scholarly journals A spectrophotometric study of the secondary structure of precursor ribosomal ribonucleic acid from Krebs ascites-tumour cells

1973 ◽  
Vol 135 (2) ◽  
pp. 349-351 ◽  
Author(s):  
A. A. Hadjiolov ◽  
R. A. Cox
Keyword(s):  
Secondary Structure ◽  
Ribonucleic Acid ◽  
18S Rrna ◽  
Spectrophotometric Study ◽  
Spectrophotometric Analysis ◽  
28S Rrna ◽  
Ascites Tumour ◽  
Helical Content ◽  
Ribosomal Ribonucleic Acid ◽  
Ascites Tumour Cells

The spectrophotometric analysis of 45S precursor rRNA shows that it contains more G and C residues than does mature 28S or 18S rRNA. The helical content and the length of double-helical segments in 45S and 28S rRNA are similar.

scholarly journals Identical 3′-terminal octanucleotide sequence in 18S ribosomal ribonucleic acid from different eukaryotes. A proposed role for this sequence in the recognition of terminator codons

1974 ◽  
Vol 141 (3) ◽  
pp. 609-615 ◽  
Author(s):  
John Shine ◽  
Lynn Dalgarno
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Ribonucleic Acid ◽  
18S Rrna ◽  
Base Sequence ◽  
Terminal Sequence ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species

The 3′-terminal sequence of 18S ribosomal RNA from Drosophila melanogaster and Saccharomyces cerevisiae was determined by stepwise degradation from the 3′-terminus and labelling with [3H]isoniazid. The sequence G-A-U-C-A-U-U-AOH was found at the 3′-terminus of both 18S rRNA species. Less extensive data for 18S RNA from a number of other eukaryotes are consistent with the same 3′-terminal sequence, and an identical sequence has previously been reported for the 3′-end of rabbit reticulocyte 18S rRNA (Hunt, 1970). These results suggest that the base sequence in this region is strongly conserved and may be identical in all eukaryotes. As the 3′-terminal hexanucleotide is complementary to eukaryotic terminator codons we discuss the possibility that the 3′-end of 18S rRNA may have a direct base-pairing role in the termination of protein synthesis.

scholarly journals The presence of a high-molecular-weight (guanine-plus-cytosine)-rich segment at the 3' end of rabbit 28S ribosomal ribonucleic acid.

1975 ◽  
Vol 147 (3) ◽  
pp. 625-628 ◽  
Author(s):  
A A Hadjiolov ◽  
R A Cox ◽  
P Huvos
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ribonucleic Acid ◽  
Average Molecular Weight ◽  
28S Rrna ◽  
Number Average Molecular Weight ◽  
Ribonuclease T1 ◽  
Naphthoic Acid ◽  
Rrna Molecule ◽  
Ribosomal Ribonucleic Acid

The 3′ hydroxyl end of 28S L-rRNA (major RNA species of the larger subribosomal particle) was labelled by coupling its 2-hydroxy-3-naphthoic acid hydrazine with diazotized [3H]aniline. The RNA was hydrolysed partially with ribonuclease T1 and fractionated on Sephadex G-200. The results show that a highly structured segment with 78% G+C content and a number-average molecular weight of at least 1.0×10(5)-1.8×10(5) is located at the 3′ hydroxyl end of the 28S rRNA molecule.

scholarly journals Intranuclear maturation pathways of rat liver ribosomal ribonucleic acids

1976 ◽  
Vol 160 (3) ◽  
pp. 495-503 ◽  
Author(s):  
M D Dabeva ◽  
K P Dudov ◽  
A A Hadjiolov ◽  
I Emanuilov ◽  
B N Todorov
Keyword(s):  
Secondary Structure ◽  
Rat Liver ◽  
Mammalian Cells ◽  
18S Rrna ◽  
Electron Microscopic Observation ◽  
28S Rrna ◽  
Electron Microscopic ◽  
Rrna Species ◽  
A Minor

The maturation of pre-rRNA (precursor to rRNA)in liver nuclei is studied by agar/ureagel electrophoresis, kinetics of labelling in vivo with [14C] orotate and electron-microscopic observation of secondary structure of RNA molecules. (1) Processing starts from primary pre-rRNA molecules with average mol. wt. 4.6×10(6)(45S) containing the segments of both 28S and 18S rRNA. These molecules form a heterogeneous peak on electrophoresis. The 28S rRNA segment is homogeneous in its secondary structure. However, the large transcribed spacer segment (presumably at the 5′-end) is heterogeneous in size and secondary structure. A minor early labelled RNA component with mol.wt. about 5.8×10(6) is reproducibly found, but its role as a pre-rRNA species remains to be determined. (2) The following intermediate pre-rRNA species are identified: 3.25×10(6) mol.wt.(41S), a precursor common to both mature rRNA species; 2.60×10(6)(36S) and 2.15×10(6)(32S) precursors to 28S rRNA; 1.05×10(6) (21S) precursor to 18S rRNA. The pre-rRNA molecules in rat liver are identical in size and secondary structure with those observed in other mammalian cells. These results suggest that the endonuclease-cleavage sites along the pre-rRNA chain are identical in all mammalian cells. (3) Labelling kinetics and the simultaneous existence of both 36S and 21S pre-rRNA reveal that processing of primary pre-rRNA in adult rat liver occurs simultaneously by at least two major pathways: (i) 45S → 41S → 32S+21S → 28S+18S rRNA and (ii) 45S → 41S → 36S+18S → 32S → 28S rRNA. The two pathways differ by the temporal sequence of endonuclease attack along the 41 S pre-rRNA chain. A minor fraction (mol.wt.2.9×10(6), 39S) is identified as most likely originating by a direct split of 28S rRNA from 45S pre-rRNA. These results show that in liver considerable flexibility exists in the order of cleavage of pre-rRNA molecules during processing.

scholarly journals A spectrophotometric study of the secondary structure of ribonucleic acid isolated from the smaller and larger ribosomal subparticles of rabbit reticulocytes

1970 ◽  
Vol 117 (1) ◽  
pp. 101-118 ◽  
Author(s):  
R. A. Cox
Keyword(s):  
Escherichia Coli ◽  
Ionic Strength ◽  
Secondary Structure ◽  
Ribonucleic Acid ◽  
Spectrophotometric Study ◽  
Urea Concentration ◽  
Model Systems ◽  
Base Pairs ◽  
Virus Like Particles ◽  
Rabbit Reticulocytes

The spectrum of RNA from the smaller and larger subparticles of rabbit reticulocyte ribosomes was studied as a function of pH, ionic strength, urea concentration and temperature. It was inferred that both RNA species form short double-helical segments of not more than about 10 base-pairs in length. Not more than about 70% of the base residues may be located in double-helical segments. RNA from the larger subparticle is richer in guanine and cytosine residues and its secondary structure is the more stable. These conclusions are based on the use of double-helical RNA from virus-like particles and of unfractionated Escherichia coli tRNA as model systems.

scholarly journals Biosynthesis of a hypermodified nucleotide in Saccharomyces carlsbergensis 17S and HeLa-cell 18S ribosomal ribonucleic acid

1978 ◽  
Vol 169 (1) ◽  
pp. 71-77 ◽  
Author(s):  
R C Brand ◽  
J Klootwijk ◽  
R J Planta ◽  
B E H Maden
Keyword(s):  
Hela Cell ◽  
Hela Cells ◽  
Ribonucleic Acid ◽  
18S Rrna ◽  
Saccharomyces Carlsbergensis ◽  
Ribosomal Ribonucleic Acid ◽  
Precursor Molecules

The biosynthesis of a hypermodified nucleotide, similar to or identical with 3-(3-amino-3-carboxypropyl)-1-methylpseudouridine monophosphate, present in Saccharomyces carlsbergensis 17S and HeLa-cell 18S rRNA, was investigated with respect to the sequence of reactions required for synthesis and their timing in ribosome maturation. In both yeast and HeLa cells methylation precedes attachment of the 3-amino-3-carboxypropyl group. In yeast the methylated precursor nucleotide was tentatively characterized as 1-methylpseudouridine. This precursor nucleotide was demonstrated in both 37S and most of the cytoplasmic 18S pre-rRNA (rRNA precursor) molecules. The synthesis of the hypermodified nucleotide is completed just before the final cleavage of 18S pre-rRNA to give 17S rRNA, so that the final addition of the 3-amino-3-carboxypropyl group is a cytoplasmic event. Comparable experiments with HeLa cells indicated that formation of 1-methylpseudouridine occurs at the level of 45S RNA and addition of the 3-amino-3-carboxypropyl group occurs in the cytoplasm on newly synthesized 18S RNA.

scholarly journals Molecular integrity of chloroplast ribosomal ribonucleic acid

1973 ◽  
Vol 135 (1) ◽  
pp. 237-240 ◽  
Author(s):  
Christopher J. Leaver
Keyword(s):  
Secondary Structure ◽  
Hydrogen Bonds ◽  
Ribonucleic Acid ◽  
Low Temperatures ◽  
Ribosomal Ribonucleic Acid ◽  
Polynucleotide Chain

The majority of chloroplast 1.1X106-mol.wt. rRNA molecules are nicked at specific points in the polynucleotide chain, the molecules being kept intact at low temperatures by their secondary structure. Conditions that break hydrogen bonds and lead to loss of secondary structure cause dissociation of the molecule.

scholarly journals A study of the influence of magnesium ions on the conformation of ribosomal ribonucleic acid and on the stability of the larger subribosomal particle of rabbit reticulocytes

1976 ◽  
Vol 160 (3) ◽  
pp. 505-519 ◽  
Author(s):  
R A Cox ◽  
W Hirst
Keyword(s):  
Escherichia Coli ◽  
Secondary Structure ◽  
Ribonucleic Acid ◽  
Magnesium Ions ◽  
Base Pairs ◽  
E Coli ◽  
Ribosomal Ribonucleic Acid ◽  
The Stability ◽  
Rabbit Reticulocytes

Mg2+ was shown to affect the conformation of rRNA over the range of 0.03-1.2M-KCl. The species studies were Escherichia coli S-rRNA and L-rRNA (the RNA moieties of the smaller and larger subribosomal particles respectively) and rabbits S-rRNA and L-rRNA. 2. The addition of Mg2+ to rRNA in reconstitution buffer (0.35M-KCl0.01M-Tris/HCl, pH7.2) at 20° C let to an increase in bihelical secondary structure through the formation of additional (mainly A-U) base-pairs (e.g. an additional approx. 58 A-U base-pairs per molecule of E. coli S-rRNA as judged by u.v. difference spectrophotometry…

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