scholarly journals Higher-plant mitochondrial ribosomes contain a 5S ribosomal ribonucleic acid component

1976 ◽  
Vol 157 (1) ◽  
pp. 275-277 ◽  
Author(s):  
C J Leaver ◽  
M A Harmey
Keyword(s):  
Ribonucleic Acid ◽  
Plant Mitochondria ◽  
5S Rrna ◽  
Higher Plant ◽  
Acid Component ◽  
Mitochondrial Ribosomes ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Hydrogen Bonded

Ribosomes from higher-plant mitochondria contain 5S rRNA, in contrast with the mitochondrial ribosomes of animals and fungi, in which such a component has not been detected. In common with the ribosomes of prokaryotes and chloroplasts, higher-plant mitochondrial ribosomes do not appear to contain an RNA equivalent to the 5.8 S rRNA that is found in eukaryoytes hydrogen-bonded to the largest of the cytoplasmic rRNA species.

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.

The ribosomes of Plasmodium berghei: isolation and ribosomal ribonucleic acid analysis

Parasitology ◽  
1978 ◽  
Vol 77 (3) ◽  
pp. 345-366 ◽  
Author(s):  
F. W. Miller ◽  
Judith Ilan
Keyword(s):  
Plasmodium Berghei ◽  
Ribonucleic Acid ◽  
Ribosomal Subunit ◽  
High Yield ◽  
Small Component ◽  
40S Ribosomal Subunit ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Specific Degradation ◽  
Triton X

SummaryRibosomes and high molecular weight ribosomal ribonucleic acid (rRNA) from the blood stages of Plasmodium berghei parasites were studied in preparations free from host ribosome contamination. Purified malarial ribosomes were isolated in high yield from a population of ultrastructurally intact, viable parasites by hypertonic lysis with Triton X-100 and differential centrifugation. These ribosomes were shown to be derived from active polysomes and could be dissociated into subunits by puromycin–0·5 m KCl treatment. Malarial rRNA extracted from purified 40S and 60S ribosomal subunits was characterized by electrophoretic, sedimentation and base ratio analyses. Like certain other protozoa, the P. berghei 40S ribosomal subunit possessed an exceptionally large RNA species (mol. wt 0·9 × 106), while RNA isolated from the parasite's 60S subunit (mol. wt 1·5 × 106) was specifically ‘nicked’ to produce one large component (mol.wt 1·2 × 106) and one small component (mol.wt 0·3 × 106) in equimolar quantities. These rRNA's migrate identically on polyacrylamide gels after heating to 63°C for 5 mm or under denaturing conditions in the presence of formamide, indicating an absence of aggregation and non-specific degradation of the rRNA species. Base composition studies showed P. berghei rRNA to be low in guanosine and cytosine content, as is the case for protozoa generally.

scholarly journals Nucleotide sequences of chloroplast 5S ribosomal ribonucleic acid in flowering plants

1979 ◽  
Vol 183 (3) ◽  
pp. 595-604 ◽  
Author(s):  
T A Dyer ◽  
C M Bowman
Keyword(s):  
Lemna Minor ◽  
Structural Features ◽  
Flowering Plants ◽  
5S Rrna ◽  
5S Rna ◽  
Homologous Sequences ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Strong Resemblance ◽  
Complete Digestion

Evidence for the sequence of duckweed (Lemna minor) chloroplast 5S rRNA was derived from the analysis of partial and complete enzymic digests of the 32P-labelled molecule. The possible sequence of the chloroplast 5S rRNA from three other flowering plants was deduced by complete digestion with T1 ribonuclease and comparison of the sequences of the oligonucleotide products with homologous sequences in the duckweed 5S rRNA. This analysis indicates that the chloroplast 5S rNA species differ appreciably from their cytosol counterparts but bear a strong resemblance to one another and to the 5S rRNA species of prokaryotes. Structural features apparently common to all 5S rRNA molecules are also discussed.

scholarly journals The molecular integrity of chloroplast ribosomal ribonucleic acid

1971 ◽  
Vol 123 (2) ◽  
pp. 235-243 ◽  
Author(s):  
C. J. Leaver ◽  
J. Ingle
Keyword(s):  
Plant Species ◽  
Ribonucleic Acid ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Chloroplast Rna ◽  
The Stability

Instability of chloroplast rRNA has been observed with essentially all chloroplast RNA preparations. This paper describes experiments that show that, under normal conditions of preparation and fractionation, only the heavy chloroplast component (mol.wt. 1.1×106) is unstable, the light chloroplast rRNA (mol.wt. 0.56×106) and the cytoplasmic rRNA species (mol.wt. 1.3×106 and 0.70×106) being stable. The stability of the 1.1×106-mol. wt. molecule varies with different plant species, as also does the size and the number of fragments produced. Cleavages in three particular regions of the molecule are very frequent within the range of tissues studied. The 1.1×106-mol.wt. rRNA is, however, stabilized by the presence of Mg2+ during the preparation and fractionation of the RNA.

scholarly journals Nucleotide sequence analyses of the cytoplasmic 5S ribosomal ribonucleic acid from five species of flowering plants

1973 ◽  
Vol 135 (4) ◽  
pp. 845-851 ◽  
Author(s):  
P. I. Payne ◽  
M. J. Corry ◽  
T. A. Dyer
Keyword(s):  
Broad Bean ◽  
Flowering Plants ◽  
5S Rrna ◽  
Sequence Analyses ◽  
Two Dimensional Electrophoresis ◽  
Complementary Sequences ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Dimensional Electrophoresis ◽  
Dwarf Bean

Broad-bean 5S rRNA labelled with32P was digested separately with T1 and pancreatic A ribonucleases and the resulting oligonucleotides (20 and 18 respectively) were fractionated by two-dimensional electrophoresis. The oligonucleotides were analysed further and 32 of them have been completely sequenced. They were compared with those of 5S rRNA from dwarf bean, sunflower, tomato and rye. Sequence differences were found at both the 3′- and 5′-termini and at up to nine other positions. Most base substitutions were transitions between C and U. In common with other 5S rRNA species that have been analysed the ends of the molecule in each plant species have complementary sequences.

scholarly journals Human mitochondrial ribosomes can switch their structural RNA composition

2016 ◽  
Vol 113 (43) ◽  
pp. 12198-12201 ◽  
Author(s):  
Joanna Rorbach ◽  
Fei Gao ◽  
Christopher A. Powell ◽  
Aaron D’Souza ◽  
Robert N. Lightowlers ◽  
...  
Keyword(s):  
Steady State ◽  
Adaptive Response ◽  
5S Rrna ◽  
Mitochondrial Ribosomes ◽  
Single Organism ◽  
Recent Developments ◽  
Rrna Species ◽  
Specific Variation ◽  
Steady State Levels ◽  
Refractory Structures

The recent developments in cryo-EM have revolutionized our access to previously refractory structures. In particular, such studies of mammalian mitoribosomes have confirmed the absence of any 5S rRNA species and revealed the unexpected presence of a mitochondrially encoded tRNA (mt-tRNA) that usurps this position. Although the cryo-EM structures resolved the conundrum of whether mammalian mitoribosomes contain a 5S rRNA, they introduced a new dilemma: Why do human and porcine mitoribosomes integrate contrasting mt-tRNAs? Human mitoribosomes have been shown to integrate mt-tRNAVal compared with the porcine use of mt-tRNAPhe. We have explored this observation further. Our studies examine whether a range of mt-tRNAs are used by different mammals, or whether the mt-tRNA selection is strictly limited to only these two species of the 22 tRNAs encoded by the mitochondrial genome (mtDNA); whether there is tissue-specific variation within a single organism; and what happens to the human mitoribosome when levels of the mt-tRNAVal are depleted. Our data demonstrate that only mt-tRNAVal or mt-tRNAPhe are found in the mitoribosomes of five different mammals, each mammal favors the same mt-tRNA in all tissue types, and strikingly, when steady-state levels of mt-tRNAVal are reduced, human mitoribosome biogenesis displays an adaptive response by switching to the incorporation of mt-tRNAPhe to generate translationally competent machinery.

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