scholarly journals STABILITIES OF NUCLEAR AND MESSENGER RNA MOLECULES IN SEA URCHIN EMBRYOS

1972 ◽  
Vol 53 (2) ◽  
pp. 474-482 ◽  
Author(s):  
Bruce P. Brandhorst ◽  
Tom Humphreys
Keyword(s):  
Steady State ◽  
Sea Urchin ◽  
Half Life ◽  
Messenger Rna ◽  
Cell Fractionation ◽  
Rna Molecules ◽  
Sea Urchin Embryos ◽  
Cytoplasmic Rna ◽  
Nuclear Rna ◽  
Kinetics Of

The kinetics of accumulation of radioactive adenosine in adenosine triphosphate and in RNA of nuclear, cytoplasmic, and polysomal fractions of sea urchin embryos have been analyzed. 85% of the RNA synthesized decays in the nucleus with an apparently uniform half-life of about 7 min. The remaining 15% goes to the cytoplasm, mostly entering polysomes, and decays with a quite uniform half-life of about 75 min. The nuclear RNA accounts for one-third and the cytoplasmic RNA accounts for two-thirds of the total unstable RNA which accumulates at steady state in the embryo. The size distribution of short-labeled nuclear RNA is very similar to that of long-labeled messenger RNA, when both are extracted directly from the cells without a previous cell fractionation.

Sign in / Sign up

Export Citation Format

Share Document